We have developed a protocol for computing the acidity constant (pK a ) of organic compounds via ab initio quantum chemistry and continuum solvation methods. Density functional (DFT) calculations employing large basis sets are used to determine the gas-phase deprotonation energies. Solvation effects are treated via a self-consistent reaction field (SCRF) formalism involving accurate numerical solution of the Poisson-Boltzmann equation. Dielectric radii are parametrized for each functional group of interest to optimize solvation free energy calculations for neutral and charged species. While the intrinsic accuracy of these approaches is quite impressive (errors on the order of a few kcal/mol), it is not quite good enough to achieve the target accuracy that we have set for pK a prediction of 0.5 pK a units. Consequently, two further empirical parameters, scaling and additive factors, are determined for every functional group of interest by linear fitting directly to pK a data for a training set. With this additional parametrization, an average accuracy on the order of 0.5 pK a units is achieved. A wide range of coverage of ionizable groups is presented with special focus on chemistry of importance in pharmaceutically active compounds. In addition to obtaining data for large and diverse training sets, we have also selected a subset of known drugs for which pK a 's have been measured and made predictions for these compounds without further adjustment of parameters. The results are similar in quality to that of the training set despite the considerable size and complexity of many of these molecules, demonstrating the ability of the method to accurately handle substituent effects without explicit parametrization thereof. The method has been optimized from a computational viewpoint so that it is tractable even for relatively large pharmaceutical compounds in the 50-100 atom range.

Electrochemical capacitor systems based on Al ions can offer the possibilities of low cost and high safety, together with a three-electron redox-mechanism-based high capacity, and thus are expected to provide a feasible solution to meet ever-increasing energy demands. Here, highly efficient Al-ion intercalation into W O nanowires (W O NWs) with wide lattice spacing and layered single-crystal structure for electrochemical storage is demonstrated. Moreover, a freestanding composite film with a hierarchical porous structure is prepared through vacuum-assisted filtration of a mixed dispersion containing W O NWs and single-walled carbon nanotubes. The as-prepared composite electrode exhibits extremely high areal capacitances of 1.11-2.92 F cm and 459 F cm at 2 mA cm , enhanced electrochemical stability in the Al electrolyte, as well as excellent mechanical properties. An Al-ion-based, flexible, asymmetric electrochemical capacitor is assembled that displays a high volumetric energy density of 19.0 mWh cm at a high power density of 295 mW cm . Finally, the Al-ion-based asymmetric supercapacitor is used as the power source for poly(3-hexylthiophene)-based electrochromic devices, demonstrating their promising capability in flexible electronic devices.

We experimentally observed that the photonic band gap (reflection band) of polymer stabilized cholesteric liquid crystals with negative dielectric anisotropies can be greatly broadened under DC electric fields. We explored the underlying mechanism. We found that the dispersed polymer network moved when DC voltages were applied across the liquid crystal cell. The motion of the polymer network stretched the helical pitch of the liquid crystal on one side of the cell and compressed the helical pitch on the other side of the cell. We proposed a phenomenological theory to explain the motion of the polymer network and the effect of the polymer network on the helical pitch, and this theoretical prediction agreed well with the experimental results.

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Injection at the source contact critically determines the behavior of depletion-type organic electrochemical transistors (OETs). The contact resistance of OETs increases exponentially with the gate voltage and strongly influences the modulation of the drain current by the gate voltage over a wide voltage range. A modified standard model accounting contact resistance can explain the particular shape of the transconductance.

