Electron Transport and CO Sensing Characteristics of Fe(II) Porphyrin with Single-Walled Carbon Nanotube Electrodes

Electron transport and carbon monoxide (CO) sensitive characteristics of Fe­(II) porphyrin (PP-Fe) with two single-walled carbon nanotube electrodes (SWCNTs) were studied using nonequilibrium Green’s function (NEGF) formalism combined first-principles density functional theory (DFT). When PP-Fe is connected to SWCNT electrodes in diagonal configuration, owing to the fact that the electron passes through the Fe center, it shows higher CO sensitivity than that in para connection mode. Meanwhile, the PP-Fe sensor with armchair SWCNTs is more sensitive to CO than that in zigzag junction, since the coupling interaction between central molecule and armchair SWCNT electrodes is stronger. The PP-Fe sensor anchored on armchair SWCNTs in diagonal configuration can reach a current on–off ratio of 2.1 × 10⁴ in response to the chemisorption of CO, showing better CO sensitive characteristics than that with zigzag SWCNTs and metallic electrodes. With the development of experimental techniques, it is completely possible to fabricate this kind of CO sensor by experimental means

Surface Charge Transfer Doping of Monolayer Phosphorene via Molecular Adsorption

Monolayer phosphorene has attracted much attention owing to its extraordinary electronic, optical, and structural properties. Rationally tuning the electrical transport characteristics of monolayer phosphorene is essential to its applications in electronic and optoelectronic devices. Herein, we study the electronic transport behaviors of monolayer phosphorene with surface charge transfer doping of electrophilic molecules, including 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), NO₂, and MoO₃, using density functional theory combined with the nonequilibrium Green’s function formalism. F4TCNQ shows optimal performance in enhancing the p-type conductance of monolayer phosphorene. Static electronic properties indicate that the enhancement is originated from the charge transfer between adsorbed molecule and phosphorene layer. Dynamic transport behaviors demonstrate that additional channels for hole transport in host monolayer phosphorene were generated upon the adsorption of molecule. Our work unveils the great potential of surface charge transfer doping in tuning the electronic properties of monolayer phosphorene and is of significance to its application in high-performance devices

Short-term insulin intensive therapy decreases MCP-1 and NF-κB expression of peripheral blood monocyte and the serum MCP-1 concentration in newlydiagnosed type 2 diabetics

<div><p>ABSTRACT Objective To observe the effect of short-term insulin intensive treatment on the monocyte chemoattractant protein-1 (MCP-1) as well as on the nuclear factor-kappa B (NF-κB) expression of peripheral blood monocyte. This is also in addition to observing the serum MCP-1 level in newlydiagnosed type 2 diabetic patients and probing its anti-inflammation effects. Subjects and methods Twenty newly-diagnosed type 2 diabetic patients were treated with an insulin intensive treatment for 2 weeks. MCP-1 and NF-κB expression on the monocyte surface were measured with flow cytometry, the serum MCP-1 level was measured by enzyme linked immunosorbent assay (ELISA) during pretreatment and post-treatment. Results After 2 weeks of the treatment, MCP-1 and NF-κB protein expression of peripheral blood monocyte and serum MCP-1 levels decreased significantly compared with those of pre-treatment, which were (0.50 ± 0.18)% vs (0.89 ± 0.26)% (12.22 ± 2.80)% vs (15.53 ± 2.49)% and (44.53 ± 3.97) pg/mL vs (49.53 ± 3.47) pg/mL, respectively (P < 0.01). The MCP-1 expression on monocyte surface had a significant positive relationship with serum MCP-1 levels (r = 0.47, P < 0.01). Conclusions Short-term insulin intensive therapy plays a role in alleviating the increased inflammation reaction in type 2 diabetics.</p></div

Surface Charge Transfer Doping <i>via</i> Transition Metal Oxides for Efficient p‑Type Doping of II–VI Nanostructures

