Defect-Rich, Highly Porous PtAg Nanoflowers with Superior Anti-Poisoning Ability for Efficient Methanol Oxidation Reaction.

The design of efficient and sustainable Pt-based catalysts is the key to the development of direct methanol fuel cells. However, most Pt-based catalysts still exhibit disadvantages including unsatisfied catalytic activity and serious CO poisoning in the methanol oxidation reaction (MOR). Herein, highly porous PtAg nanoflowers (NFs) with rich defects are synthesized by using liquid reduction combining chemical etching. It is demonstrated that the proportion of precursors determines the inhomogeneity of alloy elements, and the strong corrosiveness of nitric acid to silver leads to the eventual porous flower-like structure. Impressively, the optimal etched Pt1 Ag2 NFs have the mixed defects of surface steps, dislocations, and bulk holes, and their mass activity (1136 mA mgPt-1 ) is 2.6 times higher than that of commercial Pt/C catalysts, while the ratio of forward and backward peak current density (If /Ib ) can reach 3.2, exhibiting an excellent anti-poisoning ability. Density functional theory calculations further verify their high anti-poison properties from both an adsorption and an oxidation perspective of CO intermediate. The introduction of Ag makes it easier for CO to be oxidized and removed. This study provides a facile approach to prepare rich defects and porous alloy with excellent MOR performance and superior anti-poisoning ability.

PtCuRu Nanoflowers with Ru-Rich Edge for Efficient Fuel-Cell Electrocatalysis.

Enhancing the catalytic activity of Pt-based alloy by a rational structural design is the key to addressing the sluggish kinetics of direct alcohol fuel cells. Herein, a facile one-pot method is reported to synthesize PtCuRu nanoflowers (NFs). The synergetic effect among Pt, Cu, and Ru can lower the d-band center of Pt, regulate the morphology, generate Ru-rich edge, and allow the exposure of more high index facets. The optimized Pt0.68 Cu0.18 Ru0.14 NFs exhibit outstanding electrocatalytic performances and excellent anti-poisoning abilities. The specific activities for the methanol oxidation reaction (MOR) (7.65 mA cm-2 ) and ethanol oxidation reaction (EOR) (7.90 mA cm-2 ) are 6.0 and 7.1 times higher than commercial Pt/C, respectively. The CO stripping experiment and the chronoamperometric (5000 s) demonstrate the superior anti-poisoning property and durability performance. Density functional theory calculations confirm that high metallization degree leads to the decrease of d-band center, the promotion of oxidation of CO, and improvement of the inherent activity and anti-poisoning ability. A Ru-rich edge exposes abundant high index facets to accelerate the reaction kinetics of rate-determining steps by decreasing the energy barrier for forming *HCOOH (MOR) and CC bond breaking (EOR).

N-Doped MoS2 Nanoflowers for Efficient Cr(VI) Removal.

The removal of Cr(VI) has attracted extensive attention since it causes serious harm to public health. Herein, we report a two-step method to synthesize N-doped MoS2 nanoflowers (NFs) with controllable sizes, which are first utilized for Cr(VI) removal and display outstanding removal performance. The N-MoS2 NFs with an average size of 40 nm (N-MoS2 NFs-40 nm) can rapidly remove Cr(VI) in 15 min under optimal conditions. The maximum adsorption capacity of N-MoS2 NFs-40 nm can reach 787.41 mg·g-1, which is significantly larger than that of N-MoS2 NFs-150 and -400 nm (314.46 and 229.88 mg·g-1). Meanwhile, N-MoS2 NFs-400 nm have a higher maximum adsorption capacity than pure MoS2 NFs-400 nm (172.12 mg·g-1). In this adsorption/reduction process, N-MoS2 NFs have abundant adsorption sites due to a high surface area. N doping can generate more sulfur vacancy defects in the MoS2 NF structure to accelerate electron transfer and enhance the reduction of Cr(VI) to low-toxicity Cr(III). This study provides a facile approach to fabricating N-MoS2 nanoflowers and demonstrates their superior removal ability for Cr(VI).

