Regulating the electronic properties of the WGe2N4 monolayer by adsorption of 4d transition metal atoms towards spintronic devices.

We study the regulation of the electronic and spin transport properties of the WGe2N4 monolayer by adsorbing 4d transition metal atoms (Y-Cd) using density functional theory combined with non-equilibrium Green's function. It is found that the adsorption of transition metal atoms (except Pd, Ag and Cd atoms) can introduce a magnetic moment into the WGe2N4 monolayer. Among the transition metal atoms, the adsorption of Nb and Rh atoms transforms WGe2N4 from a semiconductor to a half-metal and a highly spin-polarized semiconductor, respectively. The half-metallic Nb-adsorbed WGe2N4 system is selected to investigate the spin transport properties, and a high magnetoresistance ratio of 107% is achieved. In both parallel and antiparallel magnetization configurations, the spin filtering efficiency reaches close to 100% in the whole bias range, and the antiparallel magnetization configuration exhibits a dual spin filtering effect with a rectification ratio of up to 104. Our study predicts that the adsorption of 4d transition metal heteroatoms is an effective method to regulate the electronic and magnetic properties of WGe2N4 towards high-performance spintronic devices.

Design of multifunctional spin logic gates based on manganese porphyrin molecules connected to graphene electrodes.

The spin-resolved transport properties of molecular logic devices composed of two Mn porphyrin molecules connected to each other via a six-carbon atomic chain were studied using the non-equilibrium Green's function combined with density functional theory. The molecules were symmetrically connected to armchair graphene nanoribbon electrodes through four-carbon atomic chains on the left- and right-hand sides. Our calculations revealed that the spin-resolved current-voltage curves depend on the initial spin setting of the transition metal Mn atoms and carbon atoms on the zigzag edges where the electrodes come in contact with the molecule. By simultaneously regulating the spin orientations of the intermediate functional molecules and the zigzag edges of the armchair graphene nanoribbon electrodes, seven spin polarization configurations were obtained. These configurations were examined in this study considering the spin-related symmetry of molecular junctions. By meticulously selecting different combinations according to the specific input and output signals, YES, NOT, OR, NOR, and XOR multifarious spin logic devices were created. The findings of this study are expected to contribute toward the extension of molecular junction functions in future spintronic integrated circuit design and further miniaturization.

Schottky diodes based on blue phosphorene nanoribbon homojunctions.

Diodes have been widely studied as one of the most commonly used electronic components in circuits, and it is important to find diodes with an excellent rectification performance. Herein, we investigate the electronic and transport properties of Schottky contact diodes based on zigzag hydrogenated blue phosphorene nanoribbons, by employing density functional theory combined with the non-equilibrium Green's function. It is found that the adsorption of transition metal atoms Sc/Cr/Ti and Ni on the top site of blue phosphorene nanoribbons leads to metallic and semiconducting properties, respectively. Devices consisting of the planar contact of the metallic and semiconducting nanoribbons show rectifying behavior due to the Schottky barriers of the homojunctions. The current is preferential to flow from the semiconducting side to the metallic side. The rectification ratio of the Sc-Ni device and the Cr-Ni device can reach up to 108, which is much higher than that of traditional p-n junctions of about 105-107. The high rectification ratio at low bias regions, together with the low threshold voltages and negligible reverse currents, make blue phosphorene nanoribbon homojunctions ideal rectifier diodes.

Increased miR-6875-5p inhibits plasmacytoid dendritic cell differentiation via the STAT3/E2-2 pathway in recurrent spontaneous abortion.

