Atomic Insights into the Relationship between Molecular Structure and Dispersion Performance of Phenyl Polymer on Graphene Oxide.

The adsorption of organic polymers onto the surface of graphene oxide is known to improve its dispersibility in cement-based materials. However, the mechanism of this improvement at the atomic level is not yet fully understood. In this study, we employ a combination of DFT static calculation and umbrella sampling to explore the reactivity of polymers and investigate the effects of varying amounts of phenyl groups on their adsorption capacity on the surface of graphene oxide. Quantitative analysis is utilized to study the structural reconstruction and charge transfer caused by polymers from multiple perspectives. The interfacial reaction between the polymer and graphene oxide surface is further clarified, indicating that the adsorption process is promoted by hydrogen bond interactions and π-π stacking effects. This study sheds light on the adsorption mechanism of polymer-graphene oxide systems and has important implications for the design of more effective graphene oxide dispersants at the atomic level.

Surface Engineering of Migratory Corrosion Inhibitors: Controlling the Wettability of Calcium Silicate Hydrate in the Nanoscale.

Migratory corrosion inhibitors (MCIs) are regarded as effective additives to prevent harmful ion transmission and improve concrete durability, but their behavior in the porosity of concrete is still unclarified. This paper proposes a unique perspective to evaluate the effects of surfactant-like MCIs in calcium silicate hydrate (C-S-H) nanoporosity through molecular and electronic structural information. Advanced enhanced sampling methods and perturbation theory methods were applied to evaluate the role of different MCIs. The reduced density gradient of MCI molecules was obtained by using quantum chemical calculations. This calculation is instrumental in elucidating the intensity of interactions among distinct MCI molecule head groups and the C-S-H matrix. It is found that MCIs can effectively improve the interfacial tension (IFT) between C-S-H and water, which corresponds to the inhibitory ability of transmission. Free energy indicates that the MCI has the properties of strong adsorption and weak dissolution, facilitating the improvement of IFT. The relationship between the MCI functional group and the ability of adsorption and dissolution is revealed. This study suggests that MCIs work as surface controllers of C-S-H pores and that their properties can be assessed on the nanoscale.

Atomistic Insights into the Deposition of Corrosion Products on the Surfaces of Steels and Passivation Films.

The deposition of corrosion products on the surface of the steel is a key step for understanding the generation of corrosion products. To clarify the molecular mechanism for corrosion product deposition, the reactive molecular dynamics were utilized to study the deposition process of ferric hydroxide (Fe(OH)3) on iron and passivation film substrates. It is shown that the deposition phenomenon mainly occurs on the iron surface, while the surface of the passivation film cannot adsorb Fe(OH)3. Further analysis indicates that the interaction between hydroxyl groups in γ-FeOOH and Fe(OH)3 is very weak, which is unfavorable to the deposition of Fe(OH)3. Moreover, the degree of ordered water in the two systems is affected slightly by deposition but the oxygen in water corrodes Fe(OH)3, breaking its Fe-O bonds, which is more obvious in the Fe system due to its instability. This work has revealed the nanoscale deposition process of corrosion products on the passivation film in a solution environment by reproducing the bonding and breaking of atoms at the molecular level, which is a case in point to the conclusion of the protection of steel bars by passivation film.

BiVO4-Deposited MIL-101-NH2 for Efficient Photocatalytic Elimination of Cr(VI).

In this study, a flower-like BiVO4/MIL-101-NH2 composite is synthesized by a facile and surfactant-free process. The -COO--Bi3+ ionic bond construction was conductive to enhance the interface affinity between BiVO4 and MIL-101-NH2. Due to the highly efficient light capture and sufficient electron traps induced by oxygen vacancies and the formation of a heterostructure, the improved separation and transportation rates of charge carriers are realized. In addition, the MIL-101-NH2/BiVO4 composite is favorable for Cr(VI) photocatalytic removal (91.2%). Moreover, FNBV-3 (Fe/Bi = 0.25) also exhibited an excellent reusability after five cycles.

