In the total sample, we found no evidence of beneficial effects of maternal use of iodine-containing supplements  on child ADHD diagnosis or symptom score. Initiation of iodine supplement use in gestational weeks 0–12 was associated with an increased risk of child ADHD (both measures). In conclusion, insufficient maternal iodine intake was associated with increased child ADHD symptom scores at eight years of age, but not with ADHD diagnosis. No reduction of risk was associated with maternal iodine supplement use. Current knowledge about the relationship between mild to moderately inadequate maternal iodine intake and/or supplemental iodine on child neurodevelopment is sparse. Using information from 77,164 mother-child pairs in the Norwegian Mother and Child Cohort Study, this study explored associations between maternal iodine intake and child attention-deficit/hyperactivity disorder (ADHD) diagnosis, registered in the Norwegian Patient Registry and maternally-reported child ADHD symptoms at eight years of age. Pregnant women reported food and supplement intakes by questionnaire in gestational week 22. In total, 1725 children (2.2%) were diagnosed with ADHD. In non-users of supplemental iodine , we found no association between iodine intake from food and risk of child ADHD diagnosis ( Iodine deficiency (ID) is among the most common micronutrient deficiencies worldwide and is recognized by the World Health Organization (WHO) as the number one cause of potentially preventable brain damage . Iodine The worldwide prevalence of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents is estimated to be in the range 6.7–7.8%, based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) . ADHD isThis paper is a follow-up of a previous publication from The Norwegian Mother and Child Cohort Study (MoBa), where we found that inadequate iodine intake in pregnancy was associated with maternally reported child language delay, behavior problems  and fine motor delay, but not with gross motor delay at three years of age, or risk of not walking unaided at 17 months of age . RegardiThe main aim of the current study was to explore the association between iodine intake from food in pregnancy (as a proxy for long-term iodine intake and status) and (i) risk of specialist-diagnosed ADHD in the child and (ii) maternal report of child ADHD symptoms at eight years of age. A second aim was to explore the associations between maternal use of iodine-containing supplements prior to and during pregnancy and the same outcome measures.This study is based on data from MoBa, a prospective population-based pregnancy cohort study, conducted by the Norwegian Institute of Public Health . Women pTo be included in this study, mothers had to have responded to a general questionnaire at around gestational week (GW) 17, and a food frequency questionnaire (FFQ) at around GW 22. Only singleton pregnancies were included. Mothers reporting the use of thyroid medication at any time during pregnancy were excluded from the study. Only participants with information on all covariates were included in the analysis because of the large sample size and low rates of missing values. FFQs with more than three blank pages or with calculated energy intakes <4.5 MJ or >20 MJ were excluded . A total of 77,164 mother-child pairs were included in this study, and for 27,945 there were data on maternally reported ADHD scores when the child was aged eight years . For theThe MoBa FFQ  was specAs reported previously , the MoBn = 1950) was 61 µg/L (interquartile range (IQR): 32–104 µg/L). In iodine supplement users (n = 988), the median UIC was 86 µg/L (IQR: 43–140 µg/L). Total iodine intake, calculated by the FFQ, correlated with spot UIC (µg/g creatinine) . An analysis of urinary iodine in spot samples from GW 18 has also been performed in a MoBa subsample comprising women with singleton deliveries . MedianIodine intake from supplements was categorized into three groups , and the timing of initiation of iodine containing supplements up to GW 22 was divided in four categories .We obtained information about children’s ADHD diagnoses from the Norwegian Patient Registry (NPR) . From 20In an international meta-study, prevalence estimates were 4.1% lower using the ICD-10 than the DSM-IV criteria . HKD reqr = 0.53; p < 0.001). There was high agreement between maternally reported ADHD scores at eight years of age and registered ADHD diagnosis, and the median score was +2.4 SD  in children with ADHD diagnoses.Child ADHD symptoms were assessed in the eight-year-old questionnaire from MoBa on a four-point Likert scale  covering inattention problems (nine items) and hyperactivity/impulsivity (nine items) from the ADHD Rating Scale . Mean scn-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from food and dietary supplements, were calculated, based on the FFQ. Information on smoking in pregnancy was obtained from questionnaire 1 and, if available, questionnaires 3 (GW 30) and 4 (child’s age: six months) for three categories: no reported smoking in pregnancy, reported occasional smoking or stopped smoking before GW 12, and daily smoking at any time in pregnancy and had not stopped smoking before GW 12. A predefined set of covariates were included in the analysis, based on previous knowledge and a theoretic causal diagram . VariablOther potential covariates were explored, but not included in the final analysis, since they had no/only negligible effects on the estimates of interest—maternal intake of alcohol (g/day), year of birth, marital status, paternal education, parents’ incomes, bilingual parent(s) (mother tongue other than Norwegian: yes/no), and maternal chronic illness .The MoBa was conducted according to the guidelines laid down in the Declaration of Helsinki and written informed consent was obtained from all participants. MoBa has obtained a license from the Norwegian Data Inspectorate. The current study was approved by The Regional Committee for Medical Research Ethics South East Norway 2013/594. p-value < 0.05 was considered statistically significant. The association between iodine intake and risk of ADHD diagnoses was explored with Cox proportional hazards regression. Associations to maternally reported ADHD symptoms at eight years of age were modelled by generalized linear models, with gamma family and log link functions. All models were adjusted for random effects of sibling clusters, since some mothers participated with more than one pregnancy. Results are reported as hazard ratios (HR) for ADHD diagnoses and standardized betas for ADHD symptom scores and include robust 95% confidence intervals (CI). A To isolate the effect of long term iodine intake, we performed analyses on associations between iodine intake from food and ADHD outcomes, restricted to participants who had not reported the use of supplemental iodine in the FFQ. We examined a potential nonlinear dose-response relationship between iodine intake from food and ADHD diagnosis, by modelling iodine intake using restricted cubic splines with four knots . P-values are reported for overall associations between exposure and outcomes, by testing the coefficients of all spline transformations equal to zero. The tests for non-linearity were performed by testing the coefficients of the second and third spline transformations equal to zero. Potential interactions were explored by testing all interaction coefficients equal to zero. Graphs and tabular results were calculated based on the spline models. All regression models (including crude models) were adjusted for energy intake  to control for measurement error in calculated iodine intake. Adjusted models also included the following baseline maternal and family characteristics based on a causal diagram: maternal age, education, parity, pre-pregnancy BMI (including BMI squared), fiber intake, and smoking in pregnancy. Child sex and birth season were also included in models with continuous outcome variables, since they are important predictors of ADHD. Possible interaction effects were explored for maternal BMI, age, smoking, child sex and parity. The reference level of iodine intake was set at 160 µg/day, the estimated average requirement (EAR) for iodine during pregnancy by the Institute of Medicine . P-valueWe also explored associations between iodine intake from food and ADHD outcome with iodine intake categorized (six categories), and the results were in agreement with results from the flexible spline models (results not included). The impact of dosage of iodine from supplements was explored by including interaction terms between iodine from supplements  and iodine from food (in two categories: less than the EAR (<160) and above (≥160 µg/day)). The models were adjusted with the same covariates as described above, but in addition, maternal folic acid supplement within the interval from 4 weeks beforehand to 8 weeks after conception and total EPA/DHA intake were included in the adjusted models. The impact of the timing of introduction of iodine-containing supplements  was explored in participants who had reported an intake of 1–200 µg/day of iodine from supplements in the FFQ, and who had also reported timing of use in the general questionnaires. Timing was explored in the same way as dosage, including an interaction term with iodine from food (above/below the EAR) and adjusting for the same covariates.Additionally, we performed matched control analyses to further assess the potential causal effects of iodine supplement use (both for dosage and timing). Since supplemental iodine was not generally recommended for pregnant women in Norway at the time, we restricted the control group to participants who had reported the use of supplemental vitamins and minerals other than the recommended ). This was possible since some multi-supplements contained iodine whereas others did not. More comparable controls enabled us to control for the health-seeking behavior of taking an additional supplement as a precaution, and, to some extent, to control for confounding by other nutrients in the multi-supplements.Statistical analyses were performed using STATA software . Including the package xblc for calculating tabular estimates based on the flexible spline models . n = 77,164) was 9.9 years in December 2015 (range: 6.4–13.8 years). The calculated iodine intake from food (not supplements) in the first half of pregnancy ranged from 9 to 792 µg/day  and 74% had an estimated intake from food lower than the EAR in pregnancy (160 µg/day). Supplemental iodine was reported by 31% of the pregnant women . ADHD diagnosis was registered in 1725 children (2.2%) by December 2015, and the median age at diagnosis was 8.2 years . The median age of all children in our MoBa sample , but iodine intake from food was also related to the calculated total energy intake  and to other nutrients and foods . Iodine intake from food did not differ between iodine supplement users and non-users .The maternal and child characteristics by iodine intake from food and supplements are