Recurrent spontaneous abortion (RSA) is a common complication of early pregnancy. Dendritic cells (DCs) are thought to confer fetal-maternal immunotolerance and play a crucial role in ensuring a successful pregnancy. A decrease of plasmacytoid dendritic cells (pDCs) was found to be involved in RSA, but the underlying mechanisms of decreased pDC in RSA remain unclear. MicroRNAs (miRNAs) play critical roles in RSA as well as the development, differentiation and functional regulation of pDCs; however, the regulatory effect of miRNAs on pDC in RSA has not been fully investigated. Here we demonstrated that both the proportion of pDC and signal transducer and activator of transcription (STAT3)/transcription factor 4 (Tcf4/E2-2) expression decreased in the peripheral blood mononuclear cells and decidua of patients with RSA compared to those with normal pregnancy (NP), and there was a significantly positive correlation between pDC and STAT3 mRNA. MiRNA microarray assay and quantitative reverse transcription PCR results showed that miR-6875-5p expression was markedly increased in women with RSA and negatively correlated with mRNA expression level of STAT3. Up-regulated miR-6875-5p could sensitively discriminate patients with RSA from NP subjects. Overexpression of miR-6875-5p significantly down-regulated the mRNA expression of STAT3 and E2-2 as well as the protein and phosphorylation level of STAT3, while miR-6875-5p knockdown showed opposite results. Dual luciferase reporter verified that miR-6875-5p regulated STAT3 expression by directly binding to its 3'untranslated region. Overall, our results suggested that increased miR-6875-5p is involved in RSA by decreasing the differentiation of pDCs via inhibition of the STAT3/E2-2 signaling pathway. miR-6875-5p may be explored as a promising diagnostic marker and therapeutic target for RSA.

An ultra-sensitive gas sensor based on a two-dimensional manganese porphyrin monolayer.

The development of highly sensitive, low-power consuming, stable and recyclable gas sensing devices at room temperature has become an important solution for environmental safety detection. Utilizing a two-dimensional metalloporphyrin monolayer for gas sensing is appealing due to its large specific surface area and high surface activity. A two-dimensional manganese porphyrin monolayer (2DMnPr) is selected from 2D metalloporphyrins with 3d metal centers due to its semi-metallicity to explore its gas sensing properties. Using first-principles calculations, we systematically investigate the electronic structures and adsorption characteristics of gas molecules with toxicity and greenhouse effect on the surface of 2DMnPr, including H2S, CO, CO2, SO2, NO and NO2. The strength of the interaction and charge transfer between the 2DMnPr surface and the adsorbed molecules have a direct effect on the electronic properties and the sensing properties of the adsorbent surface. The sensing performance of the 2DMnPr adsorbent is evaluated via two observable parameters: work function and electrical conductivity. The work functions of 2DMnPr after the adsorption of CO, SO2, NO and NO2 gas molecules increase by different degrees depending on the charge transfer, and those of the H2S and CO2 cases decrease. In our simulation, adsorption of CO, SO2, NO and NO2 gas molecules affects the electronic properties of 2DMnPr markedly, and current-voltage characteristics within a low bias range uncover the superior sensitivity of the conductivity of the 2DMnPr monolayer to these molecules. Besides, the sensing performance is demonstrated to be stable under strain and at room temperature. The desorption time of a gas is positively related to its adsorption energy. The recovery time of CO is predicted to be short enough to realize sustainable detection at room temperature, and the SO2, NO and NO2 gases can also be desorbed at higher temperatures. These results demonstrate that 2DMnPr enables the sensitive detection of these gases and predict the potential application of 2DMnPr as an ultra-sensitive, low-power, stable and recyclable gas sensor at room temperature.

Pervasive Ohmic contacts of monolayer 4-hT2 graphdiyne transistors.

