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Nuclear medicine treatment requires patient-specific dose assessment as treatment plan reference. Voxelized dose results can give three-dimensional dose distribution. The conventional MIRD method assumes that the source is uniformly distributed within the organ, and the calculated dose results in an organ-averaged dose. In this study, based on molecular imaging data, the non-uniform distribution of the source term within the organ was obtained, and the voxel-level dose distribution was calculated for nuclear medicine patients using the following method. With accurate quantitative analyze of 131I SPECT images and CT images of patients, voxel S-value method and direct Monte Carlo (MC) method were used to calculate voxel-level dose distribution in nuclear medicine patients. The voxel S-factor is defined as the average absorbed dose of each radioactive decay in the source voxel to the target voxel, both of which are contained in an infinite homogeneous tissue. The voxel S-value is calculated to evaluate the dose of multiple surrounding source voxels to the target voxel. The three-dimensional dose distribution is calculated based on the source distribution obtained from the SPECT images. The MC simulation was processed based on the source distribution obtained from SPECT images and CT images. The HU value of each voxel in the patient’s body was obtained from the CT images, and the density value of each voxel was further obtained. The material of each voxel was divided according to the density to construct the voxel phantom. The voxel-level activity distribution was obtained based on the SPECT images to construct the source term distribution model. The MC simulation based on CT images was used to count the energy deposition of each voxel to obtain the accurate voxel-level dose distribution in the patient’s body. A 400x speedup was achieved using GPU MC simulation. The results of the S-value method and the MC method show a maximum difference of over 40% in the lung area. Voxel-level dose simulation can obtain the dose distribution in sub-organ and tumor, which provides a valuable reference for precision treatment of clinical nuclear medicine. The S-factor method can quickly give the dose distribution of patients, but this method ignores the tissue inhomogeneity, and the dose calculation results are not accurate in tissues and organs with large density differences, such as lung and bone, etc. The MC voxelized simulation can accurately give the dose distribution in patients, which is important for the accurate assessment of clinical dose in nuclear medicine.

Alloparenting refers to any type of parental care provided by an individual to non-descendant offspring. Alloparenting is not merely an altruistic behavior; it confers benefits to both care receivers and caregivers. Here, we report 3 cases where 3 adult Great Tits (Parus major) simultaneously provided food to chicks in the same nest boxes during the breeding season of 2019. All 3 cases were found in nest boxes where parent removal experiments were carried out. In our 3 d experiments, one of the parenting adults was temporarily removed from the nest box early on the second day and was back on its nest box at the end of that same day. In 2 of the nest boxes, the 3-adult brood-feeding started upon removing one of the brooding parents and continued on day 3, after the removed adult was returned. In one case, an alloparent was recorded feeding chicks alongside a parent since day I and continued feeding chicks on day 2. Our reports are the first documented examples of Great Tits involving a third adult in brooding. It presents an interesting finding for a well-studied bird species and may provide possibilities for in-depth research. Key words: alloparenting, breeding, monogamy, nest box, third individual. [phrase omitted], Instances of more than 2 adult birds providing care to a brood are quite common in nature. The care provided by additional individuals other than the parents is referred to [...]

The experimental removal of either the male or female from breeding pairs of Cinereous Tits Parus cinereus revealed that both sexes could increase their nestling provisioning rate to compensate fully for the loss. However, single females but not males delivered lower quality food. Parents would benefit from transferring the burden of costly parental care onto their mates, which leads to sexual conflict. Here, we tested how each sex might change their investment when their partners were temporarily removed. We used video recordings at nests of 24 pairs of Cinereous Tits to compare the nestling provisioning rate and prey quality of parents before, during and after the experimental, temporary removal of the other parent. Under biparental care, male and female parents had the same rate of food delivery to their broods, but females provided a higher proportion of higher quality food. When either parent was removed, the remaining parent increased their provisioning rate to equal that of the pair before the removal. However, while males increased the quality of food items to compensate for their removed females, females provisioned with lower quality food when their males were removed. Our results suggest that males and females face different energetic costs when provisioning nestlings. We also show the importance of considering food quality, as well as food quantity, when considering parental care compensation that might arise as a result of sexual conflict. [ABSTRACT FROM AUTHOR]

