The Importance of Sintering-Induced Grain Boundaries in Copper Catalysis to Improve Carbon-Carbon Coupling.

Syngas conversion serves as a gas-to-liquid technology to produce liquid fuels and valuable chemicals from coal, natural gas, or biomass. During syngas conversion, sintering is known to deactivate the catalyst owing to the loss of active surface area. However, the growth of nanoparticles might induce the formation of new active sites such as grain boundaries (GBs) which perform differently from the original nanoparticles. Herein, we reported a unique Cu-based catalyst, Cu nanoparticles with in situ generated GBs confined in zeolite Y (denoted as activated Cu/Y), which exhibited a high selectivity for C5+ hydrocarbons (65.3 C%) during syngas conversion. Such high selectivity for long-chain products distinguished activated Cu/Y from typical copper-based catalysts which mainly catalyze methanol synthesis. This unique performance was attributed to the GBs, while the zeolite assisted the stabilization through spatial confinement. Specifically, the GBs enabled H-assisted dissociation of CO and subsequent hydrogenation into CHx*. CHx* species not only serve as the initiator but also directly polymerize on Cu GBs, known as the carbide mechanism. Meanwhile, the synergy of GBs and their vicinal low-index facets led to the CO insertion where non-dissociative adsorbed CO on low-index facets migrated to GBs and inserted into the metal-alkyl bond for the chain growth.

The role of long noncoding RNA MEG3 in fibrosis diseases.

Fibrosis is a prevalent pathological condition observed in various organs and tissues. It primarily arises from the excessive and abnormal accumulation of the extracellular matrix, resulting in the structural and functional impairment of tissues and organs, which can culminate in death. Many forms of fibrosis, including liver, cardiac, pulmonary, and renal fibrosis, are considered irreversible. Maternally expressed gene 3 (MEG3) is an imprinted RNA gene. Historically, the downregulation of MEG3 has been linked to tumor pathogenesis. However, recent studies indicate an emerging association of MEG3 with fibrotic diseases. In this review, we delve into the current understanding of MEG3's role in fibrosis, aiming to shed light on the molecular mechanisms of fibrosis and the potential of MEG3 as a novel therapeutic target.

What is already known on this topic ­ Fibrosis, a condition characterized by excess build-up of the extracellular matrix in various organs, can lead to organ failure and is often irreparable. This includes fibrosis of the liver, heart, lungs, and kidneys. MEG3, an RNA gene, which is known to be downregulated in tumors, has recently been linked to fibrosis. What is already known on this topic ­ Our review investigates this new connection between MEG3 and fibrosis. We aim to provide insights into the molecular mechanisms of fibrosis and illuminate the potential role of MEG3 as a promising therapeutic target for fibrosis treatments. What is already known on this topic ­ Our review investigates this new connection between MEG3 and fibrosis. We aim to provide insights into the molecular mechanisms of fibrosis and illuminate the potential role of MEG3 as a promising therapeutic target for fibrosis treatments.

Novel manganese and nitrogen co-doped biochar based on sodium bicarbonate activation for efficient removal of bisphenol A: Mechanism insight and role analysis of manganese and nitrogen by combination of characterizations, experiments and density functional theory calculations.

A novel porous manganese and nitrogen co-doped biochar (Mn-N@SBC) was synthesized via one-step pyrolysis, utilizing loofah agricultural waste as the precursor and NaHCO3 as the activator. The behavior of bisphenol A adsorbed on Mn-N@SBC was evaluated using static batch adsorption experiments. Compared to direct manganese-nitrogen co-doping, co-doping based on NaHCO3 activation significantly increased the specific surface area (231 to 1027 m2·g-1) and adsorption capacity (15 to 351 mg·g-1). Wide pH (2-10) and good resistance to cation/anion, humic acid and actual water demonstrated the robust adaptability of Mn-N@SBC to environmental factors. The significantly reduced specific surface area after adsorption, adverse effects of ethanol and phenanthrene on the removal of bisphenol A, and theoretically predicted interaction sites indicated the primary adsorption mechanisms involved pore filling, hydrophobicity, and π-π-electron-donor-acceptor interaction. This work presented an approach to create high-efficiency adsorbents from agricultural waste, offering theoretical and practical guidance for the removal of pollutants.

Long-term Radiological and Pulmonary Function Abnormalities at 3-year post COVID-19 Hospitalization: A Longitudinal Cohort Study.

