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Vanadium dioxide (VO2) is a well-known phase-changing material that goes from a semiconducting state to a metallic one at a critical temperature of 68 °C, which is the closest to room temperature (25 °C). The electrical transition is also accompanied by structural and optical changes. The optical transition upon heating-also known as thermochromism-makes VO2 a possible coating for “intelligent” windows. In this work, the relationship between the thermochromic performance of VO2 films and the surface morphology was investigated using Temperature-dependent Atomic Force Microscopy (T-AFM) in conjunction with the X-ray Diffraction technique and Scanning Electron Microscopy. In particular, VO2 films were deposited using the rf sputtering technique on Silicon and glass substrates at a substrate temperature of 300 °C, which is one of the lowest for this technique to grow the thermochromic monoclinic phase of VO2. It was found that upon heating (25–100 °C), there was a decrease in RMS roughness for all films independent from the substrate; the value of RMS roughness, however, varied depending on the substrate. Finally, the thermochromic parameters of the VO2 films were correlated with the surface morphology and appeared to be dependent on the kind of substrate used.

Background: Level of care-need (LOC) is an indicator of elderly person’s disability level and is officially used to determine the care services provided in Japan’s long-term care insurance (LTCI) system. The 2018 Japan Floods, which struck western Japan in July 2018, were the country’s second largest water disaster. This study determined the extent to which the disaster affected the LOC of victims and compared it with that of non-victims. Methods: This is a retrospective cohort study, based on the Japanese long-term care insurance claims from two months before (May 2018) to five months after the disaster (December 2018) in Hiroshima, Okayama, and Ehime prefectures, which were the most severely damaged areas in the country. A code indicating victim status, certified by a residential municipality, was used to distinguish between victims and non-victims. Those aged 64 years or younger, those who had the most severe LOC before the disaster, and those whose LOC increased even before the disaster were excluded. The primary endpoint was the augmentation of pre-disaster LOC after the disaster, which was evaluated using the survival time analysis. Age, gender, and type of care service were used as covariates. Results: Of the total 193,723 participants, 1,407 (0.7%) were certified disaster victims. Five months after the disaster, 135 (9.6%) of victims and 14,817 (7.7%) of non-victims experienced the rise of LOC. The victim group was significantly more likely to experience an augmentation of LOC than the non-victim group (adjusted hazard ratio 1.24; 95% confidence interval 1.06–1.45). Conclusions: Older people who were affected by the disaster needed more care than before and the degree of care-need increase was substantially more than non-victims. The result suggests that natural disasters generate more demand for care services among the older people, and incur more resources and cost for society than before.

Abstract Genetic and epidemiological evidence has suggested that genetic factors are important in schizophrenia, although its pathophysiology is poorly understood. This study used whole-exome sequencing to investigate potential novel schizophrenia-causing genes in a Japanese family containing several members affected by severe or treatment-resistant schizophrenia. A missense variant, chr12:132064747C>T (rs200626129, P2805L), in the E1A-binding protein P400 (EP400) gene completely segregated with schizophrenia in this family. Furthermore, numerous other EP400 mutations were identified in the targeted sequencing of a schizophrenia patient cohort. We also created two lines of Ep400 gene-edited mice, which had anxiety-like behaviours and reduced axon diameters. Our findings suggest that rs200626129 in EP400 is likely to cause schizophrenia in this Japanese family, and may lead to a better understanding and treatment of schizophrenia.