Abstract The adsorption of phthalate esters (PAEs) in mangrove sediment greatly influences their availability to aquatic organisms, however, the adsorption processes of PAEs in mangrove sediment, as well as the effects of root exudates, are poorly understood. In this study, dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) was used as model PAEs to determine the effects and mechanism of citric acid on the adsorption kinetics and isotherms of PAEs in the mangrove sediments. The adsorption kinetics followed pseudo-second order model, describing the characteristics of heterogeneous chemisorption of PAEs in mangrove sediments. The adsorption isotherms of DMP and DEP followed Freundlich model, implying the characteristics of surface multilayer heterogeneous adsorption; while the Henry model better described the adsorption isotherms of DBP, suggesting that hydrophobic partition accounted for DBP adsorption in the mangrove sediments. Inter-chemical variability was observed in adsorption capacity (q e) with the sequence of DBP > DEP > DMP. Surface polarity index ((C-O + COOH + C˭O)%) of particulate organic matter (POM) regulated the adsorption capacity of DMP and DEP in mangrove sediments, while different POM content among mangrove sediments explained the difference in the sorption strength for DBP. The presence of citric acid enhanced the q e of the three PAEs by 6.4–12.6%. These findings are of great significance to reveal that the root exudates play a crucial role in the PAEs adsorption in mangrove sediments, and provide valuable information for availability of PAEs in mangrove ecosystem. Graphical abstract fx1 Highlights • Surface polarity index of POM dominated the adsorption of DMP and DEP in sediments. • Hydrophobic partition to POM regulated DBP adsorption in mangrove sediments. • Citric acid increased the adsorption capacity of PAEs to mangrove sediments. [ABSTRACT FROM AUTHOR]

Nitrated polycyclic aromatic hydrocarbons (NPAHs) are PAH derivatives with more toxic effects to ecosystem, and the partitioning of NPAHs in crop system constitutes the potential exposure to human health through the dietary pathway. In the present study, a novel method for in situ detection of 9-nitroanthracene (9-NAnt) and 3-nitrofluoranthene (3-NFla) adsorbed onto the leaf surfaces of living soybean and maize seedlings was established based on the fiber-optic fluorimetry combined with graphene quantum dots (GQDs) as a fluorescent probe. The detection limits for the in situ quantification of the two adsorbed NPAHs ranged from 0.8 to 1.6 ng/spot (spot represents determination unit, 0.28 cm 2 per spot). Using the novel method, the effects of GQDs on the adsorption of individual 9-NAnt and 3-NFla by the living soybean and maize leaf surfaces were in situ investigated. The presence of GQDs altered the adsorption mechanism from the sole film diffusion to the combination of film diffusion and intra-particle diffusion, and shortened the time required to achieving adsorption equilibrium by 15.8–21.7%. Significant inter-species and inter-chemical variability existed in terms of the equilibrated adsorption capacity ( q e ) with the sequence of soybean > maize and 3-NFla > 9-NAnt. The occurrence of GQDs enlarged the q e values of 9-NAnt and 3-NFla by 22.8% versus 28.7% for soybean, and 16.2% versus 20.3% for maize, respectively, which was largely attributed to GQDs-induced expansion to the surface area for adsorbing NPHAs and the stronger electrostatic interaction between the -NO 2 of NPAH molecules and the functional groups ( e.g., -COOH, -OH) of GQDs outer surfaces. And, the varied enhancement degrees in the order of 3-NFla > 9-NAnt might be explained by the steric effects that resulted in the easier accessibility of -NO 2 of 3-NFla to the outer surface of GQDs. Summarily, the GQDs increased the retention of NPAHs on crop leaf surfaces, potentially threatening the crop security. [ABSTRACT FROM AUTHOR]

The partitioning of atmospheric polycyclic aromatic hydrocarbons (PAHs) into crop systems raises concerns about their potential harm to ecosystem and human health. To assess parent and alkylated PAHs accumulation accurately, the uptake of individual 7-isopropyl-1-methylphenanthrene (Retene), 3-methyl-phenanthrene (3-MP) and phenanthrene (Phe) by living maize, soybean and potato leaf surfaces, as well as the effects of cationic cetyltrimethylammonium bromide (CTMAB) and anionic sodium dodecyl benzene sulfonate (SDBS), were examined in situ using fiber-optic fluorimetry. For each of three PAH chemicals, the uptake achieved equilibrium between the air and living crop leaf surfaces within the 120-h monitoring period. There is inter-chemical and inter-species variability in terms of both the time required reaching equilibrium, the equilibrated adsorption concentration (EAC) and the overall air-surfaces mass transfer coefficient ( k AS ). The EAC of the three PAHs for each of the three crops’ leaf surfaces increased with the number of alkyl substitutions on the aromatic ring. For any given PAHs, the EAC values followed the sequence of potato > soybean > maize, which was dominantly controlled by their leaf surface polarity index ((O+N)/C). The presence of CTMAB and SDBS increased the EAC of PAHs in the three crops’ leaf surfaces by 6.5–17.1%, due to the plasticizing effect induced by the surface-sorbed surfactants, and the enhancement degree was closely associated with leaf-wax content and lg K OW values of PAHs. In addition, the two surfactants promoted the k AS values of the three chemicals by 7.7–23.3%. These results demonstrated that surfactants promoted the uptake of PAHs onto the crop leaf surfaces, potentially threatening the agricultural product safety. [ABSTRACT FROM AUTHOR]