Wide band gap II–VI nanostructures are important building blocks for new-generation electronic and optoelectronic devices. However, the difficulty of realizing p-type conductivity in these materials <i>via</i> conventional doping methods has severely handicapped the fabrication of p–n homojunctions and complementary circuits, which are the fundamental components for high-performance devices. Herein, by using first-principles density functional theory calculations, we demonstrated a simple yet efficient way to achieve controlled p-type doping on II–VI nanostructures <i>via</i> surface charge transfer doping (SCTD) using high work function transition metal oxides such as MoO₃, WO₃, CrO₃, and V₂O₅ as dopants. Our calculations revealed that these oxides were capable of drawing electrons from II–VI nanostructures, leading to accumulation of positive charges (holes injection) in the II–VI nanostructures. As a result, Fermi levels of the II–VI nanostructures were shifted toward the valence band regions after surface modifications, along with the large enhancement of work functions. <i>In situ</i> ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy characterizations verified the significant interfacial charge transfer between II–VI nanostructures and surface dopants. Both theoretical calculations and electrical transfer measurements on the II–VI nanostructure-based field-effect transistors clearly showed the p-type conductivity of the nanostructures after surface modifications. Strikingly, II–VI nanowires could undergo semiconductor-to-metal transition by further increasing the SCTD level. SCTD offers the possibility to create a variety of electronic and optoelectronic devices from the II–VI nanostructures <i>via</i> realization of complementary doping

Regional Impact of Climate on Japanese Encephalitis in Areas Located near the Three Gorges Dam

<div><p>Background</p><p>In this study, we aim to identify key climatic factors that are associated with the transmission of Japanese encephalitis virus in areas located near the Three Gorges Dam, between 1997 and 2008.</p><p>Methods</p><p>We identified three geographical regions of Chongqing, based on their distance from the Three Gorges Dam. Collectively, the three regions consisted of 12 districts from which study information was collected. Zero-Inflated Poisson Regression models were run to identify key climatic factors of the transmission of Japanese encephalitis virus for both the whole study area and for each individual region; linear regression models were conducted to examine the fluctuation of climatic variables over time during the construction of the Three Gorges Dam.</p><p>Results</p><p>Between 1997 and 2008, the incidence of Japanese encephalitis decreased throughout the entire city of Chongqing, with noticeable variations taking place in 2000, 2001 and 2006. The eastern region, which is closest to the Three Gorges Dam, suffered the highest incidence of Japanese encephalitis, while the western region experienced the lowest incidence. Linear regression models revealed that there were seasonal fluctuations of climatic variables during this period. Zero-Inflated Poisson Regression models indicated a significant positive association between temperature (with a lag of 1 and 3 months) and Japanese encephalitis incidence, and a significant negative association between rainfall (with a lag of 0 and 4 months) and Japanese encephalitis incidence.</p><p>Conclusion</p><p>The spatial and temporal trends of Japanese encephalitis incidence that occurred in the City of Chongqing were associated with temperature and rainfall. Seasonal fluctuations of climatic variables during this period were also observed. Additional studies that focus on long-term data collection are needed to validate the findings of this study and to further explore the effects of the Three Gorges Dam on Japanese encephalitis and other related diseases.</p></div

The association between GDP and JE incidence in different regions from 1997 to 2008. Coefficients of GDP in the Zero-inflation Poisson Regression Model (preliminary analysis).

<p>The association between GDP and JE incidence in different regions from 1997 to 2008. Coefficients of GDP in the Zero-inflation Poisson Regression Model (preliminary analysis).</p

The association between climatic variables and JE incidence controlling for GDP by region from 1997 to 2008, based on ZIPR models.

<p>The association between climatic variables and JE incidence controlling for GDP by region from 1997 to 2008, based on ZIPR models.</p

Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in the middle region of Chongqing.

<p>Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in the middle region of Chongqing.</p

Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in western Chongqing.

<p>Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in western Chongqing.</p

Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in eastern Chongqing.

<p>Simple linear regression coefficients of the monthly climatic variables over the time (1997–2008) in eastern Chongqing.</p