shown in nd foods . Iodine p overall = 0.001) , and it did not reach statistical significance for the hyperactivity subscale . Tabular results from unadjusted and adjusted analyses are provided in Associations between maternal iodine intake from food and child ADHD are illustrated in = 0.001) , but not= 0.001) . The negNo significant interaction effects were detected for iodine with the covariates, BMI, education, parity, smoking, or child sex. The associations between maternal iodine intake from food and ADHD outcomes by child sex are presented in Supplemental iodine originated almost exclusively from multi-nutrient supplements, and only nine mothers reported use of supplements only containing iodine. Among iodine supplement users who reported taking up to 200 µg supplemental iodine per day in the FFQ, 64% also gave information on timing of use in the general questionnaires. Of these mothers, 39% reported their first use at 0–26 weeks before pregnancy, 29% in GW 0–12 and 32% in GW 13 or later. There was no data on the dosage or frequency of use before pregnancy, only information on any use (yes or no) in the given time period.The potential impact of iodine from supplements was explored in two groups by maternal iodine intake from food (less than or above the EAR of iodine from food) . p = 0.053) and a 0.06 SD higher average score on ADHD symptoms at eight years of age   . In partThe main findings in this study were that maternal iodine intake of less than ~200 µg/day was associated with an increased risk of maternally reported child ADHD symptoms at eight years of age, but not significantly with risk of child ADHD diagnosis. Also, we found no evidence of any beneficial effect of supplemental iodine in pregnancy. On the contrary, initiating iodine supplement use within the first trimester in mothers with inadequate iodine intake from food (<EAR) was associated with both an increased risk of ADHD diagnosis and higher ADHD symptom score at eight years of age. A negative effect of iodine supplement use was also indicated for mothers with adequate iodine in their diet. Short-term use of supplemental iodine might have a different impact on thyroid function than long-term iodine intake ,33. We tp < 0.001) [We have previously reported that low maternal iodine intake from food in pregnancy (below ~200 µg/day) was related to increased scores on maternally reported child behavior problems at three years of age in a dose-response manner (< 0.001) . The cur< 0.001) . The ass< 0.001) . This co< 0.001) . Thus, wn = 2397 children) reported a higher prevalence of attention deficit syndrome (without hyperactivity) in an area with ID compared to an area without ID [Iodine status is closely linked to risks of thyroid dysfunction and thyroid autoimmunity ,38. In athout ID  (only thn = 692 mother-child pairs), van Mil et al. [In the Generation R study there have been several publications reporting associations between maternal thyroid or iodine measures and child behavior. In a sub-study  on iodine supplementation . The autJust recently, the world’s first RCT study, exploring the effect of iodine supplementation in mildly iodine deficient pregnant women (median UIC: 131 µg/L) on child neurodevelopment was published . GowachiStrengths of this study include the large sample size, prospective design, extensive collection of data, and the possibility of linking the cohort to national registries like the NPR securing minimal loss to follow up. Maternally reported child ADHD symptoms provided an alternative, continuous outcome measure, strengthening the potential of identifying risks of ADHD.The considerable variation in iodine intake between mothers and the high prevalence of low intake make MoBa ideal for exploring maternal iodine intake as an exposure. In Norway, tap water and iodized salt contribute only negligible amounts of iodine and there are only few food sources of iodine. A dietary survey method is thus suitable for estimating iodine intake at an individual level, as was previously documented in a validation study in MoBa . HowThere were no substantial differences in maternal age, BMI, parity, or socioeconomic status indicators, either by maternal iodine intake or by iodine supplement use. This might be explained by a very low awareness of iodine among pregnant women in Norway , and no Some multi-supplements reported by the MoBa mothers contained iodine, whereas others did not. This allowed us to apply a quasi-experimental design with matched controls, which strengthened the evidence for a causal link. Weaknesses included the observational design, meaning that we cannot rule out the possibility of residual confounding. For example, heritable psychological traits are associated with medication use during pregnancy  . PassiveThis study adds supporting evidence that insufficient maternal iodine intake might be a risk factor for offspring ADHD. Our analyses also indicate an increase in the risk of ADHD in children of mothers using iodine-containing supplements, and this is alarming given the high rate of supplement use in many countries. The current recommendation from the WHO is to promote iodine supplements in areas of insufficient iodine intake for women of childbearing age and in pregnancy and lactation . The resThis study showed that low maternal iodine intake during pregnancy was associated with increased ADHD symptom score at eight years of age, but not with the risk of child ADHD diagnosis. There was no indication of any beneficial effects of maternal use of supplemental iodine on child ADHD, and initiating iodine supplement use in the first trimester was associated with an increased risk.


Sasa albo‐marginata, has been reported to suppress significantly human cytomegalovirus (HCMV) replication in human embryonic lung (HEL) fibroblast cells. However, the target protein of tricin remains unclear. This study focused on the anti‐HCMV activity of tricin in terms of its binding affinity to cyclin‐dependent kinase 9 (CDK9). A molecular docking study predicted that tricin binds well to the ATP‐binding site of CDK9. Experimental measurements then revealed that tricin inhibits the kinase activity of CDK9 and affects the phosphorylation of the carboxy‐terminal domain of RNA polymerase II. Based on these results, we conclude that CDK9 is one of the target proteins of tricin. We also found that tricin possesses anti‐HCMV activity with no cytotoxicity against HEL cells.4′,5,7‐trihydroxy‐3′,5′‐dimethoxyflavone (tricin), derived from  We also evaluated the cellular antiviral potency of tricin and its cytotoxicity, which were compared with those of flavopiridol.In this study, we investigated whether tricin binds to CDK9 and suppresses viral RNA transcription. For this purpose, we first performed molecular docking simulations using a novel optimization algorithm called fitness learning‐based artificial bee colony with proximity stimuli (F3BLRlABCps 3) at the ATP‐binding site of CDK9, in which the AutoDock force field lABCps was set to 2 500 000.The structures of tricin and flavopiridol shown in Fig. Human embryonic lung (HEL) fibroblast cells Tricin was synthesized as described previously m Tris (pH 7.5), 20 mm MgCl2, 0.1 mg·mL−1 BSA, and 50 μm dithiothreitol] supplemented with 10 μm ATP, CDK9/CycK kinase, and PDKtide synthetic peptide as substrates, according to the manufacturer's protocol. Briefly, kinase reactions were started by adding 2 μL of the ATP/substrate  to mixtures of 1 μL of 5× concentrated drug  and 2 μL of kinase solution (containing 30 ng CDK9/CycK), incubated for 2 h at room temperature (22–25 °C), and then stopped by adding 5 μL of ADP‐Glo reagent. After incubation of the reaction mixture at room temperature for 40 min, 10 μL of kinase detection reagent was added, and then the mixture was incubated for an additional 40 min. Subsequently, the luminescence intensity was measured by a luminometer . This assay is sensitive enough to detect very low amounts of ADP (20 nm) in a linear fashion. No‐enzyme and no‐inhibitor reactions represented background luminescence (0% activity) and noninhibited kinase activity (100% activity), respectively. The percent kinase activity was calculated by (a) subtracting the averaged value of no‐enzyme reaction luminescence from that of the kinase‐containing reaction with or without inhibitor and (b) converting these net luminescence values to percent activity based on no‐inhibitor reactions, which represented 100% kinase activity.As CDK9 activation requires binding of CycT or cyclin K (CycK), we used a CDK9/CycK kinase assay in this study. Kinase activity and inhibition were measured by quantifying the amount of ADP converted from ATP during a kinase reaction by the ADP‐Glo™ kinase assay . Kinase reactions were performed in kinase reaction buffer  and cell lysates were subjected to electrophoresis on 5–15% SDS/PAGE  and transferred to polyvinylidene difluoride membranes ). The blots were blocked in TBS‐T  with 5% skim milk for 1 h and reacted with primary antibody diluted in TBS‐T plus 5% skim milk overnight at 4 °C. After washing with TBS‐T, the blots were incubated with horseradish peroxidase‐conjugated anti‐IgG  in TBS‐T plus 5% skim milk for 1 h, washed in TBS‐T, and then developed by enhanced chemiluminescence according to the manufacturer's protocol . For a loading control, after detection of the protein of interest, the membrane was stripped and reprobed with anti‐β‐actin antibody conjugated with horseradish peroxidase  according to the Amersham ECL protocol. Anti‐phospho‐Ser2 RNA pol II and anti‐phospho‐Ser5 RNA pol II antibodies, which specifically recognize the Ser2‐ and Ser5‐phosphorylated forms within the CTD of RNA pol II, respectively, were purchased from Bethyl Laboratories .Western blot analysis was performed as described previously HEL cells were grown in 24‐well plates to more than 90% confluence and infected with HCMV at around 100 PFU per well. Following 90‐min adsorption, the medium was aspirated from the wells, and fresh medium containing selected drug dilutions of tricin and flavopiridol and 0.4% of agarose was added into triplicate wells. After incubation at 37 °C for 6–8 days, the cell monolayer was fixed with 10% formalin and then stained with 0.05% crystal violet. Plaques were counted microscopically under low power. Drug effects were calculated as the percent reduction in the number of plaques in the presence of each drug concentration to the number of plaques observed in the absence of drug.To measure cytotoxic effects of tricin and flavopiridol, the CytoTox 96 assay kit (Promega Japan Inc.) was used according to the manufacturer's instructions. The CytoTox 96 assay kit quantitatively measures a cytosolic enzyme, lactate dehydrogenase (LDH), which is released upon cell lysis. A total of 10 000 cells were plated in a 96‐well tissue culture plate in triplicate, and serum‐free medium containing various concentrations of the drug was present before the cytotoxicity assays. The released LDH is able to convert the substrate tetrazolium