RESUMEN

Inhibin beta A (INHBA) and its homodimer activin A have pleiotropic effects on modulation of immune responses and tumor progression, but it remains uncertain whether tumors may release activin A to regulate anti-tumor immunity. In this study we investigated the effects and mechanisms of tumor intrinsic INHBA on carcinogenesis, tumor immunity and PD-L1 blockade. Bioinformatic analysis on the TCGA database revealed that INHBA expression levels were elevated in 33 cancer types, including breast cancer (BRCA) and colon adenocarcinoma (COAD). In addition, survival analysis also corroborated that INHBA expression was negatively correlated with the prognosis of many types of cancer patients. We demonstrated that gain or loss function of Inhba did not alter in vitro growth of colorectal cancer CT26 cells, but had striking impact on mouse tumor models including CT26, MC38, B16 and 4T1 models. By using the TIMER 2.0 tool, we figured out that in most cancer types, Inhba expression in tumors was inversely associated with the infiltration of CD4+ T and CD8+ T cells. In CT26 tumor-bearing mice, overexpression of tumor INHBA eliminated the anti-tumor effect of the PD-L1 antibody atezolizumab, whereas INHBA deficiency enhanced the efficacy of atezolizumab. We revealed that tumor INHBA significantly downregulated the interferon-γ (IFN-γ) signaling pathway. Tumor INHBA overexpression led to lower expression of PD-L1 induced by IFN-γ, resulting in poor responsiveness to anti-PD-L1 treatment. On the other hand, decreased secretion of IFN-γ-stimulated chemokines, including C-X-C motif chemokine 9 (CXCL9) and 10 (CXCL10), impaired the infiltration of effector T cells into the tumor microenvironment (TME). Furthermore, the activin A-specific antibody garetosmab improved anti-tumor immunity and its combination with the anti-PD-L1 antibody atezolizumab showed a superior therapeutic effect to monotherapy with garetosmab or atezolizumab. We demonstrate that INHBA and activin A are involved in anti-tumor immunity by inhibiting the IFN-γ signaling pathway, which can be considered as potential targets to improve the responsive rate of PD-1/PD-L1 blockade.

RESUMEN

This study aimed to investigate the impact of different nitrogen forms on soil physicochemical properties and microbial community structure in perennial alpine cultivated grasslands, in order to provide scientific basis for developing nitrogen addition strategies for perennial alpine cultivated grasslands. In June 2022, a 4-year-old Qinghai grassland mixed with Poa pratensis Qinghai and Festuca sinensis Qinghai was established at the Bakatai Farm in Gonghe County, Hainan Tibetan Autonomous Prefecture, Qinghai Province. The study was conducted without fertilization as a control (CK), and three different forms of nitrogen treatments were set up, namely, U:urea (amide nitrogen), A:ammonium sulfate (ammonium nitrogen), and N:calcium nitrate (nitrate nitrogen); the nitrogen application rate for each treatment was 67.5 kg·(hm2·a)-1, and the composition and diversity of soil nutrients and microbial communities under different treatments were analyzed. The results showed that the input of exogenous ammonium nitrogen significantly increased NH4+-N content, AP content, and EC; amide nitrogen input significantly increased SOC content and TN content; and nitrate nitrogen input significantly increased NO3--N content, AN content, and TC content. Exogenous nitrogen input changed the structure of soil bacterial and fungal communities, as well as the relative abundance of dominant phyla and genera, but it did not significantly affect the alpha diversity of bacterial and fungal communities. Principal coordinate analysis (PCoA) showed that different forms of nitrogen addition had a significant impact on the Beta diversity of bacterial communities, whereas the impact on fungal communities was not significant. Redundancy analysis (RDA) indicated that nitrogen addition mainly changed the composition and structure of microbial communities through soil ammonium nitrogen. Overall, ammonium nitrogen fertilizer should be given priority in the soil remediation process of perennial cultivated grasslands in the Qinghai Tibet Plateau.