Monolayer (ML) graphdiyne, a two-dimensional semiconductor with appropriate band gap and high carrier mobility, is a promising candidate for channel material in field effect transistors (FETs). Using density functional theory combined with non-equilibrium Green's function method, we systematically investigate the contact and transport properties of graphdiyne FETs with various electrodes, including metals (Cu, Au, Ni, Al and Ag) and MXenes (Cr2C, Ta2C and V2C). Strong interaction can be found between ML graphdiyne and the Cu, Ni and MXenes electrodes with indistinguishable band structure of ML graphdiyne, while weak or medium interaction exists in the contacts of ML graphdiyne and the Au, Al and Ag electrodes where the band structure of ML graphdiyne remains intact. Despite the different contact interactions, Ohmic contacts are generated with all considered electrode materials owing to the weak Fermi level pinning of graphdiyne. The linear I-V characteristic curve verifies the Ohmic contact between Au electrode and graphdiyne ultimately. The theoretically calculated Schottky barrier heights of graphdiyne with Cu electrode are consistent with the available experimental data. Our calculation suggests that graphdiyne is an excellent channel material of FETs forming desired Ohmic contacts with wide-ranging electrodes and thus is promising to fabricate high performance FETs.

Surface decoration of phosphorene nanoribbons with 4d transition metal atoms for spintronics.

The recent production of phosphorene nanoribbons provides a platform for designing phosphorene-based high-speed electronic devices. Introducing a magnetic moment to phosphorene nanoribbons for spintronics application is attractive. Based on density functional theory combined with the non-equilibrium Green's function method, the electronic, magnetic and spin-polarized transport properties of phosphorene nanoribbons modified by adsorption and substitutional doping of 4d transition metal atoms (Y, Zr, Nb and Mo) are investigated systematically. The results show that both the adsorption and the doping of 4d transition metal atoms can introduce a magnetic moment into phosphorene nanoribbons, except the Y- and Nb-doping cases. The adsorption shows superior performance in terms of modulating the electronic and magnetic properties of phosphorene nanoribbons compared to substitutional doping, exhibiting higher spin polarization near the Fermi level with a narrower band gap. This discrepancy originates from the different electronic redistribution in the adsorption and doping situations. Furthermore, the nanoribbons with adsorbed 4d transition metal atoms exhibit excellent spin-polarized transport properties: a giant magnetoresistance ratio of the Mo-adsorbed nanoribbon reaches over 108 under low bias; the Y-Mo-adsorbed nanoribbons with parallel spin configurations show a spin filtering effect of about 100% with the bias larger than 0.1 V, and those with antiparallel spin configurations exhibit a dual spin filtering effect in an applied bias range of (-0.2 V, 0.2 V). Our results demonstrate that 4d-transition-metal-atom adsorption is a favourable approach to modify the electronic, magnetic and transport properties of phosphorene nanoribbons, thus providing a reference for the rational design of spintronic devices based on phosphorene nanoribbons.

Anisotropic interfacial properties of monolayer C2N field effect transistors.

Monolayer C2N is promising for next-generation electronic and optoelectronic applications due to its appropriate band gap and high carrier efficiency. However, relative studies have been held back due to the lack of high-quality electrode contacts. Here, we comprehensively study the electronic and transport properties of monolayer C2N with a series of electrode materials (Al, Ti, Ni, Cu, Ag, Pt, V2C, Cr2C and graphene) by using the nonequilibrium Green's function (NEGF) method combined with density functional theory (DFT). The monolayer C2N forms Ohmic contacts with the Ti/Cu/Ag electrode material in both armchair and zigzag directions, whereas Ohmic contact is only formed in the zigzag direction of the C2N-Al field effect transistor. However, the C2N-Ni, -Pt, -V2C, -Mo2C, -graphene contact systems form n-type Schottky contacts in either the armchair or zigzag direction owing to the relatively strong Fermi level pinning (the pinning factor S = 0.32 in the armchair direction and S = 0.26 in the zigzag direction). By insertion of BN or graphene between the C2N and Pt electrode in the armchair direction of contact systems, the Fermi level pinning can be effectively weakened due to the suppression of metal-induced gap states. Conspicuously, an Ohmic contact is realized in the C2N field effect transistors with the BN-Pt electrode, suggesting a possible approach to fabricating high-performance devices. Our study is conducive to selecting appropriate electrode materials for C2N-based field effect transistors.