Chapter Open for the Excited-State Intramolecular Thiol Proton Transfer in the Room-Temperature Solution.

We report here, for the first time, the experimental observation on the excited-state intramolecular proton transfer (ESIPT) reaction of the thiol proton in room-temperature solution. This phenomenon is demonstrated by a derivative of 3-thiolflavone (3TF), namely, 2-(4-(diethylamino)phenyl)-3-mercapto-4H-chromen-4-one (3NTF), which possesses an -S-H···O═ intramolecular H-bond (denoted by the dashed line) and has an S1 absorption at 383 nm. Upon photoexcitation, 3NTF exhibits a distinctly red emission maximized at 710 nm in cyclohexane with an anomalously large Stokes shift of 12 230 cm-1. Upon methylation on the thiol group, 3MeNTF, lacking the thiol proton, exhibits a normal Stokes-shifted emission at 472 nm. These, in combination with the computational approaches, lead to the conclusion of thiol-type ESIPT unambiguously. Further time-resolved study renders an unresolvable (<180 fs) ESIPT rate for 3NTF, followed by a tautomer emission lifetime of 120 ps. In sharp contrast to 3NTF, both 3TF and 3-mercapto-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one (3FTF) are non-emissive. Detailed computational approaches indicate that all studied thiols undergo thermally favorable ESIPT. However, once forming the proton-transferred tautomer, the lone-pair electrons on the sulfur atom brings non-negligible nπ* contribution to the S1' state (prime indicates the proton-transferred tautomer), for which the relaxation is dominated by the non-radiative deactivation. For 3NTF, the extension of π-electron delocalization by the diethylamino electron-donating group endows the S1' state primarily in the ππ* configuration, exhibiting the prominent tautomer emission. The results open a new chapter in the field of ESIPT, covering the non-canonical sulfur intramolecular H-bond and its associated ESIPT at ambient temperature.

Broadening the Horizon of the Bell-Evans-Polanyi Principle towards Optically Triggered Structure Planarization.

Finding a relationship between kinetics and thermodynamics may be difficult. However, semi-empirical rules exist to compensate for this shortcoming, among which the Bell-Evans-Polanyi (B-E-P) principle is an example for reactions involving bond breakage and reformation. We expand the B-E-P principle to a new territory by probing photoinduced structure planarization (PISP) of a series of dibenz[b,f]azepine derivatives incorporating bent-to-planar and rotation motion. The latter involves twisting of the partial double bond character, thereby inducing a barrier that is substituent dependent at the para N-phenyl position. The transition-state structure and frequency data satisfy and broaden the B-E-P principle to PISP reactions without bond rearrangement. Together with dual emissions during PISP, this makes possible harnessing of the kinetics/thermodynamics relationship and hence ratiometric luminescence properties for excited-state structural transformations.

High-Sensitivity, Quantified, Linear and Mediator-Free Resonator-Based Microwave Biosensor for Glucose Detection.

This article presents a high-sensitivity, quantified, linear, and mediator-free resonator-based microwave biosensor for glucose sensing application. The proposed biosensor comprises an air-bridge-type asymmetrical differential inductor (L) and a center-loaded circular finger-based inter-digital capacitor (C) fabricated on Gallium Arsenide (GaAs) substrate using advanced micro-fabrication technology. The intertwined asymmetrical differential inductor is used to achieve a high inductance value with a suitable Q-factor, and the centralized inter-digital capacitor is introduced to generate an intensified electric field. The designed microwave sensor is optimized to operate at a low resonating frequency that increases the electric field penetration depth and interaction area in the glucose sample. The microwave biosensor is tested with different glucose concentrations (0.3-5 mg/ml), under different ambient temperatures (10-50 °C). The involvement of advanced micro-fabrication technology effectively miniaturized the microwave biosensor (0.006λ0 × 0.005λ0) and enhanced its filling factor. The proposed microwave biosensor demonstrates a high sensitivity of 117.5 MHz/mgmL-1 with a linear response (r2 = 0.9987), good amplitude variation of 0.49 dB/mgmL-1 with a linear response (r2 = 0.9954), and maximum reproducibility of 0.78% at 2 mg/mL. Additionally, mathematical modelling was performed to estimate the dielectric value of the frequency-dependent glucose sample. The measured and analyzed results indicate that the proposed biosensor is suitable for real-time blood glucose detection measurements.

