High Temperature Levels Research Articles

Modification effects of ambient temperature on associations of ambient ozone exposure before and during pregnancy with adverse birth outcomes: A multicity study in China

BackgroundEpidemiological studies suggest that both ambient ozone (O3) and temperature were associated with increased risks of adverse birth outcomes. However, very few studies explored their interaction effects, especially for small for gestational age (SGA) and large for gestational age (LGA). ObjectivesTo estimate the modification effects of ambient temperature on associations of ambient O3 exposure before and during pregnancy with preterm birth (PTB), low birth weight (LBW), SGA and LGA based on multicity birth cohorts. MethodsA total of 56,905 singleton pregnant women from three birth cohorts conducted in Tianjin, Beijing and Maoming, China, were included in the study. Maximum daily 8-h average O3 concentrations of each pregnant woman from the preconception period to delivery for every day were estimated by matching their home addresses with the Tracking Air Pollution in China (TAP) datasets. We first applied the Cox proportional-hazards regression model to evaluate the city-specific effects of O3 exposure before and during pregnancy on adverse birth outcomes at different temperature levels with adjustment for potential confounders, and then a meta-analysis across three birth cohorts was conducted to calculate the pooled associations. ResultsIn pooled analysis, significant modification effects of ambient temperature on associations of ambient O3 with PTB, LBW and LGA were observed (Pinteraction < 0.05). For a 10 μg/m3 increase in ambient O3 exposure at high temperature level (> 75th percentile), the risk of LBW increased by 28 % (HR: 1.28, 95% CI: 1.13–1.46) during the second trimester and the risk of LGA increased by 116% (HR: 2.16, 95%CI: 1.16–4.00) during the entire pregnancy, while the null or weaker association was observed at corresponding low (≤ 25th percentile) and medium (> 25th and ≤ 75th percentile) temperature levels. ConclusionThis multicity study added new evidence that ambient high temperature may enhance the potential effects of ambient O3 on adverse birth outcomes.

The synthesis and the mechanism of a five-membered ring formation between an isothiocyanate and an amide leading to the yield of Enzalutamide anticancer API; a joint experimental and theoretical study

This paper has been prepared to investigate the question "why the five-membered ring formation to give Enzalutamide, needs at least a portion of dimethyl sulfoxide (DMSO) as the solvent and a high level of temperature about 95 °C?". By understanding the role of DMSO as solvent in the mechanism of such ring closing, this question might be answered. In addition, with the aid of the potential energy surface (PES) (dE) calculations, and the density functional theory (DFT) investigations, the PES curves of the reaction were designed to find the probable energy valleys and barriers of the process.The results of the experimental as well as theoretical studies showed that by choosing a suitable catalyst in DMSO: Isopropyl acetate (IPOAC) as the solvent mixture, we could handle the synthesis of Enzalutamide anti-cancer active pharmaceutical ingredient (API) in a milder condition with a lower temperature (about 70 °C), and also a shorter time (about 18 h instead of 24 h). Also, the developed HPLC-UV method showed that after crystallization, the API powder would have a total purity profile up to 99%.

Apparent Temperature Modifies the Effects of Air Pollution on Cardiovascular Disease Mortality in Cape Town, South Africa

Cardiovascular disease (CVD) is the top cause of mortality and a main contributor to disability globally. The evidence so far is varied on whether cold or heat modifies the CVD effects of air pollution. Weather conditions and air pollution sources and levels are different in different countries. Studies in low-and middle-income countries are lacking. Mortality data were obtained from Statistics South Africa. Air pollution and meteorological data were obtained from the South African Weather Service. A time-stratified case–crossover epidemiological design was applied. The association between air pollutants (PM10, NO2 and SO2) and CVD mortality was investigated using conditional logistic regression models. Susceptibility by sex and age groups was investigated. In total, 54,356 CVD deaths were included in the 10-year study. The daily PM10, NO2 and SO2 levels exceeded the daily WHO guidelines on 463, 421 and 8 days of the 3652 days, respectively. Higher air pollution risks were observed in this study compared to those reported in meta-analyses. In general, the elderly and females seemed to be vulnerable to air pollutants, especially at high and moderate apparent temperature levels. Harvesting effects were observed at longer lags. The results can be used to develop an early warning system for the city.