The spatial distribution and breeding behavior of neighboring birds (conspecific and heterospecific) may influence reproduction and the effects differ across species. In this study, we investigated intra- and inter-specific spatial distribution of breeding via artificial nestboxes and examined whether overlap with neighbors affected reproductive success of the focal breeding pair. Regarding spatial distribution, Varied Tits (Sittiparus varius) and Cinereous Tits (Parus cinereus) showed similar pattern: distances of nestboxes containing conspecific tits were greater than those with heterospecific ones. In terms of breeding behavior, reproductive success was not significantly related to the distance from their neighbor's nest. The reproductive success of Varied Tits was significantly related to that of their neighbors, while in Cinereous Tits, no strong link was found to any recorded reproductive behavior of the neighbors. These findings explain spatial variation in nest site selection of Varied Tits and Cinereous Tits. Reproductive success rate of Varied Tits is affected by that of the neighbors while that of Cinereous Tits is not. The results highlight that there are differences in reproductive outcome among related species and offer suggestions on the use of artificial nestboxes in experiment and conservation programs. [ABSTRACT FROM AUTHOR]

Epithelial-mesenchymal transformation (EMT) is one of the important mechanisms of malignancy in endometrial cancer, and detection of EMT targets is a key challenge to explore the mechanism of endometrial carcinoma (EC) malignancy and discover novel therapeutic targets. This study attempts to use surface-enhanced Raman spectroscopy (SERS), a highly sensitive, ultrafast, and highly specific analytical technology, to rapidly detect microRNA-200a-3p and ZEB1 in endometrial cancer cell lines. The silver nanoparticles were decorated with iodine and calcium ions, can capture the SERS fingerprints of microRNA-200a-3p and ZEB1 protein, and effectively avoid the interference of impurity signals. At the same time, the method has high sensitivity for the detection of the above EMT targets, and the lowest detection limits for microRNA-200a-3p and ZEB1 are 4.5 pmol/mL and 10 ng/mL, respectively. At the lowest detection concentration, the method still has high stability. In addition, principal component analysis can not only identify microRNA-200a-3p and ZEB1 protein from a variety of EMT-associated microRNA and proteins but also identify them in the total RNA and total protein of endometrial cancer cell lines and normal endometrial epithelial cell lines. This study modified silver nanoparticles with iodine and calcium ions and for the first time captured the fingerprints of EMT-related targets microRNA-200a-3p and ZEB1 at the same time without label, and the method has high sensitivity and stability. This SERS-based method has immense potential for elucidating the molecular mechanisms of EMT-related EC, as well as identifying biomarkers for malignant degree and prognosis prediction.

Pediatric patients are in a growing stage with more dividing cells than adults. Therefore, they are more sensitive to the radiation dose when undergoing computed tomography (CT) scanning. It is necessary and essential to assess the organ absorbed dose and effective dose to children. Monte Carlo simulation with computational phantoms is one of the most used methods for dose calculation in medical imaging and radiotherapy. Because of the vast change of the pediatric body with age increasing, many research groups developed series pediatric phantoms for various ages. However, most of the existing pediatric reference phantoms were developed based on Caucasian populations, which is not conformable to Chinese pediatric patients. The use of different phantoms can contribute to a difference in the dose calculation. To assess the CT dose of Chinese pediatric patients more accurately, we developed the Chinese pediatric reference phantoms series, including the 3-month (CRC3m), 1-year-old (CRC01), 5-year-old (CRC05), 10-year-old (CRC10), 15-year-old male (CRCM15), and a 15-year-old female (CRCF15) phantoms. Furthermore, we applied them to dose assessment of patients undergoing CT scanning. The GE LightSpeed 16 CT scanner was simulated and the paper presents the detailed process of phantoms development and the establishment of the CT dose database (with x-ray tube voltages of 120, 100 and 80 kVp, with collimators of 20, 10, and 5 mm width, with filters for head and body), compares for the 1-year-old results with other results based on different phantoms and analyzes the CT dose calculation results. It was found that the difference in phantoms' characteristics, organ masses and positions had a significant impact on the CT dose calculation outcomes. For the 1-year-old phantom, the dose results of organs fully covered by the x-ray beam were within 10% difference from the results of other studies. For organs partially covered and not covered by the scan range, the maximum differences came up to 84% (stomach dose, chest examinations) and 463% (gonads dose, chest examinations) respectively. The findings are helpful for the dose optimization of Chinese pediatric patients undergoing CT scanning. The developed phantoms could be applied in dose estimation of other medical modalities., (© 2021 Institute of Physics and Engineering in Medicine.)