BACKGROUND: This study aimed to evaluate the longitudinal progression of residual lung abnormalities (ground-glass opacities, reticulations, and fibrotic-like changes) and pulmonary function, three years following coronavirus disease 2019(COVID-19). METHODS: This prospective, longitudinal cohort study enrolled COVID-19 survivors who exhibited residual lung abnormalities upon discharge from two hospitals. Follow-up assessments were conducted at 6 months, 12 months, 2 years, and 3 years post-discharge, and included pulmonary function tests, 6-minute walk distance (6MWD), chest CT scans, and symptom questionnaires. Non-COVID-19 controls were retrospectively recruited for comparative analysis. RESULTS: 728 COVID-19 survivors and 792 controls were included. From 6 months to 3 years, there was a gradual improvement in reduced diffusing capacity of the lungs for carbon monoxide (DLCO＜80% predicted, 49% versus 38%, p=0.001), 6MWD (496 m versus 510 m, p=0.002) and residual lung abnormalities(46% versus 36%, p<0.001), regardless of the disease severity. Patients with residual lung abnormalities at 3 years more commonly had respiratory symptoms (32% versus 16%, p<0.001), lower 6MWD (494 m versus 510 m, p=0.003), and abnormal DLCO (57% versus 27%, p<0.001) compared to those with complete resolution. Compared to the controls, the proportion of DLCO impairment (38% versus 17%, p<0.001) and respiratory symptoms (23% versus 2.2%, p<0.001) were significantly higher in the matched COVID-19 survivors at the 3-year follow-up. CONCLUSIONS: Most patients exhibited improvement in radiological abnormalities and pulmonary function over time following COVID-19. However, more than one-third continued to have persistent lung abnormalities at the 3-year mark, which were associated with respiratory symptoms and reduced diffusion capacity.

A review of changes at the phenotypic, physiological, biochemical, and molecular levels of plants due to high temperatures.

MAIN CONCLUSION: This review summarizes the physiological, biochemical, and molecular regulatory network changes in plants in response to high temperature. With the continuous rise in temperature, high temperature has become an important issue limiting global plant growth and development, affecting the phenotype and physiological and biochemical processes of plants and seriously restricting crop yield and tree growth speed. As sessile organisms, plants inevitably encounter high temperatures and improve their heat tolerance by activating molecular networks related to heat stress, such as signal transduction, synthesis of metabolites, and gene expression. Heat tolerance is a polygenic trait regulated by a variety of genes, transcription factors, proteins, and metabolites. Therefore, this review summarizes the changes in physiological, biochemical and molecular regulatory networks in plants under high-temperature conditions to lay a foundation for an in-depth understanding of the mechanisms involved in plant heat tolerance responses.

Prognostic value of platelet-to-lymphocyte ratio in patients with unresectable hepatocellular carcinoma undergoing transarterial chemoembolization and tyrosine kinase inhibitors plus immune checkpoints inhibitors.

Purpose: To investigate the prognostic value of platelet-to-lymphocyte ratio (PLR) in patients with unresectable hepatocellular carcinoma (uHCC) treated with transarterial chemoembolization (TACE) and tailored tyrosine kinase inhibitors (TKIs) plus immune checkpoints inhibitors (ICIs). Materials and methods: Ninety-eight patients from May 2018 to January 2022 in our hospital were enrolled in this study. The receiver operating characteristic (ROC) curve analysis was performed and the corresponding Youden index was used to determine the optimal PLR cut-off. Overall survival (OS), progression-free survival (PFS), and adverse events (AEs) of patients were evaluated based on the PLR cut-off. The factors affecting survival were assessed using univariate and multivariate Cox proportional hazards regression analyses. Results: The PLR cut-off was 98.89. There were 49 patients in the low pretreatment PLR group (PLR ≤ 98.89) and 49 patients in the high PLR group (PLR > 98.89). Patients with low pretreatment PLR had significantly longer median OS (25.7 months vs 16.1 months; P < 0.001) and PFS (14.9 months vs 10.2 months; P < 0.001) than those with high pretreatment PLR. The multivariate analysis revealed that ALT, tumor size, and PLR are risk factors affecting OS. The three independent factors affecting PFS are tumor size, AFP, and PLR. The AEs were tolerable and manageable. Conclusion: The low pretreatment PLR (PLR ≤ 98.89) was an independent protective factor for the survival outcomes of patients in this study. PLR was helpful for clinicians to predict the prognosis and identify the patients with uHCC who were most likely to benefit from TACE + TKIs + ICIs.