Asunto(s)

RESUMEN

Direct methanol fuel cells (DMFCs) have attracted increasing attention as a very promising and important energy source. In this paper, density functional theory (DFT) is used to study the structure and O-H fracture mechanism of methanol adsorption on PtnCu4-n (111) (n = 1, 2, 3) binary metal catalyst surfaces under different coverages. By comparing the adsorption energy and dehydrogenation energy barriers of methanol, it is found that the adsorption strength and dehydrogenation energy barriers of methanol on Pt and Cu sites decreased with increasing coverage. At the same Pt and Cu ratio, methanol is more easily adsorbed on Cu sites. When Pt/Cu = 3:1 and 1:3, the PtCu binary catalyst has a significant impact on the energy barrier of breaking the O-H bond in methanol with the increase of coverage. Especially when Pt/Cu = 1:3 and the coverage is 1/4 ML, the energy barriers of O-H bond breaking in methanol on Pt and Cu sites are 0.63 and 0.61 eV, respectively, which are lower than that on pure Pt. It means that the Cu sites played a very important role in reducing the O-H fracture energy barrier of methanol. When Pt/Cu = 1:1, the change in the dehydrogenation energy barrier of methanol on Pt sites and Cu sites is not significant, indicating that the coverage has little effect on it.

RESUMEN

Objective: The study established a nomogram based on quantitative parameters of spectral computed tomography (CT) and clinical characteristics, aiming to evaluate its predictive value for preoperative lymphovascular invasion (LVI) in gastric cancer (GC). Methods: From December 2019 to December 2021, 171 patients with pathologically confirmed GC were retrospectively collected with corresponding clinical data and spectral CT quantitative data. Patients were divided into LVI-positive and LVI-negative groups based on their pathological results. The univariate and multivariate logistic regression analyses were used to identify the risk factors and construct a nomogram. The calibration curve and receiver operating characteristic (ROC) curve were adopted to evaluate the predictive accuracy of nomogram. Results: Four clinical characteristics or spectral CT quantitative parameters, including Borrmann classification (P = 0.039), CA724 (P = 0.007), tumor thickness (P = 0.031), and iodine concentration in the venous phase (VIC) (P = 0.004) were identified as independent factors for LVI in GC patients. The nomogram was established based on the four factors, which had a potent predictive accuracy in the training, internal validation and external validation cohorts, with the area under the ROC curve (AUC) of 0.864 (95% CI, 0.798-0.930), 0.964 (95% CI, 0.903-1.000) and 0.877 (95% CI, 0.759-0.996), respectively. Conclusion: This study constructed a comprehensive nomogram consisting spectral CT quantitative parameters and clinical characteristics of GC, which exhibited a robust efficiency in predicting LVI in GC patients.

RESUMEN

Background: A high aspartate aminotransferase/platelet ratio index (APRI) predicts mortality in patients with severe infection. This study aims to assess the potential of APRI as a predictor for mortality in patients with HIV-associated Talaromyces marneffei (HTM). Methods: Associations between APRI and CD4 count, white blood cell count, C-reactive protein (CRP) level, procalcitonin (PCT) level, and cytokines were assessed in 119 patients. Univariate and multivariate Cox regression models were used to predict APRI on 24-week mortality. Results: APRI was positively associated with CRP (r = 0.190, P = .039), PCT (r = 0.220, P = .018), interleukin 6 (r = 0.723, P < .001), interleukin 10 (r = 0.416, P = .006), and tumor necrosis factor α (r = 0.575, P < .001) and negatively associated with CD4 count (r = -0.234, P = .011). In total, 20.2% (24/119) of patients died within the 24-week follow-up. The 24-week survival rate was 88.0% for patients with APRI <5.6% and 61.1% for those with APRI ≥5.6 (log-rank P < .001). After adjustment for sex, age, body mass index, and CD4 count, as well as serum levels of hemoglobin, APRI ≥5.6 (adjusted hazard ratio [95% CI]; 3.0 [1.2-7.1], P = .015), PCT ≥1.7 ng/mL (3.7 [1.5-9.6], P = .006), and non-amphotericin B deoxycholate treatment (2.8 [1.2-6.6], P = .018) were independent risk factors for 24-week mortality. Conclusions: For patients with HTM, APRI is associated with severity and is an independent risk factor for 24-week mortality.

RESUMEN

The COVID-19 pandemic led to an initial increase in the incidence of carbapenem-resistant Enterobacterales (CRE) from clinical cultures in South-East Asia hospitals, which was unsustained as the pandemic progressed. Conversely, there was a decrease in CRE incidence from surveillance cultures and overall combined incidence. Further studies are needed for future pandemic preparedness.

