TiO2nanorod arrays/Ti3C2TxMXene nanosheet composites with efficient photocatalytic activity.

Semiconductor photocatalysis holds significant promise in addressing both environmental and energy challenges. However, a major hurdle in photocatalytic processes remains the efficient separation of photoinduced charge carriers. In this study, TiO2nanorod arrays were employed by glancing angle deposition technique, onto which Ti3C2TxMXene was deposited through a spin-coating process. This hybrid approach aims to amplify the photocatalytic efficacy of TiO2nanorod arrays. Through photocurrent efficiency characterization testing, an optimal loading of TiO2/Ti3C2Txcomposites is identified. Remarkably, this composite exhibits a 40% increase in photocurrent density in comparison to pristine TiO2. This enhancement is attributed to the exceptional electrical conductivity and expansive specific surface area inherent to Ti3C2TxMXene. These attributes facilitate swift transport of photoinduced electrons, consequently refining the separation and migration of electron-hole pairs. The synergistic TiO2/Ti3C2Txcomposite showcases its potential across various domains including photoelectrochemical water splitting and diverse photocatalytic devices. As such, this composite material stands as a novel and promising entity for advancing photocatalytic applications. This study can offer an innovative approach for designing simple and efficient photocatalytic materials composed of MXene co-catalysts and TiO2for efficient water electrolysis on semiconductors.

Laser-induced transverse voltage effect inc-axis inclined LaxSr1-xTiO3thin films prepared by MOCVD.

Light and thermal detectors based on the laser-induced transverse voltage (LITV) effect have garnered significant interest for their rapid and broad spectral response. In this study, we prepared the La-doped SrTiO3(STO) epitaxial thin films on the 12° inclined single crystal LaAlO3(LAO) (100) substrates using our home-designed metal-organic chemical vapor deposition system. Under the illumination of a 248 nm laser, the LITV signals of LaxSr1-xTiO3films were observed and showed dependence on the La doping level, which can be explained by the changes in the light absorption coefficient, thermal conductivity, and optical penetration depth. The optimized LITV signal was observed with a peak voltage of 23.25 V and a decay time of 106 ns under the laser power density of 1.0 mJ mm-2. The high peak voltage and fast response time of LaxSr1-xTiO3show great potential in the field of light and thermal detection.

Novel two-dimensional beta-XTe (X = Ge, Sn, Pb) as promising room-temperature thermoelectrics.

In this paper, we designed novel low-symmetry two-dimensional (2D) structures based on conventional XTe (X = Ge, Sn, Pb) thermoelectrics with large average atomic mass. The first-principles calculations combined with Boltzmann transport theory show that the beta-XTe exhibit good stability, high electron carrier mobility, and ultralow ΚL. The subsequent analyses show that the ultralow ΚL stems from the coexistence of resonant bonding, weak bonding, and lone-pair electrons in beta-XTe, which leads to large anharmonicities. On the other hand, the lowest energy conduction band of beta-GeTe and beta-SnTe show the convergence of the low-lying Æ© band, which is the source of the high-power factor in the two systems. The calculated maximum ZT of beta-XTe (X = Ge, Sn, Pb) are 3.08, 1.60, and 0.57 at 300 K, respectively, which is significantly greater than that of the previously reported high-symmetry 2D alpha-XTe and the commercial thermoelectrics. We hope that this work can provide important guidance for the development of thermoelectric materials.

The Investigation of a SAW Oxygen Gas Sensor Operated at Room Temperature, Based on Nanostructured ZnxFeyO Films.

In this paper, we report a wireless gas sensor based on surface acoustic waves (SAW). For room temperature detection of oxygen gas, a novel nanostructured ZnxFeyO gas-sensitive film was deposited on the surface of a SAW resonator by an oblique magnetron co-sputtering method. The measurements of X-ray diffraction (XRD) and a scanning electron microscope (SEM) showed that the crystal phase composition and the microstructures of ZnxFeyO films were significantly affected by the content of Fe. The experimental results showed that the sensors had a good response to O2 at room temperature. The max frequency shift of the sensors reached 258 kHz as the O2 partial pressure was 20%. Moreover, X-ray photoelectron spectroscopy (XPS) was performed to analyze the role of Fe in the sensitization process of the ZnxFeyO film. In addition, the internal relationship between the Fe content of the film and the sensitivity of the sensor was presented and discussed. The research indicates that the nanostructured ZnxFeyO film has a good potential for room temperature O2 gas detection applications.

