Electrochemical Knocking-Down of Zn Metal Clusters into Single Atoms

Single Atoms Catalysts (SACs) have emerged as a class of highly promising heterogeneous catalysts, where the traditional bottom-up synthesis approaches often encounter considerable challenges in relation to aggregation issues and poor stability. Consequently, achieving densely dispersed atomic species in a reliable and efficient manner remains a key focus in the field. Herein, we report a new facile electrochemical knock-down strategy for the formation of SACs, whereby the metal Zn clusters are transformed into single atoms. While a defect-rich substrate plays a pivotal role in capturing and stabilizing isolated Zn atoms, the feasibility of this novel strategy is demonstrated through a comprehensive investigation, combining experimental and theoretical studies. Furthermore, when studied in exploring for potential applications, the material prepared shows a remarkable improvement of 58.21% for the Li+ storage and delivers a capacity over 300 Wh kg-1 after 500 cycles upon the transformation of Zn clusters into single atoms.

Synergizing Fe2O3 Nanoparticles on Single Atom Fe-N-C for Nitrate Reduction to Ammonia at Industrial Current Densities

The electrochemical reduction of nitrates (NO3 -) enables a pathway for the carbon neutral synthesis of ammonia (NH3), via the nitrate reduction reaction (NO3RR), which has been demonstrated at high selectivity. However, to make NH3 synthesis cost-competitive with current technologies, high NH3 partial current densities (jNH3) must be achieved to reduce the levelized cost of NH3. Here, the high NO3RR activity of Fe-based materials is leveraged to synthesize a novel active particle-active support system with Fe2O3 nanoparticles supported on atomically dispersed Fe-N-C. The optimized 3×Fe2O3/Fe-N-C catalyst demonstrates an ultrahigh NO3RR activity, reaching a maximum jNH3 of 1.95 A cm-2 at a Faradaic efficiency (FE) for NH3 of 100% and an NH3 yield rate over 9 mmol hr-1 cm-2. Operando XANES and post-mortem XPS reveal the importance of a pre-reduction activation step, reducing the surface Fe2O3 (Fe3+) to highly active Fe0 sites, which are maintained during electrolysis. Durability studies demonstrate the robustness of both the Fe2O3 particles and Fe-Nx sites at highly cathodic potentials, maintaining a current of -1.3 A cm-2 over 24 hours. This work exhibits an effective and durable active particle-active support system enhancing the performance of the NO3RR, enabling industrially relevant current densities and near 100% selectivity.

Distribution of Pt single atom coordination environments on anatase TiO2 supports controls reactivity

Single-atom catalysts (SACs) offer efficient metal utilization and distinct reactivity compared to supported metal nanoparticles. Structure-function relationships for SACs often assume that active sites have uniform coordination environments at particular binding sites on support surfaces. Here, we investigate the distribution of coordination environments of Pt SAs dispersed on shape-controlled anatase TiO2 supports specifically exposing (001) and (101) surfaces. Pt SAs on (101) are found on the surface, consistent with existing structural models, whereas those on (001) are beneath the surface after calcination. Pt SAs under (001) surfaces exhibit lower reactivity for CO oxidation than those on (101) surfaces due to their limited accessibility to gas phase species. Pt SAs deposited on commercial-TiO2 are found both at the surface and in the bulk, posing challenges to structure-function relationship development. This study highlights heterogeneity in SA coordination environments on oxide supports, emphasizing a previously overlooked consideration in the design of SACs.

Atomic Layers of B2 CuPd on Cu Nanocubes as Catalysts for Selective Hydrogenation

The search for highly active and selective catalysts with high precious metal atom utilization efficiency has attracted increasing interest in both the fundamental synthesis of materials and important industrial reactions. Here, we report the synthesis of Pd-Cu nanocubes with a Cu core and an ordered B2 intermetallic CuPd shell with controllable atomic layers on the surface (denoted as Cu/B2 CuPd), which can efficiently and robustly catalyze the selective hydrogenation of acetylene (C2H2) to ethylene (C2H4) under mild conditions. The optimized Cu/B2 CuPd with a Pd loading of 9.5 at. % exhibited outstanding performance in the C2H2 semi-hydrogenation with 100% C2H2 conversion and 95.2% C2H4 selectivity at 90 °C. We attributed this outstanding performance to the core/shell structure with a high surface density of active Pd sites isolated by Cu in the B2 intermetallic matrix, representing a structural motif of single-atom alloys (SAAs) on the surface. The combined experimental and computational studies further revealed that the electronic states of Pd and Cu are modulated by SAAs from the synergistic effect between Pd and Cu, leading to enhanced performance compared with pristine Pd and Cu catalysts. This study provides a new synthetic methodology for making single-atom catalysts with high precious metal atom utilization efficiency, enabling simultaneous tuning of both geometric and electronic structures of Pd active sites for enhanced catalysis.