RESUMEN

Carbon-based anode materials have become a research hotspot for alkali metal ion batteries. Crucially, the electrochemical performance of carbon materials must be improved by appropriate means such as micro-nano structure design and atomic doping. Herein, antimony doped hard carbon materials are prepared by anchoring Sb atoms on nitrogen-doped carbon (SbNC). The coordination of non-metal atoms can better disperse Sb atoms on the carbon matrix, and the synergistic effect between Sb atoms, coordinated non-metal atoms, and hard carbon matrix endows SbNC anode with good electrochemical performance. When used in sodium-ion half-cells, the SbNC anode showed high rate capacity of 109 mAh g-1 at 20 A g-1 and good cycling performance (254 mAh g-1 at 1 A g-1 after 2000 cycles). In addition, when used in potassium-ion half-cells, the SbNC anode exhibited initial charge capacity of 382 mAh g-1 at 0.1 A g-1 and rate capacity of 152 mAh g-1 at 5 A g-1. This research shows that compared with ordinary nitrogen doping, Sb-N coordination active sites on carbon matrix can provide much more adsorption capacity, improve ion filling and diffusion properties as well as enhance the kinetics of electrochemical reaction for the sodium/potassium storage.

RESUMEN

Bismuth (Bi)-based materials have attracted great attention as anodes in potassium ion batteries (PIBs) for their high theoretical capacity and suitable voltage range. Herein, the authors report a unique spindle-like structured Bi@N-doped carbon composite (SPB@NC) consisting of interconnected nano-Bi coated heteroatom-doped hard carbon layer via an interesting in situ carbon thermal reduction method. The special interconnected Bi nanoparticles gradually form porous structure with ample inner voids for accommodating volume variations while the N-doped carbon layer not only keeps the electrode stable, but also contributes to rapid electron/ion transfer. As a result, such a robust framework endows SPB@NC fast potassium storage with outstanding capacity of 276.5 mAh g-1  at 30 A g-1 (i.e., 1 min for discharge/charge) and durable cycling performance of 299.3 mAh g-1  at 5 A g-1  after 2000 cycles. Notably, a full cell assembled with potassium vanadate cathode is promising for practical applications. A series of ex situ techniques reveals the in-depth potassium storage mechanism and kinetics reactions. This work illuminates helpful insights into Bi-based anodes for PIBs.

RESUMEN

Shigella flexneri is a major diarrhoeal pathogen, and the emergence of multidrug-resistant S. flexneri is of public health concern. We report the detection of a clonal cluster of multidrug-resistant serotype 1c (7a) S. flexneri in Singapore in April 2022. Long-read whole-genome sequence analysis found five S. flexneri isolates to be clonal and harboring the extended-spectrum ß-lactamases bla CTX-M-15 and bla TEM-1. The isolates were phenotypically resistant to ceftriaxone and had intermediate susceptibility to ciprofloxacin. The S. flexneri clonal cluster was first detected in a tertiary hospital diagnostic laboratory (sentinel-site), to which the S. flexneri isolates were sent from other hospitals for routine serogrouping. Long-read whole-genome sequence analysis was performed in the sentinel-site near real-time in view of the unusually high number of S. flexneri isolates received within a short time frame. This study demonstrates that near real-time sentinel-site sequence-based surveillance of convenience samples can detect possible clonal outbreak clusters and may provide alerts useful for public health mitigations at the earliest possible opportunity.

RESUMEN

Numerous methods have been used for preparing porous materials; however, these techniques can not uniformly incorporate inorganic additives into the pore structure. Therefore, a novel method has been presented to fabricate an oil-absorbing resin composite with three-dimensional porous structure by using a double Pickering emulsion template. First, an oil-in-water-in-oil double Pickering emulsion was prepared using attapulgite (ATP) and modified Fe3 O4 . Second, the Pickering emulsion was employed as a template to synthesize the ATP/P(n-BuMA-St)/Fe3 O4 oil-absorbing resin composite by utilizing butyl methacrylate (n-BuMA) and styrene (St) as comonomers, divinylbenzene as the crosslinking agent, and benzoyl peroxide as the initiator. Finally, the oil absorption performance of the resin composite was explored. The oil absorption ratio of the resin goes up to 754.75 %, while its oil retention rate approximately equals 84 %; when the mass ratio of St and poly (butyl methacrylate) is 2 : 1, the mass percentages of crosslinking agent, initiator, emulsifier, and ATP are observed to be 2 %, 0.4 %, 3 %, and 0.6 %, respectively. Overall, this work provides a novel strategy for preparing an oil-absorbing composite resin, which is expected to be popularized and utilized for oil spill remediation and oily wastewater treatment.