The DNA Methylome and Association of Differentially Methylated Regions with Differential Gene Expression during Heat Stress in Brassica rapa.

Cytosine DNA methylation is a critical epigenetic mechanism in the silencing of transposable elements, imprinting and regulating gene expression. However, little is known about the potential role of mC in response to heat stress. To determine and explore the functions of the dynamic DNA methylome during heat stress, we characterized single-base resolution methylome maps of Brassica rapa and assessed the dynamic changes of mC under heat stress using whole genome bisulfite sequencing. On average, the DNA methylation levels of CG, CHG and CHH are 39.3%, 15.38% and 5.24% in non-heading Chinese cabbage (NHCC), respectively. We found that the patterns of methylation are similar to other eudicot plants, but with higher CHH methylation levels. Further comparative analysis revealed varying patterns for three sequence contexts (mCG, mCHG and mCHH) under heat stress indicating context- and position-dependent methylation regulation. DNA methylation near the TSS and TES may be closely associated with methylation-dependent transcriptional silencing. Association analysis of differential methylation and differential gene expression revealed a different set of methDEGs involved at early and late stages under heat stress. The systemic characterization of the dynamic DNA methylome during heat stress will improve our understanding of the mechanism of epigenetic regulation under heat stress.

The association of changes in DNA methylation with temperature-dependent sex determination in cucumber.

Cucumber (Cucumis sativus L.) is characterized by its diverse and flexible sexual types. Here, we evaluated the effect of low temperature (LT) exposure on cucumber femaleness under short-day conditions. Shoot apices were subjected to whole-genome bisulfate sequencing (WGBS), mRNA-seq, and sRNA-seq. The results showed that temperature had a substantial and global impact on transposable element (TE)-related small RNA-directed DNA methylation (RdDM) mechanisms, resulting in large amounts of CHH-type cytosine demethylation. In the cucumber genome, TEs are common in regions near genes that are also subject to DNA demethylation. TE-gene interactions showed very strong reactions to LT treatment, as nearly 80% of the differentially methylated regions (DMRs) were distributed in genic regions. Demethylation near genes led to the co-ordinated expression of genes and TEs. More importantly, genome-wide de novo methylation changes also resulted in small amounts of CG- and CHG-type DMRs. Methylation changes in CG-DMRs located <600 bp from the transcription start and end sites (TSSs/TESs) negatively correlated with transcription changes in differentially expressed genes (DEGs), probably indicating epiregulation. Ethylene is called the 'sex hormone' of cucumbers. We observed the up-regulation of ethylene biosynthesis-related CsACO3 and the down-regulation of an Arabidopsis RAP2.4-like ethylene-responsive (AP2/ERF) transcription factor, demonstrating the inferred epiregulation. Our study characterized the response of the apex methylome to LT and predicted the possible epiregulation of temperature-dependent sex determination (TSD) in cucumber.

The Feasibility and Safety of Interventional Occlusion Treatment of Intracristal Ventricular Septal Defects: Clinical Report of 56 Cases.

BACKGROUND: To investigate the feasibility and safety of the O eccentric shape occluder in the interventional occlusion treatment of intracristal ventricular septal defect (IVSD). METHODS: A retrospective analysis of the clinical data of 56 IVSD patients treated by interventional occlusion at our center, as well as recording of their intraoperative and postoperative status, was performed. RESULTS: Of the 56 patients, a total of 48 patients underwent successful occlusion during the first surgical attempt. Four patients were transferred to the Surgery Department after occlusion when the largest occluder failed because of large defects. Two patients exhibited aortic valve regurgitation; 1 patient had mild regurgitation, which was not worsened after 6 months of follow-up. One patient had severe aortic regurgitation, and 2 days after the operation, the patient underwent a second operation. One patient exhibited a residual shunt, which was above the occluder; after 1 year of follow-up, re-occlusion was successful and eliminated the shunt. One patient developed complete right bundle branch block. CONCLUSION: Most IVSD interventional occlusion treatments are feasible and safe.

