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Carbon materials are the preferred anode materials for Li-ion batteries. Here, we propose an easy and sustainable strategy to prepare honeycomb-shaped porous carbon (HPC) electrode materials through a process involving simple calcination and subsequent water washing by using polyvinyl-pyrrolidone (PVP) as carbon source and NaCl as pore-forming agent. A controllable cavity size and distribution of the carbon materials can be readily obtained solely by adjusting the NaCl amount. Results showed that the optimized HPC sample had a relatively uniform cavity distribution and a highly porous structure. Moreover, the special honeycomb-shaped structure was conducive to the electronic conductivity of the electrode materials, provided a short path for Li-ion transport and a wide interface with the electrolyte, and buffered the volume change of active materials. The special honeycomb-shaped structure was also maintained well after long cycles, which improved electrode stability. When used as anode materials for Li-ion batteries (LIBs), the sample demonstrated excellent cycling stability and rate performance, with a high specific capacity of 230 mA h g−1 and a reversible capacity of 197 mA h g−1, after 1200 cycles at 2 C. Overall, we introduced a simple strategy for the potential mass production of porous carbon materials for LIBs.

H5N6 highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4 not only exhibits unprecedented intercontinental spread in poultry, but can also cause serious infection in humans, posing a public health threat. Phylogenetic analyses show that 40% (8/20) of H5N6 viruses that infected humans carried H9N2 virus-derived internal genes. However, the precise contribution of H9N2 virus-derived internal genes to H5N6 virus infection in humans is unclear. Here, we report on the functional contribution of the H9N2 virus-derived matrix protein 1 (M1) to enhanced H5N6 virus replication capacity in mammalian cells. Unlike H5N1 virus-derived M1 protein, H9N2 virus-derived M1 protein showed high binding affinity for H5N6 hemagglutinin (HA) protein and increased viral progeny particle release in different mammalian cell lines. Human host factor, G protein subunit beta 1 (GNB1), exhibited strong binding to H9N2 virus-derived M1 protein to facilitate M1 transport to budding sites at the cell membrane. GNB1 knockdown inhibited the interaction between H9N2 virus-derived M1 and HA protein, and reduced influenza virus-like particles (VLPs) release. Our findings indicate that H9N2 virus-derived M1 protein promotes avian H5N6 influenza virus release from mammalian, in particular human cells, which could be a major viral factor for H5N6 virus cross-species infection., Author summary H9N2 avian influenza viruses (AIVs), through reassortment of their internal genes with other circulating AIVs subtypes (H5N6, H7N9, H10N8 and H10N3 viruses), are known to enable the resulting novel reassortants to infect humans. However, the precise roles of H9N2 virus-derived internal genes in human infection remain unknown. Here, we found that H9N2 virus-derived (but not H5N1 virus-derived) M1 protein showed strong interaction with host GNB1 protein to enhance M1 protein transport to budding sites at the cell membrane to promote progeny virus release, hence facilitating H5N6 reassortants to infect human cells.

Manipulation of artificial molecular rotors/motors is a key issue in the field of molecular nanomachines. Here we assemble non-planar SnPc molecules on an FeO film to form two kinds of rotors with different apparent morphologies, rotational speeds and stabilities. Both kinds of rotors can switch to each other

Reassortant Eurasian avian-like (EA) H1N1 virus, possessing 2009 pandemic (pdm/09) and triple-reassortant (TR)-derived internal genes, namely G4 genotype, has replaced the G1 genotype EA H1N1 virus (all the genes were of EA origin) and become predominant in swine populations in China. Understanding the pathogenicity of G4 viruses in pigs is of great importance for disease control. Here, we conducted comprehensive analyses of replication and pathogenicity of G4 and G1 EA H1N1 viruses in pigs. G4 virus exhibited enhanced replication, increased duration of virus shedding, and caused more severe respiratory lesions in pigs compared with G1 virus. G4 virus, with viral ribonucleoprotein (vRNP) complex genes of pdm/09 origin, exhibited higher levels of nuclear accumulation and higher polymerase activity, which is essential for improved replication of G4 virus. These findings indicate that G4 virus poses a great threat to both swine industry and public health, and control measures should be urgently implemented.