salt into a red formazan product, which can be measured at 492 nm in a 96‐well tissue culture plate. To determine the percent cytotoxicity, the amount of LDH released by cells after drug treatment was compared and normalized with the amount of LDH released after complete cell lysis.3BLR). As a result, the lowest energy pose of flavopiridol successfully reproduced the crystal structure with a root‐mean‐square deviation (RMSD) of 0.53 Å. The docking poses with the RMSD < 1.0 Å were obtained 848 times out of 1000 runs. These results showed that the FlABCps method is applicable to this system.We first performed redocking calculations 1000 times with the crystal structure of CDK9 and flavopiridol  of tricin was evaluated to be 1.38 ± 0.83 μm, which resulted in a higher value than those of other CDK9 inhibitors 50 of flavopiridol was calculated to be 8.20 ± 2.54 nm, similar to previously published values  of 2.09 ± 0.50 μm, which showed a similar value to the CDK9 kinase inhibitory activity (1.38 ± 0.83 μm). Conversely, the EC50 of flavopiridol was 15.8 ± 3.2 nm . These results strongly suggest that the anti‐HCMV effects of tricin are also caused by the inhibition of the CDK9 kinase activity.To further investigate the anti‐HCMV effects of tricin and flavopiridol, the plaque reduction assay was performed. As shown by the black line in Fig.  nm Fig. B. This v50 value obtained by the plaque reduction assay  of 176 ± 29 nm for flavopiridol. Taking into account the EC50 value of flavopiridol (15.8 ± 3.2 nm), the selective index (SI = CC50/EC50) of flavopiridol was calculated to be 11.1, indicating low to moderate potential as an antiviral agent. From these results, we could confirm that flavopiridol possesses not only strong anti‐HCMV activity but also strong cytotoxicity. In contrast, no cytotoxic effect was observed for tricin in the present experiment; thus, tricin is considered the preferred candidate for anti‐HCMV drug development.Although flavopiridol is well known as a potent CDK inhibitor lABCps method predicted that tricin binds well to the binding site of CDK9. As X‐ray crystallographic analysis was not performed in this study, we cannot compare the predicted pose of tricin with the crystal structure. However, the predicted structure of tricin is considered to be reliable because FlABCps successfully reproduced the correct binding pose of flavopiridol with an RMSD of 0.53 Å from the crystal structure. It should be noted that redocking with crystal structure is not a trivial problem for molecular docking study −1. This value was larger by 0.52 kcal·mol−1 than the lowest binding energy obtained with FlABCps . As mentioned above, the lowest energy pose of flavopiridol was almost the same as the crystal structure (RMSD = 0.53 Å); thus, these results may indicate that a slight difference in the ligand structure  strongly influences the interactions between CDK9 and flavopiridol. Molecular docking study also predicted that the binding affinity for tricin to CDK9 is weaker than that of flavopiridol to CDK9. Despite their similar structures, the binding poses of tricin and flavopiridol showed different directions, which resulted in different binding energy values.In this study, we investigated the anti‐HCMV effect of tricin in terms of its binding affinity to CDK9. Molecular docking study with the F50 value of tricin was approximately 170‐fold higher than that of flavopiridol. Subsequently, we investigated the influence of tricin on the phosphorylation at Ser2 and Ser5 within the CTD of RNA pol II. The experimental analysis revealed that tricin inhibits the phosphorylation of both Ser2 and Ser5, and its time course profile is similar to that of flavopiridol. Flavopiridol is known to reduce the phosphorylation activity of CDK9 at Ser2 and Ser5 within the CTD of RNA pol II. Therefore, the present results strongly suggested that the reduction in the phosphorylation at Ser2 and Ser5 by tricin is attributed to the inhibition of the CDK9 kinase activity.The computational predictions were next verified experimentally by measuring the kinase inhibitory activity of tricin against CDK9, where flavopiridol was also evaluated for comparison. As predicted by the docking simulations, the experimental results clearly demonstrated that tricin inhibits the CDK9 kinase activity, while the IC50 value of tricin on the anti‐HCMV activity was shown to be comparable to the IC50 value on the CDK9 kinase inhibitory activity. These results could be interpreted that the anti‐HCMV effects of tricin are caused by the inhibition of the CDK9 kinase activity. Based on these results, we concluded that CDK9 is one of the target proteins of tricin.We also evaluated the cellular anti‐HCMV potencies of tricin and flavopiridol. Tricin was shown to have anti‐HCMV activity, although its potency was weaker than that of flavopiridol. Moreover, the ECet al. We finally measured the cytotoxicity of tricin and flavopiridol. Flavopiridol demonstrated strong cytotoxicity against HEL cells, while no cytotoxic effect was observed for tricin. Furthermore, the SI value of flavopiridol was estimated to be 11.1, which indicated that flavopiridol has low to moderate potential as an antiviral agent. Conversely, Sakai In this study, we focused on the CDK9 kinase inhibitory activity of tricin and concluded that CDK9 is one of the target proteins of tricin. On the other hand, we have also revealed that the action of tricin affects the expression of chemokines KJF and TM conceived and supervised the study; HS and TM designed experiments; KJF performed simulation studies; HS, YS, and TI performed experiments; HS, MT, and TD analyzed data; KJF and HS wrote the manuscript; TM, MT, and TD made manuscript revisions.


The 2D geometry of the graphene nanoplatelets enables a unique lamellar structure upon fuel consolidation by spark plasma sintering. The thermal conductivity along the radial direction of the sintered fuel pellets at room temperature reaches 12.7 and 19.1 wm−1K−1 at 1 wt.% and 5 wt.% loadings of the graphene nanoplatelets, respectively, representing at least 74% and 162% enhancements as compared to pure UO2 fuel pellets. Indentation testing suggests great capability of the 2D graphene nanoplatelets to deflect and pin crack propagation, drastically improving the crack propagation resistance of fuel matrix. The estimated indentation fracture toughness reaches 3.5 MPa·m1/2 by 1 wt.% loading of graphene nano-platelets, representing a 150% improvement over 1.4 MPa·m1/2 for pure UO2 fuel pellets. Isothermal annealing of the composite fuel indicates that the graphene nano-platelet is able to retain its structure and properties against reaction with UO2 matrix up to 1150 °C.Low thermal transport behavior along the radial direction of nuclear fuel pellets and pellet-cladding mechanical interaction significantly impact fuel performance and the safety of current nuclear energy systems. Here we report a new strategy of advanced fuel design in which highly thermally-conductive and mechanically-robust graphene nanoplatelets are incorporated into UO The low thermal transfer efficiency results in a large temperature gradient within the fuel pellet, high centerline temperature, and thermal stress. The fuel cladding mechanical interaction and fission product retention capability limit the lifetime of UO2 fuel pins in the reactor, presenting the great challenges for extending fuel burn-up, effective utilization of nuclear resources, and minimization of nuclear waste accumulation. Breakthrough technologies of advanced fuel designs are necessary that can greatly improve thermal-mechanical properties and thus enhanced fuel performance under both normal operation and beyond design conditions.Advanced fuels with enhanced safety margin and accident tolerance are of vital importance for the safe operation of current light water reactor fleets and the development of future advanced nuclear energy systems. The current UO1, high fissile density fuels3, and oxide fuels with additives5. Highly thermally-conductive secondary phases, such as SiC and carbon nanotubes, were incorporated into UO2 fuel pellets to increase thermal conductivity. For instance, a UO2–10 vol.% silicon carbide (SiC) composite pellet shows a 62% improvement of thermal conductivity as compared with pure UO26, and UO2-5 vol.% carbon nanotube shows 29.7% increase in thermal conductivity5. Graphene, a 2D single sheet of carbon atoms bonding in a hexagonal arrangement, has extremely high in-plane thermal conductivity (3000 W m−1 K−1)7 and mechanical stiffness (1060 GPa)8, and thus is a potential filler as the reinforced component of composite fuels to improve their thermal-mechanical properties. A theoretical study9 shows UO2-graphene composite fuels have a better performance that monolithic UO2 fuels due to the potential benefits of incorporating highly thermally-conductive graphene nano-platelet with low neutron absorption cross section.Various concepts of accident tolerance fuels (ATFs) have been proposed such as a fully ceramic microencapsulated (FCM) fuel2 composite fuel pellets with various graphene nano-platelet (hereafter referred as GNP) loadings from 1 wt.% to 5 wt.% are consolidated into dense fuel pellets by spark plasma sintering (SPS) showing a unique lamellar interconnection along in-plane direction and thus improved thermal diffusivity/conductivity along the radial direction of the fuel matrix. Incorporation of mechanically-robust graphitic nanoplatelets significantly increases the resistance of the fuel pellets against cracking propagation upon mechanical loadings and indentation. The stability of GNP upon sintering and reacting with surrounding UO2 matrix is also explored and GNP can be well preserved up to 1150 °C in a helium atmosphere.In this paper, UO2 pellets with a theoretical density (TD) of 98.36% (10.79 g/cc) were prepared by SPS at 1500 °C for 5 mins under an applied pressure of 40 MPa in a vacuum atmosphere from as procured powder  diffraction peak (2θ) shifts from 28.45° of the starting powder to 28.22° of the sintered pellets. These results indicate the capability of SPS graphite dies to in-situ reduce the hyper-stoichiometric starting powders to a lower degree of oxygen enrichment during sintering. Calculation using Braggs’ law from peaks from 20 to 90° yields a lattice parameter of 5.473 ± 0.001 Å, closely in line with the value of 5.472 ± 0.009 Å reported in the literature for stoichiometric UO212, and indicates the pellet sintered by SPS at 1500 °C for 5 mins is very close to stoichiometric UO2. Hyper-stoichiometric UO2 powder was claimed to be reduced by graphite dies during SPS process11, attributing to the reduction of U5+ and U6+ into U4+ with a larger ionic radius resulting in lattice expansion and XRD peak shifts to lower angles according to Braggs’ law.XRD patterns indicate no phase change before and after SPS Fig. ; however15 to pin atomic diffusion and grain boundary migration during sintering and thus reduces physical density and average grain