How Pt Influences H2 Reactions on High Surface-Area Pt/CeO2 Powder Catalyst Surfaces

The addition of platinum-group metals (PGMs, e.g., Pt) to CeO2 is used in heterogeneous catalysis to promote the rate of redox surface reactions. Well-defined model system studies have shown that PGMs facilitate H2 dissociation, H-spillover onto CeO2 surfaces, and CeO2 surface reduction. However, it remains unclear how the heterogeneous structures and interfaces that exist on powder catalysts influence the mechanistic picture of PGM-promoted H2 reactions on CeO2 surfaces developed from model system studies. Here, controlled catalyst synthesis, temperature-programmed reduction (TPR), in situ infrared spectroscopy (IR), and in situ electron energy loss spectroscopy (EELS) were used to interrogate the mechanisms of how Pt nanoclusters and single atoms influence H2 reactions on high-surface area Pt/CeO2 powder catalysts. TPR showed that Pt promotes H2 consumption rates on Pt/CeO2 even when Pt exists on a small fraction of CeO2 particles, suggesting that H-spillover proceeds far from Pt-CeO2 interfaces and across CeO2-CeO2 particle interfaces. IR and EELS measurements provided evidence that Pt changes the mechanism of H2 activation and the rate limiting step for Ce3+, oxygen vacancy, and water formation as compared to pure CeO2. As a result, higher-saturation surface hydroxyl coverages can be achieved on Pt/CeO2 compared to pure CeO2. Further, Ce3+ formed by spillover-H from Pt is heterogeneously distributed and localized at and around interparticle CeO2-CeO2 boundaries, while activated H2 on pure CeO2 results in homogeneously distributed Ce3+. Ce3+ localization at and around CeO2-CeO2 boundaries for Pt/CeO2 is accompanied by surface reconstruction that enables faster rates of H2 consumption. This study reconciles the materials gap between model structures and powder catalysts for H2 reactions with Pt/CeO2 and highlights how the spatial heterogeneity of powder catalysts dictates the influence of Pt on H2 reactions at CeO2 surfaces.

Elucidating electrochemical nitrate and nitrite reduction over atomically-dispersed transition metal sites

Electrocatalytic reduction of waste nitrates (NO₃^-) enables the synthesis of ammonia (NH₃) in a carbon neutral and decentralized manner. Atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts demonstrate a high catalytic activity and uniquely favor mono-nitrogen products. However, the reaction fundamentals remain largely underexplored. Herein, we report a set of 14; 3d-, 4d-, 5d- and f-block M-N-C catalysts. The selectivity and activity of NO₃^- reduction to NH₃ in neutral media, with a specific focus on deciphering the role of the NO₂^- intermediate in the reaction cascade, reveals strong correlations (R=0.9) between the NO₂^- reduction activity and NO₃^- reduction selectivity for NH₃. Moreover, theoretical computations reveal the associative/dissociative adsorption pathways for NO₂^- evolution, over the normal M-N₄ sites and their oxo-form (O-M-N₄) for oxyphilic metals. This work provides a platform for designing multi-element NO₃RR cascades with single-atom sites or their hybridization with extended catalytic surfaces.

Ferromagnetic single-atom spin catalyst for boosting water splitting

Heterogeneous single-atom spin catalysts combined with magnetic fields provide a powerful means for accelerating chemical reactions with enhanced metal utilization and reaction efficiency. However, designing these catalysts remains challenging due to the need for a high density of atomically dispersed active sites with a short-range quantum spin exchange interaction and long-range ferromagnetic ordering. Here, we devised a scalable hydrothermal approach involving an operando acidic environment for synthesizing various single-atom spin catalysts with widely tunable substitutional magnetic atoms (M₁) in a MoS₂ host. Among all the M₁/MoS₂ species, Ni₁/MoS₂ adopts a distorted tetragonal structure that prompts both ferromagnetic coupling to nearby S atoms as well as adjacent Ni₁ sites, resulting in global room-temperature ferromagnetism. Such coupling benefits spin-selective charge transfer in oxygen evolution reactions to produce triplet O₂. Furthermore, a mild magnetic field of ~0.5 T enhances the oxygen evolution reaction magnetocurrent by ~2,880% over Ni₁/MoS₂, leading to excellent activity and stability in both seawater and pure water splitting cells. As supported by operando characterizations and theoretical calculations, a great magnetic-field-enhanced oxygen evolution reaction performance over Ni₁/MoS₂ is attributed to a field-induced spin alignment and spin density optimization over S active sites arising from field-regulated S(p)-Ni(d) hybridization, which in turn optimizes the adsorption energies for radical intermediates to reduce overall reaction barriers.

Insight into Key Parameters for Fabricating Stable Single-Atom Pt-Nix Alloy by Reduction Environment-Induced Anti-Ostwald Effects

Developing single-atom catalysts with superior stability under reduction conditions is essential for hydrogenation/dehydrogenation catalysis and green hydrogen generation. In this contribution, single-atom Pt catalysts were achieved via a reduction environment-induced anti-Ostwald approach in the highly confined Ni species (Pt-Ni_x ) on nonreducible Al₂ O₃ matrix. In-situ X-ray absorption spectroscopy indicated that the isolated Pt-Ni_x metallic bonds, generated at high reduction temperature, dominated the formation of single Pt atoms. A relatively large cluster of metallic Ni would benefit the stabilization of Pt single atom as observed via high-angle annular dark-field scanning transmission electron microscopy and validated by density functional theory simulation. Excellent performance on cellulose hydrogenolysis was demonstrated under harsh reductive and hydrothermal conditions, potentially expandable to other hydrogen involved reactions like CO₂ hydrogenation, green hydrogen production from different hydrogen carriers, and beyond.