Background: long noncoding RNAs (lncRNAs) have attracted attention recently. However, many inconsistencies frequently appeared for the early diagnosis of digestive tract cancers (DTCs). We performed this meta-analysis to describe the diagnostic performance of lncRNAs in the discrimination of DTCs. Methods: data were extracted from PubMed, Web of Science, Embase, and Cochrane Library. Their quality was evaluated using the revised Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Such parameters as sensitivity and specificity were included for pooled analyses. The STATA 12.0 and Meta-Disc 1.4 software packages were used to perform the statistical analysis. Results: sixty-nine papers were included in this meta-analysis. The pooled analysis of DTCs showed that lncRNAs had a sensitivity of 0.78 and a specificity of 0.80. The area under the summary ROC curve (AUC) was 0.86. For gastric cancer (GC), the pooled sensitivity and specificity were 0.77 (95 % CI: 0.72-0.81) and 0.75 (95 % CI: 0.71-0.79), respectively, and the AUC was 0.83. For colorectal cancer (CRC), these three parameters were 0.82 (95 % CI: 0.76-0.86), 0.84 (95 % CI: 0.79-0.88), and 0.90, respectively. For esophageal cancer (EC) sensitivity was 0.74 (95 % CI: 0.67-0.80) and specificity reached 0.86 (95 % CI: 0.72-0.93), with an AUC of 0.82. Conclusions: LncRNAs show potential diagnostic value for discrimination between DTCs.

Purpose A growing number of researches manifest that DNA methylation has been considered as biomarker for the prognosis of bladder cancer (BC). However, the results are still in a discrepancy. Materials and methods This meta-analysis was conducted in accordance with PRISMA guidelines. Studies evaluating the practicability of methylated DNA as a prognostic marker for BC were thoroughly searched via the PubMed, Web of science and the Cochrane Library databases from January 1st, 2000 to May 5th, 2018. The association between DNA methylation and overall survival (OS) and progression-free survival (PFS) was analyzed. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to assess the correlation between methylated DNA and prognostic value in BC by using multivariate survival analysis. Results Nineteen studies were included. Patients with methylated DNA had poorer OS, compared with those with unmethylated DNA, the combined HR was 2.766 (95%CI: 2.099–3.806). Simultaneously, methylated DNA was considerably associated with shorter PFS (HR = 2.872, 95%CI: 1.971–4.185). Furthermore, DNA methylation had a significant association with gender (male vs female: OR = 1.486, 95% CI = 1.090–2.025), grade (3 vs 1–2: OR = 3.153, 95% CI = 2.006–4.955), tumor diameter (≤3 cm vs >3 cm: OR = 0.408, 95% CI = 0.277–0.602), number of tumors (single vs multiple: OR = 0.683, 95% CI = 0.501–0.932), stage (Ta vs T1: OR = 0.472, 95% CI = 0.342–0.654), (Ta-T1 vs T2-T4: OR = 0.338, 95% CI =0.210–0.543). Conclusions DNA methylation was negatively correlated with the prognosis of BC patients and might become a promising biomarker.

To avoid large currents caused by closing-loop operations in medium-voltage distribution grids, it is necessary to develop an effective method for rapid and accurate calculation of the closing-loop currents. In this paper, theoretical analysis is conducted to obtain the typical equivalent circuit for the calculation and analysis of the typical 10kV closing-loop system in Shanghai Grid. Three methods considering both the calculation complexity and the result accuracy, namely detailed power flow analysis method, simplified power flow analysis method and approximate formula method are proposed based on the typical equivalent closing-loop system. In the case study, the closing-loop currents of 10kV distribution grid of Shanghai under various operation scenarios are calculated with the three methods respectively, and the influence of the load levels and transformers’ tap positions on the closing-loop currents are analyzed in accordance with the practical requirements of dispatching. The validity of the three methods is confirmed through comparison of the calculation results with full-network simulation results through BPA software. Furthermore, the convergence, accuracy and practical applicability of the three methods are compared, thus to provide a feasible and reliable decision basis for practical distribution grids dispatching.