Modulating the electronic structures of blue phosphorene towards spintronics.

Modulation of the electronic and magnetic structure of blue phosphorene nanoribbons to explore the potential application in spintronics is appealing. Using density functional theory in combination with the non-equilibrium Green's function method, the energetic, electronic, magnetic, and spin-resolved transport properties of hydrogenated armchair and zigzag blue phosphorene nanoribbons with surface modification by 3d transition metal atoms (ranging from Sc to Ni) were systematically investigated. The blue phosphorene nanoribbons were found to be highly capable of adsorbing impurity atoms, and the adatoms prefer a 2D growth mode on the nanoribbons. The band structures of the blue phosphorene nanoribbons were effectively modulated by the adatoms: the bandgap dramatically decreased with remarkable spin-polarization, except in the case of Ni. The spin-resolved transport properties of Sc-adsorbed zigzag blue phosphorene nanoribbons were selectively investigated to explore the potential application in spintronics, and a giant magnetoresistance effect of above 500 was found. This work suggests that the surface adsorption of 3d transition metal heteroatoms is a feasible and effective approach to functionalize blue phosphorene nanoribbons for spintronic applications.

Surface engineering of phosphorene nanoribbons by transition metal heteroatoms for spintronics.

Modulating the electronic and magnetic properties of phosphorene is important for fabricating multi-functional electronic and spintronic devices. Employing density functional theory combined with the non-equilibrium Green's function, we systematically investigate the electronic, magnetic and transport properties of hydrogenated armchair phosphorene nanoribbons chemically modified by 3d transition metal atoms (Sc, Ti, V, Cr, Mn, Fe, Co and Ni). With chemical adsorption of transition metal atoms, the phosphorene nanoribbons exhibit excellent spin-polarized transport properties. A giant magnetoresistance effect is found with Ti, Fe and Mn adsorption, in which ratios higher than 102 for the Ti and Mn cases, and 105 for the Fe case, are exhibited. Moreover, in the bias range of (-0.2 V, 0.2 V), the Ti, V, Mn and Fe-adsorbed nanoribbons with parallel spin configurations demonstrate a remarkable bias-independent spin filtering efficiency at about 100%, while the Fe and Mn-adsorbed nanoribbons with antiparallel spin configuration show a dual spin filtering effect. The spin-polarized electronic transport properties are closely related to the band structures. Remarkable spin-polarization of the current occurs when the dispersed and flat bands near the Fermi level originate from different spin orientations. The magnetic moments of transition metal adatoms on nanoribbons are reduced by 0.2-2 µB relative to the isolated atoms due to electron rearrangement and charge transfer, which results in various degrees of spin polarization. These results provide a fundamental understanding of the electronic, magnetic and transport properties of transition metal modified hydrogenated armchair phosphorene nanoribbons, and suggest a referential approach to manufacture spintronic devices based on phosphorene.

Neuroprotective effects of a novel peptide through the Rho-integrin-Tie2 and PI3K/Akt pathways in experimental autoimmune encephalomyelitis model.

Purpose: The interaction between inflammatory cells and integrin in the endothelium plays a key role during infiltration. Previous evidence has shown that synthetic C16 peptide selectively binds to integrins αvß3 and α5ß1 and exhibits a neuroprotective effect. It has also been reported to inhibit the differentiation of microglia into the M1 (pro-inflammatory) phenotype while promoting its differentiation to the M2 (anti-inflammatory) phenotype. This study aimed to investigate the mechanisms of action of the C16 peptide in multiple sclerosis using a rodent model. Methods: Molecular, morphological, and neurophysiological assays were used to investigate the neuroprotective effects of C16 peptide and related signaling pathways in a model of EAE. Results: The results showed that C16 significantly improved the clinical score and cortical somatosensory/motor evoked potential. It also alleviated inflammatory responses, including microglial activation and leukocyte infiltration, relieved the impairment of the brain blood barrier and edema, and reduced neuronal apoptosis, axonal loss, and demyelination induced by EAE. The C16 peptide increased the expressions of pTie-2 and Tie-2, integrin αvß3, and α5ß1 and activated the PI3K/Akt signal pathway but decreased the expression of Rho. Co-treatment of C16 with Tie-2 inhibitor and PI3K inhibitor LY294002 attenuated these effects of C16. Conclusion: The C16 peptide demonstrated neuroprotection in the EAE model through the integrin, Tie-2, and PI3K/Akt signaling pathways, and it could be a potential strategy for treating inflammation-related diseases in the central nervous system.