Metal-Metal Oxide Catalytic Interface Formation and Structural Evolution: A Discovery of Strong Metal-Support Bonding, Ordered Intermetallics, and Single Atoms

In-depth investigation of metal-metal oxide interactions and their corresponding evolution is of paramount importance to heterogeneous catalysis as it allows the understanding and maneuvering of the structure of catalytic motifs. Herein, using a series of core/shell metal/iron oxide (M/FeO_x, M = Pd, Pt, Au) nanoparticles and through a combination of in situ and ex situ electron and X-ray investigations, we revealed anomalous and dissimilar M-FeO_x interactions among different systems under reducing conditions. Pd interacts strongly with FeO_x after high-temperature reductive treatment, featured by the formation of Pd single atoms in the FeO_x matrix and increased Pd-Fe bonding, while Pt transforms into ordered PtFe intermetallics and Pt single atoms immediately upon the coating of FeO_x. In contrast, Au does not manifest strong bonding with FeO_x. As a proof of concept of tailoring metal-metal oxide interactions for catalysis, optimized Pd/FeO_x demonstrates 100% conversion and 86.5% selectivity at 60 °C for acetylene semihydrogenation.

Quasi-Paired Pt Atomic Sites on Mo2 C Promoting Selective Four-Electron Oxygen Reduction

Atomically dispersed Pt species are advocated as a promising electrocatalyst for the oxygen reduction reaction (ORR) to boost noble metal utilization efficiency. However, when assembled on various substrates, isolated Pt single atoms are often demonstrated to proceed through the two-electron ORR pathway due to the unfavorable O─O bond cleavage thermodynamics in the absence of catalytic ensemble sites. In addition, although their distinct local coordination environments at the exact single active sites are intensively explored, the interactions and synergy between closely neighboring single atom sites remain elusive. Herein, atomically dispersed Pt monomers strongly interacting on a Mo₂ C support is demonstrated as a model catalyst in the four-electron ORR, and the beneficial interactions between two closely neighboring and yet non-contiguous Pt single atom sites (named as quasi-paired Pt single atoms) are shown. Compared to isolated Pt single atom sites, the quasi-paired Pt single atoms deliver a superior mass activity of 0.224 A mg^-1 _Pt and near-100% selectivity toward four-electron ORR due to the synergistic interaction from the two quasi-paired Pt atom sites in modulating the binding mode of reaction intermediates. Our first-principles calculations reveal a unique mechanism of such quasi-paired configuration for promoting four-electron ORR.

Efficient Hydrogen Evolution of Oxidized Ni-N3 Defective Sites for Alkaline Freshwater and Seawater Electrolysis

For mass production of high-purity hydrogen fuel by electrochemical water splitting, seawater electrolysis is an attractive alternative to the traditional freshwater electrolysis due to the abundance and low cost of seawater in nature. However, the undesirable chlorine ion oxidation reactions occurring simultaneously with seawater electrolysis greatly hinder the overall performance of seawater electrolysis. To tackle this problem, electrocatalysts of high activity and selectivity with purposely modulated coordination and an alkaline environment are urgently required. Herein, it is demonstrated that atomically dispersed Ni with triple nitrogen coordination (Ni-N₃ ) can achieve efficient hydrogen evolution reaction (HER) performance in alkaline media. The atomically dispersed Ni electrocatalysts exhibit overpotentials as low as 102 and 139 mV at 10 mA cm^-2 in alkaline freshwater and seawater electrolytes, respectively, which compare favorably with those previously reported. They also deliver large current densities beyond 200 mA cm^-2 at lower overpotentials than Pt/C, as well as show negligible current attenuation over 14 h. The X-ray absorption fine structure (XAFS) experimental analysis and density functional theory (DFT) calculations verify that the Ni-N₃ coordination, which exhibits a lower coordination number than Ni-N₄ , facilitates water dissociation and hydrogen adsorption, and hence enhances the HER activity.

Synergizing Mo Single Atoms and Mo2 C Nanoparticles on CNTs Synchronizes Selectivity and Activity of Electrocatalytic N2 Reduction to Ammonia