Asunto(s)

RESUMEN

Due to their characteristics of high capacity and appropriate potassiation/depotassiation potential, Sb-based materials have become a class of promising anode materials for potassium ion batteries (PIBs). However, the huge strain induced by potassiation/depotassiation limits their ability to periodically accept/release K+ . Herein, a composite with FeSb2 nanoparticles embedded in a 3D porous carbon framework (FeSb2 @3DPC) is successfully constructed as an extremely stable anode material for PIBs. Benefiting from the synergistic effect of the design of nano and porous structures, the introduction of the inactive metal Fe, the firm anchoring of the FeSb2 nanoparticles by the carbon material, and the incomplete reaction of the FeSb2 , the FeSb2 @3DPC can achieve an ultra-long cycle life of over 4000 cycles at a current density of 500 mA g-1 . Furthermore, ex situ X-ray diffraction and transmission electron microscopy reveal a gradual activation process of FeSb2 for potassium storage. Fortunately, after activation, the electrochemical polarization of the FeSb2 @3DPC anode gradually alleviates and the capacitance-controlled charge storage mode further dominates compared with the diffusion-controlled mode, all of which promote the FeSb2 @3DPC to maintain the stable potassium storage capability.

RESUMEN

Antimony (Sb) has attracted considerable attention as an anode material for potassium ion batteries (PIBs) because of its high theoretical capacity. Nevertheless, owing to the large radius of K+, apparent volume expansion occurs during the reaction between Sb and K+, which will undermine the stability of the electrode. Accordingly, a dual-carbon confinement strategy is regarded as an effective method for handling this issue. Herein, Sb is firstly captured by mesoporous carbon sphere (MCS) to form a composite of Sb/MCS, and then reduced graphene oxide (rGO) is adopted as an outer layer to wrap the Sb/MCS to obtain the dual-carbon confinement material (Sb/MCS@rGO). Given the synergistic confinement effects of the MCS and rGO, the Sb/MCS@rGO electrode realizes an excellent rate capacity of 341.9 mAh g-1 at 1000 mA g-1 and prominent cycling stability with around 100% retention at 50 mA g-1 after 100 cycles. Besides, the discussion on galvanostatic charge-discharge test, cyclic voltammetry and ex-situ XRD illustrates the stepwise potassium storage mechanism of Sb. Benefiting from the dual-carbon confinement effects, the Sb/MCS@rGO electrode processes promising electrochemical reaction kinetics. Furthermore, the application of the Sb/MCS@rGO in full cells also demonstrates its superior rate capacity (212.3 mAh g-1 at 1000 mA g-1).

RESUMEN

It is of great significance to develop a new kind of green and environmentally friendly potassium ion energy storage device, with stable structures and large specific capacity. In this manuscript, a facile and robust way is reported to construct nitrogen doped porous carbon flake (NPCF) through NaCl template and pyrolysis method. 3D porous structures can be formed and interconnected NPCF are used as potassium ion batteries (PIBs) anode. High content of pyridinic N/pyrrolic N and enlarged interlayer distance of NPCF are obtained. Specifically, the anode delivers a high reversible capacity of 326.3 mAh g-1 at the current density of 50 mA g-1, and shows up outstanding cycle stability and represents long cycle life of 10,000 cycles at a current density of 5000 mA g-1. Moreover, the cyclic voltammetry kinetic analysis shows that the main capacitive process plays a leading role in the potassium storage mechanism. Consequently, equipped with activate carbon (AC) as cathode and NPCF as anode, the assembled potassium ion hybrid capacitors (PIHCs) achieve an energy density of 65.8 Wh kg-1 at 100 mA g-1, and maintains 30 Wh kg-1 even at a high current density of 5000 mA g-1.