Dual-band polarization convertor based on electromagnetically induced transparency (EIT) effect in all-dielectric metamaterial.

In this study, electromagnetically induced transparency (EIT) effect in all-dielectric metamaterial for dual-band linear-to-circular (LTC) polarization conversion is demonstrated numerically and experimentally. The unit cell is composed of three ceramic blocks with different sizes. Due to the anisotropy of metamaterial and polarization dependence of subsequent EIT effects, transmission spectra for x- and y-polarized incident waves are realized to induce LTC polarization conversion. It is numerically demonstrated that a linearly polarized incident wave is transformed to a nearly perfect circularly polarized wave at around 6.24 and 6.38 GHz. The corresponding ellipticity and transmittivity are about 0.96, 0.6 and 0.94, 0.37, respectively. A metamaterial sample is fabricated and its transmission spectra are measured. The measured results are nearly equal to the simulated results. This LTC polarization convertor, with low loss and ultra thinness, may expand the application of EIT metamaterials, and it can be extended to terahertz up to optical bands. Such a design may find potential applications in microwave wave plates and metamaterial antennas, or other electromagnetic control devices.

Mono-Heteroatom Substitution for Harnessing Excited-State Structural Planarization of Dihydrodibenzo[a,c]phenazines.

With the aim of generalizing the structure-properties relationship of bending heterocyclic molecules that undergo prominent photoinduced structural planarization (PISP), a series of new dihydrodibenzo[ac]phenazine derivatives in which one nitrogen atom is replaced by oxygen (PNO), sulfur (PNS), selenium (PNSe), or dimethylmethanediyl (PNC) was strategically designed and synthesized. Compounds PNO, PNS, and PNSe have significantly nonplanar geometries in the ground state, which undergo PISP to give a planarlike conformer and hence a large emission Stokes shift. A combination of femtosecond early relaxation dynamics and computational approaches established an R*→I* (intermediate)→P* sequential kinetic pattern for PNS and PNSe, whereas PNO undergoes R*→P* one-step kinetics. The polarization ability of the substituted heteroatoms, which is in the order O

Numerical investigation of nematic liquid crystals in the THz band based on EIT sensor.

This paper introduces the concept of electromagnetically induced transparency (EIT) into the permittivity extraction of an anisotropic material-nematic liquid crystal (NLC). A novel two-step strategy is presented to extract the complex permittivity of the NLC at the THz band, which evaluates the relative permittivity tensor from the resonant frequencies and then determines the loss tangent from the quality factor Q of the EIT sensor. The proposed method features high accuracy due to the sharp resonance of the EIT sensor and also high robustness to the thickness of the NLC layer because only amplitude rather than phase information of the transmission coefficients is required. The NLC filled EIT sensor shows a sensitivity of 56.8 µm/RIU (the resonance wavelength shift over the refractive index change unit (RIU)) and Figure of Merit (FoM) of 6.92. The uncertainty of the proposed technique in the relative permittivity and loss tangent is 3% and 8.2%, respectively.

A polymorphism in the promoter region of PD-L1 serves as a binding-site for SP1 and is associated with PD-L1 overexpression and increased occurrence of gastric cancer.