Previous research of molybdenum-based electrocatalysts for nitrogen reduction reaction (NRR) has been largely considered on either isolated Mo single atoms (MoSAs) or Mo carbide particles (e.g., Mo₂ C) separately, while an integrated synergy (MoSAs-Mo₂ C) of the two has never been considered. The theoretical calculations show that the Mo single atoms and Mo₂ C nanoparticles exhibit, respectively, different catalytic hydrogen evolution reaction and NRR selectivity. Therefore, a new role-playing synergistic mechanism can be well enabled for the multistep NRR, when the two are combined on the same N-doped carbon nanotubes (NCNTs). This hypothesis is confirmed experimentally, where the MoSAs-Mo₂ C assembled on NCNTs (MoSAs-Mo₂ C/NCNTs) yields an ammonia formation rate of 16.1 µg h^-1 cm_cat ^-2 at -0.25 V versus reversible hydrogen electrode, which is about four times that by the Mo₂ C alone (Mo₂ C/NCNTs) and 4.5 times that by the MoSAs alone (MoSAs/NCNTs). Moreover, the Faradic efficiency of the MoSAs-Mo₂ C/NCNTs is raised up to twofold and sevenfold of the Mo₂ C/NCNTs and MoSAs/NCNTs, respectively. The MoSAs-Mo₂ C/NCNTs also demonstrate outstanding stability by the almost unchanged catalytic performance over 10 h of the chronoamperometric test. The present study provides a promising new prototype of synchronizing the selectivity and activity for the multistep catalytic reactions.

Dendrobine attenuates isoniazid- and rifampicin-induced liver injury by inhibiting miR-295-5p

The present study aims to investigate the protective effects of Dendrobine and its underlying mechanisms on liver injury induced by isoniazid (INH) and rifampicin (RIF). A mouse model of liver injury was induced by intragastrically administration of 100 mg/kg INH and 100 mg/kg RIF for 14 days. The mice were intragastrically administrated with Dendrobine (50, 100, and 200 mg/kg) before the administration of INH and RIF. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Oxidative stress markers including glutathione, superoxide dismutase, and malondialdehyde in the liver were measured and liver histopathological examinations were performed. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were applied to determine the mRNA and protein expressions, respectively. Luciferase reporter assay was used to evaluate the interactions between miR-295-5p and CYP1A2. Dendrobine significantly decreased serum ALT and AST and inhibited the liver index and ameliorated the liver histological changes induced by INH and RIF. Besides, Dendrobine also regulated oxidative stress status in the liver by the regulation of CYP1A2. Moreover, mmu-miR-295-5p was identified to target CYP1A2 and to regulate the expression of CYP1A2. In summary, Dendrobine ameliorated INH and RIF induced mouse liver injury by miR-295-5p-mediated CYP1A2 expression.

Boosted electrochemical ammonia synthesis by high-percentage metallic transition metal dichalcogenide quantum dots

The electrochemical method can directly convert N2 into the high-value-added NH3 under ambient conditions and is considered to be a green and sustainable alternative to the traditional Haber-Bosch process. However, the electrochemical nitrogen reduction reaction (NRR) suffers from a low ammonia yield rate over the reported electrocatalysts. Herein, we have developed a general strategy to boost the NRR performance, enabled by the metallic 1T phase dominated transition metal dichalcogenide quantum dots (TMD QDs). Impressively, the obtained MoSe2 QDs achieved a superior ammonia yield rate of 340 μg mg-1 cat. h-1 with excellent ammonia generation sustainability. Experimental and theoretical studies revealed that the excellent catalytic activity of MoSe2 QDs mainly originates from the ultra-small quantized size (high surface area and high-density active edge/defect sites) and high-percentage metallic 1T phase (the N2 adsorption on the 1T phase is spontaneous, and the energy barrier of the potential determining step on the 1T phase is very low). Most importantly, our concept is universal for TMD materials (i.e., MoS2, WSe2, WS2 and NbSe2) that also exhibit a much-enhanced ammonia yield rate as compared to other electrocatalysts.

Single atom catalysts: a surface heterocompound perspective

The concept of single atom catalysts (SACs) originated from reducing the amount of noble metals used, by steadily refining the particle size loaded on a substrate surface. It has been rapidly moving to non-noble elements and their compounds in recent years, notably transition metals and even non-metals. They are of heterogeneous types, where the active species are refined to atomic dispersion scales on the surfaces/sub-surfaces of the solid support. The catalytic performance is governed by both the type and population of accessible active sites, and their bond and coordination environment, largely as a result of the interactions with the substrate surface. Unlike the internal structure within a crystalline solid, there is a large spatial variation in the bond and coordination environment of different atoms on the solid surface across different length scales, and in particular with the unsaturated surface, where there are various defects. They can also be dramatically altered during both the catalyst synthesis and actual catalysis process. In a way, they form a "surface heterocompound", where the local bonds for each metal atom are of a compound type, while there can be a large variation from one to another. Herein, we will look into the evolution from traditional heterogeneous catalysts to SACs, from the surface heterocompound perspective. Discussion will then be made on the on-going strategies and challenges in manipulating and identifying the local bond and coordination environment on the hetero-surfaces, in an attempt to develop efficient catalysts for the targeted applications, where both synthesis techniques and analytical tools are critically important, and computational studies can provide the key guiding principles. With selected paradigm studies, we will briefly examine the future perspectives for this newly emerging catalysis frontier.