RESUMEN

BACKGROUND/AIM: Central administration of cocaine- and amphetamine-regulated transcript peptides (CARTp) alters gastrointestinal motility and reduces food intake in rats. Since neurons in the dorsal motor nucleus of the vagus (DMV) receive GABAergic and glutamatergic inputs and innervate the smooth muscle of gastrointestinal organs, we hypothesized that CARTp acts on the DMV or presynaptic neurons. METHODS: We used 3,3'-dioctadecyloxa-carbocyanine perchlorate (DiO) retrograde tracing with electrophysiological methods to record DMV neurons innervating the stomach antrum or cecum in brainstem slices from adult rats. RESULTS: DiO application did not change the electrophysiological properties of DMV neurons. CART55-102 had no effect on the basal firing rates of neurons in either the stomach antrum-labeled group (SLG) or cecum-labeled group (CLG). When presynaptic inputs were blocked, CART55-102 further increased the firing rates of the SLG, suggesting a direct excitatory effect. Spontaneous inhibitory postsynaptic currents (sIPSCs) occurred at a higher frequency in SLG neurons than in CLG neurons. CART55-102 reduced the amplitude and the frequency of sIPSCs in SLG neurons dose-dependently, with higher doses also reducing spontaneous excitatory postsynaptic currents (sEPSCs). Higher doses of CART55-102 reduced sIPSC and sEPSC amplitudes in CLG neurons, suggesting a postsynaptic effect. In response to incremental current injections, the SLG neurons exhibited less increases in firing activity. Simultaneous applications of current injections and CART55-102 decreased the firing activity of the CLG. Therefore, stomach antrum-projecting DMV neurons possess a higher gating ability to stabilize firing activity. CONCLUSION: The mechanism by which CARTp mediates anorectic actions may be through a direct reduction in cecum-projecting DMV neuron excitability and, to a lesser extent, that of antrum-projecting DMV neurons, by acting on receptors of these neurons.

Asunto(s)

RESUMEN

The advancement of potassium ion batteries (PIBs) stimulated by the dearth of lithium resources is accelerating. Major progresses on the electrochemical properties are based on the optimization of electrode materials, electrolytes, and other components. More significantly, the prerequisites for optimizing these key compositions are in-depth and comprehensive exploration of electrochemical reaction processes, including the evolution of morphology and structure, phase transition, interface behaviors, and K+ movement, etc. As a result, the obtained K+ storage mechanism via analyzing aforementioned reaction processes sheds light on furthering practical application of PIBs. Typical electrochemical analysis methods are capable of obtaining physical and chemical characteristics. The advent of in situ electrochemical measurements enables dynamic observation and monitoring, thereby gaining extensive insights into the intricate mechanism of capacity degradation and interface kinetics. By coupling with these powerful electrochemical characterization techniques, inspiring works in PIBs will burgeon into wide realms of energy storage fields. In this review, some typical electroanalytical tests and in situ hyphenated measurements are described with the main concentration on how these techniques play a role in investigating the potassium storage mechanism for PIBs and achieving encouraging results.

RESUMEN

Potassium-ion batteries (PIBs) have attracted widespread attention in recent years due to their potential advantages such as low cost and high energy density. However, the large radius of K+ and the low potassium storage capacity of some electrode materials limit their development. Antimony (Sb)-based materials are considered to be promising anode materials for PIBs in view of their high K storage capacity and low potassiation potential. Nonetheless, the huge volume variation caused by potassiation/depotassiation often leads to their failure. Previous works have proved that carbon coating and nanostructure design are important means to alleviate the volume effect. Herein, the carbon-coating technology and nanostructure design were combined to prepare a Sb-based nanomaterial with Sb/Sb2S3 hybrid nanorod fragments confined in a carbon hollow tube (Sb/Sb2S3@CHT). Such a nanostructure is beneficial to alleviate the volume change of the Sb/Sb2S3 hybrids while facilitating the kinetics of the electrochemical reaction. As a consequence, the Sb/Sb2S3@CHT anode electrode exhibits high rate performance and outstanding cycle stability characterized by retaining a high specific capacity of 400.9 mA h g-1 after cycling for 200 cycles at 200 mA g-1.

RESUMEN

Squalene is widely used in pharmaceutical, nutraceutical, cosmetics and other fields because of its strong antioxidative, antibacterial and anti-tumor activities. In order to produce squalene, a gene ispA encoding farnesyl pyrophosphate synthase was overexpressed in a previously engineered Escherichia coli strain capable of efficiently producing terpenoids, resulting in a chassis strain that efficiently synthesizes triterpenoids. Through phylogenetic analysis, screening, cloning and expression of squalene synthase derived from different prokaryotes, engineered E. coli strains capable of efficiently producing squalene were obtained. Among them, squalene produced by strains harboring squalene synthase derived from Thermosynechococcus elongatus and Synechococcus lividus reached (16.5±1.4) mg/g DCW ((167.1±14.3) mg/L broth) and (12.0±1.9) mg/g DCW ((121.8±19.5) mg/L broth), respectively. Compared with the first-generation strains harboring the human-derived squalene synthase, the squalene synthase derived from T. elongatus and S. lividus remarkably increased the squalene production by 3.3 times and 2.4 times, respectively, making progress toward the cost-effective heterologous production of squalene.