Marked methylation changes in intestinal genes during the perinatal period of preterm neonates.

BACKGROUND: The serious feeding- and microbiota-associated intestinal disease, necrotizing enterocolitis (NEC), occurs mainly in infants born prematurely (5-10% of all newborns) and most frequently after formula-feeding. We hypothesized that changes in gene methylation is involved in the prenatal maturation of the intestine and its response to the first days of formula feeding, potentially leading to NEC in preterm pigs used as models for preterm infants. RESULTS: Reduced Representation Bisulfite Sequencing (RRBS) was used to assess if changes in intestinal DNA methylation are associated with formula-induced NEC outbreak and advancing age from 10 days before birth to 4 days after birth. Selected key genes with differentially methylated gene regions (DMRs) between groups were further validated by HiSeq-based bisulfite sequencing PCR and RT-qPCR to assess methylation and expression levels. Consistent with the maturation of many intestinal functions in the perinatal period, methylation level of most genes decreased with advancing pre- and postnatal age. The highest number of DMRs was identified between the newborn and 4 d-old preterm pigs. There were few intestinal DMR differences between unaffected pigs and pigs with initial evidence of NEC. In the 4 d-old formula-fed preterm pigs, four genes associated with intestinal metabolism (CYP2W1, GPR146, TOP1MT, CEND1) showed significant hyper-methylation in their promoter CGIs, and thus, down-regulated transcription. Methylation-driven down-regulation of such genes may predispose the immature intestine to later metabolic dysfunctions and severe NEC lesions. CONCLUSIONS: Pre- and postnatal changes in intestinal DNA methylation may contribute to high NEC sensitivity in preterm neonates. Optimizing gene methylation changes via environmental stimuli (e.g. diet, nutrition, gut microbiota), may help to make immature newborn infants more resistant to gut dysfunctions, both short and long term.

Genome-wide DNA methylation changes in skeletal muscle between young and middle-aged pigs.

BACKGROUND: Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. RESULTS: We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. CONCLUSIONS: This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research.

DNA methylation and mRNA and microRNA expression of SLE CD4+ T cells correlate with disease phenotype.

Systemic lupus erythematosus (SLE) is an autoimmune disease well known for its clinical heterogeneity, and its etiology secondary to a cross-talk involving genetic predisposition and environmental stimuli. Although genome-wide analysis has contributed greatly to our understanding of the genetic basis of SLE, there is increasing evidence for a role of epigenetics. Indeed, recent data have demonstrated that in patients with SLE, there are striking alterations of DNA methylation, histone modifications, and deregulated microRNA expression, the sum of which contribute to over-expression of select autoimmune-related genes and loss of tolerance. To address this issue at the level of clinical phenotype, we performed DNA methylation, mRNA and microRNA expression screening using high-throughput sequencing of purified CD4+ T cells from patients with SLE, compared to age and sex matched controls. In particular, we studied 42 patients with SLE and divided this group into three clinical phenotypes: a) the presence of skin lesions without signs of systemic pathology; b) skin lesions but also chronic renal pathology; and c) skin lesions, chronic renal pathology and polyarticular disease. Interestingly, and as expected, sequencing data revealed changes in DNA methylation in SLE compared to controls. However, and more importantly, although there were common methylation changes found in all groups of SLE compared to controls, there was specific DNA methylation changes that correlated with clinical phenotype. These included changes in the novel key target genes NLRP2, CD300LB and S1PR3, as well as changes in the critical pathways, including the adherens junction and leukocyte transendothelial migration. We also noted that a significant proportion of genes undergoing DNA methylation changes were inversely correlated with gene expression and that miRNA screening revealed the existence of subsets with changes in expression. Integrated analysis of this data highlights specific sets of miRNAs controlled by DNA methylation, and genes that are altered by methylation and targeted by miRNAs. In conclusion, our findings suggest select epigenetic mechanisms that contribute to clinical phenotypes and further shed light on a new venue for basic SLE research.

[Application value of bone cement containing rhbFGF and RHBMP-2 in PKP treatment of osteoporotic lumbar compression fracture].

