Asymmetric Atomic Dual-Sites for Photocatalytic CO2 Reduction.

Atomically dispersed active sites in a photocatalyst offer unique advantages such as locally tuned electronic structures, quantum size effects, and maximum utilization of atomic species. Among these, asymmetric atomic dual-sites are of particular interest because their asymmetric charge distribution generates a local built-in electric potential to enhance charge separation and transfer. Moreover, the dual sites provide flexibility for tuning complex multielectron and multireaction pathways, such as CO2 reduction reactions. The coordination of dual sites opens new possibilities for engineering the structure-activity-selectivity relationship. This comprehensive overview discusses efficient and sustainable photocatalysis processes in photocatalytic CO2 reduction, focusing on strategic active-site design and future challenges. It serves as a timely reference for the design and development of photocatalytic conversion processes, specifically exploring the utilization of asymmetric atomic dual-sites for complex photocatalytic conversion pathways, here exemplified by the conversion of CO2 into valuable chemicals.

Hydrogen-Bond-Enhanced Photoreforming of Biomass Furans over a Urea-Incorporated Cu(II) Porphyrin Framework.

Solar-driven upgrading of biomass-derived 5-hydroxylmethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) holds great promise for sustainable production of bio-plastics and resins. However, the process is limited by poor selectivity and sluggish kinetics due to the vertical coordination of HMF at relatively strong metal sites. Here, we purposely developed a Cu(II) porphyrin framework featuring side-chain incorporated urea linkages, denoted as TBUPP-Cu MOF, to render HMF a weak hydrogen bond at the urea site and flat adsorption via π-π stacking with the benzene moiety. The unique configuration promotes the approaching of -CHO of HMF to the photoexcited porphyrin ring towards kinetically and thermodynamically favourable intermediate formation and subsequent desorption. The charge localisation and orbital energy alignment enable the selective activation of O2 over the porphyrin to generate ⋅O2 - and 1O2 instead of highly oxidative H2O2 and ⋅OH via spin-flip electron transfer, which drive the ambient oxidation of proximal -CHO. The effective utilisation of redox species and circumvented over-oxidation facilitate a FDCA selectivity of >90 % with a high turnover number of 193 molHMF molCu -1. The facile purification of high-purity FDCA and zero-waste recycling of intermediates and durable catalyst feature TBUPP-Cu MOF a promising photo-oxidation platform towards net-zero biorefining and organic transformations.

Improved antioxidant activity of pretreated lignin nanoparticles: Evaluation and self-assembly.

Lignin nanoparticles (LNPs) have gained significant attention for their potential as natural antioxidants. This study investigated the effect of various pretreatment methods on the lignin structure and subsequent antioxidant activity of LNPs. Among four pretreated LNPs, hydrothermal LNPs exhibited the highest antioxidant activity, surpassing unpretreated, acid-pretreated and kraft LNPs, with an impressive efficacy of 91.6%. The relationship between LNPs' structure and antioxidant activity was revealed by 2D heteronuclear singular quantum correlation (1H13C HSQC) and 31P nuclear magnetic resonance (NMR). 1H13C HSQC suggested the cleavage of ß-O-4 ether bonds, as well as a decrease in ferulic acid and p-coumaric acid, which directly influenced the antioxidant activity of LNPs. 31P NMR demonstrated a positive correlation between the total hydroxyl group content and the antioxidant activity. Besides, an isothermal kinetic model for scavenging free radicals was established based on Langmuir kinetic model instead of Freundlich model. Moreover, multilayer LNPs, based on layer-by-layer self-assembly, were prepared and exhibited remarkable antioxidant activity of 95.8%. More importantly, when blended with pure cosmetic cream, the multilayer LNPs maintained antioxidant activity of 86.7%. These finding may promote the practical applications of biomolecules, e.g. lignin additives in cosmetics and pharmaceuticals.

Lithiophilic Chemistry Facilitated Ultrathin Lithium for Scalable Prelithiation.

Prelithiation plays a crucial role in advancing the development of high-energy-density batteries, and ultrathin lithium (UTL) has been proven to be a promising anode prelithiation reagent. However, there remains a need to explore an adjustable, efficient, and cost-effective method for manufacturing UTL. In this study, we introduce a method for producing UTL with adjustable thicknesses ranging from 1.5 to 10 µm through blade coating of molten lithium on poly(vinylidene fluoride)-modified copper current collectors. By employing the transfer-printing method, prelithiated graphite and Si-C composite electrodes are prepared, which exhibit significantly improved initial Coulombic efficiencies of 99.60% and 99.32% in half-cells, respectively. Moreover, the energy densities of Li(NiCoMn)1/3O2 and LiFePO4 full cells assembled with the prelithiated graphite electrodes increase by 13.1% and 23.6%, respectively.