Intraoperative metabolic changes associated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

BackgroundCytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) causes considerable hemodynamic, respiratory, and metabolic changes during the perioperative period.ObjectivesTo evaluate metabolic changes associated with this procedure. Understanding perioperative factors and their association with morbidity may improve the perioperative management of patients undergoing this treatment.MethodsA retrospective review of a prospectively maintained database was performed. All consecutive unselected patients who underwent CRS plus HIPEC between January 2018 and December 2020 (n = 219) were included.ResultsThe mean age was 58 ± 11.7 years and 167 (76.3%) were female. The most frequent histology diagnosis was serous ovarian carcinoma 49.3% (n = 108) and colon carcinoma 36.1% (n = 79). Mean peritoneal cancer index was 14.07 ± 10.47. There were significant variations in pH, lactic acid, sodium, potassium, glycemia, bicarbonate, excess bases, and temperature (p < 0.05) between the pre-HIPEC and post-HIPEC periods. The closed HIPEC technique resulted in higher levels of temperature than the open technique (p < 0.05). Age, potassium level post-HIPEC potassium level, and pre-HIPEC glycemia were identified as prognostic factors for morbidity in multivariate analysis.ConclusionThe administration of HIPEC after CRS causes significant changes in internal homeostasis. Although the closed technique causes a greater increase in temperature, it is not related to higher morbidity rates. The patient’s age, post-HIPEC potassium level, and pre-HIPEC glycemia are predictive factors for morbidity.

Diverse flowering responses subjecting to ambient high temperature in soybean under short-day conditions.

Flowering time is one of important agronomic traits determining the crop yield and affected by high temperature. When facing high ambient temperature, plants often initiate early flowering as an adaptive strategy to escape the stress and ensure successful reproduction. However, here we find opposing ways in the short-day crop soybean to respond to different levels of high temperatures, in which flowering accelerates when temperature changes from 25 to 30 °C, but delays when temperature reaches 35 °C under short day. phyA-E1, possibly photoperiodic pathway, is crucial for 35 °C-mediated late flowering, however, does not contribute to promoting flowering at 30 °C. 30 °C-induced up-regulation of FT2a and FT5a leads to early flowering, independent of E1. Therefore, distinct responsive mechanisms are adopted by soybean when facing different levels of high temperatures for successful flowering and reproduction.

Cropping systems and agricultural management strategies affect soil organic carbon dynamics in semi-arid regions

IntroductionSoil organic carbon (SOC) dynamic is one of the important factors that directly influence soil properties and quality. In agro-ecosystems, the SOC dynamics are strongly linked to agricultural management practices.MethodsIn this study, we investigated the response of SOC and its fractions to various combination of agricultural management practices based on measurements obtained from an experiment conducted over four growing seasons from 2018 to 2020 in Ahvaz, Iran. The experimental treatments involved three agricultural strategies combined with four crop rotation systems. The agricultural strategies comprised conventional (CON: mineral fertilizer, removal of all crop residues), organic (ORG: organic fertilizer, 30% return of crop residues to the soil), and integrated (INT: mineral/organic fertilizer, 15% return of crop residues) strategies. The crop rotation systems were: fallow-wheat (F-W), corn-wheat (C-W), sesame-wheat (S-W), and mung bean-wheat (B-W). Soil samples were collected from all treatments and SOC, labile-C, and non-labile-C were measured.Results and discussionAfter two years of experiment, no significant improvement was found in SOC of CON strategy (p ≤ 0.05). The ORG and INT strategies contained on average 1.1 and 1.06 times more SOC than the CON strategy, respectively. The value of labile-C was decreased during summer cultivations and increased in the soil samples collected after winter cultivations. However, although the quantity of labile-C in ORG (2 g kg−1) was higher than INT (1.83 g kg−1) and CON (1.87 g kg−1) overall during the experiment time, after the second summer cultivation despite the gradual accumulation of organic matter due to high levels of temperature and humidity, the content in ORG reduced to1.47 g kg−1. In all three agricultural management strategies, the SOC content in the four rotation systems was according to the following descending order B-W (5.7 g kg−1) &amp;gt; C-W (5.29 g kg−1) &amp;gt; S-W (5.23 g kg−1) &amp;gt; F-W (4.52 g kg−1). Therefore, for this region M-W and S-W crop rotation systems are recommended in addition to C-W (which is the most common rotation system). However, crop rotation systems were more beneficial for C-sequestration when combined with organic and inorganic fertilization and crop residue incorporation. This study gives promising results for implementing INT and ORG strategies under long-term cropping systems containing various summer crops in rotation with wheat for improving SOC dynamics in semi-arid regions in Iran.