OBJECTIVE: To investigate the effect of bone cement containing recombinant human basic fibroblast growth factor (rhbFGF) and recombinant human bone morphogenetic protein-2 (rhBMP-2) in percutaneous kyphoplasty(PKP)treatment of osteoporotic vertebral compression fracture(OVCF). METHODS: A total of 103 OVCF patients who underwent PKP from January 2018 to January 2021 were retrospectively analyzed, including 40 males and 63 females, aged from 61 to 78 years old with an average of (65.72±3.29) years old. The injury mechanism included slipping 33 patients, falling 42 patients, and lifting injury 28 patients. The patients were divided into three groups according to the filling of bone cement. Calcium phosphate consisted of 34 patients, aged(65.1±3.3) years old, 14 males and 20 females, who were filled with calcium phosphate bone cement. rhBMP-2 consisted of 34 patients, aged (64.8±3.2) years old, 12 males and 22 females, who were filled with bone cement containing rhBMP-2. And rhbFGF+rhBMP-2 consisted of 35 patients, aged (65.1±3.6) years old, 14 males and 21 females, who were filled with bone cement containing rhbFGF and rhBMP-2. Oswestry disability index (ODI), bone mineral density, anterior edge loss height, anterior edge compression rate of injured vertebra, visual analog scale (VAS) of pain, and the incidence of refracture were compared between groups. RESULTS: All patients were followed for 12 months. Postoperative ODI and VAS score of the three groups decreased (P<0.001), while bone mineral density increased (P<0.001), anterior edge loss height, anterior edge compression rate of injured vertebra decreased first and then slowly increased (P<0.001). ODI and VAS of group calcium phosphate after 1 months, 6 months, 12 months were lower than that of rhBMP-2 and group rhbFGF+rhBMP-2(P<0.05), bone mineral density after 6 months, 12 months was higher than that of rhBMP-2 and group calcium phosphate(P<0.05), and anterior edge loss height, anterior edge compression rate of injured vertebra of group rhbFGF+rhBMP-2 after 6 months and 12 months were lower than that of group rhBMP-2 and group calcium phosphate(P<0.05). There was no statistical difference in the incidence of re-fracture among the three groups (P>0.05). CONCLUSION: Bone cement containing rhbFGF and rhBMP-2 could more effectively increase bone mineral density in patients with OVCF, obtain satisfactory clinical and radiological effects after operation, and significantly improve clinical symptoms.

The pivotal role of bromine in FeMnKBr/YNa catalyst for CO2 hydrogenation to light olefins.

Light olefins are key intermediates in the synthesis of petrochemicals, and the conversion of stabilized carbon dioxide to light olefins using catalysts containing halogenated elements such as chlorine is a major challenge. Building on previous reports emphasizing the toxic effects of halogen elements on catalysts, we present the synthesis of FeMnKBr/YNa catalysts. This involved the synthesis of the catalyst by melt permeation using Br-containing potassium salts, other metal nitrates and YNa zeolites. The catalyst performed well in converting syngas (H2/CO2 = 3) to light olefins with a selectivity of 56.2%, CO2 conversion of 34.4%, and CO selectivity of 13.6%. Adding Br aids in reducing the Fe phase, boosts catalyst carburization, and produces more iron carbide species. It also moderately deposits carbon on the active center's surface, enhancing active phase dispersion. Br's electronegativity mitigates the influence of K, reducing catalyst's carbon-carbon coupling ability, leading to more low-carbon olefins generation.

Double restriction-enzyme digestion improves the coverage and accuracy of genome-wide CpG methylation profiling by reduced representation bisulfite sequencing.

BACKGROUND: Reduced representation bisulfite sequencing (RRBS) was developed to measure DNA methylation of high-CG regions at single base-pair resolution, and has been widely used because of its minimal DNA requirements and cost efficacy; however, the CpG coverage of genomic regions is restricted and important regions with low-CG will be ignored in DNA methylation profiling. This method could be improved to generate a more comprehensive representation. RESULTS: Based on in silico simulation of enzyme digestion of human and mouse genomes, we have optimized the current single-enzyme RRBS by applying double enzyme digestion in the library construction to interrogate more representative regions. CpG coverage of genomic regions was considerably increased in both high-CG and low-CG regions using the double-enzyme RRBS method, leading to more accurate detection of their average methylation levels and identification of differential methylation regions between samples. We also applied this double-enzyme RRBS method to comprehensively analyze the CpG methylation profiles of two colorectal cancer cell lines. CONCLUSION: The double-enzyme RRBS increases the CpG coverage of genomic regions considerably over the previous single-enzyme RRBS method, leading to more accurate detection of their average methylation levels. It will facilitate genome-wide DNA methylation studies in multiple and complex clinical samples.