PD-L1 is a member of the B7 family co-inhibitory molecules and plays a critical role in tumor immune escape. In this study, we found a polymorphism rs10815225 in the PD-L1 promoter region was significantly associated with the occurrence of gastric cancer. The GG homozygous frequency was higher in the cancer patients than that in the precancerous lesions, which was higher than that in the health controls. This polymorphism locates in the binding-site of Sp1 transcription factor (SP1). The expression level of PD-L1 mRNA in the GG homozygous cancer patients was apparently higher than that in the GC heterozygotes. Luciferase reporter results showed that SP1 bonded to rs10815225 G-allelic PD-L1 promoter instead of C-allelic. Upregulation and knockdown of SP1 resulted in elevation and attenuation of PD-L1 in SGC-7901 cells, respectively. The chromatin immunoprecipitation results further confirmed the binding of SP1 to the promoter of PD-L1. Additionally, rs10815225 was found to be in disequilibrium with a functional polymorphism rs4143815 in the PD-L1 3'-UTR, and the haplotypes of these two polymorphisms were also markedly related to gastric cancer risk. These results revealed a novel mechanism underlying genetic polymorphisms influencing PD-L1 expression modify gastric cancer susceptibility.

N-H-Type Excited-State Proton Transfer in Compounds Possessing a Seven-Membered-Ring Intramolecular Hydrogen Bond.

A series of compounds containing 5-(2-aminobenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one (o-ABDI) as the core chromophore with a seven-membered-ring N-H-type intramolecular hydrogen bond have been synthesized and characterized. The acidity of the N-H proton and thus the hydrogen-bond strength can be fine-tuned by replacing one of the amino hydrogen atoms by a substituent R, the acidity increasing with increasing electron-withdrawing strength of R, that is, in the order H

Stereoselective formation of eight-membered rings by radical cyclization of silylenedioxy-tethered bis-methacrylate derivatives.

Radical-initiated addition of CCl4, Cl3CBr, PhSH, and (TMS)3SiH to (bisisopropyl)silylenedioxy-tethered bis-methacrylate derivatives gives the corresponding eight-membered ring cyclic adducts stereoselectively. Hydrolysis of halo-substituted cyclic adducts with HCl in methanol affords the corresponding valerolactones, and the stereochemistry was determined by the X-ray crystallography on a dibromobenzoate derivative. DFT calculation on the eight-membered radical intermediate offers a plausible rationale for the stereoselectivity of the reaction.

Complex-Amplitude Programmable Versatile Metasurface Platform Driven by Guided Wave.

Metasurfaces have shown unparalleled controllability of electromagnetic (EM) waves. However, most of the metasurfaces need external spatial feeding sources, which renders practical implementation quite challenging. Here, a low-profile programmable metasurface with 0.05λ0 thickness driven by guided waves is proposed to achieve dynamic control of both amplitude and phase simultaneously. The metasurface is fed by a guided wave traveling in a substrate-integrated waveguide, avoiding external spatial sources and complex power divider networks. By manipulating the state of the p-i-n diodes embedded in each meta-atom, the proposed metasurface enables 1-bit amplitude switching between radiating and nonradiating states, as well as a 1-bit phase switching between 0° and 180°. As a proof of concept, two advanced functionalities, namely, low sidelobe-level beam scanning and Airy beam generation, are experimentally demonstrated with a single platform operating in the far- and near-field respectively. Such complex-amplitude, programmable, and low-profile metasurfaces can overcome integration limitations of traditional metasurfaces, and open up new avenues for more accurate and advanced EM wave control within an unprecedented degree of freedom.

Polarization manipulation based on electromagnetically induced transparency-like (EIT-like) effect.

We proposed, designed and fabricated a high transparency of metasurface-based polarization controller at microwave frequencies, which consists of orthogonal two pairs of cut wires. The high transmission and the strong dispersion properties governed by electromagnetically induced transparency-like (EIT-like) effects for both incident polarizations make our device efficiently manipulating the polarization of EM waves. In particular, the proposed polarization device is ultrathin (~0.017λ), as opposed to bulky polarization devices. Microwave experiments are performed to successfully demonstrate our ideas, and measured results are in reasonable agreement with numerical simulations.

Allo-HSCT for acute leukemia of ambiguous lineage in adults: the comparison between standard conditioning and intensified conditioning regimens.