Introduction: Solutions for geographic maldistribution of physicians is challenging around the world, but primary care specialists are expected to resolve this issue. This study compares the geographic distribution of family physicians in Japan and the USA, both of which are developed countries without a major system for physician allocation by the public sector; however, the two countries differ greatly in the maturity of family medicine (ie length of its history as part of the healthcare system and the population of qualified family medicine experts). Methods: This cross-sectional comparative study used publicly available online databases for Japan in 2018 and 2017 in the USA. The municipalities in Japan and counties in the USA were divided into quintile groups according to population density. The number of family physicians per unit population in each group of areas was calculated, and was evaluated with a residual analysis. The geographic distribution of all physicians in Japan was simulated assuming that the proportion of family physicians among all physicians in Japan (0.16%) was increased to match that in the USA (11.8%). Results: Of 320 084 physicians in Japan and 899 244 in the USA, 519 (77.2%) family physicians in Japan and 105 999 (100%) in the USA were included. The distribution of family physicians in Japan was noticeably shifted to areas with the lowest population density. In contrast, family physicians in the USA were distributed equally across areas. The distribution of physicians of other specialties (general internists, pediatricians, surgeons and obstetricians/gynecologists) was shifted heavily to areas with the highest population densities in both countries. The simulation analysis showed the geographic maldistribution of the total number of physicians improved substantially if the proportion of family physicians in Japan is increased to match that in the USA. Conclusion: The distribution of family physicians is more equitable than that of other medical specialists; however, an immature family medicine system can lead to an aggregation of family physicians in rural areas. This aggregation supports equity due to the broader scope of practice required by family physicians in rural areas. In countries where family medicine has not yet matured as a specialty, provided that the equitable aggregation of family physicians in rural areas can be maintained, increasing the number of family physicians as a proportion of the total number of physicians may improve the geographic maldistribution of the total number of physicians.

Abstract Background Copy number variants (CNVs) have been reported to be associated with diseases, traits, and evolution. However, it is hard to determine which gene should have priority as a target for further functional experiments if a CNV is rare or a singleton. In this study, we attempted to overcome this issue by using two approaches: by assessing the influences of gene dosage sensitivity and gene expression sensitivity. Dosage sensitive genes derived from two-round whole-genome duplication in previous studies. In addition, we proposed a cross-sectional omics approach that utilizes open data from GTEx to assess the effect of whole-genome CNVs on gene expression. Methods Affymetrix Genome-Wide SNP Array 6.0 was used to detect CNVs by PennCNV and CNV Workshop. After quality controls for population stratification, family relationship and CNV detection, 287 patients with narcolepsy, 133 patients with essential hypersomnia, 380 patients with panic disorders, 164 patients with autism, 784 patients with Alzheimer disease and 1280 healthy individuals remained for the enrichment analysis. Results Overall, significant enrichment of dosage sensitive genes was found across patients with narcolepsy, panic disorders and autism. Particularly, significant enrichment of dosage-sensitive genes in duplications was observed across all diseases except for Alzheimer disease. For deletions, less or no enrichment of dosage-sensitive genes with deletions was seen in the patients when compared to the healthy individuals. Interestingly, significant enrichments of genes with expression sensitivity in brain were observed in patients with panic disorder and autism. While duplications presented a higher burden, deletions did not cause significant differences when compared to the healthy individuals. When we assess the effect of sensitivity to genome dosage and gene expression at the same time, the highest ratio of enrichment was observed in the group including dosage-sensitive genes and genes with expression sensitivity only in brain. In addition, shared CNV regions among the five neuropsychiatric diseases were also investigated. Conclusions This study contributed the evidence that dosage-sensitive genes are associated with CNVs among neuropsychiatric diseases. In addition, we utilized open data from GTEx to assess the effect of whole-genome CNVs on gene expression. We also investigated shared CNV region among neuropsychiatric diseases.

In the Siemens method, high-purity Si is produced by reducing SiHCl3 source gas with H2 ambient under atmospheric pressure. Since the pyrolysis of SiHCl3, which produces SiCl4 as a byproduct, occurs dominantly in the practical Siemens process, the Si yield is low (~30%). In the present study, we generated hydrogen radicals (H-radicals) at pressures greater than 1 atm using tungsten filaments and transported the H-radicals into a reactor. On the basis of the absorbance at 600 nm of WO3-glass exposed to H-radicals in the reactor, we observed that H-radicals with a density of ~1.1 × 1012 cm−3 were transported approximately 30 cm under 1 atm. When SiCl4 was supplied as a source into the reactor containing H-radicals and allowed to react at 850°C or 900°C, Si was produced more efficiently than in reactions conducted under H2 ambient. Because the H-radicals can effectively reduce SiCl4, which is a byproduct in the Siemens method, their use is expected to increase the Si yield for this method.

