In vivo photosensitizer tomography inside the human prostate

Interstitial photodynamic therapy (IPDT) provides a promising means to treat large cancerous tumors and solid organs inside the human body. The treatment outcome is dependent on the distributions of light, photosensitizer, and tissue oxygenation. We present a scheme for reconstructing the spatial distribution of a fluorescent photosensitizer. The reconstruction is based on measurements performed in the human prostate, acquired during an ongoing IPDT clinical trial, as well as in optical phantoms. We show that in an experimental setup we can quantitatively reconstruct a fluorescent inclusion in a fluorescent background. We also show reconstructions from a patient showing a heterogeneous distribution of the photosensitizer mTHPC in the human prostate. (C) 2009 Optical Society of Americ

Comparison of spatially and temporally resolved diffuse-reflectance measurement systems for determination of biomedical optical properties

Time-resolved and spatially resolved measurements of the diffuse reflectance from biological tissue are two well-established techniques for extracting the reduced scattering and absorption coefficients. We have performed a comparison study of the performance of a spatially resolved and a time-resolved instrument at wavelengths 660 and 785 nm and also of an integrating-sphere setup at 550-800 nm. The first system records the diffuse reflectance from a diode laser by means of a fiber bundle probe in contact with the sample. The time-resolved system utilizes picosecond laser pulses and a single-photon-counting detection scheme. We extracted the optical properties by calibration using known standards for the spatially resolved system, by fitting to the diffusion equation for the time-resolved system, and by using an inverse Monte Carlo model for the integrating sphere. The measurements were performed on a set of solid epoxy tissue phantoms. The results showed less than 10% difference in the evaluation of the reduced scattering coefficient among the systems for the phantoms in the range 9-20 cm(-1), and absolute differences of less than 0.05 cm(-1) for the absorption coefficient in the interval 0.05-0.30 cm(-1). (C) 2003 Optical Society of America

Are the old International Board for Plant Genetic Resources (IBPGR) base collections available through the Plant Treaty's multilateral system of access and benefit sharing? A review

In 1975, the International Board for Plant Genetic Resources created the first internationally linked system of genebanks, known as the Registry of Base Collections (RBC), to conserve plant germplasm and make it available globally for agricultural research and development. Over time, international efforts shifted away from enhancing and building the RBC toward other means to promote the conservation and sustainable use of plant genetic resources. Perhaps the most important development in this regard was the negotiation of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty or ITPGRFA) and the development of its multilateral system for access and benefit sharing (multilateral system). Our study aimed to ascertain whether the RBC materials are still being conserved/curated in the original recipient organizations. We also sought to assess whether those materials have been included in, and are available through, the ITPGRFA's multilateral system. This outcome would be significant since, in many ways, the multilateral system reflects the spirit, commitment, and objectives of the RBC, with important additional components (e.g. obligations to share monetary benefits derived from the uses of plant genetic resources for food and agriculture). We identify four levels of probability that RBC materials are included in, and available through, the multilateral system. Ultimately, we find that there is a high level of probability that approximately 80% of the RBC materials are currently available through the multilateral system. We further identify a number of possible interventions that could be made to ensure that all RBC materials are conserved and made available through the multilateral system (or on similar terms and conditions of facilitated access and benefit sharing)

Ethical Considerations in Agro-biodiversity Research, Collecting, and Use

Humans have always played a crucial role in the evolutionary dynamics of agricultural biodiversity and thus there is a strong relationship between these resources and human cultures. These agricultural resources have long been treated as a global public good, and constitute the livelihoods of millions of predominantly poor people. At the same time, agricultural biodiversity is under serious threat in many parts of the world despite extensive conservation efforts. Ethical considerations regarding the collecting, research, and use of agricultural biodiversity are currently topics of great concern. For example, easy access to genetic resources for breeding purposes is important, but international agreements and legal frameworks are necessary to ensure adequate recognition of the contributions of local communities and traditional farmers in creating and nurturing these resources. Here, we assess ethical principles in the context of existing codes of conduct that are relevant for agro-biodiversity researchers. We aim to create awareness among scientists and policy makers who are concerned with agro-biodiversity research and its potential impact on local communities. We encourage a serious assessment of the ethical principles presented here and hope to facilitate an integration of these principles into the reader's personal ethical framework. Key ethical principles considered here include the importance of obtaining prior informed consent, equity, and the inalienability of rights of local communities and farmers

Light Scattering By Multiple Red Blood Cells

The interaction of light with multiple red blood cells was systematically investigated by the finite-different time-domain method. The simulations show that the lateral multiple scattering between red blood cells is very weak. The polarization is shown to have an almost insignificant influence on the distribution of the scattered light. The numerical results were compared with three approximate methods: the superposition approximation, the Rytov approximation and the discrete dipole approximation. The agreement was very good