Metabolic dysfunction-associated fatty liver disease and liver fibrosis: Prevalence and associated factors in the middle-aged and older US population.

AIM: The global burden of chronic liver disease is substantial. Limited studies have reported the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) and liver fibrosis among middle-aged and older people. Therefore, we aimed to determine the nationwide prevalence of and associated factors for MAFLD and fibrosis in adults aged 45-79 years from the United States. METHODS: This cross-sectional study utilized data from the 2017-2018 cycle of the National Health and Nutrition Examination Survey conducted with a nationally representative sample of the civilian, noninstitutionalized US population. Hepatic steatosis and fibrosis were assessed by transient elastography with controlled attenuation parameter and liver stiffness measurement, respectively. RESULTS: A total of 1186 eligible participants aged 45-79 years were finally included in the analyses. The estimated prevalence of MAFLD, significant fibrosis (F ≥ F2), and advanced fibrosis (F ≥ F3) was 48.6% (95% confidence interval [CI], 43.1%-54.0%), 9.5% (95% CI, 6.8%-12.7%), and 6.7% (95% CI, 4.1%-10.1%), respectively. Multivariable logistic regression revealed an increased MAFLD predisposition in subjects with metabolic disorders including overweight/obesity, abdominal obesity, hypertension, and diabetes mellitus. Moreover, the presence of depression was an independent and strong predictor of MAFLD risk (odds ratio = 3.23; 95% CI, 1.37-7.11). Elevated liver enzymes, hypertension, diabetes mellitus, hepatitis virus infection, and steatosis were associated with a high risk of significant fibrosis. CONCLUSIONS: Newly defined MAFLD is highly prevalent in the US middle-aged and older population. Approximately 1 in 10 people has significant liver fibrosis. In addition to metabolic disorders, the presence of depression potentially increases the risk of MAFLD.

Effects of different molar mass chitooligosaccharides on growth, antioxidant capacity, non-specific immune response, and resistance to Aeromonas hydrophila in GIFT tilapia Oreochromis niloticus.

A feeding trial was conducted to evaluate the effects of different molar mass chitooligosaccharides (1000 Da, 3000 Da and 8000 Da) on growth, antioxidant capacity, non-specific immune response, and resistance to Aeromonas hydrophila in GIFT tilapia (Oreochromis niloticus). A total of 600 fish were divided into four treatments with five replicates of thirty fish per tank. The results showed that the supplementation of 1000 Da and 3000 Da COS significantly improved the growth performance and feed utilization in GIFT tilapia. The trend of decreasing total cholesterol, triglyceride, ALT, and ACP activity was observed in fish fed diet supplemented COS. The supplementation of 1000 Da and 3000 Da COS significantly improved the serum TAC activity, and decreased the serum MDA and catalase activities (P < 0.05). The lysozyme activity of blood, liver, and gills in fish fed diets supplemented with 1000 Da and 3000 Da COS was significantly higher than that of fish fed control diet after 56 days of feeding (P < 0.05). The phagocytic activity and phagocytic index of fish fed diets supplemented with 1000 Da and 3000 Da COS were significantly higher than those of fish fed control diet. Post-challenge test showed that fish mortality in 1000 Da, 3000 Da, and 8000 Da COS groups were significantly lower than that of fish in control group (P < 0.05). In conclusion, the present study indicated that dietary 1000 Da and 3000 Da COS supplementation could enhance more performance and immune response of GIFT tilapia than 8000 Da COS.

An evaluation of mixed plant protein in the diet of Yellow River carp (Cyprinus carpio): growth, body composition, biochemical parameters, and growth hormone/insulin-like growth factor 1.