Purpose: Wolfram syndrome is a rare genetic disorder characterized by juvenile onset of diabetes mellitus with bilateral optic atrophy. We report a case of adult onset Wolfram syndrome with diabetes mellitus at age 22 and optic atrophy after age 40. The WFS1 gene sequence was analyzed in the patient and her father. Observations: A 46-year-old woman presented with bilateral vision loss. She had developed diabetes mellitus at age 22 and underwent bilateral cataract surgery at age 37. Visual acuity was 20/50 in the right eye and 20/200 in the left eye. The pupillary light reflex was sluggish in both eyes. Fundus examination showed bilateral optic atrophy, but there was no diabetic retinopathy. Cecocentral scotoma of both eyes was observed in Goldmann perimetry. There were no intracranial lesions on magnetic resonance imaging. Audiometry demonstrated high-frequency sensorineural hearing loss. Sequence analysis of the WFS1 gene revealed compound heterozygous mutation: c.908T>C p.L303P and c.1232_1233del, p.S411Cfs*131 in the patient and heterozygous mutation c. 908 T>C, p. L303P in her father. Conclusions and importance: The patient was diagnosed with adult-onset Wolfram syndrome with compound heterozygous mutations of the WFS1 alleles. Wolfram syndrome must be ruled out even in adult-onset diabetic patients with optic atrophy.

The aim of this review is to investigate the diagnostic accuracy or performance of contrast‐enhanced computed tomography (CT) and magnetic resonance imaging (MRI) for acute pelvic inflammatory disease (PID) in an emergency care setting. We searched for studies on the diagnostic test accuracy of contrast‐enhanced CT or MRI for women of reproductive age with acute abdominal pain using MEDLINE, Embase, Cochrane Central Register of Controlled Trials, International Clinical Trials Registry Platform, and ClinicalTrials.gov. The reference standard was gynecological examinations by gynecologists using standard diagnostic criteria with or without laparoscopy or transcervical endometrial biopsy. Two reviewers undertook screening of records, data extraction, and assessment of the risk of bias in each included study using the Quality Assessment of Diagnostic Accuracy Studies‐2 tool. A bivariate model was used for the meta‐analysis. Of 2,619 screened studies, three studies investigating contrast‐enhanced CT and one study investigating MRI were eligible, including a total 635 patients and with a median prevalence of acute PID of 29%. All of the included studies had a high risk of bias for a reference standard and had some applicability concerns. Contrast‐enhanced CT had a pooled sensitivity of 0.79 (95% confidence interval [CI], 0.52–0.93) and specificity of 0.99 (95% CI, 0.94–1.00). Magnetic resonance imaging had a sensitivity of 0.95 (95% CI, 0.76–1.00) and specificity of 0.89 (95% CI, 0.52–1.00). Contrast‐enhanced CT might serve as a practical alternative to gynecological examination in the diagnosis of acute PID in an emergency care setting, however, the evidence was uncertain. The evidence on MRI was also very uncertain.

ObjectiveThe impact of the 2018 Japan Floods on prescriptions of Yokukansan was evaluated.MethodsThis was a retrospective cohort study based on the National Database of Health Insurance Claims which covers all the prescriptions issued in Japan. Participants were patients aged 65 or older who received any medical care at medical institutions located in the three most-severely affected prefectures between 1 year before and after the disaster. We analyzed the number of new prescriptions of Yokukansan and other Kampo drugs among those who had not been prescribed any Kampo for 1 year before the disaster. Kaplan-Meier analysis and a Cox proportional hazards model were used to evaluate the risk of the disaster for a new prescription.ResultsSubjects comprised 1,372,417 people (including 12,787 victims, 0.93%). The hazard ratio (HR) of the disaster for Yokukansan prescriptions was 1.49 [95% confidence intervals (CI): 1.25–1.78], and 1.54 (95% CI: 1.29–1.84) in the crude and age-sex adjusted model, respectively. The HR of the disaster for prescription of other Kampo drugs in the crude and adjusted model was 1.33 (95% CI: 1.27–1.39), and 1.32 (95% CI: 1.27–1.38), respectively. The magnitude of increase of victims prescribed Yokukansan (31.4%) was statistically higher than for those prescribed other Kampo drugs (19.3%) (p < 0.001).ConclusionThe disaster increased prescriptions of both Yokukansan and other Kampo drugs among elderly victims. The increase was more remarkable in Yokukansan than other Kampo drugs. Clinicians and policymakers should be aware of the increased need for Yokukansan in times of natural disaster.