Oxygen-deficient TiO2-x interlayer enabling Li-rich Mn-based layered oxide cathodes with enhanced reversible capacity and cyclability.

The unique anion redox mechanism of Li-rich Mn-based layered oxide (LMLO) cathodes endows them with a higher specific capacity compared with conventional cathodes. However, the irreversible anion redox reactions can cause structural degradation and sluggish electrochemical kinetics in the cathode, resulting in a poor electrochemical performance in the batteries. Thus, to address these issues, a single-sided conductive oxygen-deficient TiO2-x interlayer was applied on a commercial Celgard separator as a coating layer towards the LMLO cathode. After coating TiO2-x, the initial coulombic efficiency (ICE) of the cathode increased from 92.1% to 95.8%, the capacity retention improved from 84.2% to 91.7% after 100 cycles, and the rate performance of the cathode was significantly enhanced from 91.3 mA h g-1 to 203.9 mA h g-1 at 5C. Operando differential electrochemical mass spectroscopy (DEMS) showed that the coating layer could restrain the release of oxygen in the battery, especially from the initial formation process. The X-ray photoelectron spectroscopy (XPS) results demonstrated that the favorable oxygen absorption by the TiO2-x interlayer benefitted the suppression of side reactions and cathode structural evolution and favored the formation of a uniform cathode-electrolyte interphase on the LMLO cathode. This work provides an alternative path to address the issue of oxygen release in LMLO cathodes.

Selective saccharification of crude glycerol pretreated sugarcane bagasse via fast pyrolysis: Reaction kinetics and life cycle assessment.

Saccharification is a pivotal step in the conversion of lignocellulose to biofuels and chemicals. In this study, crude glycerol derived from biodiesel production was used in pretreatment to facilitate efficient and clean pyrolytic saccharification of sugarcane bagasse. Delignification, demineralization, destruction of lignin-carbohydrate complex structure, and cellulose crystallinity improvement in crude glycerol pretreated biomass could enhance levoglucosan producing reactions against competitive reactions, and therefore facilitate a kinetically controlled pyrolysis with apparent activation energy increased by 2-fold. Accordingly, selective levoglucosan production (44.4%) was promoted by 6-fold whilst light oxygenates and lignin monomers were limited to <25% in bio-oil. Owing to the high-efficiency saccharification, life cycle assessment suggested that the environmental impacts of the integrated process were less than those of typical acid pretreatment and petroleum-based processes, especially on the acidification (8-fold less) and global warming potential. This study provides an environmentally benign approach to efficient biorefinery and waste management.

AIEgens/Mitochondria Nanohybrids as Bioactive Microwave Sensitizers for Non-Thermal Microwave Cancer Therapy.

Aggregation-induced emission luminogens (AIEgens) are widely used as photosensitizers for image-guided photodynamic therapy (PDT). Due to the limited penetration depth of light in biological tissues, the treatments of deep-seated tumors by visible-light-sensitized aggregation-induced emission (AIE) photosensitizers are severely hampered. Microwave dynamic therapy attracts much attention because microwave irradiation can penetrate very deep tissues and sensitize the photosensitizers to generate reactive oxygen species (ROS). In this work, a mitochondrial-targeting AIEgen (DCPy) is integrated with living mitochondria to form a bioactive AIE nanohybrid. This nanohybrid can not only generate ROS under microwave irradiation to induce apoptosis of deep-seated cancer cells but also reprogram the metabolism pathway of cancer cells through retrieving oxidative phosphorylation (OXPHOS) instead of glycolysis to enhance the efficiency of microwave dynamic therapy. This work demonstrates an effective strategy to integrate synthetic AIEgens and natural living organelles, which would inspire more researchers to develop advanced bioactive nanohybrids for cancer synergistic therapy.

The parallel electron transfer pathways of biofilm and self-secreted electron shuttles in gram-positive strain Rhodococcus pyridinivorans HR-1 inoculated microbial fuel cell.