Highly Sensitive H2S Gas Sensor Based on a Lead-Free CsCu2I3 Perovskite Film at Room Temperature.

Recently, there have been reports of lead halide perovskite-based sensors demonstrating their potential for gas sensing applications. However, the toxicity of lead and the instability of lead-based perovskites have limited their applications. This study addressed this issue by developing a H2S gas sensor based on a lead-free CsCu2I3 film prepared using a one-step CVD method. The sensor demonstrated excellent sensing properties, including a high response and selectivity toward H2S, even at low concentrations (0.2 ppm) at room temperature. Furthermore, a reasonable sensing mechanism was proposed. It is suggested that the sensing mechanism sheds light on the role of defects in perovskite materials, the impact of H2S as an electron donor, and the occurrence of reversible chemical reactions. These findings suggest that lead-free CsCu2I3 has great potential in the field of H2S gas sensing.

The Nrf2 in Obesity: A Friend or Foe?

Obesity and its complications have become serious global health concerns recently and increasing work has been carried out to explicate the underlying mechanism of the disease development. The recognized correlations suggest oxidative stress and inflammation in expanding adipose tissue with excessive fat accumulation play important roles in the pathogenesis of obesity, as well as its associated metabolic syndromes. In adipose tissue, obesity-mediated insulin resistance strongly correlates with increased oxidative stress and inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been described as a key modulator of antioxidant signaling, which regulates the transcription of various genes coding antioxidant enzymes and cytoprotective proteins. Furthermore, an increasing number of studies have demonstrated that Nrf2 is a pivotal target of obesity and its related metabolic disorders. However, its effects are controversial and even contradictory. This review aims to clarify the complicated interplay among Nrf2, oxidative stress, lipid metabolism, insulin signaling and chronic inflammation in obesity. Elucidating the implications of Nrf2 modulation on obesity would provide novel insights for potential therapeutic approaches in obesity and its comorbidities.

Simulation and Operational Optimization of RO Based Desalination for Coal-Fired Power Plants' Wastewater.

Focusing on the problems of opaqueness and high energy consumption in coal-fired power plant wastewater recycling processes, this paper studies the simulation and operational optimization of coal-fired power plant wastewater treatment by taking a coal-fired power plant system in Inner Mongolia as an example. Firstly, based on the solution-diffusion theory, pressure drop, and osmotic concentration polarization, a mechanistic model equation for coal-fired power plant wastewater treatment is developed. Secondly, the equation fitness and equation parameters are calibrated to obtain an accurate model. Thirdly, the system is simulated and analyzed so as to obtain the influence and change trajectories of different feed flowrates, temperatures, pressures, and concentrations on various aspects of the system's performance, such as water recovery rate, salt rejection rate, and so on. Finally, in order to reduce the operating cost of the system, an optimization analysis is carried out, with the lowest specific energy consumption and average daily operating cost as optimization goals, and the performance changes of the system before and after optimization under three different working conditions are compared. The results show that adopting the given optimal strategy can significantly reduce the system's operational cost. This research is helpful for the digitization and low-carbon operation of coal-fired power plant wastewater treatment systems.

Modeling and Structural Optimization of MSF-RO Desalination System.