Knowledge concerning the clinical and biological characteristics of acute leukemia of ambiguous lineage (ALAL) is limited so that there has been a lack of uniformity in treatment. In this report, we retrospectively investigated the effect of intensified conditioning on adult ALAL undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). A total of 59 patients with ALAL (male in 37 cases and female in 22 cases) were consecutively enrolled in the data analyses. Twenty-four patients received the standard conditioning (total body irradiation (TBI) + cyclophosphamide (CY) or busulfan + CY protocol) and 35 received the intensified conditioning (TBI + CY + etoposide or fludarabine + cytarabine plus TBI + CY + etoposide protocol). Five-year transplant-related mortality was 17.6 ± 9.6 % and 25.5 ± 8.0 %, the 5-year overall survival (OS) post-transplantation was 23.8 ± 8.9 % and 64.0 ± 8.4 %, disease-free survival was 16.7 ± 7.6 % and 55.8 ± 9.4 %, the 5-year cumulative incidence of relapse was 80.8 ± 8.5 % and 28.8 ± 9.9 %, respectively, in the standard and the intensified group (P = 0.380, P = 0.029, P = 0.005, and P < 0.001). Both univariate and multivariate analysis indicated that the intensified conditioning regimen and acute graft-versus-host disease were favorable factors to reduce the relapse. The younger patients, patients with CR at the time of transplantation, and the intensified conditioning regimen were favorable factors to elevate the survival. In conclusion, intensified conditioning regimens followed by allo-HSCT might improve long-term survival and decrease relapse of leukemia in adult ALAL compared to the standard conditioning regimens.

Low-cost laser cutting fabricated all-metallic metamaterial near-field focusing lens.

In this work, a low-cost all-metal metamaterial near-field lens based on laser cutting technology is proposed. A novel spiral-slot structure is proposed to achieve miniaturized unit cells with an adjustable 360-degree phase shift at a length smaller than 0.2 times the operating wavelength. Since the unit is entirely constructed of stainless steel, it is resistant to high temperatures and high pressures compared to existing results. Moreover, a four-layer structure is used to increase the transmission coefficient. The final L-band near-field lens is constructed of 20 × 20 units. Simulation and measured results show that the half-power beamwidth of the focus is less than 211 mm from 1.52 GHz to 1.68 GHz at the focal spot observation plane of 500 mm from the lens. Since numerically controlled machine tools and three-dimensional printing are prohibitively expensive for machining large metal components, a low-cost all-metallic lens was manufactured using laser cutting technology. The measured results are in agreement with the simulation results.

Multi-band slow light metamaterial.

In this paper, a multi-band slow light metamaterial is presented and investigated. The metamaterial unit cell is composed of three cut wires of different sizes and parallel to each other. Two transparency windows induced by two-two overlaps of absorption bands of three cut wires are observed. The multi-band transmission characteristics and the slow light properties of metamaterial are verified by numerical simulation, which is in a good agreement with theoretical predictions. The impacts of structure parameters on transparency windows are also investigated. Simulation results show the spectral properties can be tuned by adjusting structure parameters of metamaterial. The equivalent circuit model and the synthesis method of the multi-band slow light metamaterial are presented. It is seen from simulation results that the synthesis method accurately predicts the center frequency of the multi-band metamaterial, which opens a door to a quick and accurate construction for multi-band slow light metamaterial.

Correlation between imatinib trough concentration and efficacy in Chinese chronic myelocytic leukemia patients.