Objective: In order to provide regenerative therapy for millions of patients suffering from corneal blindness globally, we derived corneal endothelial cell substitute (CECSi) cells from induced pluripotent stem cells (iPSCs) to treat corneal edema due to endothelial dysfunction (bullous keratopathy). Methods and results: We developed an efficient xeno-free protocol to produce CECSi cells from both research grade (Ff-MH09s01 and Ff-I01s04) and clinical grade (QHJI01s04) iPSCs. CECSi cells formed a hexagonal confluent monolayer with Na, K-ATPase alpha 1 subunit expression (ATP1A1), tight junctions, N-cadherin adherence junction formation, and nuclear PITX2 expression, which are all characteristics of corneal endothelial cells. CECSi cells can be cryopreserved, and thawed CECSi cell suspensions also expressed N-cadherin and ATP1A1. Residual undifferentiated iPSCs in QHJI01s04-derived CECSi cells was below 0.01%. Frozen stocks of Ff-I01s04- and QHJI01s04-derived CECSi cells were transported, thawed and transplanted into a monkey corneal edema model. CECSi-transplanted eyes significantly reduced corneal edema compared to control group. Conclusion: Our results show a promising approach to provide bullous keratopathy patients with an iPS-cell-based cell therapy to recover useful vision.

Background and Objectives: Adequate initial fixation of the uncemented acetabular component in total hip arthroplasty is necessary to achieve long-term survival. Although screw fixation contributes to improved cup stability, there is currently no consensus on the use of this method. This study aimed to assess the existing randomized controlled trials (RCTs) on the efficacy and safety of cup fixation in total hip arthroplasty without screws. Materials and Methods: We searched the EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov databases to identify RCTs published before February 2022. Primary outcomes were reoperation, cup migration, and Harris Hip Score. Secondary outcomes were the presence of a radiolucent line in the acetabular region, translation and rotation movement, and polyethylene wear. We conducted meta-analyses using the random-effects models. The revised Cochrane risk-of-bias tool was used to assess the risk of bias for outcomes of interest; the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to summarize the body of evidence. Results: We included six reports from four studies. Total hip arthroplasty without screw fixation to the acetabular cup had little to no effect on reoperation (pooled relative risk, 0.98; 95% confidence interval, 0.14–6.68; I2 = 0%), cup migration (pooled relative risk, 1.72; 95% confidence interval, 0.29–10.33; I2 = 1%), Harris Hip Score (mean difference, 1.19; 95% confidence interval, −1.31–3.70; I2 = 0%), radiolucent line (pooled relative risk, 5.91; 95% confidence interval, 0.32–109.35), translation and rotation of all axes, and polyethylene wear (mean difference, 0.01; 95% confidence interval, −0.01–0.04; I2 = 0%), with very low certainty of evidence on all measures. Conclusions: The efficacy of acetabular cups without screw fixation in total hip arthroplasty remains uncertain, suggesting the need for prudent clinical application. Further large-scale, well-designed studies with low risk of bias are required.

Various genomic variants were linked to inherited peripheral neuropathies (IPNs), including large duplication/deletion and repeat expansion, making genetic diagnosis challenging. This large case series aimed to identify the genetic characteristics of Japanese patients with IPNs. We collected data on 2695 IPN cases throughout Japan, in which PMP22 copy number variation (CNV) was pre-excluded. Genetic analyses were performed using DNA microarrays, next-generation sequencing-based gene panel sequencing, whole-exome sequencing, CNV analysis, and RFC1 repeat expansion analysis. The overall diagnostic rate and the genetic spectrum of patients were summarized. We identified 909 cases with suspected IPNs, pathogenic or likely pathogenic variants. The most common causative genes were MFN2, GJB1, MPZ, and MME. MFN2 was the most common cause for early-onset patients, whereas GJB1 and MPZ were the leading causes of middle-onset and late-onset patients, respectively. Meanwhile, GJB1 and MFN2 were leading causes for demyelinating and axonal subtypes, respectively. Additionally, we identified CNVs in MPZ and GJB1 genes and RFC1 repeat expansions. Comprehensive genetic analyses explicitly demonstrated the genetic basis of our IPN case series. A further understanding of the clinical characteristics of IPN and genetic spectrum would assist in developing efficient genetic testing strategies and facilitate early diagnosis.