Assembling of Bi atoms on TiO2 nanorods boosts photoelectrochemical water splitting of semiconductors

Low photoconversion efficiency, high charge transfer resistance and fast recombination rate are the bottlenecks of semiconductor nanomaterials in photoelectrochemical (PEC) water splitting, where the introduction of an appropriate co-catalyst is an effective strategy to improve their performance. In the present study, we have purposely designed atomic-scale dispersed bismuth (Bi) assembled on titanium dioxide nanorods (TiO2), and demonstrated its effective role as a co-catalyst in enhancing the PEC water splitting performance of TiO2. As a result, functionalized Bi/TiO2 generates a high photocurrent intensity at 1.23 VRHE under simulated solar light irradiation, which is 4-fold higher than that of pristine TiO2, exhibiting a significantly improved PEC performance for water splitting. The strategy presented in this study opens a new window for the construction of non-precious metals dispersed at atomic scales as efficient co-catalysts for realizing sustainable solar energy-driven energy conversion and storage.

Twinned Tungsten Carbonitride Nanocrystals Boost Hydrogen Evolution Activity and Stability

Synergistic integration of two active metal-based compounds can lead to much higher electrocatalytic activity than either of the two individually, due to the interfacial effects. Herein, a proof-of-concept strategy is creatively developed for the successful fabrication of twinned tungsten carbonitride (WCN) nanocrystals, where W₂ C and WN are chemically bonded at the molecule level. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy analyses demonstrate that the intergrowth of W₂ C and WN in the WCN nanocrystals produces abundant N-W-C interfaces, leading to a significant enhancement in catalytic activity and stability for hydrogen evolution reaction (HER). Indeed, it shows 14.2 times higher and 140 mV lower in the respective turn-over frequency (TOF) and overpotential at 10 mA cm^-2 compared to W₂ C alone. To complement the experimental observation, the theoretical calculations demonstrate that the WCN endows more favorable hydrogen evolution reaction than the single W₂ C or WN crystals due to abundant interfaces, beneficial electronic states, lower work function, and more active W sites at the N-W-C interfaces.

Strong Charge Transfer at 2H-1T Phase Boundary of MoS2 for Superb High-Performance Energy Storage

Transition metal dichalcogenides exhibit several different phases (e.g., semiconducting 2H, metallic 1T, 1T') arising from the collective and sluggish atomic displacements rooted in the charge-lattice interaction. The coexistence of multiphase in a single sheet enables ubiquitous heterophase and inhomogeneous charge distribution. Herein, by combining the first-principles calculations and experimental investigations, a strong charge transfer ability at the heterophase boundary of molybdenum disulfide (MoS₂ ) assembled together with graphene is reported. By modulating the phase composition in MoS₂ , the performance of the nanohybrid for energy storage can be modulated, whereby remarkable gravimetric and volumetric capacitances of 272 F g^-1 and 685 F cm^-3 are demonstrated. As a proof of concept for energy application, a flexible solid-state asymmetric supercapacitor is constructed with the MoS₂ -graphene heterolayers, which shows superb energy and power densities (46.3 mWh cm^-3 and 3.013 W cm^-3 , respectively). The present work demonstrates a new pathway for efficient charge flow and application in energy storage by engineering the phase boundary and interface in 2D materials of transition metal dichalcogenides.

Flexible and Wearable All-Solid-State Al-Air Battery Based on Iron Carbide Encapsulated in Electrospun Porous Carbon Nanofibers

In this work, electrospinning N-doped carbon nanofibers containing iron carbide (Fe₃C@N-CFs) are synthesized and employed as the cathode in the flexible Al-air battery. Benefiting from the excellent catalytic activity of the iron carbide which is uniformly encapsulated in the N-doped carbon matrix, as well as the large specific surface area of the cross-linked network nanostructure, the as-prepared Fe₃C@N-CFs show outstanding catalytic activity and stability toward oxygen reduction reaction. The as-fabricated all-solid-state Al-air batteries with Fe₃C@N-CF catalyst show a stable discharge voltage (1.61 V) for 8 h, giving a capacity of 1287.3 mA h g^-1.

A comparative study of proximal femoral locking compress plate, proximal femoral nail antirotation and dynamic hip screw in intertrochanteric fractures

OBJECTIVE

We aimed to compare the clinical efficacy of three different internal fixation methods, i.e. proximal femoral locking compress plate (PF-LCP), proximal femoral nail antirotation (PFNA) and dynamic hip screw (DHS) system in intertrochanteric femur fracture.

PATIENTS AND METHODS

We selected a total of 150 patients with Intertrochanteric femur fracture who were admitted to this hospital between January 2015 and December 2016 for treatment, and those patients were divided into three groups according to the difference in treatment methods, i.e., Group A (n=50), Group B (n=50) and Group C (n=50). For patients in Group A, they received the PF-LCP treatment, patients in Group B received PFNA treatment while those in Group C received DHS treatment; ultimately, clinical efficacy was compared among three groups.

RESULTS

In Group B, the efficacy was superior to those in Group A and C in terms of comparison of surgical duration, bleeding amount, time point of callus formation, healing time of fracture and length of stay (LOS) in hospital (p<0.05); after operation, the prevalence rate of complication in Group B was significantly lower than those in Group A and Group C (p<0.05); in comparison of preoperative Harris score among three groups, the different had no statistical significance (p>0.05). The Harris scores in Group B at the 1st, 3rd, and 6th month after operation were all significantly higher than those in Group A and C (p<0.05).