Asunto(s)

RESUMEN

BACKGROUND: The prenatal test of cell-free fetal DNA (cffDNA) is also known as noninvasive prenatal testing (NIPT) with high sensitivity and specificity. This study is to evaluate the performance of NIPT and its clinical relevance with various clinical indications. METHODS: A retrospective analysis was conducted on 14,316 pregnant women with prenatal indications, including advanced maternal age (≥35 years), maternal serum screening abnormalities, the thickened nuchal translucency (≥2.5 mm) and other ultrasound abnormalities, twin pregnancy/IVF-ET pregnancy, etc. The whole-genome sequencing (WGS) of maternal plasma cffDNA was employed in this study. RESULTS: A total of 189 (1.32%) positive NIPT cases were identified, and 113/189 (59.79%)cases were confirmed by invasive prenatal testing. Abnormal serological screening (53.14%) was the most common indication, followed by elderly pregnancy (23.02%). The positive prediction value for T21, T18, T13, sex chromosome abnormalities, other autosomal aneuploidy abnormalities, and CNV abnormalities were 91.84, 68.75,37.50, 66.67, 14.29, and 6.45%, respectively. The positive rate and the true positive rate of nuchal translucency (NT) thickening were the highest (4.17 and 3.33%), followed by the voluntary requirement group (3.49 and 1.90%) in the various prenatal screening indications. The cffDNA concentration was linearly correlated with gestational age (≥10 weeks) and the positive NIPT group's Z-score values. CONCLUSIONS: whole-genome sequencing of cffDNA has extremely high sensitivity and specificity for T21, high sensitivity for T18, sex chromosome abnormalities, and T13. It also provides evidence for other abnormal chromosomal karyotypes (CNV and non-21/18/13 autosomal aneuploidy abnormalities). The cffDNA concentration is closely related to the gestational age and determines the specificity of NIPT. Our results highlight NIPT's clinical significance, which is an effective prenatal screening tool for high-quality care of pregnancy.

Asunto(s)

RESUMEN

In view of rich potassium resources and their working potential, potassium-ion batteries (PIBs) are deemed as next generation rechargeable batteries. Owing to carbon materials with the preponderance of durability and economic price, they are widely employed in PIBs anode materials. Currently, porosity design and heteroatom doping as efficacious improvement strategies have been applied to the structural design of carbon materials to improve their electrochemical performances. Herein, nitrogen-doped mesoporous carbon spheres (MCS) are synthesized by a facile hard template method. The MCS demonstrate larger interlayer spacing in a short range, high specific surface area, abundant mesoporous structures and active sites, enhancing K-ion migration and diffusion. Furthermore, we screen out the pyrolysis temperature of 900 °C and the pore diameter of 7 nm as optimized conditions for MCS to improve performances. In detail, the optimized MCS-7-900 electrode achieves high rate capacity (107.9 mAh g-1 at 5000 mA g-1) and stably brings about 3600 cycles at 1000 mA g-1. According to electrochemical kinetic analysis, the capacitive-controlled effects play dominant roles in total storage mechanism. Additionally, the full-cell equipped MCS-7-900 as anode is successfully constructed to evaluate the practicality of MCS.

RESUMEN

A large number of experiments show that PtCu catalyst has a good catalytic effect on methanol decomposition. Therefore, density functional theory (DFT) was used to further study the dehydrogenation of methanol catalyzed by PtnCum (n = 1-3, m = 0-2). The energy diagrams of O-adsorption path and H-adsorption path were drawn. By calculation, the Pt is the active site of the whole reaction process, and the barrier energy of the rate-determining step is 11.09 kcal mol-1 by Pt2Cu, which is lower than that of Pt3 and PtCu2. However, the complete dehydrogenation product of methanol, CO, is easier to dissociate from PtCu2 clusters than from Pt3 and Pt2Cu clusters. Therefore, Cu doping can improve the catalytic activity and anti-CO toxicity of Pt to a certain extent.