Microbial fuel cell (MFC) exhibits huge potentials in disposing wastewater and extra energy consumption. Exploring useful microorganisms for MFC is the crucial section. Herein, the electrochemical mechanism of extracellular anaerobic respiration in MFC inoculated with gram-positive Rhodococcus pyridinivorans HR-1, was first revealed. The MFC exhibited rapid recovery of currents on anode, and could recover to maximum output within one hour, with redox peaks near -0.38 and -0.18 V through electron transfer between the biofilm and anode. When the biofilm-based pathway was blocked by wrapping the anode with Millipore filter membrane, HR-1 inoculated MFC could still generate electricity within a longer recovery period (∼35 h) during anolyte exchange. This was proposed as a self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1. Cyclic voltammetry analysis revealed that the biofilm-based and self-secreted electron shuttle-based pathways co-existed in R. pyridinivorans HR-1 inoculated MFC, which could play synergistic roles in electricity generation.

Mitigation of Oxygen Evolution and Phase Transition of Li-Rich Mn-Based Layered Oxide Cathodes by Coating with Oxygen-Deficient Perovskite Compounds.

Li-rich Mn-based layered oxide cathodes with a high discharge capacity hold great promise for high energy density lithium-ion batteries. However, application is hampered by voltage and capacity decay and gas evolution during cycling due to interfacial side reactions. Here, we report coating by oxygen-deficient perovskite La0.9Sr0.1CoO3 using the Pechini process. X-ray photoelectron spectroscopy and scanning transmission electron microscopy both exhibit a uniform coating layer with a high oxygen vacancy concentration. The coating effectively mitigates the first cycle irreversible capacity loss and voltage decay while increasing cyclability. Optimized coating improves capacity retention from 55.6% to 84.8% after 400 cycles at 2 C. Operando differential electrochemical mass spectroscopy shows that such a coating can significantly mitigate the release of oxygen and carbon dioxide. Electrochemical impedance spectroscopy and post-mortem analysis indicate that the coating layer forms a stable interface and restricts structure evolution and cation mixing during cycling, conferring these cathode materials with better cycling and voltage stability. The perovskite can be applied to other cathodes with high voltage and capacity to suppress interfacial side reactions toward developing stable high energy density batteries.

A Dynamic Constitutive Model and Simulation of Braided CFRP under High-Speed Tensile Loading.

In this study, a dynamic constitutive model for woven-carbon-fiber-reinforced plastics (CFRP) is formulated by combining dynamic tensile test data and fitting curves and incorporating variation rules established for the modulus of elasticity, strength, and fracture strain with respect to the strain rate. The dynamic constitutive model is then implemented with finite element software. The accuracy and applicability of the dynamic constitutive model are evaluated by comparing the numerically predicted load-displacement curves and strain distributions with the test data. The stress distribution, failure factor, modulus, and strength of the material under dynamic tension are also explored. The results show that the response simulated with the dynamic constitutive model is in good agreement with the experimental results. The strain is uniformly distributed during the elastic phase compared with the DIC strain field. Subsequently, it becomes nonuniform when stress exceeds 600 MPa. Then, the brittle fracture occurs. With the increase in the strain rate, the input modulus decreased, and the tensile strength increased. When the displacement was 0.13 mm, the simulation model was damaged at a low strain rate, and the stress value was 837.8 MPa. When it reached the high strain rate of 800 s-1, no failure occurred, and the maximum stress value was 432.5 MPa. For the same specimen, the strain rate was the smallest on both clamped ends, and the modulus and strength were large at the ends and small in the middle. The fitting curve derived from the test data was completely input into the dynamic constitutive model to better capture the dynamic change in the material properties.

Revealing the key role of structural cross-link between lignin and polysaccharides during fast pyrolysis of lignocellulose.

Lignin-carbohydrate complex (LCC) is the native existing form of major components in lignocellulose. In this study, the structural cross-link between lignin and polysaccharides in lignocellulose was quantitatively estimated with carboxymethylation-separation (CM-Sep) method, and its influence on lignocellulose pyrolysis was systematically investigated. The cross-linked lignin was found to positively correlate with the production of small molecules and furan derivatives while negatively affecting the generation of anhydrous sugars. Content of small molecules was increased by 97% while that of anhydrous sugars was decreased by 47% in pyrolytic products with levoglucosan yield lowered by 54 wt% in the existence of cross-linked lignin. Furthermore, the impact of cross-linked lignin was revealed to be significantly distinguished from free lignin. Impeded glycosidic end formation and boosted glycosyl ring scission as well as lignin fragmentation were responsible for the distinction. Excellent correlations between structural cross-link and lignocellulose pyrolytome could facilitate product prediction and process design.