The aim of this work is to evaluate the effects of dietary inclusion of mixed plant protein (MP) (rapeseed meal:cottonseed meal:peanut meal = 1:1:1) on growth, body composition, blood biochemical parameters, growth hormone/insulin-like growth factor 1, and relative non-specific immune response in Yellow River carp Cyprinus carpio. Five isonitrogenous and isoenergetic trial diets were formulated to replace fish meal at 0 (MP0, control), 25% (MP25), 50% (MP50), 75% (MP75), and 100% (MP100) mixed plant protein, respectively. The 25% mixed plant protein did not affect the weight gain, specific growth rate, and protein efficiency ratio, whereas these parameters were depressed by 50% and above mixed plant protein. The whole body protein content gradually decreased with increasing dietary MP; meanwhile, the whole body lipid content is the opposite. The MP75 and MP100 diets adversely affected the glucose level, total cholesterol value, alanine transaminase, and aspartate transaminase activity of serum. Fish fed MP75 and MP100 diets showed higher growth hormone level than that of MP0 diet; however, the insulin-like growth factor 1 level got the opposite result. The 50% and above inclusion of MP decreased lysozyme activity and increased malondialdehyde content. In conclusion, no more than 50% of fish meal could be replaced by mixed plant protein in diet. However, 50% and above inclusion of mixed plant protein in diet could depress the growth, insulin-like growth factor 1 level, and non-specific immune response, and significantly affect the whole body composition and serum biochemical parameters in Yellow River carp.

Supraclavicular lymph node incisional biopsies have no influence on the prognosis of advanced non-small cell lung cancer patients: a retrospective study.

BACKGROUND: Supraclavicular lymph node (SCLN) biopsies play an important role in diagnosing and staging lung cancer. However, not all patients with SCLN metastasis can have a complete resection. It is still unknown whether SCLN incisional biopsies affect the prognosis of non-small cell lung cancer (NSCLC) patients. METHODS: Patients who were histologically confirmed to have NSCLC with SCLN metastasis were enrolled in the study from January 2007 to December 2012 at Guangdong Lung Cancer Institute. The primary endpoint was OS, and the secondary endpoints were complications and local recurrence/progression. RESULTS: Two hundred two consecutive patients who had histologically confirmed NSCLC with SCLN metastasis were identified, 163 with excisional and 39 with incisional biopsies. The median OS was not significantly different between the excisional (10.9 months, 95% CI 8.7-13.2) and incisional biopsy groups (10.1 months, 95% CI 6.3-13.9), P = 0.569. Multivariable analysis showed that an Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥2 (HR = 2.75, 95% CI 1.71-4.38, P < 0.001) indicated a worse prognosis. Having an epidermal growth factor receptor (EGFR) mutation (HR = 0.58, 95% CI 0.40-0.84, P = 0.004) and receiving systemic treatment (HR = 0.36, 95% CI 0.25-0.53, P < 0.001) were associated with a favorable OS. Neither the number (multiple vs. single) nor site (bilateral vs. unilateral) of SCLNs was associated with an unfavorable OS, and SCLN size or fixed SCLNs did not affect OS. CONCLUSIONS: SCLN incisional biopsies did not negatively influence the prognosis of NSCLC patients. It was safe and feasible to partly remove a metastatic SCLN as a last resort in advanced NSCLC.

Distribution and prognosis of uncommon metastases from non-small cell lung cancer.

BACKGROUND: According to the literature and our experience, the most common sites of non-small cell lung cancer (NSCLC) metastases include the brain, bone, liver, adrenal glands, contralateral lung and distant lymph nodes. Metastases to other organs are relatively rare. There have been numerous case reports and a few small case series of uncommon metastases derived from NSCLC. METHODS: We defined all organs except the common metastatic sites mentioned above as uncommon sites of metastasis. Patients with uncommon metastases among 2,872 consecutive NSCLC patients with stage IV disease at the Guangdong Lung Cancer Institute (GLCI) from 2006 to 2012 were included in this study. The diagnosis of uncommon metastases was based on pathology or imaging studies. RESULTS: Uncommon metastases were diagnosed in 193 cases at anatomical sites such as the soft tissue, kidney, pancreas, spleen, peritoneum, intestine, bone marrow, eye, ovary, thyroid, heart, breast, tonsil and nasal cavity. Uncommon metastases were identified as independent poor prognostic factors through a multivariate analysis with a HR (hazard ratio) of 1.29 [95% confidence interval (CI) 1.09-1.52, P < 0.01]. Those patients who received systemic therapy plus local treatment had a better survival rate than did those who received systemic therapy only (P < 0.01); all patients received best supportive care. CONCLUSIONS: Metastases to the above mentioned sites are infrequent. The presentation of uncommon metastases tends to indicate a poor outcome, and selected patients may benefit from local treatment.