BACKGROUND: Trough imatinib plasma concentration, intracellular drug levels and expression of drug transporters can be indicative of clinical responses in chronic myelocytic leukemia (CML) patients receiving imatinib. We aimed to determine plasma imatinib concentration, intracellular imatinib concentration, human organic cation transporter 1 (hOCT1) and adenosine triphosphate-binding cassette subfamily B member 1 (ABCB1) mRNA expression in bone marrow cells of CML patients in order to evaluate the potential usefulness of these measures as markers of imatinib efficacy and understand their clinical relationships. METHODS: Eighty-four CML patients receiving imatinib treatment were included in this study. Imatinib trough concentration was determined by high-performance liquid chromatography-tandem mass spectrometry. Real-time quantitative PCR with a TaqMan probe was used to assess hOCT1 and ABCB1 mRNA expression in bone marrow cells. All patients were divided into the major molecular response (MMR), complete cytogenetic response (CCyR), partial cytogenetic response (PCyR) or drug-resistant groups according to their response. RESULTS: The plasma imatinib trough concentration was significantly higher in the MMR group than in the PCyR (p = 0.002) or drug-resistant groups (p = 0.011). The plasma imatinib trough concentration was also significantly higher in the CCyR group than in the PCyR group (p = 0.027). There were no significant differences between the CCyR and MMR groups with regard to the plasma imatinib trough concentration (p = 0.136). The intracellular imatinib concentration in bone marrow cells was significantly higher in the CCyR group compared to the drug-resistant or PCyR groups (p = 0.013). The hOCT1 mRNA expression in bone marrow cells was significantly higher in the CCyR group than in the drug-resistant or PCyR groups (p = 0.036). The ABCB1 mRNA expression in bone marrow cells was significantly higher in the drug-resistant group than in the CCyR or PCyR groups (p = 0.013). Plasma imatinib trough concentration was positively correlated with α(1)-acid glycoprotein (r = 0.443, p < 0.001) or dose (r = 0.422, p < 0.001). CONCLUSIONS: Clinical responses in CML patients are correlated with both the plasma trough concentrations and intracellular levels of imatinib.

Influence of symmetry breaking in a planar metamaterial on transparency effect and sensing application.

The influence of symmetry breaking in a planar metamaterial on transparency effect is numerically investigated. The planar metamaterial's cell is formed by three parallel metal wires. From numerical simulation results, we can see that the transparency effect results from the asymmetric coupling between the cut wires. The excited mechanism of the transparency effect is further analyzed by using the hybridization concept. It is found that the coupling fields between the cut wires play key roles and lead to the spectral splitting of the resonance, i.e., the classical electromagnetically induced transparency effect. The metamaterial sensor based on the refractive index variation of the surrounding material is also numerically demonstrated and yields a sensitivity of 9.47 mm/RIU and a figure of merit of 13.5. In addition, the spectral response of the metamaterial is quantitatively described via the "three-particle" model. The analytically calculated results of the model show a good agreement with the simulation results.

[Effects of hOCT1 and ABCB1 gene on the efficacy of imatinib mesylate in chronic myelocytic leukemia].

OBJECTIVE: To detect the expression of hOCT1 and ABCB1 in marrow cells and examine the efficacy of imatinib mesylate (IM) in patients with chronic myelocytic leukemia (CML). METHODS: hOCT1 and ABCB1 gene in 90 samples with chronic phase CML diagnosed at our hospital from January 2008 and June 2011 were detected by taqman probe real-time reverse transcription-PCR (RT-PCR). The samples were divided into 3 groups: drug-resistant group (n = 17), partial cytological remission (PCyR) group (n = 11) and complete cytogenetic remission (CCR) group (n = 62) according to IM efficacy and 3 - 6, 7 - 12, 13 - 24, 25 - 48, > 48 months five groups (n = 21, 8, 15, 29, 17) according to IM treatment course. The relationship was explored between two genes and different disease states, course of treatment and time from first CCR. RESULTS: The hOCT1 gene mRNA expression of CCR group (-3.77 ± 0.55) was higher than drug-resistant group (-4.12 ± 0.47) and PCyR group (-4.24 ± 0.35) (P = 0.047, 0.019). The ABCB1 gene mRNA expression of drug-resistant group (-2.93 ± 0.49) was higher than CCR group (-3.02 ± 0.56) and PCyR group (-3.51 ± 0.45) (P = 0.045, 0.021). The hOCT1 and ABCB1 mRNA expressions showed no significant difference between five groups divided by IM treatment course (P = 0.270, 0.367). The median follow-up time was 30 (3 - 117) months. In same IM treatment course patients, the CCR rates in hOCT1 and ABCB1 low-expression groups were higher than that in high-expression groups separately (P = 0.006, 0.049). CONCLUSIONS: The expression levels of hOCT1 and ABCB1 vary in different disease states of patients on IM. And these two genes may influence the time from first CCR. But there is no significant relationship with course of the treatment.