Evaluation of combustion characteristics in biomass residues open burning

Open burning of biomass residues is known as major source of atmospheric pollutant in agricultural areas. Biomass open burning released several toxic compounds that endanger not only human health but also enhance global warming effect. This paper aims to evaluate the characteristics of combustion in bagasse, rice straw and leaf litter open burning. Experimental furnace is designed to mimic the open burning condition with controlled observation system of combustion parameters i.e., temperature, gas composition, and particulate concentration. It is obtained that bagasse produced the lowest emission factor compared to other biomasses combustion i.e., 35 g CO/kg biomass and 0.2 g PM/kg biomass. High temperature level is obtained to be the main factor of low emission emitted in open burning.

Transportation-Related Human Factors in High-Altitude Regions: Review, Needs, and Novelties

The low pressure at high altitudes (above 2500 m) causes hypoxia (decreased oxygen) that affects people’s physiological and psychological characteristics. Specifically, hypoxia may affect the neural function of the brain, leading to severe cognitive deficits and a significant decline in memory function and attention. This article addresses the effect of human factors on transportation design and operation at high altitudes (HA), with some details on the Tibet-China region. Specifically, the paper first reviews the basic transportation-related concepts for high altitude, including oxygen and temperature levels, driver perception-reaction time, hazard perception, vehicle speed, and walking speed. Then, the transportation users affected by high altitudes are discussed, including drivers, pedestrians, cyclists, passengers, and others. Next, the impacts of human factors on highway design and operation for HA regions are discussed along with the research needs. Finally, recent innovations to address the challenges of HA transportation are presented, along with case studies comparing some human factors of the plateau and plain areas. This article represents a valuable reference for future research in HA regions to improve transportation design and safety

Contrast the distribution, transformation, and degradation of dissolved and particulate organic matter in the South Yellow Sea, the East China Sea, and its adjacent Kuroshio Current

The distribution and bioavailability of dissolved and particulate organic matter (DOM and POM) were determined throughout the water column in sampling transects across the South Yellow Sea (SYS), East China Sea (ECS), and its adjacent Kuroshio Current (KC) during March–April 2017. The carbon (C), nitrogen (N), and amino acids (AA) levels in DOM and POM, as well as other parameters including temperature, salinity, nutrients, chlorophyll-a, and biological parameters (heterotrophic bacteria, Synechococcus, and picoeukaryotes), were used in the multi-factor analysis to explore the underlying factors contributing to the distribution patterns and degrading status of DOM and POM. The AA contents in POM (PAA) were higher at shallower depths than the deep ones, whereas total dissolved amino acids (TDAA) levels showed minor variation with depth. Specifically, glycine and serine in the PAA were selectively preserved throughout the water column. High levels of heterotrophic bacteria were associated with high temperature and high levels of ammonium in shelf waters, indicating a spot for intensive remineralization of organic nitrogen. High concentrations of bulk organic parameters (POC and PON) were found more along the coast and correlated with arginine and alanine. The Kuroshio surface water was short of PAA, POC, and PON compared with the coastal and middle shelf water. The bioavailability of surface POM indicated by the percentages of AA in POC (PAA-C%) and PON (PAA-N%) was much higher in KC than in shelf and coastal waters. This study found the distinctive characterization of bioavailability and degradation status between KC and its adjacent seas.