Efficient Adsorption of Azo Dye Acid Brilliant Red on Graphite Carbon Nitride in Aqueous Solution.

In this study, two types of graphite carbon nitrides were prepared by directly calcinating urea (U-g-C3N4) and melamine (M-g-C3N4) in a muffle furnace. Their adsorption performances on acid brilliant red (ABR) from aqueous solution were examined and compared. Results showed that, at the optimum calcination temperature of 580 °C, both the adsorption capacity of U-g-C3N4 and that of M-g-C3N4 increased strongly with decreasing solution pH. U-g-C3N4 exhibits higher adsorption capacity than M-g-C3N4 at an initial pH > 2.0. However, at an initial pH of 1.0, M-g-C3N4 displayed a much higher adsorption capacity than U-g-C3N4, where the maximum adsorption capacity of M-g-C3N4 can reach 25 635.64 mg g-1, being the highest reported to date. Adsorptions of both adsorbents followed pseudo-second-order kinetic models and the Langmuir adsorption isothermal models. The adsorption is spontaneous and exothermic and occurs mainly through electrostatic attraction between the protonated g-C3N4 and the negatively charged ABR. In addition, the used U-g-C3N4 can be easily regenerated with ethanol and the renewed U-g-C3N4 possesses comparable adsorption capability of its original form, showing its superior recyclability and broad industrial application prospects.

Channel erosion and its impact on environmental flow of riparian habitat in the Middle Yangtze River.

Evaluating environmental flow (EF) is pivotal for conserving and restoring riverine ecosystems. Yet, prevalent EF evaluations presume that a river reach's hydraulic conditions are exclusively governed by inflow discharge, presupposing a state of equilibrium in the river channel. This presumption narrows the scope of EF evaluations in expansive alluvial rivers like the Middle Yangtze River (MYR), characterized by marked channel alterations. Here we show the profound channel erosion process and its impact on EF requirements for riparian habitats within the MYR. Our research unveils that: (i) pronounced erosion has led to a mean reduction of 1.0-2.7 m in the riverbed across four sub-reaches of the MYR; (ii) notwithstanding a 37-107% increase in minimal discharges post the Three Gorges Project, the lowest river stages at some hydrometric stations diminished owing to bed erosion, signifying a notable transformation in MYR's hydraulic dynamics; (iii) a discernible rightward shift in the correlation curve between the weighted useable area and discharge from 2002 to 2020 in a specific sub-reach of the MYR, instigated by alterations in hydraulic conditions, necessitated an increase of 1500-2600 m³ s-1 in the required EF for the sub-reach; (iv) it is deduced that macroinvertebrate biomass rapidly decreases as the flow entrains the riverbed substrate, with the maximum survivable velocity for macroinvertebrates being contingent on their entrainment threshold. These findings highlight the importance of incorporating channel morphological changes in devising conservation strategies for the MYR ecosystem.

Comparison of Prognosis for Lung Transplantation between Older and Younger Donors: A Systematic Review and Meta-Analysis Based on Cohort Studies.