size of the sintering pellets. Figure 2 composite fuel pellets with different GNP loadings  upon consolidation by SPS at 1600 °C for 8 mins . For 1G-1600-8 pellets, the physical density  but with a more evident laminated microstructure and more connection of GNP along radial direction , indicating that the structural integrity of GNP is well preserved in the composite fuel pellets upon SPS densification process16. The unique laminated structure and well-preserved GNP suggest the possibility of increasing the in-plane thermal conductivity of sintered composite fuel pellets. To minimize the influence of thermal transport in across plane direction on in-plane thermal diffusivity measurements, we conducted the measurement on polished thin slices with various thicknesses using an in-plane holder17  approaching very closely to the value measured at cross-plane direction  and literature reported values19. At this thickness, the thermal conductivity of the UO2-5G pellets is 13.94 W/M·K, ~90% higher than pure UO2.Raman spectrum Fig.  shows a see Fig. . For exa2 pellets due to its brittle nature. In contrast, the UO2-GNP composite fuel pellets display greatly-enhanced resistance against mechanical polishing-induced cracks, indicating the superior ductile character of composite fuel pellets. At the thickness of 75 µm, the sample length (5 mm) for heat transport along the in-plane direction is 66 times of the sample thickness, and an in-plane thermal conductivity approaching to the true value can be obtained. The in-plane thermal conductivities of UO2-1G and UO2-5G pellets along the radial direction are 12.72 and 19.09 W/m·K, respectively, representing over ~74% and 162% improvements of thermal conductivity, respectively, as compared to pure bulk UO2. Note that the true in-plane thermal conductivities for the composite fuel pellets could be even higher since the thermal diffusivity measurement may still be affected by the temperature gradient across-plane through the thickness (75 microns). Additionally, the layered structure  and GNP layers (~3 µm). For more accurate measurement of the true in-plane thermal diffusivity of the composite fuel pellets, it is better to polish the samples down to ~20 µm thick containing only one layer of GNP at the center, which is difficult to achieve a proper geometry for laser flash measurement with a uniform thickness.Further thickness reduction by mechanical polishing leads to the fragmentation of the pure UOure Fig.  has a al2 pellets is 1.4 ± 0.2 MPa·m1/2, which matches very well with previously reported values23  is crucial for improving the reactor operation safety margin and accident tolerance. Oxide fuels experience FCMI due to volumetric swelling of the fuel pellets upon burning and incorporation of the fission products. The FCMI exerts enormous stress on the cladding tubes, leading to the high temperature creep and perforation of cladding and eventually failure of fuel rods. With increasing graphene loadings, the hardness of the composite fuel pellets decreases drastically Fig. , implyin2 composite fuel pellets also shows excellent resistance to crack generation and propagation as compared with the pure UO2 pellets. Indentation test was performed on the pure UO2  at various temperature ranges from 1000 °C to 1600 °C were conducted in a helium atmosphere to thermally simulate in-pile working condition. After thermal annealing, Raman spectrum . This finding implies structural stability of UO2-graphene composite fuel pellets can be further improved by prolonging the sintering duration and improving graphene crystallinity.The structural integrity of GNP in the composite fuel pellets was also investigated by post-sintering thermal treatment. As an allotropy of carbonaceous materials, graphene may react with oxide fuels to form UC and release CO, degrading their performance of the composite fuel pellets as a potential fuel candidate. Previous studies indicated that pre-compacted high-density UOrum Fig.  shows un30. Among them, the UO2-GNP composite fuel form prepared in this study shows the greatest promise with a simultaneously improved thermal conductivity and fracture toughness at a minimum loading of GNP . A recent study9 of neutronics and fuel performance modeling using MARS-KS reported that the UO2/graphene composite fuel is capable of lowering the fuel centerline temperature from 2100 k to 1700 K, due to a 33.26% enhancement of thermal conductivity from 10 vol.% graphene. Given the significant improvement (74% to 162%) on thermal conductivity, a significant reduction of center line temperature is expected, enabling stable 2D graphene nanoplatelets in the composite fuel. The greatly enhanced thermal-mechanical properties underscore the innovative concept of fuel design using highly thermally-conductive and mechanically robust 2D graphene as reinforced agents of composite fuels to improve fuel performance and accident tolerance. On the other hand, vigorous in-pile testing under relevant reactor conditions is needed to validate fuel performance of the GNP-UO2 composite fuels and quantify the new fuel forms for potential applications.Table 2-GNP composites were developed by SPS, in which highly thermally-conductive and mechanically-strong graphene nanoplatelets were used as fillers to improve the thermal-mechanical properties and accident tolerance of nuclear fuels. A unique lamellar structure was obtained with the 2D graphene nanosheets aligned along the radial direction of the sintered fuel pellets. A 162% improvement of thermal conductivity in the radial direction (in-plane) is achieved for the UO2-5 wt.% GNP composite fuel sintered at 1600 °C for 20 mins under a uniaxial pressure of 40 MPa. Furthermore, composite fuel pellets show greatly-enhanced capability to resist crack propagation. GNP within the as sintered UO2-5 wt.% graphene composite fuel pellet is thermally stable up to 1150 °C in helium atmosphere for 10 hrs. Due to the greatly enhanced thermal transport along the radial direction and the capability against crack propagation, the UO2-GNP composite fuel may show great potentials as a candidate to reduce the center line temperature, enhance safety margin of the fuel system, minimize FCMI and thus significantly improve fuel performance.UO31. Pure UO2 powders as shown in Fig. 2 crystallites. UO2-GNP powder mixtures were pre-processed by high energy ball milling (HEBM)  thorugh a half hour dry milling at a speed of 500 rpm using 10 mm WC balls. Sintering of the composite fuel pellets . Carl Xeiss Supra  field emission Scanning electron microscopy (SEM) was used to characterize microstructure features of the sintered pellets, mainly UO2 grain size and GNPs distribution.Phase composition and crystallinity of the sintered pellets were investigated by X-ray diffraction using a Panalytical X’ Pert  diffractometer . Both surfaces of the polished pellets are coated with graphite spray before the test to eliminate the influence of infrared signal reflection. The measurement was conducted in argon inert atmosphere at a flow rate of 150 ml/min. Half time for temperature raise was restricted to be shorter than 200 ms. Cape-Lehman + pulse correction was used to fit the signal – time curve to derive thermal diffusivity values. Thermal conductivity can be calculated as the product of density, thermal diffusivity, and specific thermal capacity. The densities of the sintered fuel pellets are measured on a scale system based on Archimedes principle at room temperature. The specific heat capacities of pristine UO2, UO2-1G, and UO2-5G pellets are calculated based on the rule of mixture. A value of 0.237 J/g·K is used for UO235; while 0.711 J/g·K, the value for graphite, is used for GNP since the values for the two carbon materials are identical above 100 K36.Thermal diffusivity of the sintered pellets was measured by a laser flash apparatus . For cross-plane measurement, a 8 mm square sample was cut from the sintered pellet along the in-plane direction by a low-speed diamond saw and grinded and polished down to ~0.5 mm thick. For in-plane measurement, samples were loaded into a special sample holder37:KIC is estimated fracture toughness; H is measured hardness; E is the elastic modulus of UO2 with a value of 220 GPa38, P is the applied loading used to initiate the cracking which is 1 Kg; and c is measured crack length from the center of indent produced by a 15 s holding at the peak loading of 1 Kg.Mechanical properties, including hardness and fracture toughness, of sintered fuel pellet was investigated by Vickers microhardness indentation technique (LECO 400 FT) on polished sample surface with final step polishing using 0.5 μm diamond film. Hardness values were obtained by using small loading of 100 g for 10 s holding at the peak value. Fracture toughness was estimated by typical cracking method using the following equationPost-sintering structural thermal stability of the composite fuel pellets was evaluated by annealing the sintered pellets at various temperatures  in helium inert atmosphere for 10 hours. Raman spectrum  with 532 nm laser source was utilized to study structural integrity of GNPs at room temperature after thermal annealing.Supplementary information


Objective: To systematically review, synthesize, and appraise available evidence, connecting adult ADHD with somatic disease. Method: Embase, Psychinfo, and Medline databases were searched for studies published from 1994 to 2015 addressing adult ADHD and somatic comorbidity. Somatic conditions were classified according to International Classification of Diseases (ICD-10) codes. Levels of evidence were graded as inconclusive, tentative, or well documented. Results: Most of the 126 studies included in the qualitative synthesis were small and of modest quality. Obesity, sleep disorders, and asthma were well-documented comorbidities in adult ADHD. Tentative evidence was found for an association between adult ADHD and migraine and celiac disease. In a large health registry study, cardiovascular disease was not associated with adult ADHD. Conclusion: There are few large systematic studies using standardized diagnostic criteria evaluating adult ADHD and somatic comorbidities. Significant associations are found between adult ADHD and several somatic diseases, and these are important to consider when assessing and treating either adult ADHD or the somatic diseases. ADHD is a common neuropsychiatric disorder defined by a persistent pattern of inattention and/or hyperactivity/impulsivity that interferes with functioning or development . The firIn addition to the core clinical symptoms of ADHD, psychiatric and non-psychiatric coexisting problems and clinical conditions have been described in ADHD patients . In partDiagnostic and Statistical Manual of Mental Disorders . Reviews are omitted from this table (Supplementary 4 for list). Some additional studies not fulfilling the inclusion criteria have been mentioned as part of the discussion.All the 126 studies, both the individual studies and reviews, are