Two-dimensional MoSi2As4-based field-effect transistors integrating switching and gas-sensing functions.

Multifunctional nanoscale devices integrating multiple functions are of great importance for meeting the requirements of next-generation electronics. Herein, using first-principles calculations, we propose multifunctional devices based on the two-dimensional monolayer MoSi2As4, where a single-gate field-effect transistor (FET) and FET-type gas sensor are integrated. After introducing the optimizing strategies, such as underlap structures and dielectrics with a high dielectric constant (κ), we designed a 5 nm gate-length MoSi2As4 FET, whose performance fulfilled the key criteria of the International Technology Roadmap for Semiconductors (ITRS) for high-performance semiconductors. Under the joint adjustment of the underlap structure and high-κ dielectric material, the on/off ratio of the 5 nm gate-length FET reached up to 1.38 × 104. In addition, driven by the high-performance FET, the MoSi2As4-based FET-type gas sensor showed a sensitivity of 38% for NH3 and 46% for NO2. Moreover, the weak interaction between NH3 (NO2) and MoSi2As4 favored the recycling of the sensor. Furthermore, the sensitivity of the sensor could be effectively improved by the gate voltage, and was increased up to 67% (74%) for NH3 (NO2). Our work provides theoretical guidance for the fabrication of multifunctional devices combining a high-performance FET and sensitive gas sensor.

Novel nano-carriers with N-formylmethionyl-leucyl-phenylalanine-modified liposomes improve effects of C16-angiopoietin 1 in acute animal model of multiple sclerosis.

Gradual loss of neuronal structure and function due to impaired blood-brain barrier (BBB) and neuroinflammation are important factors in multiple sclerosis (MS) progression. Our previous studies demonstrated that the C16 peptide and angiopoietin 1 (Ang-1) compound (C + A) could modulate inflammation and vascular protection in many models of MS. In this study, nanotechnology and a novel nanovector of the leukocyte chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) were used to examine the effects of C + A on MS. The acute experimental autoimmune encephalomyelitis (EAE) model of MS was established in Lewis rats. The C + A compounds were conjugated to control nano-carriers and fMLP-nano-carriers and administered to animals by intravenous injection. The neuropathological changes in the brain cortex and spinal cord were examined using multiple approaches. The stimulation of vascular injection sites was examined using rabbits. The results showed that all C + A compounds (C + A alone, nano-carrier C + A, and fMLP-nano-carrier C + A) reduced neuronal inflammation, axonal demyelination, gliosis, neuronal apoptosis, vascular leakage, and BBB impairment induced by EAE. In addition, the C + A compounds had minimal side effects on liver and kidney functions. Furthermore, the fMLP-nano-carrier C + A compound had better effects compared to C + A alone and the nano-carrier C + A. This study indicated that the fMLP-nano-carrier C + A could attenuate inflammation-related pathological changes in EAE and may be a potential therapeutic strategy for the treatment of MS and EAE.

Decoding the mechanical conductance switching behaviors of dipyridyl molecular junctions.