PURPOSE: This meta-analysis aimed to compare the prognosis of lung transplantation recipients based on donor age. METHODS: A detailed search was performed in PubMed, Embase, Web of Science, and the Cochrane Library for cohort studies on lung transplantation. The prognosis of lung transplant recipients was investigated based on the donor age, with the primary outcomes being 1-year overall survival (OS), 3-year OS, 5-year OS, and 5-year chronic lung allograft dysfunction (CLAD)-free survival. RESULTS: This meta-analysis included 10 cohort studies. Among the short-term outcomes, the older donor group demonstrated no significant difference from the young donor group in primary graft dysfunction within 72 hours, use of extracorporeal membrane oxygenation, length of ventilator use, and intensive care unit hours. However, a longer hospital stay was associated with the older donor group. In terms of long-term outcomes, no difference was found between the two groups in 1-year OS, 3-year OS, and 5-year OS. Notably, patients with older donors exhibited a superior 5-year CLAD-free survival. CONCLUSIONS: The results of this meta-analysis indicate that older donors are not inferior to younger donors in terms of long-term and short-term recipient outcomes. Lung transplantation using older donors is a potential therapeutic option after rigorous evaluation.

Functional activities of three Rehmannia glutinosa enzymes: Elucidation of the Rehmannia glutinosa salidroside biosynthesis pathway in Saccharomyces cerevisiae.

Rehmannia glutinosa produces many phenylethanoid glycoside (PhG) compounds, including salidroside, which not only possesses various biological activities but also is a core precursor of some medicinal PhGs, so it is very important to elucidate the species' salidroside biosynthesis pathway to enhance the production of salidroside and its derivations. Although some plant copper-containing amine oxidases (CuAOs), phenylacetaldehyde reductases (PARs) and UDP-glucose glucosyltransferases (UGTs) are thought to be vital catalytic enzymes involved in the downstream salidroside biosynthesis pathways, to date, none of these proteins or the associated genes in R. glutinosa have been characterized. To verify a postulated R. glutinosa salidroside biosynthetic pathway starting from tyrosine, this study identified and characterized a set of R. glutinosa genes encoding RgCuAO, RgPAR and RgUGT enzymes for salidroside biosynthesis. The functional activities of these proteins were tested in vitro by heterologous expression of these genes in Escherichia coli, confirming these catalytic abilities in these corresponding reaction steps of the biosynthetic pathway. Importantly, four enzyme-encoding genes (including the previously reported RgTyDC2 encoding tyrosine decarboxylase and the RgCuAO1, RgPAR1 and RgUGT2 genes) were cointegrated into Saccharomyces cerevisiae to reconstitute the R. glutinosa salidroside biosynthetic pathway, achieving an engineered strain that produced salidroside and validating these enzymes' catalytic functions. This study elucidates the complete R. glutinosa salidroside biosynthesis pathway from tyrosine metabolism in S. cerevisiae, establishing a basic platform for the efficient production of salidroside and its derivatives.

Study on the relationship between net primary productivity and site quality in Japanese larch plantations in mountainous areas of eastern Liaoning.

Plantation forests enhance carbon storage in terrestrial ecosystems in China. Larix kaempferi (Lamb.) Carrière (Lamb.) (Larix olgensis Henry) is the main species for afforestation in the eastern Liaoning Province. Therefore, it is important to understand the correlation between the site class and carbon sink potential of Larix kaempferi plantations in Liaoning Province for afforestation and carbon sink in this area. The model was fitted using three classical theoretical growth equations: the Richards model, the Korf model, and the Hossfeld model. This study used the forest resource inventory data for management in Liaoning Province in 2011 to build six dynamic height-age models for a Larix kaempferi plantation in Dandong City regardless of base-age. The optimal model derived by the generalized algebraic difference approach (GADA) method was compared with the model derived by the algebraic difference approach (ADA) method. The superiority of GADA was demonstrated by comparison. The Levenberg-Marquardt algorithm was used to fit the model. The statistical and biological characteristics were considered synthetically when comparing the models. The best model was screened out by statistical analysis and graphic analysis. The results show that the differential height-age model derived from Richards equation can well explain the growth process of Larix kaempferi in Dandong City, Liaoning Province under different conditions. The site index model based on Richards equation and derived by GADA was used to calculate the site class of a Larix kaempferi plantation in Dandong City. The net primary productivity (NPP) value from the past ten years was extracted from the MOD17A3HGF data set. Spearman correlation analysis and Kendall correlation analysis were used to show that there is a significant positive correlation between NPP value and site class of Larix kaempferi plantation in Dandong City. Among them, the highest growth occurred in 2016; NPP increased by about 3.914 gC/m2/year for every two increases in height-age grade; the lowest increase in NPP was in 2014; NPP increased by about 2.113 gC/m2/year for every two increases in height-age grade; and for every two increases in height-age grade in the recent ten years, the average NPP value increased by about 2.731 gC/m2/year.