referred to in the text. Sources of bias in the 98 individual studies were considered to be mainly related to study design, the selection of participants, the size of the study, and the methods used to define ADHD and the comorbid disorders. All these characteristics were therefore assessed and are tabulated in a supplementary table (Supplementary 2), different protocols have been used to classify individuals as having adult ADHD, that is, either (a) adult ADHD clinically diagnosed, included the use of semi-structured interviews; (b) ADHD medication used as a proxy for ADHD diagnosis; (c) symptoms of ADHD measured by a validated ADHD Symptom Rating scale; (d) information on ADHD cases from clinical databases. The properties and utility of some adult ADHD instruments have been reviewed (Supplementary 3.Studies focusing on the comorbidity between somatic disease and ADHD in adults (i.e. 18 years or older) were included. ADHD was defined according to ICD or DSM criteria (ICD-9/ICD-10/DSM-III/DSM-IV/DSM-5). As indicated in a reviewed  and are Supplementary 2.For all studies, the reported diagnoses of somatic disease/comorbidity were fit into broad disease categories as defined in the ICD-10. In the cited studies, these diagnoses were obtained either after clinical evaluation or from self-reports. Due to the large number of somatic comorbidities studied and the different protocols involved, it was not feasible to systematically describe the inclusion criteria for each of the individual somatic comorbidities, but an overview of how the somatic diseases are defined, is summarized in Supplementary 3.Instruments used for ADHD assessment and the most commonly used methods to assess for comorbid disorders described in the included studies are briefly described and listed in only children and adolescents, (c) publications not subject to peer review, (d) non-English papers, (e) single case studies, (f) studies describing only psychiatric comorbidities as classified in ICD-10 Chapter V: Mental and behavioral disorders, and (g) pharmacological trials, for example, focusing on specific treatment options and not on the comorbid disorder itself. We also excluded studies on traumatic incidents, as we consider these to be outside our main focus which is somatic diseases comorbid with adult ADHD.The following exclusion criteria were applied: (a) studies not including ADHD as described under inclusion criteria, (b) studies including Based on available evidence, the 98 individual studies were classified into three categories . CategorThe somatic diseases included in the present review have been broadly grouped using ICD-10 codes, although this classification in some instances may be arbitrary (e.g. classifications of sleep problems), due to the application of various diagnostic criteria.Supplement 3.The Adult ADHD Self-Report Scale (ASRS) was developed in conjunction with the World Health Organization and is designed to measure current ADHD symptoms. A high symptom score on ASRS is not sufficient to clinically diagnose ADHD in adults but is frequently used in research literature to define study populations with possible ADHD . The Wen2 is defined as underweight, 18.5 to <25 kg/m2 is defined as normal, 25.0 to <30 kg/m2 is defined as overweight, and a BMI of ≥30 kg/m2 is defined as obese (Supplement 3.Body mass index (BMI) is defined as weight in kilograms divided by height in meters squared. In adults, <18.5 kg/mas obese . BMI is as obese . For addSupplement 3.Polysomnography is used to record several physiologic parameters relevant to sleep, such as electroencephalography (EEG), electrooculography (EOG), electrocardiography (ECG), chin- and anterio tibialis electromyography (EMG), respiratory effort, airflow, and oximetry . PolysomA range of different medical conditions have been studied in connection with ADHD in adults, as shown in The diagnostic protocols and quality of the clinical assessments of ADHD varied between studies, as was the case for the somatic/medical comorbid conditions. However, for the purpose of this literature study, we did not consider it appropriate to limit this overview to a specific diagnostic protocol or classification system. Thus, the cited prevalences are not directly comparable.ADHD comorbidity with sleep disorders or obesity has previously been reviewed. However, for the majority of conditions mentioned, the differences in research designs, the limited number of cases, and the fact that most conditions were only described in few studies made it unfeasible to perform meaningful meta-analyses of prevalences.n = 31,752) to non-ADHD , adults with ADHD had more physical comorbidities and were more likely to use non-psychiatric health care compared with controls , 23 of the participants were clinically diagnosed with ADHD  compared with 54 age- and race-matched controls  and community controls (n = 675), the prevalence of migraine was higher in the patient group compared with the controls   . The difADHD and ADHD symptoms in adults are related to a variety of sleep problems and sleep-related disturbances, both in clinical and non-clinical samples . Fisher Excessive daytime sleepiness affects 37% of adults with ADHD , and appStudies investigating the association between ADHD and comorbid sleep disorders with respect to ADHD subtypes show diverging results. Both inattentive and hyperactive-impulsive ADHD symptoms have been associated with delayed sleep timing . In a stThe severity of sleep problems is positively correlated with the number of ADHD symptoms, both among ADHD patients and in the general population , also whInsomnia implies dissatisfaction with sleep quantity or quality due to difficulty initiating sleep, maintaining sleep or early-morning awakenings. The symptoms impair daily functioning and affect about 6% to 12% of the adult population when ascertained according to formal diagnostic systems . InsomniDelayed sleep phase syndrome implies a disturbance in the normal circadian rhythm. It is characterized by a preference for late sleep and late rising, with sleep-onset insomnia when trying to get to sleep early and high activity in the late evening/night. The prevalence in the adult general population is estimated at 0.13% to 3.1% . In a DuCentral hypersomnias such as idiopathic hypersomnia (G47.1) and narcolepsy (G47.4) cause excessive daytime sleepiness not caused by disturbances in nocturnal sleep or circadian rhythm. In a study including 74 patients with narcolepsy (G47.4) or idiopathic hypersomnia (G47.1), 19% of the affected patients fulfilled the criteria for adult ADHD when using self-report measures . The oveSleep-disordered breathing includes a spectrum of sleep-related abnormalities such as upper airway resistance syndrome (G47.8) and obstructive sleep hypopnea syndrome (G47.3), with symptoms such as snoring, episodes of breathing cessation during sleep, and excessive daytime sleepiness. Approximately 13% of men and 6% of women suffer from moderate to severe sleep-disordered breathing . Of 78 sIn the disorder called periodic limb movements during sleep, contractions of muscles during sleep causes periodic episodes of repetitive limb movements. Unmedicated patients with ADHD show increased periodic limb movements during sleep compared with controls .Sleep problems are present in unmedicated adults with ADHD, but stimulant treatment is also associated with dysregulation of sleep. Common initial side effect of stimulant medication is insomnia or delayed sleep-onset latency . Atomoxen = 39; with non-stimulants, n = 15 and with no medication, n = 26), showed significantly more sleep disturbance and prolonged sleep latency compared with controls (n = 25). This result indicated that medical treatment, including stimulant treatment, did not account for the sleep quality problems in the adult ADHD group  experienced sleep improvement independent of receiving stimulant treatment or placebo , Alzheimer’s disease (n = 251), and sex-, age-, and education-matched controls (n = 149), previous symptoms of adult ADHD were associated with risk of Lewy body dementia  below the mean; however, there was no correlation between IQ and ADHD in the RTH patients.RTH usually involves mutations in the thyroid hormone receptor β gene and is often transmitted as an autosomal dominant trait. Classical features include ADHD, tachycardia, and growth delay. p ≤ .0001; Hypothyroidism is an endocrine disorder in which the thyroid gland does not produce enough thyroid hormone, leading to a large range of symptoms, including weight gain, fatigue, and poor ability to tolerate cold. In the previously mentioned study by Hodgkins et al., investigating U.S. health care claims for 2006 , hypothyroidism was significantly more common in adults with ADHD compared with those without  and controls (n = 208) found no difference in self-reported diabetes between the individuals with ADHD and controls (n = 98) and controls (n = 100) showed no significant differences in the number of self-reported diabetes  was significantly higher in the non-ADHD group compared with the ADHD group in the above-mentioned study investigating U.S. health care claims , although it varies considerably over different continents . In theiMSUD is an inborn error of metabolism, with clinical features including neuropsychiatric disturbances and neurologic deterioration. Possible increased risk of cardiovascular events due to stimulant treatment of ADHD is an important clinical issue. Long-term (≥12 months) stimulant treatment is associated with increased heart rate and increased blood pressure, but no evidence has so far indicated elevated risk of serious cardiovascular events . AlthougMage = 71.6) adults with ADHD (n = 23) and controls (n = 208) found no difference in self-reported hypertension and cardiovascular disease between the ADHD individuals and controls (n = 98) and controls (n = 100) showed no significant difference in the number of self-reported heart attacks  reported a significantly increased frequency of self-reported cardiovascular disease among adults with ADHD compared with controls . In contcontrols . In linecontrols . Further attacks .n = 5,811; ICD-9-CM diagnosis), patients with tic disorder, patients with comorbid ADHD and tic disorder (n = 349), and age/gender-matched controls were retrieved , and found that 23 patients (20.7%) had a learning disability (LD) and/or ADHD, compared with 10.5% in a control group without CD, recruited from the same pediatric gastroenterological clinic , and found that 10 of the 67 patients were positive for CD , defined by the presence of CD-specific antibodies (antigliadine and antiendomysium) in blood serum. A gluten-free diet of at least 6 months was associated with improvement of ADHD symptoms also in this patient sample  investigated psychiatric comorbidity in patients with AA and found no association with AA and adult ADHD , more frequently than controls without ADHD . Stray an = 23) and controls (n = 208), no difference in self-reported rheumatoid arthritis (ICD-10: M05-M06) was found between the ADHD patients and controls (In the Dutch study including older adults with ADHD (controls .n = 117) had more ADHD symptoms than healthy age- and sex-matched controls ; however, SLE patients had more clinically significant items in the inattention domain of the ASRS than the controls (p = .006), especially if they had previous cerebral involvement (p = .004). Anxiety and depressive symptoms correlated with ADHD symptoms.SLE (ICD-10: M32) is an autoimmune connective tissue disorder where many internal organs in the body, as well as the nervous system, may be affected. Neuropsychiatric symptoms are common, as described in a systematic review by Meszaros and coauthors in 2012 . In a re n = 64; . ADHD syN-acetylcysteine (NAC) has been reported to improve psychiatric symptoms in various disorders . In a raStudies focusing on the comorbidity between adult ADHD and FMS are few, small, and still exploratory in nature. In a sample of 201 women with FMS, 32.3% fulfilled criteria of childhood ADHD, compared with 2.5% in an aged-matched control group of healthy women .Based on clinical reports of adult ADHD with co-occurring fibromyalgic complaints, who experienced relief of their complaints after medication for ADHD, Krause et al. conducted a German pilot study to investigate the comorbidity between ADHD and FMS. Twelve patients with FMS were compared with 12 patients with pain of other origin. The FMS patients had significantly higher symptom scores of ADHD (both past and present) than the other pain patients .In a Dutch study including 44 patients with FMS, 11 (25%) of the patients met the criteria for ADHD after being clinically interviewed .LCPD is a disease which leads to deformation of the femoral head, is diagnosed in children, and is associated with early hip dysfunction and osteoarthritis of the hip. Hailer and coauthors studied health-related quality of life, physical activity, and behavior patterns in 116 adult patients with LCPD, who had been treated at Uppsala University Hospital between 1978 and 1995 . The patThis is a heterogeneous disease entity where various organ systems are affected, either as isolated anomalies with largely unknown etiology occurring sporadically or as multiple anomalies which may or may not be part of known syndromes or associations. The anomalies may be associated with environmental exposures or have well-defined genetic causes. In all instances, ADHD symptoms may be an important feature of the condition, for some genetic syndromes even the presenting feature. If all the clinical criteria of ADHD are fulfilled, it is recommended to separately diagnose this as ADHD, irrespective of its association with other well defined and perhaps underlying illnesses . Most ofTuberous sclerosis (ICD-10: Q85.1) is an autosomal dominant genetic syndrome associated with neuropsychiatric manifestations such as mental retardation, autism spectrum disorders (ASD), and ADHD  is among the most studied genetic syndromes in psychiatry. Whereas high rates of ADHD have been reported in children, psychotic disorders may be the most prominent psychiatric disorders in adulthood (Mage [SD] = 11.1 [6.9]), and this group also had a significantly greater prevalence of ADHD among their first-degree relatives. The authors concluded that ADHD in VCFS may have a genetic contribution, and that the VCFS-related developmental factors might play a lesser role.dulthood ; howeverdulthood . The clidulthood . ADHD wadulthood . Twenty-trisomy 21  when compared with a similar control group of individuals with intellectual disability  is a very rare genetic disorder usually caused by de novo mutations. In their study of 69 CdLS patients, As opposed to the mentioned chromosomal aberrations, only hyperactivity symptoms associated with ADHD were found more frequently in sability . CorneliRegarding ADHD and comorbid anatomical anomalies that are not part of a well-known syndrome, there are few studies in adults. A large registry-based study from 2012 found an increased risk of ADHD persisting to adulthood in individuals born with oral clefts  and two smaller studies showed no association between adult ADHD and diseases of the circulatory system (In our systematic review, we have included 126 papers over the past 20 years mentioning adult ADHD in connection with somatic disease. We found a consistent association between adult ADHD and increased risk of obesity, sleep disorders, and asthma. Associations were also consistent for migraine and celiac disease. Less robust associations have been reported for a number of different disorders such as enuresis, irritable bowel syndrome, restless legs, epilepsy, chronic fatigue syndrome, fibromyalgic syndrome, systemic lupus erythematosus and atopic dermatitis. One large population-based study (adult ADHD: y system . In contWe noticed several methodological limitations in the evaluated studies. Most studies were small. Many studies compared a case group with a control/comparison group. However, while the case group might be well defined and characterized, the control group was often less well defined, often based on self-selection and from a different source population than the cases. Information on recruitment and participation rates was sparse, and selection bias was difficult to assess. While the diagnosis of ADHD was often based on clinical interviews or validated self-report questionnaires, the comorbid conditions were sometimes based entirely on a single question to the individual about the condition being present or not. An example is the study by Bijlenga et al., which includes 202 clinically diagnosed ADHD patients and 189 controls non-randomly recruited from students and their acquaintances, and self-selected by posters in libraries and municipal buildings . The numThe larger studies were often based entirely on self-report questionnaires or on registries and databases. Large population-based disease registries may be more suitable to study comorbidity across many different diagnoses, in particular for less prevalent conditions. However, such registries can also be subject to systematic bias, depending on the diagnostic traditions in different countries  and the Supplementary 2.For details on characteristics of the individual studies with their associated sources of bias, see table in DSM-IV Axis I Disorders (SCID-I; Many studies on psychiatric comorbidity in somatic conditions have explicitly excluded “childhood” psychiatric conditions such as ADHD, as they are not included in commonly used structured psychiatric diagnostic interviews, such as The Structured Clinical Interview for  SCID-I;  or The M SCID-I; . This syAs mentioned in many of the cited articles, there are many reasons to systematically search for psychiatric disorders in somatic conditions and to screen for somatic diseases among psychiatric patients. For the individual patient, it is important to detect potentially treatable somatic diseases masking as a psychiatric disorder. The utility of this approach was illustrated in a recent report, showing that metabolic screening of individuals with psychosis revealed treatable metabolic disorders in a significant number of cases .ADHD is a prevalent condition, and patients with many different somatic conditions may exhibit ADHD symptoms either as a comorbid condition or as part of the somatic disease. Likewise, the lifestyle of ADHD patients may make them more vulnerable to certain somatic diseases. Thus, the identification of other treatable and possibly underlying conditions should be addressed in every diagnostic workup.The presence of a known co-occurring somatic condition has important implications for ADHD treatment. For instance, stimulant therapy may be contraindicated or need careful monitoring in the presence of cardiac disease, hypertension, glaucoma, or liver failure . HoweverConditions classically thought to be disorders of the nervous system may also include alterations in other physiological systems, for example, involving immunological or endocrine signaling mechanisms . ClassicDifferent hypotheses regarding underlying pathophysiological mechanisms are further elaborated for some of the most commonly associated diseases.Several mechanisms may account for the reported association between ADHD and obesity. Shared neurobiological or genetic mechanisms may be common to both ADHD and obesity ; ADHD anObesity and disorders related to obesity could also create symptoms resembling ADHD symptoms, such as sleep-disordered breathing, which can lead to inattentive symptoms during the day . ADHD itThe cause of sleep problems in ADHD appears to be multifactorial and complex , and theAs for ADHD, the dopaminergic system has also been suggested as a possible factor involved in the pathophysiology of asthma, as dopaminergic receptors are present in sensory nerves in the airways, and inhaled dopamine may induce bronchodilation during asthma attacks . Other cThere is substantial evidence that dopaminergic mechanisms are involved in migraine. It is therefore possible that changes in dopaminergic systems may represent common etiological factors for ADHD and migraine .A number of shortcomings have been identified in the literature cited in this review.Different research designs have been utilized to explore the relationship between ADHD and somatic health. As each of these designs has their inherent limitations, there is a need to establish the prevalence of somatic diseases in representative samples of ADHD.In many studies, the patients were simply screened for ADHD symptoms. We need to know what proportion of these patients has the full clinical syndrome, including impairment criteria. Harmonization of diagnostic protocols should increase reliability of such data.It is suspected that many of the reported associated conditions are due to recognized or previously unknown confounders. Future research should investigate how much of the comorbidities are actually due to confounding factors, for example, that headache or sleep disorders may be confounding factors for the association between obesity and ADHD , or thatMany of the existing studies are small. To be able to reveal a true association between ADHD and comorbid somatic diseases with adequate control for potential confounders, large studies are needed. The possibilities of combining the use of population-based registries and common diagnostic protocols should be investigated.From a practical perspective, we need to know how current diagnostic and treatment algorithms should be optimized to account for coexisting conditions.Access to biomarkers from large samples of ADHD cases and its comorbid conditions will allow systematic studies of their shared pathophysiology. This information should also inform future decisions regarding diagnoses and treatment.Even for the best documented conditions, the literature was dominated by a few authors, research groups, and study populations. More research should be conducted in different geographical areas and ethnic groups.