Dipyridyl molecular junctions often show intriguing conductance switching behaviors with mechanical modulations, but the mechanisms are still not completely revealed. By applying the ab initio-based adiabatic simulation method, the configuration evolution and electron transport properties of dipyridyl molecular junctions in stretching and compressing processes are systematically investigated. The numerical results reveal that the dipyridyl molecular junctions tend to form specific contact configurations during formation processes. In small electrode gaps, the pyridyls almost vertically adsorb on the second Au layers of the tip electrodes by pushing the top Au atoms aside. These specific contact configurations result in stronger molecule-electrode couplings and larger electronic incident cross-sectional areas, which consequently lead to large breaking forces and high conductance. On further elongating the molecular junctions, the pyridyls shift to the top Au atoms of the tip electrodes. The additional scattering of the top Au atoms dramatically decreases the conductance and switches the molecular junctions to the lower conductive states. Perfect cyclical conductance switches are obtained as observed in the experiments by repeatedly stretching and compressing the molecular junctions. The O atom in the side-group tends to hinder the pyridyl from adsorbing on the second Au layer and further inhibits the conductance switch of the dipyridyl molecular junction.

Co-Application of C16 and Ang-1 Improves the Effects of Levodopa in Parkinson Disease Treatment.

Background: Levodopa is regarded as a standard medication in Parkinson disease (PD) treatment. However, long-term administration of levodopa leads to levodopa-induced dyskinesia (LID), which can markedly affect patient quality of life. Previous studies have shown that neuroinflammation in the brain plays a role in LID and increases potential neuroinflammatory mediators associated with the side effects of levodopa. Objective: The treatment effect of C16 (a peptide that competitively binds integrin αvß3 and inhibits inflammatory cell infiltration) and angiopoietin-1 (Ang-1; a vascular endothelial growth factor vital for blood vessel protection), along with levodopa, was evaluated in a rodent model of PD. Methods: We administered a combination of C16 and Ang-1 in a rodent model of PD induced by MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). Seventy-five mice were randomly divided into five treatment groups: control, vehicle, levodopa, C16+Ang-1, and levodopa+C16+Ang-1. Behavioral, histological, and electrophysiological experiments were used to determine neuron function and recovery. Results: The results showed that C16+Ang-1 treatment alleviated neuroinflammation in the CNS and promoted the recovery effects of levodopa on neural function. Conclusion: Our study suggests that C16+Ang-1 can compensate for the shortcomings of levodopa, improve the CNS microenvironment, and ameliorate the effects of levodopa. This treatment strategy could be developed as a combinatorial therapeutic in the future.

Combined treatment with C16 peptide and angiopoietin-1 confers neuroprotection and reduces inflammation in 3-nitropropionic acid-induced dystonia mice.

Dystonia is a disorder associated with abnormalities in many brain regions including the basal ganglia and cerebellum. The toxin 3-Nitropropionic acid (3-NP) can induce neuropathologies in the mice striatum and nigra substance, including excitotoxicity, neuroinflammation, and extensive neuronal atrophy, characterized by progressive motor dysfunction, dystonia, and memory loss, mimicking those observed in humans. We established a mouse model of dystonia by administering 3-NP. Given the reported neuroprotective effects of the endothelial growth factor angiopoietin-1 (Ang-1) and the anti-inflammatory integrin αvß3 binding peptide C16, we performed this study to evaluate their combined effects on 3-NP striatal toxicity and their therapeutic potential with multiple methods using an in vivo mouse model. Sixty mice were equally and randomly divided into three groups: control, 3-NP treatment, and 3-NP+C16+Ang-1 treatment. Behavioral and electrophysiological tests were conducted and the effect of the combined C16+Ang-1 treatment on neural function recovery was determined. We found that C16+Ang-1 treatment alleviated 3-NP-induced behavioral, biochemical, and cellular alterations in the central nervous system and promoted function recovery by restoring vascular permeability and reducing inflammation in the micro-environment. In conclusion, our results confirmed the neuroprotective effect of combined C16+Ang-1 treatment and suggest their potential as a complementary therapeutic against 3-NP-induced dystonia.

Adjusting vascular permeability, leukocyte infiltration, and microglial cell activation to rescue dopaminergic neurons in rodent models of Parkinson's disease.