Shrimp hemocyanin elicits a potent humoral response in mammals and is favorable to hapten conjugation.

Conjugation to a carrier protein is essential to give rise to the antigenicity of hapten. Three carrier proteins e.g. KLH (Keyhole Limpet hemocyanin), BSA (bovine serum albumin), and OVA (Ovalbumin) were used mostly. KLH is advantageous to the others, majorly owing to its strong immunogenicity and limited usage in other biological assays. However, the cost of obtaining Keyhole Limpet is high and the solubility of KLH is not as well as the other carriers, especially after hapten conjugation. Here, we extracted the shrimp hemocyanin (SHC) from Litopenaeus vannamei (L. vannamei), which is a commonly sea product worldwide. The high pure SHC could be acquired by two-step purification, with a production yield of > 1 g proteins (98% pure) per 1 kg shrimp. Compared to KLH, the peptide-SHC conjugates exhibit higher solubility after hapten conjugation. Meanwhile, compared with KLH, SHC induces comparable antibody production efficiency in mammals, with or without conjugation. Furthermore, rabbit polyclonal antibodies or mouse monoclonal antibodies were generated by immunizing SHC-peptide conjugates, and the subsequent antibodies were confirmed to be used in western blot, immunofluorescence and immunohistochemistry. Therefore, we demonstrated that SHC may be used as a substitute for KLH in future antibody and vaccine development.

Ligand-Screened Cerium-Based MOF Microcapsules Promote Nerve Regeneration via Mitochondrial Energy Supply.

Although mitochondria are crucial for recovery after spinal cord injury (SCI), therapeutic strategies to modulate mitochondrial metabolic energy to coordinate the immune response and nerve regeneration are lacking. Here, a ligand-screened cerium-based metal-organic framework (MOF) with better ROS scavenging and drug-loading abilities is encapsulated with polydopamine after loading creatine to obtain microcapsules (Cr/Ce@PDA nanoparticles), which reverse the energy deficits in both macrophages and neuronal cells by combining ROS scavenging and energy supplementation. It reprogrames inflammatory macrophages to the proregenerative phenotype via the succinate/HIF-1α/IL-1ß signaling axis. It also promotes the regeneration and differentiation of neural cells by activating the mTOR pathway and paracrine function of macrophages. In vivo experiments further confirm the effect of the microcapsules in regulating early ROS-inflammation positive-feedback chain reactions and continuously promoting nerve regeneration. This study provides a new strategy for correcting mitochondrial energy deficiency in the immune response and nerve regeneration following SCI.

Resting-state coupling between HbO and Hb measured by fNIRS in autism spectrum disorder.

To distinguish between children with autism spectrum disorder (ASD) and typically developing (TD) children, we have uncovered a new discriminative feature, hemoglobin coupling. Functional near-infrared spectroscopy (fNIRS) was used to record resting-state hemodynamic fluctuations in the bilateral temporal lobes in 25 children with ASD and 22 TD children, in which the coupling between low frequency oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (Hb) fluctuations was evaluated by Pearson correlation coefficient. The results showed significantly weak coupling in children with ASD in both the left and right, and throughout the whole temporal cortex. To explain this observation, a simulation study was performed using a balloon model, in which we found four related parameters could impact the coupling. This study suggested that hemoglobin coupling might be applied as a new cerebral hemodynamic characteristic for ASD screening or diagnostics.