This study is a meta-analysis and aims to determine the value of urinary survivin for detecting bladder cancer (BC) on the basis of preceding statistical performance and to compare their diagnostic value. Considering that the urinary survivin data were from both RNA and protein levels, the key words “bladder cancer” AND “survivin” and “bladder cancer” AND “survivin RNA” were used; and PubMed, Web of Science, and Cochrane Library were systematically searched to identify relevant articles. The methodological quality of each study was assessed by QUADAS-2. Data were analyzed by STATA 12.0 and Meta-disc v.1.4 software package. A random-effects model was used and subgroup analysis was carried out to identify possible sources of heterogeneity. Nine articles for survivin protein test with 789 patients and 684 controls, and 12 articles for survivin RNA test with 880 patients and 922 controls were identified. The results showed that the pooled sensitivity was 0.79 (95% CI 0.73, 0.84), specificity was 0.87 (95% CI 0.79, 0.92) of the survivin protein test for bladder cancer, and the sensitivity and specificity was 0.84 (95% CI 0.79, 0.88) and 0.94 (95% CI 0.89, 0.97) of the survivin RNA test. The AUC of the two approaches was 0.89 (95% CI 0.86, 0.91) and 0.94 (95% CI 0.92, 0.96), respectively. The survivin protein and survivin RNA both had great potential as biomarkers for BC detection, and survivin RNA showed higher accuracy than survivin protein on BC diagnosis.

Monolayer and few layer antimony allotropes fabricated on oxide layers are essential for practical applications in fields of solar cells, electronic and photonic devices. Here the antimony structural phases are systemically studied on corrugated copper oxide of Cu(111) by atomically-resolved scanning tunneling microscopy (STM). We find that initial deposition of Sb atoms causes the structural changes of the underlying oxide layer and sequentially gives rise to the formation of flat (√7 × √7)-Sb and buckled antimonene phases. Finally, a nanoring-like antimony configuration is observed with triangle-shaped atomic arrays closely packing and shows high stabilities for oxygen exposure. The (√7 × √7) phase exhibits the metallic property with energetically continuous electronic states existing near Fermi level. For the antimonene and nanoring phases, band gap signatures are observed, implying the semiconducting features. Our results provide a method for fabricating stable elemental allotropes on oxide surfaces.

Antimony nanostructures fabricated on metal oxide layers are essential for practical applications in fields of solar cells, electronic and photonic devices. Here the antimony phases were systemically studied on the copper oxide of Cu(110). By high-resolution scanning tunneling microscopy (STM), we revealed that a wrinkled antimony phase was formed on the CuO surface regardless of the initial oxide structure. It exhibited an armchair-like configuration making up of protruded and dipped Sb atoms as confirmed by STM and density functional theory calculations. Further Sb deposition caused the armchair-like phase distorting and subsequently gave rise to formation of a c(2 × 2)-Sb phase. Finally, another kind of wrinkled phase was successfully fabricated. It consisted of two zigzagged antimony chains with protruded and dipped Sb atoms alternately distributing. By analysis of the atomically-resolved STM topographies, several kinds of dislocations have been observed and the corresponding geometric models are addressed. The armchair and zigzag phases both exhibited high stabilities for oxygen exposure. Conductance measurements imply that each phase interacts with the underlying layer. Our results might provide a way for fabricating stable ultrathin materials with a well-defined edge structure on oxide surfaces.