Animal studies have indicated that increased blood-brain barrier (BBB) permeability and inflammatory cell infiltration are involved during the progression of Parkinson's disease (PD). This study used C16, a peptide that competitively binds to integrin αvß3 and inhibits inflammatory cell infiltration, as well as angiopoietin-1 (Ang-1), an endothelial growth factor crucial for blood vessel protection, to reduce inflammation and improve the central nervous system (CNS) microenvironment in murine models of PD. The combination of C16 and Ang-1 yielded better results compared to the individual drugs alone in terms of reducing dopaminergic neuronal apoptosis, ameliorating cognitive impairment, and electrophysiological dysfunction, attenuating inflammation in the CNS microenvironment, and improving the functional disability in PD mice or rats. These results suggest neuroprotective and anti-inflammatory properties of the C16 peptide plus Ang-1 in PD.

[DNA methylation of HDAC4 gene affects the trans-differentiation process of hMSCs into sweat gland like cells].

OBJECTIVE: To investigate the changesof DNA methylation in histone deacetylases 4 gene (HDAC4) and its effectduring the trans-differentiation process of human mesenchymal stem cells (hMSCs) into sweat gland like cells (SGLCs). METHODS: Selected cell lines of human mesenchymal stem cells (hMSCs) were cultured and expended in vitro, the third generation ofhMSCs and heat-shocked sweat gland cells were picked up, and were co-culturedwith adding inducible factor in the transwell chamber. The sweat gland like cells (SGLCs)in experiment group and the hMSCs in control group were collected, the changes of DNA methylation degree of CpG dinucleotide sitesin histone deacetylases 4 gene (HDAC4) promotor were detected by methylation specific PCR (MSP)andMaldi-TOF Mass Array. And then, the hMSCs in experiment group were treated with 5-aza-CdR (5-aza-2-deoxycytidine, 10 µmol/L), while the hMSCsin control group were culturedwith PBS at the same time. ThemRNA expressions of HDAC4 gene and carcino-embryonic antigen (CEA)gene in the two groups were measured by RT-PCR. RESULTS: The methylation of HDAC4gene in hMSCs was in high level before induction, the methylation degreeof CpG dinucleotide sites located in cg2463009 was 0.901, and the methylation degree of HDAC4gene in SGLCs was markedly decreased by 37% after induction, which was 0.531. The methylationlevel of CpG dinucleotide sites located in cg14823429was changed from 0.687to 0.386 after induction. The mRNA expression of HDAC4 gene was upregulated in test group after treated with 5-aza-CdR for 48 hours, the mRNA expression of CEA gene related with transdifferentiation was enhanced too at the same term, there was significantly statistic difference compared with control group (P<0.05). CONCLUSIONS: Methylation of HDAC4 gene participates in the regulation of the trans-differentiation of hMSCs into sweet gland like cells.

Rectifying properties of oligo(phenylene ethynylene) heterometallic molecular junctions: molecular length and side group effects.

The rectifying properties of α,ω-dithiol terminated oligo(phenylene ethynylene) molecules sandwiched between heterometallic electrodes, including the molecular length and side group effects, are theoretically investigated using the fully self-consistent nonequilibrium Green's function method combined with density functional theory. The results show nonlinear variation with changes in molecule length: when the molecule becomes longer, the current decreases at first and then increases while the rectification shifts in the opposite direction. This stems from the change in molecular eigenstates and the coupling between the molecule and electrodes caused by different molecular lengths. The rectifying behavior of heterometallic molecular junctions can be attributed to the asymmetric molecule-electrode contacts, which lead to asymmetric electronic tunneling spectra, molecular eigenvalues, molecular orbitals, and potential drop at reversed equivalent bias voltages. Our results provide a fundamental understanding of the rectification of heterometallic molecular junction, and a prediction of rectifiers with different rectification properties from those in the experiment, using electrodes with reduced sizes.