A review of the types, functions and regulatory mechanisms of plant spines.

Over a long period of evolution, plants have developed self-protection mechanisms, such as leaving seeds, dropping leaves, growing thorns, producing specific substances or emitting special odors to repel insects. Although studies on the taxonomic characteristics, functions and application of spines in spiny plants have been reported in China and abroad, a systematic overview of plant spines is currently lacking. This study therefore identifies the characteristics and types of plant spines based on domestic and international research on plant spines to provide clear criteria or bases for determining the types of plant spines. In addition, the functions, regulatory mechanisms, and factors influencing the formation of spines and the prospects for their development and application are described and summarized. This study will help to improve the understanding of the types, functions and regulatory mechanisms of plant spines and provide new ideas for the genetic improvement of plants from spiny to nonspiny varieties.

Effect of Eccentricity Difference on the Mechanical Response of Microfluidics-Derived Hollow Silica Microspheres during Nanoindentation.

Hollow microspheres as the filler material of syntactic foams have been adopted in extensive practical applications, where the physical parameters and their homogeneity have been proven to be critical factors during the design process, especially for high-specification scenarios. Based on double-emulsion droplet templates, hollow microspheres derived from microfluidics-enabled soft manufacturing have been validated to possess well-controlled morphology and composition with a much narrower size distribution and fewer defects compared to traditional production methods. However, for more stringent requirements, the innate density difference between the core-shell solution of the double-emulsion droplet template shall result in the wall thickness heterogeneity of the hollow microsphere, which will lead to unfavorable mechanical performance deviations. To clarify the specific mechanical response of microfluidics-derived hollow silica microspheres with varying eccentricities, a hybrid method combining experimental nanoindentation and a finite element method (FEM) simulation was proposed. The difference in eccentricity can determine the specific mechanical response of hollow microspheres during nanoindentation, including crack initiation and the evolution process, detailed fracture modes, load-bearing capacity, and energy dissipation capability, which should shed light on the necessity of optimizing the concentricity of double-emulsion droplets to improve the wall thickness homogeneity of hollow microspheres for better mechanical performance.

LC-MS and GC-MS Metabolomics Analyses Revealed That Different Exogenous Substances Improved the Quality of Blueberry Fruits under Soil Cadmium Toxicity.

Exogenous substances (ESs) can regulate plant growth and respond to environmental stress, but the effects of different ESs on blueberry fruit quality under soil cadmium (Cd) toxicity and related metabolic mechanisms are still unclear. In this study, four ES treatments [salicylic acid (SA), spermidine (Spd), 2,4-epibrassinolide (EBR), and melatonin (MT)] significantly increased blueberry fruit size, single-fruit weight, sweetness, and anthocyanin content under soil Cd toxicity and effectively reduced fruit Cd content to safe consumption levels by promoting mineral uptake (Ca, Mg, Mn, Cu and Zn). Furthermore, a total of 445, 360, 429, and 554 differentially abundant metabolites (DAMs) (LC-MS) and 63, 48, 79, and 73 DAMs (GC-MS) were identified from four comparison groups (SA/CK, Spd/CK, EBR/CK and MT/CK), respectively. The analyses revealed that ESs improved blueberry fruit quality and tolerance to Cd toxicity mainly by regulating the changes in metabolites related to ABC transporters, the TCA cycle, flavonoid biosynthesis, and phenylpropanoid biosynthesis.

Effect of blackberry anthocyanins and its combination with tea polyphenols on the oxidative stability of lard and olive oil.

To investigate the protective effect of blackberry anthocyanins (BA), tea polyphenols (TP), and their binary mixture on the oxidative stability of edible oils during storage, BA, TP, and their binary mixture were added to lard and olive oil. The changes in peroxide value (PV), thiobarbituric acid reactive substances (TBARS), acid value (AV), and scavenging capacity of DPPH and ABTS•+ of oil samples were evaluated during accelerated storage. BA were found to have a remarkable capability to enhance antioxidant properties, delay lipid oxidation, and inhibit the deterioration both of lard and olive oil at high-temperature processes. Furthermore, the antioxidant synergistic effect of BA and TP was found both in lard and olive oil for the first time. All these results suggested that BA and its combination with TP might possess the potential value to protect the quality of edible oils.

Optimized extraction technology of glutathione from 'Haidao 86' germ rice by response surface methodology.