CONCLUSIONS

Compared with PF-LCP and DHS, PFDA can better fix the intertrochanteric femur fracture with little effect on blood circulation at the fracture end and slight damage to sclerotin, thereby accelerating the recovery of hip joint function without any increase in prevalence of complications. Therefore, PFDA has a promising clinical efficacy and safety, which is worthy of being promoted in clinical practice.

Regulation network analysis in the esophageal squamous cell carcinoma

BACKGROUND

The incidence of esophageal squamous cell carcinoma (ESCC) has high regional selectivity. The molecular mechanisms of ESCC are complex and involve multiple oncogenes, tumor suppressor genes, receptor tyrosine kinases, cytoplasmic enzymes, and tumor interstitial elements.

AIM

Here we used bioinformatics to obtain some important genes and pathways involved in ESCC.

MATERIALS AND METHODS

In this article, we did Affymetrix microarray data collection from three big databases, and then selected all the differentially expressed genes (DEGs) according to some principles. On this basis, we carried out regulation network analysis and pathway enrichment analysis, obtaining ESCC related regulation network analysis, after which we selected significant pathways on regulation network and established TF-pathway regulation network.

RESULTS

In the transcription factors (TFs) regulation network we found SP1, E2F1, USF2 and SP3 form a local network which suggested that these TFs might play a more important role in ESCC. Some key pathways were also identified, such as P53 signaling pathway, melanoma and prostate cancer pathways.

CONCLUSIONS

The identification of crucial molecular pathways involved in ESCC would ultimately improve therapeutic effects and facilitate the development of new treatment strategies.

Bioinformatics analysis of two microarray gene-expression data sets to select lung adenocarcinoma marker genes

BACKGROUND

Lung adenocarcinoma (LAC) is the most frequent histologic type of lung cancer and rates of adenocarcinoma are increasing in most countries. Recently, several molecular markers have been identified to predict LAC. However, more prognostic makers and the underlying role of those makers are still imperative.

AIM

In this study, our objective was to identify a set of discriminating genes that can be used for characterization and prediction of response to LAC.

MATERIALS AND METHODS

Using the bioinformatics analysis method, we merged two LAC datasets-GSE2514 and GSE7670 to find novel target genes and pathways to explain the pathogenicity.

RESULTS

The results showed that EDNRB (endothelin receptor type B), ADRB2 (beta-adrenergic receptor), S1PR1 (sphingosine-1-phosphate receptor 1), P2RY14 (PsY purinoceptor 14), LEPR (leptin-receptor), GHR (growth hormone receptor), PPM1D (protein phosphatase-1D), and GADD45B (growth arrest and DNA-damage-inducible, beta) have high degrees in response to LAC. Additionally, EDNRB, ADRB2, S1PR1, P2RY14, LEPR, and GHR may be involved in LAC through Neuroactive ligand-receptor interaction, but PPM1D and GADD45B may be through p53 signaling pathway. Some of our prediction had been demonstrated by previous reports, such as ADRB2, S1PR1, GHR, PPM1D, and GADD45B. Therefore, we hope our study could lay a basis for further study of other target genes, such as EDNRB, P2RY14, and LEPR.

CONCLUSIONS

It is effective to identify potential molecular marker for LAC and predict their underlying functions by bioinformatics analysis and graph clustering method. However, further experiments are still indispensable to confirm our conclusion.

Bioinformatics analysis reveals potential candidate drugs for psychological stress in ovarian cancer

BACKGROUND

Women with ovarian cancer may be at increased risk for psychological distress around the time of diagnosis relative to patients diagnosed with other cancers, because of the seriousness of the disease. However, the molecular mechanism of this effect is far from clear.

AIM

We sought to investigate the influence of psychological status in regulating gene expression among women with primary ovarian cancer and to identify the small molecules which exhibit similar effects with different psychological status.

MATERIALS AND METHODS

DNA microarray analyses of 10 ovarian carcinomas (GSE9116, downloaded from GEO) identified 916 human transcripts that were differentially expressed in tumors from patients with high depression relative to grade-and stage-matched tumors from low depression patients, and pathways related to immune system were dysfunctional.

RESULTS

Our results suggest that psychosocial stress is related to impaired immunity in ovarian cancer patients. Besides, we identified a group of small molecules which can be exploited as adjuvant drug to improve therapeutic effect for ovarian cancer, such as MS-275 and adiphenine.

CONCLUSIONS

Our findings may be useful for the development of management strategies for psychological distress, and we suggest that there is a need for improvement in the quality of life of cancer outpatients being treated with chemotherapy.