Lithium-sulfur (Li-S) batteries are promising candidates for next-generation energy storage devices owing to their advantages such as high theoretical specific capacity and energy density. However, the shuttle effect of polysulfide intermediates and the slow electrochemical kinetics have a severe passive effect on the cycling stability and rate performance. A Co3 W3 C@C composite was prepared through a simple one-pot pyrolysis method and used as a modifying layer on a commercial separator. The obtained modified separator not only prevented the shuttle effect through both strong chemical interaction and a physical barrier toward polysulfides, but also acted as a catalytic membrane to catalyze the electrochemical redox of active sulfur species. By employing the coated separator, the cathode with 60 wt % sulfur delivered a high initial capacity of 1345 mAh g-1 at 0.1 A g-1 , excellent rate performance with a high capacity of 670 mAh g-1 even at 7 A g-1 , and outstanding cycle performance with a low decay rate of 0.06 % per cycle and an average Coulombic efficiency of 99.3 % within 500 cycles at 1 A g-1 . Even at a sulfur loading of 3 mg cm-1 , a high initial capacity of 869 mAh g-1 and 632 mAh g-1 after 200 cycles at 1 A g-1 were obtained. The results demonstrate the advantages of Co-W bimetallic carbide in preventing the shuttle effect and promoting the redox kinetics for high performance Li-S batteries.

To understand the effects of ambient air pollution on the prevalence of acute respiratory diseases and symptoms among adults in three cities in the Yangtze River Delta.During September to November 2015, 4144 permanent residents aged 18 years and above from four investigation sites in three cities in the Yangtze River Delta were randomly surveyed by questionnaire. Daily concentrations of air pollutants, including PM_(2. 5), NO_2、O_3、CO and SO_2 nearest to the investigation sites were collected from the department of environmental protection. Logistic regression was used to analyze the association between air pollution and acute respiratory diseases and symptoms after other risk factors were adjusted.The prevalence of acute respiratory diseases and symptoms in two weeks among adults were 0. 99% and 3. 88%, respectively. Chemicals related to air pollution(OR=2. 339, 95%CI 1. 156-4. 734) and allergy(OR=4. 857, 95%CI 2. 279-10. 350) were the risk factors of acute respiratory diseases in two weeks among adults while occupational hazards such as toxic chemicals and high temperature(OR=1. 796, 95%CI 1. 220-2. 644), family history of respiratory diseases(OR=2. 670, 95%CI 1. 865-3. 823) and allergy(OR=3. 703, 95%CI 2. 395-5. 725) were the risk factor of respiratory symptoms in two weeks among adults. In addition, the average exposure level of PM_(2. 5)in two weeks was associated with acute respiratory diseases(OR=1. 014, 95%CI 1. 000-1. 028) and symptoms(OR=1. 025, 95%CI 1. 018-1. 033) in two weeks among adults.The increases of the prevalence of acute respiratory diseases and symptoms among adults are associated with ambient air pollution in three cities in the Yangtze River Delta.

N-doped TiO 2 nanotube (NT) arrays were prepared by anodization in electrolytes containing HF, ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluoroborate ([BMIM]BF 4 ) and water. The ionic liquid, [BMIM]BF 4 , was used as the nitrogen source. The surface morphology and the composition of samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis diffuse reflectance spectra (DRS). The photocatalytic activities of samples were investigated by the degradation of methylene blue (MB) under spherical xenon lamp. The results show that the degradation rate of MB over N-doped TiO 2 NT arrays is obviously higher than that over undoped TiO 2 NT arrays. The above results are caused by the increased oxygen vacancies and the decreased band gap.

Utilizing the special institutional setting in the Chinese securities market, we examine how suppressed short-sale demand influences stock valuations and price efficiency for stocks with no short-selling activities. Based on revealed short-sale volume of shortable stocks, we employ a characteristics model to estimate the suppressed short-sale demand for non-shortable stocks, with a higher short-sale demand being suppressed indicates a more binding short-sale constraint. We find that suppressed short-sale demand negatively predicts future returns, and such relation concentrates among firms with poor information environment. Consistent with Diamond and Verrecchia (1987)’s reduced-pricing-efficiency theory, we find that a higher suppressed short-sale demand is associated with a greater price delay and a stronger post-earnings-announcement-drift.