Glutathione is an important functional component of 'Haidao 86', which has many important physiological functions in organisms and is widely used in medicine and other industries. In this study, the effects of four extraction methods (hot water extraction, formic acid extraction, ethanol extraction, and sulfuric acid extraction) on the yield of glutathione in 'Haidao 86' germ powders were studied by high-performance liquid chromatography, and the yield of glutathione in hot water extraction was the highest. The effects of material-liquid ratio, temperature, pH, and time on the extraction rate of glutathione from 'Haidao 86' were investigated by single-factor experiment and Box-Behnken combined experiment. The results showed that the order of influence on GSH yield was pH, temperature, material-liquid ratio, and time, and the interaction of extraction time and pH had a significant influence on glutathione yield of 'Haidao 86' germ powders. The optimum parameters for hot water extraction of glutathione from 'Haidao 86' germ powders were determined as follows: material-liquid ratio of 1:12, pH value of 2.8, temperature of 84.9°C, time of 14 min, and the extraction rate of glutathione was 139.68 mg/100 g. It provided the scientific proof for the development and industrial production of functional products of 'Haidao 86'.

Proteins from Blackberry Seeds: Extraction, Osborne Isolate, Characteristics, Functional Properties, and Bioactivities.

Blackberry fruit contains high levels of nutrients and phenolic compounds. Blackberry pomace accounts for 20~30% of its whole fruit during processing and is generally treated as fertilizer. Blackberry pomace has many seeds that contain carbohydrates, polyphenols, flavonoids, pectin, protein, and other bioactive nutrients. However, its functional properties and seed protein compositions have not been reported. We used a single-factor experiment, response surface, and Osborne isolate method to extract protein isolate, albumin, globulin, glutelin, and prolamin from blackberry seeds for the first time and evaluated their characteristics and functional properties. Glutelin and protein isolate showed good water-holding capacity, emulsification, and foaming capacity, while albumin and globulin showed good oil-holding capacity and thermal stability. They were found to have good antioxidant activities that might be good DPPH free radical scavengers, especially prolamin, which has the lowest IC50 value (15.76 µg/mL). Moreover, globulin had the lowest IC50 value of 5.03 µg/mL against Hela cells, 31.82 µg/mL against HepG2 cells, and 77.81 µg/mL against MCF-7 cells and a high selectivity index (SI), which suggested globulin had better anti-cervical, antihepatoma, and anti-breast activity but relatively low cytotoxicity. These seed proteins may have great prospects for the development and application of food and drugs in the future.

Ellagic Acid from Hull Blackberries: Extraction, Purification, and Potential Anticancer Activity.

Ellagic acid (EA) is present at relatively high concentrations in many berries and has many beneficial health effects, including anticancer properties. To improve the development and utilization of blackberry fruit nutrients, we divided Hull blackberry fruits into five growth periods according to color and determined the EA content in the fruits in each period. The EA content in the green fruit stage was the highest at 5.67 mg/g FW. Single-factor tests and response surface methodology were used to optimize the extraction process, while macroporous resin adsorption and alkali dissolution, acid precipitation, and solvent recrystallization were used for purification. The highest purity of the final EA powder was 90%. The anticancer assessment results determined by MTT assay showed that EA inhibited HeLa cells with an IC50 of 35 µg/mL, and the apoptosis rate of the cells increased in a dose-dependent manner, with the highest rate of about 67%. We evaluated the changes in the mRNA levels of genes related to the EA-mediated inhibition of cancer cell growth and initially verified the PI3K/PTEN/AKT/mTOR pathway as the pathway by which EA inhibits HeLa cell growth. We hope to provide a theoretical basis for the deep exploration and utilization of this functional food.

Blueberry and Blackberry Anthocyanins Ameliorate Metabolic Syndrome by Modulating Gut Microbiota and Short-Chain Fatty Acids Metabolism in High-Fat Diet-Fed C57BL/6J Mice.