Normalized mutual information of fNIRS signals as a measure for accessing typical and atypical brain activity.

Normalized mutual information (NMI) can be used to detect statistical correlations between time series. We showed possibility of using NMI to quantify synchronicity of information transmission in different brain regions, thus to characterize functional connections, and ultimately analyze differences in physiological states of brain. Resting-state brain signals were recorded from bilateral temporal lobes by functional near-infrared spectroscopy (fNIRS) in 19 young healthy (YH) adults, 25 children with autism spectrum disorder (ASD), and 22 children with typical development (TD). Using NMI of the fNIRS signals, common information volume was assessed for each of three groups. Results showed that mutual information of children with ASD was significantly smaller than that of TD children, while mutual information of YH adults was slightly larger than that of TD children. This study may suggest that NMI could be a measure for assessing brain activity with different development states.

Cross-generation pheromonal communication drives Drosophila oviposition site choice.

In a heterogeneous and changing environment, oviposition site selection strongly affects the survival and fitness of the offspring.1,2 Similarly, competition between larvae affects their prospects.3 However, little is known about the involvement of pheromones in regulating these processes.4,5,6,7,8 Here, we show that mated females of Drosophila melanogaster prefer to lay eggs on substrates containing extracts of conspecific larvae. After analyzing these extracts chemically, we test each compound in an oviposition assay and find that mated females display a dose-dependent preference to lay eggs on substrates spiked with (Z)-9-octadecenoic acid ethyl ester (OE). This egg-laying preference relies on gustatory receptor Gr32a and tarsal sensory neurons expressing this receptor. The concentration of OE also regulates larval place choice in a dose-dependent manner. Physiologically, OE activates female tarsal Gr32a+ neurons. In conclusion, our results reveal a cross-generation communication strategy essential for oviposition site selection and regulation of larval density.

Cardiac exposure in left-sided breast cancer patients undergoing deep inspiratory breath hold radiation therapy.

Background: Left-sided breast cancer (BC) patients undergoing post-operative radiation therapy (PRT) may have higher risk of late cardiovascular toxicity, which may be reduced by hearth-sparing RT techniques. This study evaluated dosimetric parameters of the deep inspiration breath hold (DIBH) compared to free breathing (FB) RT. We analysed factors impacting on doses to the heart and cardiac substructures and sought anatomic factors allowing patient selection for DIBH. Methods: The study group included 67 left-sided BC patients who underwent RT after breast-conserving surgery or mastectomy. Patients treated with DIBH were trained to hold their breath. Computed tomography (CT) scans were performed in both FB and DIBH patients. Plans were generated using 3-dimensional (3D) conformal RT. The dosimetric variables were obtained from dose-volume histograms, and the anatomical variables were derived from the CT scans. The variables in the two groups were compared by t-test, the U test, and the chi-squared test. Correlation analysis was performed using Pearson's correlation coefficient. Receiver operating characteristic curves were used to analyze the efficacy of the predictors. Results: Compared to the FB, DIBH allowed for a mean dose reduction to the heart, left anterior descending coronary artery (LAD), left ventricle (LV), and right ventricle (RV) by 30.0%, 38.7%, 39.3%, and 34.7%, respectively. DIBH markedly increased the heart height (HH), heart chest wall distance (HCWD), the mean distance between the ipsilateral lung and breast (DBIB), and decreased the heart-chest wall length (HCWL) (P<0.05). The different value of HH, DBIB, HCWL, and HCWD between DIBH and FB were 1.31, 1.95, -0.67, and 0.22 cm, respectively (all P<0.05). ΔHH was an independent predictor of the mean dose to the heart, LAD, LV, and RV, with the area under the curve values of 0.818, 0.725, 0.821, and 0.820, respectively. Conclusions: DIBH significantly reduced the dose to the entire heart and its substructures in left-sided BC patients undergoing post-operative RT. ΔHH predicts the mean dose to the heart and its substructures. These results may inform patient selection for DIBH.