Dual Utilization of Lignocellulose Biomass and Glycerol Waste to Produce Fermentable Levoglucosan via Fast Pyrolysis.

Glycerol waste was combined with microwave to pretreat lignocellulose before fast pyrolysis. After pretreatment, most alkali and alkaline earth metals (87.9%) and lignin (52.6%) were removed, and a higher crystallinity was obtained. Comparatively, glycerol waste combined with microwave was proven to be more efficient than glycerol with conventional heating. During fast pyrolysis, higher content of levoglucosan in glycerol waste-pretreated products (27.5%) was obtained, compared with those pretreated by pure glycerol (18.8%) and untreated samples (5.8%). Production of fermentative toxic aldehyde and phenol by-products was also inhibited after glycerol waste treatment. Following mechanistic study had validated that microwave in glycerol waste solvent could effectively ameliorate structure and components of lignocellulose while selectively removing lignin. Notably, under the optimal condition, the levoglucosan content in pyrolytic products was enhanced significantly from 5.8% to 32.9%. In short, this study provided an archetype to dually utilize waste resources for ameliorating lignocellulose structure and precisely manipulating complex fast pyrolysis.

Single-Crystalline Cathodes for Advanced Li-Ion Batteries: Progress and Challenges.

Single-crystalline cathodes are the most promising candidates for high-energy-density lithium-ion batteries (LIBs). Compared to their polycrystalline counterparts, single-crystalline cathodes have advantages over liquid-electrolyte-based LIBs in terms of cycle life, structural stability, thermal stability, safety, and storage but also have a potential application in solid-state LIBs. In this review, the development history and recent progress of single-crystalline cathodes are reviewed, focusing on properties, synthesis, challenges, solutions, and characterization. Synthesis of single-crystalline cathodes usually involves preparing precursors and subsequent calcination, which are summarized in the details. In the following sections, the development issues of single-crystalline cathodes, including kinetic limitations, interfacial side reactions, safety issues, reversible planar gliding and micro-cracking, and particle size distribution and agglomeration, are systematically analyzed, followed by current solutions and characterization techniques. Finally, this review is concluded with proposed research thrusts for the future development of single-crystalline cathodes.

Synthesis and Photoinduced Anisotropy of Polymers Containing Nunchaku-Like Unit with an Azobenzene and a Mesogen.

A series of polymers containing nunchaku-like unit with an azo chromophore and a mesogen group was successfully prepared and photoinduced anisotropy of the obtained polymers was minutely investigated. Firstly, monomers containing nunchaku-like unit with an azo chromophore and a mesogen group linked by flexible group were synthesized. The structure of the monomers was confirmed via NMR COSY spectra. Subsequently, the obtained monomers were polymerized into corresponding polymers through RAFT polymerization. The prepared polymer samples were characterized through NMR, FTIR, gel permeation chromatography (GPC), and UV-vis testing while the thermal properties of the samples were investigated through differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) measurements. The photoinduced isomerization of the polymers, which was researched in situ via measuring UV-vis spectra of the polymer solutions and spin-coated films under irradiation with 450 nm light or putting in darkness, demonstrated the rapid trans-cis-trans isomerization of the polymers. When irradiated with a linearly polarized light, significant photoinduced birefringence and dichroism were observed, suggesting photoinduced isomerization of azobenzene can drive orientation of mesogen in the system. This study blazes a way to design the optical materials with light-controllable birefringence and dichroism.

Five Chinese pediatric patients with leukemias possibly arising from immature natural killer cells: clinical features and courses.