[Risk of cerebrovascular disease incidence in the cohort of Mayak production association workers first employed during 1948-1958]

Incidence of cerebrovascular diseases (CVD) has been studied in a cohort of 12210 workers first employed at one of the main plants (reactors, radiochemical or plutonium) of the Mayak nuclear facility during 1948-1958 and followed up to the end of 2000. Information on external gamma doses is available for virtually all (99.9%) of these workers; the mean (+/- one standard deviation) total gamma dose was 0.91 +/- 0.95 Gy (99% percentile 3.9 Gy) for men and 0.65 +/- 0.75 Gy (99% percentile 2.99 Gy) for women. Plutonium body burden was measured only for 30.0% of workers. Amongst those monitored, the mean (+/- standard deviation) cumulative liver dose from plutonium alpha exposure was 0.40 +/- 1.15 Gy (99% percentile 5.88 Gy) for men and 0.81 +/- 4.60 Gy (99% percentile 15.95 Gy) for women 4418 cases (first diagnosis) of CVD were identified in the studied cohort. A statistically significant increasing trend in CVD incidence with total external gamma dose was revealed after adjustment for non-radiation factors and internal exposure from incorporated plutonium-239. Excess relative risk per Gy was 0.464 (95% confidence interval 0.360-0.567). Incidence of CVD was statistically significantly higher for the workers chronically exposed to external gamma rays at a dose above 1.0 Gy A statistically significant increasing trend in CVD incidence with internal liver dose from plutonium alpha exposure was observed after adjustment for non-radiation factors and external exposure. ERR per Gy was 0.155 (95% confidence interval 0.075-0.235). CVD incidence was statistically significantly higher among workers with a plutonium liver dose above 0.1 Gy, although the trend estimates differed between workers at different plants. The incidence risk estimates for external radiation are generally compatible with estimates from the study of Chernobyl clean-up workers, although the incidence data point to higher risk estimates compared to those from the Japanese A-bomb survivors.

The influence of level of feeding on growth and serum insulin-like growth factor I and insulin-like growth factor-binding proteins in growing beef cattle supplemented with somatotropin

The objective of this study was to determine the effects of level of feeding on growth, feed efficiency (gain:feed; G:F), body composition (BC), and serum concentrations of somatotropin (ST), IGF-I, and IGF-binding proteins (BP) in growing beef cattle supplemented with bovine (b) ST. In each of two consecutive years, 40 growing beef cattle were blocked by weight (average BW: yr 1 = 316 kg, yr 2 = 305 kg) and used in a 2 x 2 factorial arrangement with main effects of bST (0 or 33 microg x kg BW(-1) x d(-1)) and level of feed intake (ad libitum [AL] or 0.75 AL). Relative to uninjected cattle, treatment with bST increased ADG 9.6% (1.14 vs 1.25 kg/d; P < 0.05) and increased G:F 8.1% (12.3 vs 13.3 gain [g]:feed [kg]; P < 0.05), whereas ADG in AL animals was 39% greater than that in 0.75 AL animals (1.39 vs 1.00 kg/d; P < 0.05). There was a tendency (P = 0.10) for a bST x level of feeding interaction, such that the increase in ADG with bST was greater in AL cattle than in 0.75 AL cattle (10.6 vs 7.8%; P = 0.10). Serum concentrations of ST were greater in 0.75 AL cattle than in AL cattle (13.0 vs 8.6 ng/mL; P < 0.05) and in bST-treated cattle than in uninjected cattle (16.3 vs 5.2 ng/mL; P < 0.05). Due to a bST x level of feeding interaction (P < 0.01), the magnitude of the increase in serum ST to exogenous bST was greater (P < 0.01) in 0.75 AL cattle than in AL cattle. Relative to uninjected cattle, treatment with bST increased (P < 0.05) serum concentrations of IGF-I and IGFBP-3 and reduced (P < 0.05) concentrations of IGFBP-2. Similarly, AL cattle had greater (P < 0.05) serum concentrations of IGF-I and IGFBP-3 and reduced (P < 0.05) IGFBP-2 compared with 0.75 AL cattle. In summary, treatment with bST increased growth rate and G:F and stimulated serum IGF-I and IGFBP-3 while reducing IGFBP-2. Feeding at 0.75 ad libitum intake reduced the magnitude of response for each of these variables. Thus, limit-feeding may reduce the effect of exogenous bST on growth rate by blunting bST-induced increases in IGF-I and IGFBP-3 and bST-induced decreases in IGFBP-2.

[Thrombopoietic effect of recombinant human thrombopoietin gene transferred to mice mediated by electric pulse on normal and experimental thrombocytopenia mice]

OBJECTIVE

To investigate the thrombopoietic effect of recombinant human thrombopoietin (rhTpo) gene transferred by electric pulse to normal and experimental thrombocytopenia mice.

METHODS

Eukaryotic high expressing plasmid pcDI/Tpo was constructed by gene recombinant technology. 200 microg of the recombinant plasmid was injected into quadriceps femoris muscle of normal and experimental thrombocytopenia mice. Six times of electric pulse at 100v, 1Hz, 40ms were given immediately after the injection.The expression of rhTpo gene and its protein were assayed by RT-PCR and Western Blotting, respectively. Serum Tpo concentration was assayed by ELISA method.