In this study, blueberry (Vaccinium ssp.) anthocyanins (VA) and blackberry (Rubus L.) anthocyanins (RA) were used to investigate the effects on metabolic syndrome (MetS) and the potential mechanisms. Importantly, all of the data presented in this study were obtained from experiments conducted on mice. As a result, VA and RA reduced body weight gain and fat accumulation while improving liver damage, inflammation, glucose, and lipid metabolism induced by a high-fat diet. Moreover, VA and RA regulated the gut microbiota composition, decreasing the pro-obesity and proinflammation bacteria taxa, such as the phylum Actinobacterium and the genera Allobaculum and Bifidobacterium, and increasing those negatively associated with obesity and inflammation, such as the phylum Bacteroidetes and the genera Prevotella and Oscillospira. Additionally, the supplementation with VA and RA reversed the elevated levels of valeric, caproic, and isovaleric acids observed in the high-fat diet (HFD) group, bringing them closer to the levels observed in the Chow group. This reversal indicated that alterations in the composition and abundance of gut microbiota may contribute to the restoration of short-chain fatty acids (SCFAs) levels. Additionally, PICRUSt2 exhibited that cyanamino acid metabolism and betalain biosynthesis might be the major metabolic pathways in the HVA group compared with the HFD group, while in the HRA group, it was the phosphotransferase system. These findings suggest that VA and RA can ameliorate MetS by modulating the gut microbiota and production of SCFAs.

Fruit Quality and Metabolomic Analyses of Fresh Food Accessions Provide Insights into the Key Carbohydrate Metabolism in Blueberry.

Blueberry is a nutrient-rich berry, and its taste and flavor directly determine the consumer preference. Until now, few studies have focused on the comparison of fresh food quality and the key metabolites in superior fresh-eating blueberry cultivars. Herein, fruit quality indicators of 10 highbush blueberry cultivars were evaluated using 'Bluerain' as the control. Appearance quality analysis of fruits showed that 'Brigitta' had a larger fruit size and 'Anna' was the smallest. 'Anna' fruits, followed by 'O'Neal', had the highest ratio of soluble solids to acidity because of their lowest titratable acidity content. Despite the high soluble sugar content, the antioxidants in 'Anna' fruits such as total flavonoids, anthocyanins and vitamin C were lowest among all cultivars, while 'Duke' seemed to have opposite patterns. Furthermore, a total of 553 and 557 metabolites were identified by non-targeted metabolomics liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive and negative ion mode, respectively. Particularly, the numbers of differentially accumulated metabolites (DAMs) were the most between the 'O'Neal' vs. 'Bluerain' group. The DAMs involved in the metabolic pathways, sesquiterpenoid and triterpenoid biosynthesis, monoterpenoid biosynthesis, galactose metabolism, starch and sucrose metabolism, may be mainly related to the synthesis of flavor and carbohydrate substances. Moreover, the expression patterns of genes involved in sugar metabolism were verified by quantitative real-time PCR (qRT-PCR) analysis in different cultivars. Therefore, the systematical comparison of the quality characteristics, metabolites and expression profiles of related genes in highbush blueberries with good flavor could provide some basis for further research on fresh fruit breeding of blueberries.

Screening and Evaluation of Excellent Blackberry Cultivars and Strains Based on Nutritional Quality, Antioxidant Properties, and Genetic Diversity.

To screen and evaluate excellent blackberry cultivars and strains, 17 indexes of plant growth and fruit horticultural and nutritional characteristics were measured, 20 simple sequence repeat (SSR) markers were analyzed, the fingerprints of 23 blackberry cultivars and strains were constructed, and the processing characteristics of 10 excellent cultivars and strains were evaluated. The results showed that 'Chester' and 'Shuofeng' had the highest plant yield (6.5 kg per plant), of which the 'Chester' fruit also had the highest hardness (2.78 kg/cm2). 'Kiowa' had the highest single fruit weight (10.43 g). '10-5n-2' had the highest total anthocyanin content (225.4 mg/100 g FW) and total polyphenol content (3.24 mg/g FW), but a low plant yield. These results suggest that 'Shuofeng' and 'Chester' are the top two blackberry cultivars planted in Nanjing, with the best growth and comprehensive quality. Moreover, a total of 119 alleles were detected with an average number of 6 alleles per locus. The polymorphism information content (PIC) was 0.374~0.844, with an average of 0.739, indicating a high genetic diversity among the 23 blackberry cultivars and strains. This study provides insight into the plant growth, fruit characteristics and genetic diversity of the 23 blackberry cultivars and strains, and is thus conducive to the protection and utilization of blackberry cultivars and strains.

Quality analysis and metabolomic profiling of the effects of exogenous abscisic acid on rabbiteye blueberry.