We report on a Kondo effect on Co/Sb(111) mediating topological protection of the surface states against local magnetic perturbations. A sharp scanning tunneling spectroscopic peak near the Fermi energy is interpreted as a fingerprint of the Kondo resonance with a high Kondo temperature of about 200 K. Density function theory calculations reveal that the protruding Co adatoms are responsible for the Kondo peak, while the Co atoms underneath present as nonmagnetic impurities. By identifying the quasiparticle interference wavevectors, we demonstrate that only scattering channels related to backscattering confinements are observed for surfaces with and without the Co adsorption. It suggests that the Kondo effect suppresses the backscattering of the topological surface states and may help to expand the functionality of magnetically coupled topological materials for spintronics applications.

Programmed death‐1 (PD‐1) plays an important role in protecting against inflammation and myocyte damage in T‐cell‐mediated myocarditis. To understand whether fibrinogen‐like protein‐2 (FGL2) can affect the role of the PD‐1/PD‐L1 pathway in experimental autoimmune myocarditis (EAM), we investigated cardiac function in EAM rats over‐expressing FGL2. Over‐expression of FGL2 significantly decreased PD‐1 and deteriorated cardiac function in rats with autoimmune myocarditis. Histopathology revealed increased inflammatory cell infiltrate in EAM‐FGL2 rats compared with the control groups (EAM, EAM‐GFP and NC). Notably, transcription factor forkhead box P3 (Foxp3) and retinoic acid‐related orphan receptor γt (ROR γt) protein and mRNA levels were statistically (P

As substantial power is imported into Shanghai Grid through four HVDC systems, the operation characteristics of multi-infeed receiving-end system have emerged in Shanghai Grid. The intensive interactions between HVDC system and AC grid may aggravate the risk of cascading as well as the capability of the grid to withstand significant disturbances. In this paper, simulation of HVDC system response upon fault occurrence in AC system is performed for Shanghai Grid with the maximum power import through four HVDC transmission systems. The risk of AC grid's instability due to commutation failures and blockings of HVDC systems is investigated. Quantitative assessment of system voltage stability margin is conducted for the grid under simultaneous blockings of multiple HVDC systems. The overall security and stability risk attributed to the interactive influence between AC and DC grid is evaluated for Shanghai Grid under extreme contingencies.

Growth and surface electronic states of Co nanoislands supported by Cu-9 at%Al(111) are investigated bylaw temperature scanning tunneling microscopy. Deposition of about 0.25 monolayer of Co atoms causes the formation of flat Co nanoislands with thicknesses ranging from monolayer to triple layer. Scanning tunneling spectroscopy measurements reveal that a Tamm-type surface state exists on the Co islands and its energy varies with the thicknesses and stacking manners. In addition, density functional theory calculations conclude that the surface states of the mono- and bilayer nanoislands mainly originate from the hybridization between Co d bands and sp bands of the substrate and the Co d(3z2-r2) minority-spin bands, respectively. (C) 2013 Elsevier B.V. All rights reserved.

As multi-infeed HVDC systems are integrated into East China Grid, the operation characteristics and concerns of the grid have changed remarkably. Due to substantial power import through HVDC systems, a large quantity of local generators in the receiving-end grid have to be shut down. The resulting aggravated shortage of dynamic reactive power reserve exacerbates the capability of the grid to withstand significant disturbances. Commutation failures and blockings of multi-infeed HVDC systems may even instigate voltage instability in the receiving-end grid. Synchronous condensers are projected to be installed at HVDC converting stations so as to provide dynamic reactive power support and to improve voltage control performance in East China Grid. Simulation and comparative analysis is performed in this paper to investigate the influence of integration of synchronous condensers on various aspects of system performance involving short-circuit current, voltage stability and transient stability of the grid as well as commutation failures of HVDC systems. The comprehensive analysis results are expected to provide technical reference for allocation of synchronous condensers and determination of the appropriate parameters of the equipment.

In order to deal with the problems caused by reduced schedule of the local units, a minimum unit scheduling and evaluation technology based on the multiple security and stability constraints is developed in this paper. The process of minimum unit scheduling is determined. The quantitative method is proposed to evaluate the security and stability margin of the grid under the minimum unit schedule. In addition, the application of the technology in the scheduling of local units in Shanghai grid is presented for two typical scenarios of 2016. The study of minimum unit scheduling technology is expected to provide guidance on safe and reliable unit commitment scheduling and facilitate the implementation of “energy saving and emission reduction” program through the efficient usage of external clean power and lowering dependence on fuel-fired plants.