Fatigue life prediction of 3D braided carbon/carbon composites with braided angle variation at elevated temperature

The braiding angle of 3D braided carbon/carbon composites (C/CCs) will change during high temperature fatigue loading, which will affect the fatigue properties of 3D braided C/CCs. In order to realize this dynamic simulation in the high temperature fatigue life prediction of 3D braided C/CCs and further improve the prediction accuracy of high temperature fatigue life of 3D braided C/CCs, a high temperature fatigue life prediction model of 3D braided C/CCs considering the change of braiding angle with fatigue cycle number was established. The establishment of the prediction model mainly includes: a meso-scale representative volume elements (RVEs) of 3D braided C/CCs considering yarn direction and fiber bundle cross-section shape is established at the meso-scale; the high temperature residual stiffness and residual strength models of fiber bundles considering high temperature and stress level are established. Based on the experimental data characteristics of high temperature fatigue residual stiffness of 3D braided C/CCs, a mathematical model of cycle number/braided angles (CN/BAs) is established. The fatigue life prediction model was used to predict the 3D braided C/CCs at 700°C and stress levels of 87% and 85%. The results showed that the prediction error of single flower node was less than 5%. The fatigue life prediction error is less than two times the tolerance.

Experimental evaluation of the performance of a domestic water heating system under Baghdad climate conditions

The aim of the current study is to evaluate the performance of a domestic water heating system for residential areas in Baghdad climatic conditions for substituting electric water heaters with solar-powered water heaters using solar collectors. Many countries, such as Iraq, are sluggish with electric power issues while receiving very high solar insolation. Solar energy is a clean, non-depleting and low-cost source that can be used especially in residential areas, which forms a great percentage of energy consumption by replacing electric water heating with solar water heating to reduce electricity usage. Therefore, six flat plate solar collectors with an absorbing area of 1.92×0.85 m with one 4 mm thick glass cover are utilized for experimental investigation under the Baghdad climatic conditions. The collector was tested under steady-state settings, which assumed that sunlight intensity, ambient temperature, and inlet-outdoor temperature difference in each collector in the system were constant throughout the operation. According to the experimental results, during the test months of November, December, January, and February, the time-weighted experimental daily average collector array efficiency is found in the range of 40 % to 60 %. Furthermore, the greater energy gain and performance of the solar collector array attain a peak value at solar noon. Additionally, a solar collector with flat plates can easily achieve relatively high water temperature levels of 70 °C in the winter season. In addition, using a solar domestic hot water system as a water heater in Baghdad climatic conditions by substituting electric water heaters is useful for saving power consumption

Model-based design of a segmented reactor for the flexible operation of the methanation of CO2

As the share of renewable energies is growing, chemical plants need to adapt to the current energy availability. This is highly relevant for power-to-gas plants, where large amounts of electricity are used for hydrogen and subsequent synthetic natural gas production. A high plant flexibility allows adjusting the plant load according to the availability of feed streams. This raises the question how the methanation process can meet the high flexibility of the upstream electrolytic hydrogen production. As a possible solution, we propose a segmented, adiabatic fixed-bed reactor for the enhancement of the load range for CO2 methanation. A 1D pseudo-homogenous model is presented to investigate the reactor regarding its main thermal effects. Our findings prove the feasibility of the concept and illustrate its main features: a larger operating window and shorter start-up times compared to a conventional unit. Furthermore, unlimited standby at high temperature levels is possible, if at least one segment is actively operated.

