Histology-driven hypofractionated radiation therapy schemes for early-stage lung adenocarcinoma and squamous cell carcinoma.

BACKGROUND AND PURPOSE: Histology was found to be an important prognostic factor for local tumor control probability (TCP) after stereotactic body radiotherapy (SBRT) of early-stage non-small-cell lung cancer (NSCLC). A histology-driven SBRT approach has not been explored in routine clinical practice and histology-dependent fractionation schemes remain unknown. Here, we analyzed pooled histologic TCP data as a function of biologically effective dose (BED) to determine histology-driven fractionation schemes for SBRT and hypofractionated radiotherapy of two predominant early-stage NSCLC histologic subtypes adenocarcinoma (ADC) and squamous cell carcinoma (SCC). MATERIAL AND METHODS: The least-χ2 method was used to fit the collected histologic TCP data of 8510 early-stage NSCLC patients to determine parameters for a well-developed radiobiological model per the Hypofractionated Treatment Effects in the Clinic (HyTEC) initiative. RESULTS: A fit to the histologic TCP data yielded independent radiobiological parameter sets for radiotherapy of early-stage lung ADC and SCC. TCP increases steeply with BED and reaches an asymptotic maximal plateau, allowing us to determine model-independent optimal fractionation schemes of least doses in 1-30 fractions to achieve maximal tumor control for early-stage lung ADC and SCC, e.g., 30, 44, 48, and 51 Gy for ADC, and 32, 48, 54, and 58 Gy for SCC in 1, 3, 4, and 5 fractions, respectively. CONCLUSION: We presented the first determination of histology-dependent radiobiological parameters and model-independent histology-driven optimal SBRT and hypofractionated radiation therapy schemes for early-stage lung ADC and SCC. SCC requires substantially higher radiation doses to maximize tumor control than ADC, plausibly attributed to tumor genetic diversity and microenvironment. The determined optimal SBRT schemes agree well with clinical practice for early-stage lung ADC. These proposed optimal fractionation schemes provide first insights for histology-based personalized radiotherapy of two predominant early-stage NSCLC subtypes ADC and SCC, which require further validation with large-scale histologic TCP data.

Assessment of the oxygen reactivity in a gas storage facility by multiphase reactive transport modeling of field data for air injection into a sandstone reservoir in the Paris Basin, France.

The first objective of this study is to present unique field data on a three-year pilot test during which air containing 8 mol% O2(g) was injected as a cushion gas into a natural gas reservoir, a carbonate-cemented sandstone aquifer located in the Paris Basin (France). 10-year system survey showed that: the oxygen was fully depleted several months after injection completion, meanwhile CO2(g) was detected around 2-6 mol%; the pH decreased from 8 to 6, while reducing conditions shifted to mildly oxidizing ones with increasing concentration of sulfates in equilibrium with gypsum. 3 years after injection completion, the pH gradually returned to its near initial state and sulfates were reduced by 2 to 3 times. The second objective is to develop a multiphase reactive transport model based on the field data. Simulations were constructed using the HYTEC reactive transport code, progressing from 0D-batch to 2D-reservoir configurations. The model reproduced the gas-water-rock reactive sequence: 1/ full depletion of the injected O2(g) due to pyrite oxidation, 2/ leading to acidity production and dissolved sulfates, 3/ acidity buffering by calcite dissolution, 4/ followed by gypsum precipitation and CO2(g) exsolution. The model demonstrated that pyrite kinetics was the most significant factor governing not only the amount of O2(g), CO2(g) and dissolved minerals, but also the spatial extent of these chemical reactions and, hence, the gas spread inside the reservoir. The formulated advective Damköhler number for oxygen consumption indicated advection- and reaction-dominant regimes explaining the gas composition and extension. The developed field-based model could be used as a workflow for other gas storage facilities, e.g. biomethane, compressed air, and CO2. For underground biomethane storage, the O2(g) contents recommended in Europe, i.e. the EASEE-gas specification 2005-001-02, should have a low impact on gas composition and reservoir geochemistry when the reservoir contains efficient pH-buffers such as calcite.

Modeling of microbial kinetics and mass transfer in bioreactors simulating the natural attenuation of arsenic and iron in acid mine drainage.

Natural attenuation in acid mine drainage (AMD) due to biological iron and arsenic oxidation offers a promising strategy to treat As-rich AMD in passive bioreactors. A reactive transport model is developed in order to identify the main controlling factors. It simulates batch and flow-through experiments that reproduce natural attenuation in a high-As AMD. The 2-D model couples second-order microbial kinetics (Fe- and As- oxidation) and geochemical reactions to hydrodynamic transport. Oxidation only occurrs in the biofilm with an oxygen transfer from the air through the water column. The model correctly simulates the Fe(II)-Fe(III) and As(III)-As(V) concentrations in the outlet waters and the precipitates, over hydraulic retention times from 30 min to 800 min. It confirms that the natural attenuation at 20 °C is driven by the fast Fe(II) oxidation and slow As(III) oxidation that favors arsenite trapping by schwertmannite over amorphous ferric arsenate (AFA) formation. The localization of iron oxidation in the biofilm limits the attenuation of arsenic and iron as the water column height increases. The change in the composition of the bacterial iron-oxidizer community of the biofilm at the lowest pH boundary seems to control the Fe(II) oxidation kinetic rate besides the bacterial concentration.

A comparison of specific IgE and skin prick test results to common environmental allergens using the HYTEC™ 288.

Although skin-prick testing (SPT) is commonly used by allergists in the evaluation of allergy, in-vitro testing for specific IgE (sIgE) is an attractive alternate because it can be performed remotely and is of utility when SPT is contraindicated, as in patients on anti-histamines, or with dermatitis or severe eczema. It is, however, necessary to determine the extent of correlation between the in-vitro and in-vivo methods. In this study, we examined the qualitative concordance between SPT and sIgE as measured on the HYTEC™288 platform for 10 commonly encountered inhalant allergens in 232 subjects, and analysed the performance characteristics for the HYTEC™288. Overall concordance between SPT and sIgE was >70% for all allergens tested. Sensitivity ranged from 25% to 95%, depending on the allergen, while specificity was significantly higher for all allergens (78-97%). NPV was >85% for all allergens tested, while PPV was more variable, ranging from 22% to 88%. These results are similar to findings in other studies comparing SPT with sIgE. Lack of concordance in a percentage of samples might be partly attributed to differences in allergen preparations for SPT and HYTEC™ 288. Follow-up studies utilizing identical allergen preparations for both in-vivo and in-vitro testing may address these discrepancies.