RESULTS

The recombinant plasmid pcDI/Tpo was successfully constructed. The expression of mRNA and protein of rhTpo gene was detected in the skeletal muscle of mice after transfection. Serum Tpo level increased from 328 +/- 89 ng/L to 1185 +/- 264 ng/L, and the platelet level of transfected mice increased from (259 +/- 27) x 10(9)/L to (640 +/- 31) x 10(9)/L. After injection with carboplatin, the platelet level decreased, but the nadir point was higher in pcDI/Tpo group than that in control group, and the recovery time of platelet count in pcDI/Tpo group shortened.

CONCLUSION

The rhTpo gene could be effectively transfected to mice by electric pulse and played thrombopoietic role in vivo.

Expression and functional characterization of the cardiac muscle ryanodine receptor Ca(2+) release channel in Chinese hamster ovary cells

To study the function and regulation of the cardiac ryanodine receptor (RyR2) Ca(2+) release channel, we expressed the RyR2 proteins in a Chinese hamster ovary (CHO) cell line, and assayed its function by single channel current recording and confocal imaging of intracellular Ca(2+) ([Ca(2+)](i)). The 16-kb cDNA encoding the full-length RyR2 was introduced into CHO cells using lipofectAmine and electroporation methods. Incorporation of microsomal membrane vesicles isolated from these transfected cells into lipid bilayer membrane resulted in single Ca(2+) release channel activities similar to those of the native Ca(2+) release channels from rabbit cardiac muscle SR membranes, both in terms of gating kinetics, conductance, and ryanodine modification. The expressed RyR2 channels were found to exhibit more frequent transitions to subconductance states than the native RyR2 channels and RyR1 expressed in CHO cells. Caffeine, an exogenous activator of RyR, induced release of [Ca(2+)](i) from these cells. Confocal imaging of cells expressing RyR2 did not detect spontaneous or caffeine-induced local Ca(2+) release events (i.e., "Ca(2+) sparks") typically seen in cardiac muscle. Our data show that the RyR2 expressed in CHO cells forms functional Ca(2+) release channels. Furthermore, the lack of localized Ca(2+) release events in these cells suggests that Ca(2+) sparks observed in cardiac muscle may involve cooperative gating of a group of Ca(2+) release channels and/or their interaction with muscle-specific proteins.

[Long-term results of surgical treatment of intractable Menière's disease for control of vertigo]

OBJECTIVE

To acquire the long-term (an average of over 10 years follow-up) results of surgical treatment of patients with Meniere's disease for control of vertigo.

METHOD

Endolymphatic sac surgery was done in 6 cases (1 case of endolymphatic sac decompression and 5 cases of sac-mastoid shunting) and translabyrinth vestibular neurotomy was operated on 6 cases.

RESULT

Complete relief from symptoms of vertigo occurred in the 6 cases through vestibular neurotomy and there were no recurrence in 11-13 years follow-up. Three of 6 cases with endolymphatic sac surgery had complete control of vertigo and were cured clinically. Symptoms of vertigo of the rest 3 cases were effectively controlled.

CONCLUSION

Endolymphatic sac surgery and translabyrinth vestibular neurotomy are effective way for control of vertigo of patients with intractable Meniere's disease. Translabyrinth vestibular neurotomy are more effective for control of vertigo for appropriately selected patients.

Caffeine-induced release of intracellular Ca2+ from Chinese hamster ovary cells expressing skeletal muscle ryanodine receptor. Effects on full-length and carboxyl-terminal portion of Ca2+ release channels

The ryanodine receptor (RyR)/Ca2+ release channel is an essential component of excitation-contraction coupling in striated muscle cells. To study the function and regulation of the Ca2+ release channel, we tested the effect of caffeine on the full-length and carboxyl-terminal portion of skeletal muscle RyR expressed in a Chinese hamster ovary (CHO) cell line. Caffeine induced openings of the full length RyR channels in a concentration-dependent manner, but it had no effect on the carboxyl-terminal RyR channels. CHO cells expressing the carboxyl-terminal RyR proteins displayed spontaneous changes of intracellular [Ca2+]. Unlike the native RyR channels in muscle cells, which display localized Ca2+ release events (i.e., "Ca2+ sparks" in cardiac muscle and "local release events" in skeletal muscle), CHO cells expressing the full length RyR proteins did not exhibit detectable spontaneous or caffeine-induced local Ca2+ release events. Our data suggest that the binding site for caffeine is likely to reside within the amino-terminal portion of RyR, and the localized Ca2+ release events observed in muscle cells may involve gating of a group of Ca2+ release channels and/or interaction of RyR with muscle-specific proteins.

Performance evaluation of a Scheimpflug stereocamera for particle image velocimetry

We describe a novel stereocamera for particle image velocimetry (PIV) applications that incorporates the Scheimpflug condition that the object plane, lens plane, and image plane must be collinear. We examined the governing equations for this system using a computer-based sensitivity analysis to predict the accuracy of the in-plane and out-of-plane measurement. We evaluated the performance of the Scheimpflug PIV system with a three-dimensional uniform translation test. Results indicate that the Scheimpflug PIV stereocamera performs as expected. The larger off-axis angles possible with the Scheimpflug system can provide a higher accuracy in the out-of-plane component when compared with a translation PIV stereocamera.