Optimal regimens using recent radiotherapy (RT) equipment for bleeding gastric cancer (GC) have not been fully investigated yet. We retrospectively reviewed the clinical data of 20 patients who received RT for bleeding GC in our institution between 2016 and 2021. Three-dimensional conformal RT was performed. The effectiveness of RT was evaluated by the mean serum hemoglobin (Hb) level and the number of transfused red blood cell (RBC) units 1 month before and after RT. The median first radiation dose was a BED of 39.9 Gy. The treatment success rate was 95% and the rebleeding rate was 10.5%. There was a significant increase in the mean Hb level (8.0 ± 1.1 vs. 9.8 ± 1.3 g/dL, p = 0.01), and a significant decrease in the mean number of transfused RBC units (6.8 ± 3.3 vs. 0.6 ± 1.5 units, p < 0.01). Severe toxicity was observed in two patients (anorexia [n = 1] and gastrointestinal [GI] perforation [n = 1]). Reirradiation was attempted in three patients (for hemostasis [n = 2] and for mass reduction [n = 1]). The retreatment success rate for rebleeding was 100%. GI perforation occurred in two patients who had received hemostatic reirradiation. Palliative RT for bleeding GC using recent technology had excellent efficacy. However, it may be associated with a risk of GI perforation.

Abstract We present a new approach to formulating open superstring field theory based on the covering of the supermoduli space of super-Riemann surfaces and explicitly construct a gauge-invariant action in the Neveu-Schwarz sector up to quartic interactions. The cubic interaction takes a form of an integral over an odd modulus of disks with three punctures and the associated ghost is inserted. The quartic interaction takes a form of an integral over one even modulus and two odd moduli, and it can be interpreted as the integral over the region of the supermoduli space of disks with four punctures which is not covered by Feynman diagrams with two cubic vertices and one propagator. As our approach is based on the covering of the supermoduli space, the resulting theory naturally realizes an A ∞ structure, and the two-string product and the three-string product used in defining the cubic and quartic interactions are constructed to satisfy the A ∞ relations to this order.

The article describes how to introduce a creative movement curriculum into a classroom for emotionally disturbed children. One of the greatest obstacles to overcome is the classroom life, in which students act out violently and have to be physically restrained by their teachers. To this end, the article offers three steps to introducing the movement curriculum. The first is teaching a basic movement vocabulary. The second is teaching how to sequence movement with symmetrical spatial operations. The third is an expansion of the activities and an encouragement of creativity.

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic–inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

Weight status and self-weight perception are related to social relationship issues. Studies have suggested links between non-normal weight status or weight perception and youths having fewer confidants, but these relationships are unclear and remain to be studied. This preliminary cross-sectional study examined the effects of weight status and weight perception on the number of confidants in adolescents. Self-report data from 15,279 grade 7-12 students (54.2% boys) were analyzed. The number of confidants (0-3 or ≥ 4) was examined, according to five weight status categories (underweight, low-normal weight, mid-normal weight (reference), high-normal weight, overweight, with Body Mass Index corresponding to ≤ 18.5, ≤ 20.0, ≤ 22.5, ≤ 25.0 and > 25.0 in adults, respectively), and five weight perception categories (too thin, a bit thin, good (reference), a bit fat, too fat). Boys and girls who were overweight and those who perceived themselves to be too fat were significantly more likely to have few confidants. High-normal weight in girls and self-perception of being a bit fat in boys were also associated with having few confidants. In boys, underweight and self-perception of being too thin were additionally associated with having few confidants. Adolescents with non-normal weight status or weight perception may have fewer confidants and require more social support.