Nonlinear rheological performance characterization of styrene-butadiene-styrene and crumb rubber composite modified bitumen using large amplitude oscillatory shear tests

The crumb rubber (CR) recycled from waste tires can improve the mechanical properties of bitumen effectively. For the widely used modified bitumen today, it could work in nonlinear regime in many occasions. This study focuses on the nonlinear properties of styrene-butadiene-styrene (SBS) and CR composite modified bitumen (CMB) by analyzing the results of stress-controlled large amplitude oscillatory shear (LAOS) tests. The results show that the nonlinearity of SBS/CR CMB was significant under low load frequency, high temperature and high stress level. Lissajous curves at these conditions are distorted obviously due to the presence of higher-order harmonics. By analyzing the geometry parameters of Lissajous curves, it can be concluded that the incorporation of CR has a positive influence on the nonlinear properties of bitumen, which effectively improve the stress bearing capacity of bitumen. However, the high-order harmonic analysis indicates that improving the CR content simply does not always improve the performance of bitumen. Besides, the nonlinearity of SBS/CR CMB with lower CR content is similar to that of SBS modified bitumen through the value of I3/I1 and intrinsic nonlinear parameter Q, thus there are two critical CR contents for the prospect of modifying the nonlinearity of bitumen.

Francisco Guilhien Gomes‐Junior, Agide Gimenez Marassi, Lívia Araújo Rohr, Silvio Moure Cícero, Infrared thermographic assessment to discriminate soybean seed vigor, 2022, (https://doi.org/10.1002/agj2.21151)

The identification of differences in vigor among seed lots and individual seeds are important for research, seed industry and market. This study investigates the infrared thermographic assessment of soybean [Glycine max (L.) Merrill] seeds to discriminate seed lots based on their vigor levels. Seeds of five commercial lots were imbibed in moistened paper towel rolls (25°C for 6 h) and thermographic measurements of average temperature, maximum temperature, minimum temperature, and thermal amplitude were performed after removing the seeds from the paper towel rolls and thermal stabilization in a controlled environment (25°C and 70% relative humidity) for 15 minutes. The results indicated higher temperature levels from seeds in the lots with lower vigor than in those with higher vigor. The Pearson's correlations from traditional tests and thermo measurements were higher for the average temperature on the seed surface. The infrared thermographic assessment is a promising protocol to discriminate seed lot vigor of soybean crops. This technique can be useful as a fast and non-invasive test in plant breeding and quality control programs of seed companies. This article is protected by copyright. All rights reserved

Thermomechanical Autovaporization (MFA) as a Deodorization Process of Palm Oil.

Throughout the vegetable oil industry, there is a focus on eradicating the volatile molecules affecting the aroma or taste of the crude oil, whether it is natural or derived from the extraction process. Refining aims to reduce these compounds to a level acceptable to the consumer. In addition, the famous conventional operation of deodorization calls for high levels of temperature depending on the boiling point used to remove the atmospheric pressure of each molecule. The process implies a vacuum level between 10 to 80 kPa absolute pressure, a temperature generally between 190 and 240 °C, and a duration of 2 to 3 h. These conditions necessarily (inevitably) lead to a decrease in the quality of refined oil. Recently, the application of the Multi-Flash Autovaporization "MFA" operation has shown the possibility of eradicating volatile molecules while adopting relatively low temperature and time levels. Despite the high boiling temperature of the volatile organic compounds (VOC), MFA leads to good efficiency in reducing VOCs and preserving oil quality. The main odorant compounds in the crude palm oil were E-2-Hexenal, heptanal, octanal, nonanal, and decanal. Specific literature can indicate precise boiling temperatures under atmospheric pressure. In addition, many experimental studies have explained the evolution of each molecule and shown how they depend on the operating parameters (inlet oil pressure from 200 to 450 kPa and from 5 and 30 s time of each cycle, and the number of cycles up to 7), and how the empirical mathematical models describe the MFA deodorization, estimate the efficiency of the whole process, and optimize the operating parameters. In this research, the thermodynamic data of absolute pressure volatility versus temperature was used to better identify the removal rate (up to around 87%) implied by an abrupt pressure drop to a vacuum of 5 kPa for p = 450 kPa, t = 25 s/cycle, and the number of cycles (C = 6). The safeguarding of the fatty acid profile illustrated the maintenance of the oil quality.

