Metal‐Guided Selective Growth of 2D Materials: Demonstration of a Bottom‐Up CMOS Inverter

2D transition metal dichalcogenide (TMD) layered materials are promising for future electronic and optoelectronic applications. The realization of large‐area electronics and circuits strongly relies on wafer‐scale, selective growth of quality 2D TMDs. Here, a scalable method, namely, metal‐guided selective growth (MGSG), is reported. The success of control over the transition‐metal‐precursor vapor pressure, the first concurrent growth of two dissimilar monolayer TMDs, is demonstrated in conjunction with lateral or vertical TMD heterojunctions at precisely desired locations over the entire wafer in a single chemical vapor deposition (VCD) process. Owing to the location selectivity, MGSG allows the growth of p‐ and n‐type TMDs with spatial homogeneity and uniform electrical performance for circuit applications. As a demonstration, the first bottom‐up complementary metal‐oxide‐semiconductor inverter based on p‐type WSe₂ and n‐type MoSe₂ is achieved, which exhibits a high and reproducible voltage gain of 23 with little dependence on position.     

免疫微球检测技术----用于BCR-ABL融合蛋白的流式细胞测定

本文介绍了BD TM BCR-ABL蛋白分析工具包。它是一种检测白血病细胞溶解液中p190和p210等BCR-ABL蛋白可靠、快速、简单、方便的技术。这种分析方法不依赖于BCR和ABL基因的断裂位置,除了一台流式细胞仪之外,该方法不需要其他专门的实验室仪器,并且可在几小时内得到结果。因而,这种蛋白分析工具包,较传统方法而言,能实现对BCR-ABL阳性样品快速而简单的鉴定。     

Viscoelasticity and mechanical properties of reactive PVC plastisols

Reactive poly(vinyl chloride) (PVC) plastisols have been developed to substitute the hydrocarbon diluents generally used in low viscosity PVC plastisols. For this purpose, methacrylate monomers (5–15%) were added in the PVC suspension (based on diisononyl phtalate plasticizer) to reduce the viscosity at room temperature and to polymerize (by radical polymerization initiated by an organic peroxide) during the gelation process. Both the reactive processing and the gelation process were carried out between the plates of a rheometer cell in the linear viscoelasticity domain (small deformation) and under increasing temperature from room temperature up to 160°C (ω = 6.283 rad s^?1, = 5°C min^?1). A temperature criterion was proposed to define the right balance between the polymerization and the gelation to get the best mechanical properties (i.e., elongation and stress at break). The polymerization process must be slower than the gelation process as the polymerization must take place when PVC grains have fused together to form a homogeneous medium at least at the microscale. Actually, the polymerization kinetics can be controlled by the decomposition kinetics of the organic peroxide. Finally, triethylene glycol dimethacrylate and lauryl methacrylate monomers and dicumyl peroxide as initiator turned out to be the best reactive system for some potential industrial applications. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Label‐Free Electrical Detection of DNA Hybridization on Graphene using Hall Effect Measurements: Revisiting the Sensing Mechanism

There is broad interest in using graphene or graphene oxide sheets as a transducer for label‐free and selective electrical detection of biomolecules such as DNA. However, it is still not well explored how the DNA molecules interact with and influence the properties of graphene during the detection. Here, Hall effect measurements based on the Van der Pauw method are used to perform single‐base sequence selective detection of DNA on graphene sheets, which are prepared by chemical vapor deposition. The sheet resistance increases and the mobility decreases with the addition of either complementary or one‐base mismatched DNA to the graphene device. The hole carrier concentration of the graphene devices increases significantly with the addition of complementary DNA but it is less affected by the one‐base mismatched DNA. It is concluded that the increase in hole carrier density, indicating p‐doping to graphene, is better correlated with the DNA hybridization compared to the commonly used parameters such as conductivity change. The different electrical observations of p‐doping from Hall effect measurements and n‐doping from electrolyte‐gated transistors can be explained by the characteristic morphology of partially hybridized DNA on graphene and the mismatch between DNA chain length and Debye length in electrolytes.     

2,6-Bis(1,4,7,10-tetraazacyclododecan-1-ylmethyl)pyridine and Its Benzene Analog as Nonmetallic Cleaving Agents of RNA Phosphodiester Linkages

2,6-Bis(1,4,7,10-tetraazacyclododecan-1-ylmethyl)pyridine (11a) and 1,3-bis(1,4,7,10-tetraazacyclododecan-1-ylmethyl)benzene (11b) have been shown to accelerate at 50 mmol·L⁻¹ concentration both the cleavage and mutual isomerization of uridylyl-3′,5′-uridine and uridylyl-2′,5′-uridine by up to two orders of magnitude. The catalytically active ionic forms are the tri- (in the case of 11b) tetra- and pentacations. The pyridine nitrogen is not critical for efficient catalysis, since the activity of 11b is even slightly higher than that of 11a. On the other hand, protonation of the pyridine nitrogen still makes 11a approximately four times more efficient as a catalyst, but only for the cleavage reaction. Interestingly, the respective reactions of adenylyl-3′,5′-adenosine were not accelerated, suggesting that the catalysis is base moiety selective.     