Sotos syndrome is a congenital overgrowth disorder with an incidence of approximately 1 in 14,000. This study investigated behavioural characteristics of ASD within a large cohort of individuals with Sotos syndrome (n = 78). As measured by the Social Responsiveness Scale, second edition (SRS-2), 65 participants (83.33 %) met clinical cut-off (T-score ≥60). There was no significant gender difference in symptom severity. There was a significant effect of age, with lower scores observed in early childhood and adulthood, compared to childhood. Furthermore, individuals with Sotos syndrome appear to display a trait profile that is similar to that identified in ASD. Overall, these findings indicate that the majority of individuals with Sotos syndrome display clinically significant behavioural symptomatology associated with ASD. Autism spectrum disorder (ASD) is a developmental disorder associated with social communication impairment and restricted interests and repetitive behaviours. The disorder occurs in approximately 1 % of the population , designed to assess symptoms associated with ASD. A total score indicates severity of ASD symptomatology, with a higher score indicating greater severity. The SRS-2 has a conceptually derived two-factor structure that is consistent with the DSM-5 criteria for ASD. The factors are social communication impairment and restricted interests and repetitive behaviours. The SRS-2 has been found to be a valid measure of autistic symptomatology across cultures , school age  and adult  and the questionnaire was completed by either the parent/caregiver (n = 76), other specialist (n = 1) or spouse (n = 1) of each participant. All questionnaires were completed in English. Licensing was received by the publishers of the SRS-2 to allow online administration of the questionnaire. The study received ethical approval from the university Departmental Ethics Committee.Clinical cut-off was considered as a total T-score ≥60  = 0.93, p = .926) in total T-scores for male  and female  participants. This suggests that within the Sotos population, there are no gender differences in ASD symptom severity.In order to establish whether gender affects ASD symptom severity within the Sotos population, an independent samples F = 4.88, p = .002). Specifically, this analysis identified that the model of best fit was quadratic  = 15.98, p < .001), indicating an inverted U-shaped pattern of total T-scores. Figure In order to investigate the severity of symptoms across development, participants were categorised into 5 age groups: 2 years 6 months to 4 years 11 months (n = 16); 5 years to 9 years 11 months (n = 24); 10 years to 14 years 11 months (n = 15); 15 years to 19 years 11 months (n = 10) and 20 years and older (n = 13). A one-way ANOVA found a significant main effect of age category on total T-scores  and restricted interests and repetitive behaviours  subscales, indicating that individuals with Sotos syndrome display greater difficulty with restricted interests and repetitive behaviours, compared with social communication impairment (t(77) = 4.37, p < .001). This was a large effect (d = 0.99). This is consistent with the profile of SRS-2 scores that is found in individuals with ASD and other clinical groups  = 0.62, p = .43). There was also no significant group × subscale interaction,  = 1.40, p = .23), demonstrating that children with Sotos syndrome appear to display a very similar symptom severity and profile of behaviour to that of children with ASD  = 474.88, p < .001) as scores for the children with Sotos syndrome were considerably higher than for the unaffected siblings. A significant group × subscale interaction,  = 18.37, p < .001), indicated that the behavioural profile was also different . This indicates an important relationship between the behavioural phenotypes of Sotos syndrome and ASD.Previous research has suggested relationships between other congenital syndromes and ASD. A recent systematic review and meta-analysis reported prevalence of ASD in a number of genetic syndromes with the highest estimate of 61 % identified in Rett’s syndrome  and in adults (20+ years) when compared to children over the age of 5 years through to adolescence, in the current sample. This is an important finding as it suggests that severity of ASD symptomatology may decrease as an individual transitions into adulthood. Research investigating age-related effects of ASD symptomatology in individuals with idiopathic ASD indicates that the symptoms of ASD tend to abate, to some extent, in adolescence and young adulthood , compared with early childhood (2.5–5 years) and adulthood (20 years and older). As the majority of cases of Sotos syndrome are caused by abnormality of the NSD1 gene, our findings provide further evidence to suggest a possible genetic mechanism associated with ASD. An important clinical implication of our findings is that clinicians should screen for ASD in individuals with Sotos syndrome as there may be a number of unidentified cases of co-morbidity.


Methylphenidate (MPH), the first choice medication for attention-deficit hyperactivity disorder (ADHD), is associated with serious adverse effects like arrhythmia. Evidence on the association of ADHD with immune and oxidant-antioxidant imbalances offers potential for antioxidant and/or immunomodulatory nutritional supplements as ADHD therapy. One small randomised trial in ADHD suggests, despite various limitations, therapeutic benefit from Pycnogenol®, a herbal, polyphenol-rich extract.This phase III trial is a 10-week, randomised, double-blind, placebo and active treatment controlled multicentre trial with three parallel treatment arms to compare the effect of Pycnogenol® to MPH and placebo on the behaviour of 144 paediatric ADHD and attention-deficit disorder (ADD) patients. Evaluations of behaviour  and the Social-emotional Questionnaire (SEQ)), immunity , oxidative stress , serum zinc and neuropeptide Y level, urinary catecholamines and physical complaints  will be performed in week 10 and compared to baseline. Acceptability evaluations will be based on adherence, dropouts and reports of adverse events. Dietary habits will be taken into account.This trial takes into account comorbid behavioural and physical symptoms, as well as a broad range of innovative immune and oxidative biomarkers, expected to provide fundamental knowledge on ADHD aetiology and therapy. Research on microbiota in ADHD is novel. Moreover, the active control arm is rather unseen in research on nutritional supplements, but of great importance, as patients and parents are often concerned with the side effects of MPH.NCT02700685. Registered on 18 January 2016. EudraCT 2016-000215-32. Registered on 4 October 2016.Clinicaltrials.gov number: The online version of this article (doi:10.1186/s13063-017-1879-6) contains supplementary material, which is available to authorized users. Attention-deficit hyperactivity disorder (ADHD) is a common neurocognitive behavioural disorder with childhood onset and core symptoms of hyperactivity, impulsivity and inattention . ADHD haMethylphenidate (MPH), the first-choice medication for ADHD, is a central nervous system stimulant. It increases attentiveness and reduces hyperactivity and impulsivity by inhibition of dopamine reuptake in the striatum, without triggering its release. MPH is prescribed for chronic use to a large proportion of ADHD patients, but is linked to possible publication bias in reported efficacy –6. In adS-transferase and paraoxonase-1. These results indicate the involvement of oxidative changes and cellular immunity in ADHD [ADHD is a complex and multifactorial disorder, influenced by both genetics and the environment. Its exact pathophysiology remains, however, unclear. Dopaminergic dysfunction is involved, but also associations with immune and oxidant-antioxidant imbalances exist , 10. Var in ADHD .Still, specific immune biomarkers other than antibodies have not been systematically studied in ADHD despite growing evidence on associations in autism , 20. In Pinus pinaster) bark with a high content of polyphenolic compounds (including phenolic acids and procyanidins), Pycnogenol®, was selected for this study [Due to its antioxidant and immunomodulatory properties, a commercially available standardised extract from French maritime pine  and placebo, using the ADHD-Rating Scale (ADHD-RS) as a primary outcome measure. Secondary outcome measures are comorbid physical and psychiatric complaints (including side effects), oxidative stress, immunity, neurochemical parameters and tolerance of the intervention. Following screening and baseline assessments, 144 patients aged 6–12 years) will receive one of the three treatments for 10 weeks (see Table  years win = 60). Next to baseline and final evaluations, an extra evaluation of behaviour and physical symptoms will be conducted in week 5 by means of questionnaires. Two reminders will be sent in case questionnaires are not received within 1 week after the required date. After every blood and urine collection and when questionnaires are completed, participants will receive two movie tickets.Two visits with similar evaluations and sample collections will be conducted: at baseline and after 10 weeks. To analyse biomarkers of interest, 16 ml of venous blood will be collected at the start and the end of intervention, as well as urine. Faecal samples will be collected from participant subgroups  and Ghent (UZ Ghent) and the Hospital Network Antwerp (ZNA). With an expected inclusion rate of 30–50 patients per year , about 3 years will be required for subject recruitment. Though, as compared to inclusion rate, a ten-fold higher diagnosis rate of ADHD and ADD is expected in these centres, inclusion and exclusion criteria of the proposed trial (e.g. regarding autism or the recent intake of supplements or medication) are expected to exclude at least half of all newly diagnosed patients, while a consent rate of 30% is expected, taking into account potential reluctance regarding the use of medication or supplements, as well as ‘risk’ for placebo treatment . In addiParticipants will be randomised, stratified by trial centre, to one of the three treatment arms  by randomization.com randomisation software : patients with a body weight below 30 kg will receive 20 mg/day, those with a body weight of 30 kg or over, 30 mg/day. Treatment during the first week always contains 10 mg, increasing by 10 mg per week to limit side effectsPycnogenol®: patients with a body weight below 30 kg will receive 20 mg/day, those with a body weight of 30 kg or over, 40 mg/day, aiming