Blueberry is a characteristic berry fruit shrub of the genus Vaccinium in the Rhododendron family. The fruit is rich in anthocyanins and has a variety of nutritional and health functions. This study aimed to systematically study the effect of exogenous abscisic acid (ABA) application on ripening and metabolites in blueberry fruits. Blueberry fruit ripening was divided into six stages for further analysis. In this study, nontarget metabolomics was performed to demonstrate the effect on metabolite levels. The results showed that 1000 mg/L ABA significantly promoted fruit ripening and increased anthocyanin content. Moreover, exogenous ABA treatment can affect endogenous ABA levels and improve its antioxidant capacity. Important metabolites of the flavonoid pathway were detected, and the results showed that anthocyanin synthesis increased, and some other bioactive metabolite levels decreased. After comprehensive assessments, we believe that 1000 mg/L exogenous ABA application will have positive impacts on blueberry fruit quality and economic benefits.

Five blueberry anthocyanins and their antioxidant, hypoglycemic, and hypolipidemic effects in vitro.

The dual epidemic of obesity and diabetes mellitus is becoming an important worldwide public health issue. "Diabesity" is the term used to describe the combined detrimental health effects of both diabetes mellitus and obesity/overweight. Currently, food-derived bioactive compounds are suggested to alleviate diabesity. Blueberries are rich in bioactive anthocyanins, which are associated with contributing to preventing obesity and diabetes mellitus. However, the accurate active compounds and the underlying mechanism are still unclear. The objective of this study was to investigate the beneficial effects of blueberry anthocyanin on diabesity. In total, five anthocyanins (delphinidin-3-O-galactoside, delphinidin-3-O-glucoside, petunidin-3-O-galactoside, petunidin-3-O-glucoside, and malvidin-3-O-galactoside) were isolated from rabbiteye blueberry (Vaccinium virgatum) cultivar "Garden blue." All these anthocyanins exhibited oxygen radical absorbance capacity (ORAC), scavenging power of ABTS+, and DPPH-free radical and inhibitory activity of α-glucosidase in vitro. Moreover, some compounds improved glucose uptake and attenuated lipid accumulation in high glucose and oleic acid-treated HepG2 cells. All these results suggest that blueberry anthocyanins have potential antioxidant, hypoglycemic, and hypolipidemic effects, which may benefit the treatment of diabesity.

Effects of Different Nitrogen Forms on Blackberry Fruit Quality.

To study the optimal form of nitrogen (N) application and to determine the best harvest date for blackberries, different N fertilizers were applied during the critical growth period of blackberry plants. The results showed that NH4+-N significantly improved the appearance of blackberry fruits, including their size, firmness, and color, and promoted the accumulation of soluble solids, sugars, anthocyanin, ellagic acid, and vitamin C (VC), while fruit treated with NO3--N accumulated more flavonoids and organic acids and had improved antioxidant capacity. In addition, the fruit size, firmness, and color brightness decreased with the harvest period. While the contents of sugars, anthocyanin, ellagic acid, flavonoids, and VC were higher in the early harvests and then decreased as the season progressed, the total antioxidant capacity and DPPH radical scavenging capacity increased. In all, application of NH4+-N is recommended, as it is more beneficial to fruit appearance, taste, and nutritional quality. Harvests in the early stage help to obtain a good fruit appearance, while harvests in the middle and later stages are more beneficial to fruit taste and quality. This study may help growers to determine the best fertilization scheme for blackberries and choose the appropriate harvest time according to their needs.

Efficient solvent- and hydrogen-free upcycling of high-density polyethylene into separable cyclic hydrocarbons.

Plastic pollution is a planetary threat that has been exacerbated by the COVID-19 pandemic due to the surge in medical waste, personal protective equipment and takeaway packaging. A socially sustainable and economically viable method for plastic recycling should not use consumable materials such as co-reactants or solvents. Here we report that Ru nanoparticles on zeolitic HZSM-5 catalyse the solvent- and hydrogen-free upcycling of high-density polyethylene into a separable distribution of linear (C1 to C6) and cyclic (C7 to C15) hydrocarbons. The valuable monocyclic hydrocarbons accounted for 60.3 mol% of the total yield. Based on mechanistic studies, the dehydrogenation of polymer chains to form C=C bonds occurs on both Ru sites and acid sites in HZSM-5, whereas carbenium ions are generated on the acid sites via the protonation of the C=C bonds. Accordingly, optimizing the Ru and acid sites promoted the cyclization process, which requires the simultaneous existence of a C=C bond and a carbenium ion on a molecular chain at an appropriate distance, providing high activity and cyclic hydrocarbon selectivity.