Cross‐entropy‐based joint carrier frequency offset estimation and multiuser detection for multicarrier code division multiple access systems

This paper presents a joint carrier frequency offset estimation and multiuser detection based on a maximum likelihood approach in multicarrier code division multiple access systems. With the definition of a score function based on the log‐likelihood, the joint carrier frequency offset estimation and multiuser detection can be formulated as a nonlinear optimization problem over the joint of a multidimensional real space and a multidimensional discrete space. To reduce the computational complexity required by the joint decision statistic, while still obtaining a desirable performance, a new method using cross‐entropy optimization is proposed to solve the nonlinear optimization problem. Because of the robustness of the cross‐entropy optimization, the joint decision statistic can be efficiently solved, and, as shown by the furnished simulation results, the proposed approach can achieve satisfactory performance in various scenarios. Copyright © 2011 John Wiley & Sons, Ltd.     

Role of Boron in the Tribochemistry of Thermal Films Formed in the Presence of ZnDTP and Dispersant Additives

Thermally formed, additive-derived films are often a key precursor to tribologically protective films that are formed under the influence of mechanical stress. We have examined the tribological stability of model thermal films, tested in pure base oil under severe experimental conditions. Our aim was to exclude the self-healing mechanism of the protective film, which would be expected in a fully formulated lubricant. The thermal films were grown in the presence of various oil formulations containing combinations of ZnDTP and dispersants. The films were fully characterized by means of scanning electron microscopy and atomic force microscopy (for investigating the film morphology) in combination with X-ray photoelectron spectroscopy (for determining the chemical composition and thickness of the films). The mechanical stability of the films was evaluated via a series of tribological tests carried out applying two different contact pressures, 1.04 and 0.7 GPa, in base oil—a hydro-treated, heavy paraffinic fraction known as Yubase 4—at 100 °C. The tribological tests were performed using a ball-on-disc set-up and run until the failure of the protective film occurred. It was found that boron-containing thermal films displayed a much higher mechanical stability than their boron-free counterparts. It was also shown that the presence of boron species (8.4–11.1 at.% B) in the thermal films seems to be able to limit the formation of wear particles and prolong the lifetime of the protective coatings. Furthermore, it appears that very thin, boron-based thermal films can exhibit higher durability than films that are thicker but boron-free.     

Plasminogen activator inhibitor-1 (PAI-1) is not related to response to neoadjuvant chemotherapy in breast cancer

There is no information available on the relation between response to chemotherapy and the high-risk phenotype assessed by uPA and/or PAI-1. The clinical situation of neoadjuvant chemotherapy provides a means of rapidly assessing the sensitivity of the primary tumour to cytotoxic drug regimens. The goal of the study was to assess prospectively the predictive value of PAI-1 for response to first-line chemotherapy. PAI-1 concentration was measured on hypertonic cytosolic extracts (0.4 M potassium chloride) by ELISA before chemotherapy on a drill biopsy sample of the tumour in 69 T2 and T3 breast cancer patients (median age 46 years). Oestrogen receptor (ER) (51% ER+), progesterone receptor (PR) (58% PR+), S-phase (median 4.0%) and ploidy were also assessed in the majority of cases. The clinical response to treatment was evaluated after four cycles of FAC or FEC regimen (5-fluorouracil, epidoxorubicin or doxorubicin and cyclophosphamide) (one cycle every 4th week). PAI-1 could be assayed in 29 post-chemotherapy surgical samples. The objective response rate (complete response plus partial response) was 59% (41 out of 69). PAI-1 expressed as gram of tissue (range 19-2370 ng g(-1) tissue) was highly correlated (r = 0.98) to PAI-1 expressed as mg protein (range 0.5-68 ng mg(-1) protein). No correlation between PAI-1 level and response could be observed, with any cut-off. The post- and pre-chemotherapy PAI-1 levels were correlated (r = 0.66). Of all biological parameters, only high S-phase (cut-off 5%) was slightly correlated (chi2 = 3.91, P = 0.05) to response. These data suggest that PAI-1 is not a predictive marker of response to chemotherapy in breast cancer and that its level is not altered by neoadjuvant chemotherapy.