Interactive effects of high temperature and crude protein levels on growth performance, nitrogen excretion, and fecal characteristics of broilers.

In the present study, we aimed to explore the interactive effects of high temperature (HT) and dietary crude protein (CP) levels on nitrogen (N) excretion, fecal characteristics, and growth performance of broilers. A total of 288 broilers (Arbor Acres) were divided into six groups with eight replicates (six broilers per replicate). Two temperatures (ambient temperature: AT, 23°C; HT: 28 ~ 32 ~ 28°C) and three diets (CP: 14.90%, 18.18%, or 21.19%, with equal amounts of essential amino acids) were examined in a 2 × 3 factorial design. The experiment arrangement was from 4 to 6weeks of age. The results showed that HT led to a significant decrease in the N excretion (P < 0.0001), average daily feed intake (P < 0.0001), and weight gain of broilers (P < 0.0001), while it markedly increased the fecal pH (P = 0.015), fecal moisture (P = 0.0014), uric acid (UA) contents (P = 0.0018), and feed/gain ratio (P < 0.0001). A low CP diet significantly decreased the N excretion (P < 0.001), fecal pH (P = 0.016), fecal moisture (P < 0.0001), and UA contents (P < 0.0001), while it markedly increased the feed/gain ratio (P < 0.001). In conclusion, HT had a negative impact on the fecal characteristics and growth performance of broilers but showed positive effects on N excretion. Moreover, decreased CP levels had a positive effect on the N excretion and fecal characteristics in broilers.

Deflagration Waves Out of Hot Spots

It is widely accepted that shock initiation and detonation of heterogeneous explosives come about by a two-step process known as ignition and growth. In the first step a shock, sweeping through an explosive cell (control volume), creates hot spots that become ignition sites. In the second step deflagration waves (or burn waves) propagate out of those hot spots and transform the reactant in the cell into reaction products. The macroscopic (or average) reaction rate of the reactant in the cell depends on the speed of those deflagration waves and on the average distance between neighboring hot spots. Here we simulate the propagation of deflagration waves out of hot spots on the mesoscale in axial symmetry using a 2D hydrocode, to which we add heat conduction and bulk reaction. The propagation speed of the deflagration waves may depend on both pressure and temperature. It depends on pressure for quasistatic loading near ambient temperature, and on temperature at high temperature levels resulting from shock loading. From the simulation we obtain deflagration (or burn) fronts emanating out of the hot spots. For intermediate shock levels the emanating fronts propagate as deflagration waves to consume the explosive between hot spots. For higher shock levels the deflagration waves interact with the sweeping shock to become detonation waves on the mesoscale. From the simulation results we extract average deflagration wave speeds.

Study of asymmetrically heated flows passing through gas-pressurized solar receivers using Direct Numerical Simulations

Solar receiver flows are very complex since the heating fluid is strongly turbulent and asymmetrically heated at high temperature levels. To deepen the understanding of these flows, four DNS have been performed in different fluid heating configurations. The Navier-Stokes and the energy equations are solved under the low Mach approximation and the coupling between the dynamics and the temperature is taken into account. A simplified geometry of solar receiver is used and consists in a bi-periodical channel flow with fixed wall temperatures. The hot and cold wall temperatures are respectively 1300K and 900K and the mean friction Reynolds number is 820. Integral, mean and fluctuating quantities are investigated. Afterwards, quantitative and qualitative studies of instantaneous fields of wall heat flux and wall friction are carried out. In particular, probability density functions and 1D spectral analyses are discussed. This work highlights the strong coupling between the dynamics and the temperature. Focusing on wall heat fluxes, it seems that the ratio between the fluctuations and the mean quantity is weakly dependent of the studied conditions and is about 0.44 at both walls in all the simulations. The wall heat flux and the wall friction are highly correlated. The probability density functions indicate that the most probable wall heat fluxes, respectively wall frictions, are below the mean wall heat flux, respectively wall friction. They can be well approximated with skewed Gaussian distributions. The turbulent structures associated with wavenumbers lying between kx+=0.03 and kx+=0.05 and those associated to small wavenumbers in the spanwise direction seems to favor the heat transfer while keeping a wall friction relatively low.