Leukemias arising from immature nature killer (NK) cells have been proposed as distinct entities and are rare. Treatment and prognosis of these diseases are controversial, and data on children are limited. According to the literature, one of these distinct leukemias may be myeloid/NK cell precursor acute leukemia (MNKPL), with the blasts being cytochemically myeloperoxidase negative (MPO(-)) and phenotypically CD56(+)CD3(-)CD7(+)CD34(+) and myeloid antigens(+). The other may be myeloid/NK cell acute leukemia (MNKL), in which the blasts were cytochemically MPO(dim) and phenotypically CD56(+)CD16(-)CD3(-)CD33(+)HLA-DR(-). Between 2005 and 2008, 4 MNKPL and 1 MNKL children aged 1.3 to 12.5 years were encountered in the First Affiliated Hospital of Sun Yat-Sen University. In those with MNKPL, remarkable extramedullary involvement usually occurring in adults was not observed; however, myelofibrosis was found in 2 children. The child with MNKL abandoned treatment. Those with MNKPL were treated with a protocol designed for childhood high-risk acute lymphoblastic leukemia (ALL) containing cytarabine, mitoxantrone, etoposide, l-asparaginase, and methotrexate according to the myeloid and lymphoid characteristics of MNKPL. They responded slowly to chemotherapy and were in complete remission (CR) for 26 to 63 months, except 1 who died in CR from pneumonia. They had longer survival and seemed to have a better outcome than those reported previously. In conclusion, childhood leukemias with immature NK cell markers may have different characteristics from their adult counterparts. A protocol including agents used for acute myeloid leukemia combined with those for ALL is seemingly effective for treatment of MNKPL. However, a modified treatment strategy designed more specifically for MNKPL and longer observations are needed.

Fibroblast growth factor 21 as a possible endogenous factor inhibits apoptosis in cardiac endothelial cells.

BACKGROUND: Fibroblast growth factor 21 (FGF21) is a new member of FGF super family that is an important endogenous regulator for systemic glucose and lipid metabolism. This study aimed to explore whether FGF21 reduces atherosclerotic injury and prevents endothelial dysfunction as an independent protection factor. METHODS: The present study was designed to investigate the changes of FGF21 levels induced by oxidized-low density lipoprotein (ox-LDL), and the changes of apoptosis affected by regulating FGF21 expression. The FGF21 mRNA levels of cultured cardiac microvascular endothelial cells (CMECs) were determined by real time-PCR and the protein concentration in culture media was detected by enzyme-linked immunosorbent assay. We analyzed the different expression levels of untreated controls and CMECs incubated with ox-LDL, and the changes of CMECs apoptosis initiated by the enhancement or suppression of FGF21 levels. RESULTS: The secretion levels of FGF21 mRNA and protein were significantly upregulated in CMECs incubated with ox-LDL. Furthermore, FGF21 levels increased by 200 µmol/L bezafibrate could reduce CMECs apoptosis, and inhibit FGF21 expression by shRNA induced apoptosis (P < 0.05). CONCLUSIONS: FGF21 may be a signal of injured target tissue, and may play physiological roles in improving the endothelial function at an early stage of atherosclerosis and in stopping the development of coronary heart disease.

[Oxidized low density lipoprotein and peroxisome proliferator-activated receptor α induced endogenous fibroblast growth factor 21 upregulation is protective against apoptosis in cardiac endothelial cells].

OBJECTIVE: To investigate the effect of peroxisome proliferator-activated receptor (PPAR)α agonist bezafibrate and oxidized low density lipoprotein (ox-LDL) on fibroblast growth factor 21 (FGF21) expression and apoptosis in cardiac endothelial cells. METHODS: The mRNA level of FGF21 was determined by real time-PCR and the protein concentration of FGF21 in culture media was detected by enzyme-linked immunosorbent assay in cultured cardiac microvascular endothelial cells (CMECs) incubated with 10, 50, 100 µg/ml ox-LDL, 50, 100 or 200 µmol/L bezafibrate alone or in combination with 100 µg/ml ox-LDL. CMECs apoptosis in various treatment groups was also determined. RESULTS: FGF21 mRNA and protein expressions were significantly upregulated in proportion to increased ox-LDL, and 200 µmol/L bezafibrate alone also significantly upregulated FGF21 expression and CMECs apoptosis was significantly reduced in 200 µmol/L bezafibrate + 100 µg/ml ox-LDL group compared to 100 µg/ml ox-LDL group (P < 0.05). CONCLUSIONS: Our data suggest that bezafibrate and ox-LDL induced upregulation of FGF21 might mediate the protective effect against apoptosis. Endogenous FGF21 could thus play important roles in improving the endothelial function at the early stage of atherosclerosis and slowing the development of coronary heart disease.

Current status of diagnosis and prognosis of infant acute leukemia in China.