We examine the effects of short-sale constraints in Hong Kong where stocks can be shorted only if they are included on an official short-sale list. Using revisions to the list, we test two hypotheses — 1) that short-sale constraints lead to overvaluation and 2) that they lead to lower costs of capital. We find weak support for the Diamond and Verrecchia (1987) version of the overvaluation hypothesis, but more compelling evidence supporting the Xu (2007) version of the overvaluation hypothesis and the cost of capital hypothesis. We argue that in the context of our tests the Xu overvaluation hypothesis is actually a reformulation of the cost of capital hypothesis and that the bulk of our evidence, therefore, supports the notion that short-sale constraints reduce capital costs.

The considerably uneven distribution of power flow on 500kV Anhui-Jiangsu cross province interface during peak hours may contribute to overload conditions in case of out ages on one of the four transmission lines of this interface. Ex port of electric power from Anhui province through this inter face to Yangze Delta load center is restricted to 4800MW. Installation of thyristor-controlled phase shifting transformer (TCPST) on each of the 500kV cross province transmission lines from Dangtu substation to Huifengshan substation is reviewed to be effective solution for interface power flow control under various possible grid operation conditions. This paper evaluates the application effect of the demonstration project, which involves power flow control impact on the interface and neighboring sys tem, short circuit current limiting effect with respect to the impedance of TCPST under varying phase shifting angle as well as system stability performance related issues. The evaluation is expected to provide theoretic basis for the implementation of the demonstration project.

Fujian provincial grid was connected into East China grid through two parallel tie lines of 500kV in 2002. Out-of-step oscillation may occur between Fujian Province Grid and East China grid under the critical contingencies. System separation devices have been installed on 500kV tie-lines between Fujian grid and East China grid to maintain system stability. As the newly built UHV Binjin DC transmission system was projected to come in service in 2014, power injected into East China grid through the system was gradually increased to its full capacity in accordance with the implementation of the project by three stages. The characteristics of out-of-step oscillation between Fujian grid and East China grid may be altered due to the significant changes involving tie lines, reinforcement and reconfiguration of local system as well as the scale of power injection. To investigate the characteristics of out-of-step oscillation, extreme contingencies contributing to out-of-step oscillation are identified based on the analysis of the practical grid operation. For each stage of Binjin transmission project, the center of out-of-step oscillation is determined through the simulation analysis of the oscillation characteristics for East China grid. The applicability of the existing system separation devices is evaluated, and system separation strategy is then reviewed for East China grid to accommodate the operation of UHV Binjin DC transmission project.

Growth and image potential states of the alumina monolayer on Cu-9 at.% Al( 111) were investigated by low temperature scanning tunneling microscopy. The alumina monolayer showed a zigzagged corrugation with the rectangular unit cell that possessed a root 3 ratio between lengths of the two sides. Furthermore, the distance-voltage characteristics revealed that the energy of the n = 1 image potential state on the alumina film shifted by about 024 eV towards the vacuum level compared with that on pristine Cu-9 at.% Al(111). This shift was explained in terms of the joint modification of the surface potential by the repulsion between electrons and the alumina layer as well as by the depression of the electric field in the Stark effects. Probing the energies of image potential states provided a way to investigate how the alumina film influenced interfacial electronic structure, which showed practical applications for the development of electronic devices. (C) 2011 Elsevier B.V. All rights reserved.