Stability and Chemical Conversion of the Purified Reference Material of Gymnodimine-A under Different Temperature and pH Conditions.

Gymnodimines (GYMs) are a group of fast-acting phycotoxins and their toxicological effects on human beings are still unclear due to the lack of sufficiently well-characterized large quantities of purified toxins for toxicology studies. In this study, a certified reference material (CRM) of GYM-A was prepared from the dinoflagellate Karenia selliformis, followed by multi-step chromatography separation and purification. Subsequently, the stability of GYM-A in methanolic media was evaluated at different temperature (-20, 4, and 20 °C) and pH (3, 5, and 7) conditions for 8 months, and the conversion products of GYM-A were explored by liquid chromatography-high resolution mass spectrometry (LC-HRMS). The results show that the stability of GYM-A decreased with increasing temperature and pH values. The GYM-A was stable during storage at -20 °C regardless of pH, but it decreased rapidly (81.8% ± 9.3%) at 20 °C in pH 7 solution after 8 months. Moreover, the concentrations of GYM-A did not significantly change at all temperatures in solutions with pH 3 (p > 0.05). It is recommended that GYM-A should be stored at low temperature (≤-20 °C) and pH (≤3) conditions for long-term storage in aqueous methanolic media. In addition, two conversion products of GYM-A, tentatively named as GYM-K (m/z 540) and GYM-L (m/z 524), were identified in the samples stored at high levels of pH and temperature. Based on the LC-HRMS data, the hypothetical chemical structures of both converting derivatives were proposed. A useful strategy for long-term storage of GYM-A CRM in aqueous methanolic media was suggested and two hypothesized conversion products of GYM-A were discovered in this study.

The Relevance of High Temperatures and Short Time Intervals Between Radiation Therapy and Hyperthermia: Insights in Terms of Predicted Equivalent Enhanced Radiation Dose

The radiosensitization effect of hyperthermia can be considered and quantified as an enhanced equivalent radiation dose (EQDRT), that is, the dose needed to achieve the same effect without hyperthermia. EQDRT can be predicted using an extended linear quadratic model, with temperature-dependent parameters. Clinical data show that both the achieved temperature and time interval between radiation therapy and hyperthermia correlate with clinical outcome, but their effect on expected EQDRT is unknown and was therefore evaluated in this study. Biological modeling was performed using our in-house developed software (X-Term), considering a 23-×2-Gy external beam radiation scheme, as applied for patients with locally advanced cervical cancer. First, the EQDRT was calculated for homogeneous temperature levels, evaluating time intervals between 0 and 4 hours. Next, realistic heterogeneous hyperthermia treatment plans were combined with radiation therapy plans and the EQDRT was calculated for 10 patients. Furthermore, the effect of achieving 0.5°C to 1°C lower or higher temperatures was evaluated. EQDRT increases substantially with both increasing temperature and decreasing time interval. The effect of the time interval is most pronounced at higher temperatures (>41°C). At a typical hyperthermic temperature level of 41.5°C, an enhancement of ∼10 Gy can be realized with a 0-hour time interval, which is decreased to only ∼4 Gy enhancement with a 4-hour time interval. Most enhancement is already lost after 1 hour. Evaluation in patients predicted an average additional EQDRT (D95%) of 2.2 and 6.3 Gy for 4- and 0-hour time intervals, respectively. The effect of 0.5°C to 1°C lower or higher temperatures is most pronounced at high temperature levels and short time intervals. The additional EQDRT (D95%) ranged between 1.5 and 3.3 Gy and between 4.5 and 8.5 Gy for 4- and 0-hour time intervals, respectively. Biological modeling provides relevant insight into the relationship between treatment parameters and expected EQDRT. Both high temperatures and short time intervals are essential to maximize EQDRT.