at a daily dose of 1 mg/kg and taking into account formulation issues . TreatmePlacebo: contains excipients onlyPatients will receive all capsules required for the complete study at inclusion, at a dose based on their body weight :In case of adverse events, the investigator, principal caregiver and participant can decide to discontinue the trial medication/supplement. However, no dose adjustment will be performed. Using a standardised questionnaire, adverse events will be documented at weeks 5 and 10, also taking into account the patient’s medical records. Additionally, spontaneously reported adverse events will be recorded. In case of a serious adverse event, the trial code will be broken and treatment discontinued. In case 10% of participants experience a potentially related serious adverse event, the trial will be discontinued.Pycnogenol® and placebo will be produced in capsules identical to Medikinet® Retard (Medice GmbH). All treatments will be provided in identical jars, labelled with the subject’s trial number and week of intake. Compliance will be determined based on accountability of investigational products and self-reported adherence.As the primary objective is to assess the efficacy of Pycnogenol® for improving ADHD and ADD behaviour as rated by teachers compared to placebo and Medikinet® Retard, the primary outcome is the summed ADHD score of the ADHD-RS as rated by teachers Table . TeacherSummed ADHD score of the ADHD-RS, rated by parentsSummed ADHD score of the Social-emotional Questionnaire (SEQ), rated by parents and teachersScores on ADHD subscales of the ADHD-RS and SEQ, rated by parents and teachers Percentage of responders rated by parents and teachers, defined as participants with a reduction of at least 20% of their baseline summed ADHD-RS score ADHD/ADD behaviour Secondary outcomes related to ADHD/ADD behaviour are:Other objectives are to evaluate the effect of Pycnogenol® compared to placebo and MPH on comorbid psychiatric and physical complaints, antioxidant levels, oxidative damage, immunity and neurotransmitters. Other secondary outcomes are, therefore:Social behaviour problems subscale of the SEQ, rated by parents and teachers, to evaluate to what extent symptoms of ODD and CD are displayed Anxiety subscale of the SEQ, rated by parents and teachers, to evaluate symptoms of general anxiety, social anxiety and anxiety-depression Physical and sleep complaints, including various potential side effects, measured by the Physical Complaints Questionnaire (PCQ) Erythrocyte glutathione (GSH) level, the most important intracellular antioxidant, analysed by HPLC with electrochemical detection Lipid-soluble antioxidants: plasma vitamin E (α- and γ-tocopherol), vitamin A  and co-enzyme Q10, analysed by HPLC with coulometric detection –39Antioxidant enzyme activity  and total antioxidant status, analysed by Enzyme-linked ImmunoSorbent Assay (ELISA) , 40Gene expression, quantified by RT-qPCR, focusing on networks counteracting oxidative stress , XO) and stress-related proteins  , 42Serum zinc level, analysed by atomic absorption spectroscopy (AAS) Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) level, marker of oxidative deoxyribonucleic acid (DNA) damage, corrected for urinary creatinine concentration, analysed by ELISA Plasma malondialdehyde (MDA) level, marker of lipid peroxidation, analysed by HPLC with fluorescence detection 1–2, IgG1–4, IgE) by flow cytometry and ELISA, as markers of immune activation state and skewing [Plasma cytokines for monocytes (interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12, tumour necrosis factor (TNF)-α) and T-cells -γ) as well as antibody levels  like neutrophils, CD4, CD8 and B-cells and measurement of their functional responses (e.g. cytokine release) after stimulation, as a marker of immune activation state, skewing and responsivity , 46, 47Intestinal microbial composition, assessed using extreme throughput multiplexed sequencing of 16S ribosomal ribonucleic acid (RNA) gene pools polymerase chain reaction (PCR)-amplified from intestinal content samples , 49Urinary catecholamines  and their metabolites, determined by HPLC with coulometric detection Serum neuropeptide Y (NPY), analysed by ELISA The final objective is to investigate the acceptability of Pycnogenol® compared to Medikinet® Retard and placebo, based on the prevalence of side effects, treatment adherence (defined as more than 90% ingestion as scheduled) and proportion of dropouts.Dietary habits of participants, such as consumption of vegetables, chocolate, fruit, etc., will be assessed by a Food Frequency Questionnaire (FFQ) at the start and end of intervention , 53, to , which corresponds to a 20% improvement with active treatment as compared to placeboPatients improve by 0.75 standard deviation (SD) on the ADHD-RS summed ADHD score as rated by teachers if using Pycnogenol® for 10 weeks , 54, whiPower of 80%, dropout of 20%Two-sided testing, at a significance level of 0.05 with Bonferroni post-hoc testing correctionFor the estimation of the required sample size, the following assumptions were made:n = 144 in total).Based on these considerations, 48 patients per group will be necessary (α = 0.05) with post-hoc testing. Changes regarding secondary target variables will also be compared between the three groups, by one-way ANOVA with post-hoc analysis with multiple testing correction, Kruskal-Wallis, or Fisher’s exact test. Separate analyses for subgroups  will be performed. Noninferiority of Pycnogenol® as compared to Medikinet® Retard will be demonstrated when the difference in effect on ADHD-RS score is no more than 5 points [Data will be checked for outliers. Missing data will not be accounted for. The three groups will be compared with regard to baseline characteristics. A two-way analysis of variance (ANOVA) will be performed to investigate a potential interaction between treatment and weight. Change in ADHD-RS score as rated by teachers (primary outcome measure) will be compared between the three groups by means of a one-way ANOVA , ZNA  and UZ Ghent (2016/0969). The trial has been registered at ClinicalTrials.gov (NCT02700685) and EudraCT (2016-000215-32).The University of Antwerp  is the sponsor of this trial, with NH being the coordinating investigator. As principle investigators, BC, DVW and HV will be primarily responsible for patient inclusion. NH and AV are responsible for the analysis of oxidative stress and neurological biomarkers and questionnaire results, as well as data management. HS is responsible for the analysis of immune biomarkers and genetics. No Data Monitoring Committee will be set up. BC, HV, DVW, NH and AV will discuss potential issues regarding, e.g. subject recruitment.For more information, see both the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) Checklist and figure . The extract is standardised to contain 70 ± 5% procyanidins. Pharmacological studies employing in vitro, animal and/or human models have found potent antioxidant activity, anti-inflammatory actions, improvement of endothelial function, etc. . Pycnogen = 185). There have been no reports of serious adverse effects since its introduction into the European market around 1970 [Despite being the first choice medication for ADHD, MPH is associated with various adverse effects (including serious adverse events), some of them frequently occurring, including irritability, insomnia, loss of appetite and headache . Based ound 1970 . Safety und 1970 . TherefoDiagnostic and Statistical Manual of Mental Disorders (DSM), each marked out on a four-point rating scale [The ADHD-RS is validated and internationally accepted, and consists of nine inattention and nine impulsivity and hyperactivity items based on the ng scale . The ADHng scale , 54.In addition to the ADHD-RS, the SEQ is used in this trial. Though this increases the number of questions on behaviour significantly (72 questions), the SEQ is a behaviour evaluation list to assess core symptoms of social-emotional problems, including frequently occurring psychiatric comorbidities of ADHD. Besides ADHD, three other clusters of social-emotional problems are incorporated in the SEQ , with items covering the core symptoms of these clusters according to DSM. The SEQ can be used for screening, diagnosis and treatment evaluation. Items are rated on a five-point scale .The approved PCQ consists of 36 questions, of which 18 items are relevant with respect to specific physical and sleep complaints, including eight domains: (1) pain (e.g. headache), (2) unusual thirst or perspiration, (3) eczema, (4) asthma or rhinitis, (5) skin problems (e.g. blotches in the face), (6) tiredness, (7) gastrointestinal problems and (8) sleep problems. Items, including various potential adverse effects, are rated on a five-point scale at baseline and after 5 and 10 weeks . In addiThe FFQ consists of 50 questions on different food groups to be rated on a nine-point scale by parents at the start and end of the intervention, to assess baseline dietary habits and potential adaptations during the study, as well as to relate potential differential effects of Pycnogenol® to dietary polyphenol intake , 53. InsPatients and especially their parents are often worried about side effects of MPH, the standard medication for ADHD. It is, therefore, important to take into account side effects of Pycnogenol® and effects on comorbid complaints. In addition, the behavioural effects of Pycnogenol® compared to placebo, but also compared to MPH, will be investigated. This active control is rather unseen in research on nutritional supplements, but of great importance. In one previous trial, the effect of Pycnogenol® was compared to MPH and placebo. However, neither MPH nor Pycnogenol® outperformed placebo, possibly due to the short treatment period of 3 weeks .Most research on nutritional supplements or medication in ADHD predominantly assesses effects on ADHD behaviour. This trial, however, takes into account comorbid behavioural and physical symptoms, such as ODD, anxiety and side effects, as well as a broad range of innovative immune, oxidative and neurochemical biomarkers. The analysis of gene expression and biomarkers can indicate genetic effects and biological processes involved in the mechanism of action of Pycnogenol® and possibly affecting ADHD symptom expression. Research on microbiota in ADHD in itself is novel, too. Results of this project will, therefore, increase insight in ADHD aetiology and (dietary) treatment options, which is highly desired by medical staff, parents and patients.Not yet recruiting as of February 2016.