Bias-dependent features of the insulating NaCl layer grown on Cu(001) have been investigated by scanning tunneling microscopy/spectroscopy (STM/STS). The apparent layer thickness of the NaCl film is variable at bias voltages ranging from 2.8 to 3.2 V as well as from 4.0 to 5.0 V. and the Moire pattern induced by NaCl-Cu lattice mismatch also shows bias dependence. The z-V (dz/dV-V) curves and dl/dV mapping measurements reveal that the resonant tunneling between the image potential states (IPSs) on Cu(001) and the Fermi level of the STM tip leads to drastic variations of these features. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

Molecular rotors, motors and gears play important roles in artificial molecular machines, in which rotor and motor matrices are highly desirable for large-scale bottom-up fabrication of molecular machines. Here we demonstrate the fabrication of a highly ordered molecular rotor matrix by depositing nonplanar dipolar titanyl phthalocyanine (TiOPc, C32H16N8OTi) molecules on a Moire patterned dipolar FeO/Pt(111) substrate. TiOPc molecules with O atoms pointing outwards from the substrate (upward) or towards the substrate (downward) are alternatively adsorbed on the fcc sites by strong lateral confinement. The adsorbed molecules, i.e. two kinds of molecular rotors, show different scanning tunneling microscopy images, thermal stabilities and rotational characteristics. Density functional theory calculations clarify that TiOPc molecules anchoring upwards with high adsorption energies correspond to low-rotational-rate rotors, while those anchoring downwards with low adsorption energies correspond to high-rotational-rate rotors. A robust rotor matrix fully occupied by low-rate rotors is fabricated by depositing molecules on the substrate at elevated temperature. Such a paradigm opens up a promising route to fabricate functional molecular rotor matrices, driven motor matrices and even gear groups on solid substrates.

Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) were applied to investigate the segregation of aluminum atoms on a Cu-9 at.% Al(1 1 1) surface. We observed that the Al concentration in the top layer ranged between about 9 and 36 at.% after the sample we used was annealed at different temperatures. The phenomenon of Al atoms segregating on the surfaces was explained well by considering the diffusion length of Al atoms in bulk Cu. LEED measurements showed that ( 3 × 3 ) R30° structures grew as the concentration of Al atoms increased. The segregation phenomena on surfaces resulted in a stable two-dimensional Cu67Al33 alloy phase in the top layer.

The growth of Au on thin Pb films was studied by scanning tunneling microscopy and low energy electron diffraction. We found that the initial Au deposition resulted in a rough Au-Pb alloy interface on the thin Pb films. With further deposited Au, Moire patterns in a (root 3 x root 3)-Au layer was formed on top of a laterally contracted Au-Pb alloy surface. Finally, the Au deposition performed the Stranski-Krastanov type growth mode to form three-dimensional Au crystals. This structure information provided a possible explanation to the observed phase shift pi between the density of states near the Fermi energy and the superconducting transition temperature as a function of film thickness as reported recently [Guo et al., Science 306 (2004) 1915 and Zhang et al., Phys. Rev. Lett. 95 (2005) 096802]. (c) 2008 Elsevier B.V. All rights reserved.

Short-sales practices in the Hong Kong stock market are unique in that only stocks on a list of designated securities can be sold short. By analyzing the price effects following the addition of individual stocks to the list, we find that short-sales constraints tend to cause stock overvaluation and that the overvaluation effect is more dramatic for individual stocks for which wider dispersion of investor opinions exists. These findings are consistent with Miller's (1977) intuition and other optimism models. We also document higher volatility and less positive skewness of individual stock returns when short sales are allowed. THE QUESTION OF HOW SHORT SALES IMPACT capital markets is highly controversial, with short-sale regulations varying widely across countries and capital markets.1 Although short selling has been carried out for years in major financial markets around the world, its effects on market efficiency, especially on pricing efficiency, remain of interest to financial researchers. Miller (1977) theorizes that in the presence of short-sales constraints, security prices tend to reflect a more optimistic valuation than the average opinion of potential investors and thus tend to be upward biased. This overvaluation argument is based on two conditions: (1) A security's short sales are either prohibited or costly, and (2) investors have heterogeneous beliefs or information about the security's value. The underlying intuition is quite straightforward. Pessimistic investors are forced to sit out of the market when short sales are not available, and thus some negative information is not reflected in prices, enabling enthusiastic buyers to bid prices above the level that average investors perceive as fair. This argument has significant implications for market efficiency theories, since one of the major functions of capital markets is price discovery. Indeed, an efficient market should be "a market in which prices always