Immersion, interaction, and imagination are three features of virtual reality (VR). Existing VR systems possess fairly realistic visual and auditory feedbacks, and however, are poor with haptic feedback, by means of which human can perceive the physical world via abundant haptic properties. Haptic display is an interface aiming to enable bilateral signal communications between human and computer, and thus to greatly enhance the immersion and interaction of VR systems. This paper surveys the paradigm shift of haptic display occurred in the past 30 years, which is classified into three stages, including desktop haptics, surface haptics, and wearable haptics. The driving forces, key technologies and typical applications in each stage are critically reviewed. Toward the future high-fidelity VR interaction, research challenges are highlighted concerning handheld haptic device, multimodal haptic device, and high fidelity haptic rendering. In the end, the importance of understanding human haptic perception for designing effective haptic devices is addressed. IntroductionIn 1965, Ivan Sutherland proposed the concept "the ultimate display", which represents the birth of virtual reality (VR) [1] . In his seminal work, he introduced three features of VR: immersion, interaction, and imagination. In past 50 years, thanks to the research in computer graphics and sound synthesis, existing VR systems possess fairly realistic visual and auditory feedback. However, haptic feedback is far from user's perceptual expectations. The experiences of haptic sensation in most VR systems are rather poor compared to the abundant haptic properties that human can perceive in the physical world.Haptic feedback is indispensable for enhancing immersion, interaction, and imagination of VR systems.Interaction can be enhanced by haptic feedback as users can directly manipulate virtual objects, and obtain ·Review· Dangxiao WANG et al: Haptic display for virtual reality: progress and challenges immediate haptic feedback. Immersion of the VR system can be enhanced in terms of providing more realistic sensation to mimic the physical interaction process. Imagination of users can be inspired when haptics can provide more cues for user to mentally construct an imagined virtual world beyond spatial and/ or temporal limitations.The haptic sensation obtained through virtual interaction is severely poor compared to the sensation obtained through physical interaction. In our physical life, the haptic channel is pervasively used, such as perception of stiffness, roughness and temperature of the objects in external world, or manipulation of these objects and motion or force control tasks such as grasping, touching or walking etc. In contrary, in virtual world, haptic experiences are fairly poor in both quantity and quality. Most commercial VR games and movies only provide visual and auditory feedbacks, and a few of them provide simple haptic feedback such as vibrations. With the booming of VR in many areas such as medical simulation and product design, there is a...

The transcription factor c-Myc is an important regulator of cellular proliferation, differentiation and embryogenesis. While c-Myc can inhibit myoblast differentiation, the underlying mechanisms remain poorly understood. Here, we found that c-Myc does not only inhibits myoblast differentiation but also promotes myoblast proliferation and muscle fibre hypertrophy. By performing chromatin immunoprecipitation and high-throughput sequencing (ChIP-seq), we identified the genome-wide binding profile of c-Myc in skeletal muscle cells. c-Myc achieves its regulatory effects on myoblast proliferation and differentiation by targeting the cell cycle pathway. Additionally, c-Myc can regulate cell cycle genes by controlling miRNA expression of which dozens of miRNAs can also be regulated directly by c-Myc. Among these c-Myc-associated miRNAs (CAMs), the roles played by c-Myc-induced miRNAs in skeletal muscle cells are similar to those played by c-Myc, whereas c-Myc-repressed miRNAs play roles that are opposite to those played by c-Myc. The cell cycle, ERK-MAPK and Akt-mediated pathways are potential target pathways of the CAMs during myoblast differentiation. Interestingly, we identified four CAMs that can directly bind to the c-Myc 3' UTR and inhibit c-Myc expression, suggesting that a negative feedback loop exists between c-Myc and its target miRNAs during myoblast differentiation. c-Myc also potentially regulates many long intergenic noncoding RNAs (lincRNAs). Linc-2949 and linc-1369 are directly regulated by c-Myc, and both lincRNAs are involved in the regulation of myoblast proliferation and differentiation by competing for the binding of muscle differentiation-related miRNAs. Our findings do not only provide a genome-wide overview of the role the c-Myc plays in skeletal muscle cells but also uncover the mechanism of how c-Myc and its target genes regulate myoblast proliferation and differentiation, and muscle fibre hypertrophy.

In this study, we evaluated the diagnostic value and molecular characteristics of plasma extracellular vesicles (EVs)-derived miRNAs for patients with solitary pulmonary nodules (SPNs), particularly ground-glass nodules (GGNs). This study was registered at www.clinicaltrials.gov under registration number NCT03230019. Small RNA sequencing was performed to assess plasma EVs miRNAs in 59 patients, including 12 patients with benign nodules (2017, training set). MiRNA profiles of 40 an additional individuals were sequenced (2018, validation set). Overall, 16 pure GGNs, 21 mixed GGNs, and 42 solid nodules were included, with paired post-operative plasma samples available for 20 patients. The target miRNA/reference miRNA ratio was used to construct a support vector machine (SVM) model. The SVM model with the best specificity showed 100% specificity in both the training and validation sets independently. The model with the best sensitivity showed 100% and 96.9% sensitivity in the training and validation sets, respectively. Principal component analysis revealed that pure GGN distributions were distinct from those of solid nodules, and mixed GGNs had a diffuse distribution. Among differentially expressed miRNAs, miR-500a-3p, miR-501-3p, and miR-502-3p were upregulated in tumor tissues and enhanced overall survival. The SVM classifier accurately distinguished malignant GGNs and benign nodules. The distinct profile characteristics of miRNAs provided insights into the feasibility of EVs miRNAs as prognostic factors in lung cancer.