Based on the mathematical modeling and operational optimization studies of reverse osmosis (RO) and multistage flash (MSF) desalination, the structural optimization of the hybrid process was specially studied in this work with the consideration of reducing comprehensive expenses under given operational conditions. Firstly, according to the process mechanism and flowchart of the RO and MSF seawater desalination technologies, seven hybrid structures with different feed conditions were designed, and their connection equations were established for numerical calculation. Then, in order to evaluate the economic performance of the hybrid systems with different structures, the hourly average operational cost equations of RO and MSF processes were established and formulated as the comprehensive evaluation indicators. Next, with a given water production requirement, simulation calculations of the hybrid system with seven different structures were performed. The results show that the hybrid system with the fourth structure has the lowest operational cost of 4.6834 CNY/m3, and at the same time it has the lowest blowdown. However, if we take GOR or production water temperature as the target, the optimal structure of the hybrid system is the fifth or the seventh option. The obtained results are helpful in structural optimization of the hybrid system with aspects of operational cost reduction, maximum GOR, or minimizing the wastewater discharge.

Cadmium-Free Nanostructured Multilayer Thin Films with Bright Blue Photoluminescence and Excellent Stability.

Cadmium-based quantum dots (Cd-QDs) show decent performance for lighting applications due to good color saturation, an excellent high quantum yield, and a narrow full-width at half-maximum. However, the intrinsic toxicity of Cd is a major hindrance to related applications, especially in the biological field. ZnSe, with a band gap of 2.7 eV and lower toxicity than CdSe or CdS, is promising as a blue luminescent material. Herein, we mainly reported the preparation and luminescence properties of nanostructured ZnSe/ZnS multilayer thin films with bright blue photoluminescence. The photoluminescence spectrum contained two emission peaks, located at about 442 nm (near band-edge emission) and 550 nm (defect-related emission), respectively. More importantly, the photoluminescence performance and decay were explored in detail through low-temperature photoluminescence spectra. In addition, the nanostructured ZnSe/ZnS multilayer thin films showed favorable photostability.

Application study of three-dimensional printed navigation template between traditional and novel cortical bone trajectory on osteoporosis lumbar spine.

To investigate the safety, accuracy and indications of traditional and novel cortical bone screws placement for osteoporosis lumbar spine, 4 lumbar vertebra specimens (2 males and 2 females) were used for this study. After the computed tomography scanning data of the above anatomical specimens were three-dimensional (3D) reconstructed, one side of each anatomical specimen was randomly chosen to place traditional cortical bone screws, and the other side received novel technical placement. The safety screw trajectory was designed, and a 3D navigation template complementary to the surface anatomical structure of lumbar isthmus lateral margin-vertebral plate-spinous process part was established. The designed supporting navigation template was substantialized, and the navigation template replicated different cortical bone screw trajectory at different sides of the same one lumbar vertebra. Forty cortical bone screws were firstly placed in 3D printed vertebra and then 40 were placed in real anatomical specimens. In 3D printed specimens, the success rates of screw placement with navigation template using traditional and novel techniques were both 100%. While in anatomical specimens, the success rate of screw placement using traditional and novel navigation template was 97.5% (one out of 40 went wrong). Therefore, it is safe, accurate and reliable to place traditional and novel cortical bone screws on osteoporosis lumbar spine using 3D printed navigation template. Traditional and novel screw placement methods should be flexibly applied or combined according to specific sequence and form of vertebra.

The genomic loci of specific human tRNA genes exhibit ageing-related DNA hypermethylation.

The epigenome has been shown to deteriorate with age, potentially impacting on ageing-related disease. tRNA, while arising from only ˜46 kb (<0.002% genome), is the second most abundant cellular transcript. tRNAs also control metabolic processes known to affect ageing, through core translational and additional regulatory roles. Here, we interrogate the DNA methylation state of the genomic loci of human tRNA. We identify a genomic enrichment for age-related DNA hypermethylation at tRNA loci. Analysis in 4,350 MeDIP-seq peripheral-blood DNA methylomes (16-82 years), identifies 44 and 21 hypermethylating specific tRNAs at study-and genome-wide significance, respectively, contrasting with none hypomethylating. Validation and replication (450k array and independent targeted Bisuphite-sequencing) supported the hypermethylation of this functional unit. Tissue-specificity is a significant driver, although the strongest consistent signals, also independent of major cell-type change, occur in tRNA-iMet-CAT-1-4 and tRNA-Ser-AGA-2-6. This study presents a comprehensive evaluation of the genomic DNA methylation state of human tRNA genes and reveals a discreet hypermethylation with advancing age.