Back ground: Theoretical investigations predicting the epidemic curves of seasonal influenza have been demonstrated so far; however, there is little empirical research using ever accumulated epidemic curves. The effects of vaccine coverage and information distribution on influenza epidemics were evaluated. Materials and Methods: Four indices for epidemics (i.e., onset-peak duration, onset-end duration, ratio of the onset-peak duration to onset-end duration and steepness of epidemic curves) were defined, and the correlations between these indices and anti-flu drug prescription dose, vaccine coverage, the volume of media and search trend on influenza through internet were analyzed. Epidemiological data on seasonal influenza epidemics from 2002/2003 to 2013/2014 excluding 2009/2010 season were collected from National Institute of Infectious Diseases of Japan. Results: The onset-peak duration and its ratio to onset-end duration correlated inversely with the volume of anti-flu drug prescription. Onset-peak duration correlated positively with media information volume on influenza. The steepness of the epidemic curve, and anti-flu drug prescription dose inversely correlated with the volume of media information. Pre-epidemic search trend and media volume on influenza correlated with the vaccine coverage in the season. Vaccine coverage had no strong effect on epidemic curve. Conclusion: Education through media has an effect on the epidemic curve of seasonal influenza.

Background and study aims Recently, endoscopic closure of gastrointestinal fistulas using polyglycolic acid (PGA) sheets with fibrin glue (FG) has been attempted. A 70-year-old woman who had undergone pancreaticoduodenectomy for pancreatic cancer suffered from a refractory anastomo-cutaneous fistula at the site of gastro-jejunostomy. We attempted endoscopic closure with filling and shielding using PGA sheets and FG. After introducing a guidewire into the fistula, a small piece of PGA sheet was skewered onto the guidewire and then pushed using a tapered catheter over the guidewire and delivered into the fistula. A total of 10 sheets were delivered via the same procedure. Next, the mucosa around the fistula was ablated, and the orifice of the fistula along with the surrounding mucosa was shielded with a piece of PGA sheet fixed with hemoclips and FG. After this procedure, the leakage disappeared and the fistula was undetectable on contrast radiograms. Endoscopic closure of anastomo-cutaneous fistula with filling and shielding using PGA sheets and FG is an effective, safe, low-invasive treatment, and the filling technique using a guidewire ensures a safe, smooth procedure.

Extra-pair copulation can increase genetic diversity and offspring fitness. However, it may also increase intra-nest variability in avian hosts of brood parasites, which can decrease the discrimination ability of host parents towards the parasite. In New Caledonia, the Fan-tailed Gerygone (Gerygone flavolateralis), which is parasitized by the Shining Bronze-cuckoo (Chalcites lucidus), has two nestling morphs, dark and bright, that can occur in monomorphic and polymorphic broods. Gerygone parents recognize and eject parasite nestlings from their nest, but the presence of polymorphic broods may increase the chances of recognition errors. Using 17 microsatellite markers, we investigated the mating system of the Fan-tailed Gerygone to understand the mechanisms underlying nestling polymorphism. We hypothesised that extra-pair copulations would lead to a higher proportion of polymorphic broods caused by higher genetic variability, thus creating a trade-off between genetic benefits and host defence reliability. Extra-pair paternity occurred in 6 of 36 broods, which resulted in 6 of 69 offspring sired by extra-pair males. Broods with and without mixed paternity were comparably often parasitized. Extra-pair paternity did not influence the proportions of bright, dark and polymorphic broods. Compared to bright siblings in polymorphic broods, dark nestlings tended to have lower heterozygosity, particularly in loci associated with skin coloration. The results also suggested that there is no obstacle for genetic exchange between individuals from forest and savannah, possibly due to dispersal of offspring. We conclude that the Fan-tailed Gerygone is a socially monogamous species with a low rate of extra-pair paternity compared to closely related species. Extra-pair paternity increased offspring genetic variability without measurable associated costs by brood parasitism. The results highlight the importance of studying host mating systems to assess the trade-offs between host defence and offspring fitness in co-evolutionary arms races.