OBJECTIVE: Treatment and outcome of infant acute leukemia (IAL) in developed countries have been well documented. However, reports summarizing diagnosis and outcome of IAL in developing countries are limited. METHODS: Five hundred ninety seven pediatric patients were diagnosed with acute leukemia in our hospital between January 1997 and June 2008, of which 19 were younger than 12 months. Data from our 19 cases and the Chinese literature were analyzed. RESULTS: Of the 19 cases, 14 had acute lymphoblastic leukemia (ALL) and 5 had acute myeloid leukemia (AML) based on FAB classification. Immunophenotyping and molecular genetic analysis were performed in only 6 cases. Only 16% (3/19) of the infants received treatment. Two infants with immunophenotypic AML who abandoned treatment achieved spontaneous remission without chemotherapy within 2 and 4 months respectively. Combining our data with those from Chinese literature, less than one third of the infants had immunophenotypic and genetic verification of leukemia and 29% (18/63) of them received treatment. CONCLUSION: Family financial difficulties and physicians' lack of confidence in treatment outcome in IAL contributed to a high treatment abandonment rate and poor outcome. Public health insurance as well as physician education on current IAL treatment strategies may decrease treatment abandonment in China.

Improved outcome for Chinese children with acute promyelocytic leukemia: a comparison of two protocols.

OBJECTIVE: Acute promyelocytic leukemia (APL) is now highly curable, except in many developing countries. Introduction of current treatment strategies may improve the outcome for children with APL in these countries. METHODS: The diagnosis was based on the FAB classification and detection of PML-RAR alpha rearrangement. From December 1999 to September 2004, 16 eligible children were treated with an intensive in-house protocol including high-dose AraC and anthracycline. Subsequently, 14 cases were treated with a less intensive protocol modified from the PETHEMA LPA99. RESULTS: The 3.5 years event-free survival (EFS) was 37.5% (95% CI, 13.8-61.2%) for patients treated on initial protocol. The treatment failures were: six patients abandoned treatment (37.5%), two who died of intracranial hemorrhage at diagnosis (6.3%) and sepsis in remission (6.3%) respectively, and two who relapsed (12.5%). Those treated on modified PETHEMA had a 3.5 years EFS of 79.6% (95% CI, 52.9-106.3%). Treatment failures included: one who died of intracranial hemorrhage at diagnosis (7.1%) and one who relapsed (7.1%). The patients on modified PETHEMA had a significantly higher EFS (P = 0.012), lower frequency of sepsis during treatment (7.7% vs. 77.8%; P = 0.0015), and lower hospitalization cost (median US$ 4,700 vs. US$ 20,000; P < 0.0001) than those on in-house protocol. CONCLUSION: Treatment with the less intensive protocol based on the PETHEMA LPA99 study of childhood APL successfully reduced chemotherapy toxicity and lowered hospitalization costs without increasing relapses. This led to decreases in treatment-related morbidity and the treatment abandonment rate, thus improving overall outcome.

High-risk childhood acute lymphoblastic leukemia in China: factors influencing the treatment and outcome.

OBJECTIVE: Acute lymphoblastic leukemia (ALL) with high-risk features has an inferior outcome. Factors influencing the treatment and outcome of pediatric ALL with high-risk features in developing countries have not been well studied. METHODS: High-risk features were defined as: age <1 year or >10 years, white blood cell (WBC) > 50 x 10(9)/L, CNS or testicular involvement at diagnosis, T-ALL, BCR-ABL/MLL-AF4, poor prednisone response, slow early response to induction chemotherapy which was defined as M3 status (>25% blasts) on day 15 bone marrow with age >6 years or presenting WBC > 20 x 10(9)/L at diagnosis and/or non-remission (NR) after 33 days of induction therapy. RESULTS: Ninety-one children were analyzed. The total rate of treatment abandonment was 24.2% and treatment-related mortality was 3.3% (3/91). The event-free survival (EFS) was 52.3% (95% CI, 41.5-63.1%) at 4 years and 49.9% (95% CI, 38.9-60.9%) at 8 years, respectively. When the cases who abandoned treatment were excluded, the EFS of the remainder was 68.3% (95% CI, 56.5-80.1%) at 4 years and 65.2% (95% CI, 52.5-77.9%) at 8 years, respectively. NR on day 33 or BCR-ABL remained as an independent unfavorable prognostic factor in the Cox model even if more intense chemotherapy was administrated. CONCLUSION: A decreased treatment-related death frequency was associated with an improved outcome of leukemia. This emphasizes the importance of improving supportive care in developing countries for children with high-risk ALL who receive very intensive chemotherapy. Treatment abandonment remains a prominent reason for treatment failure in China.