Drexel University

About: Drexel University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 26770 authors who have published 51438 publications receiving 1949443 citations. The organization is also known as: Drexel & Drexel Institute.

Corporate Governance and Shareholder Initiatives: Empirical Evidence

Abstract: Judging from prior writings, many researchers and practitioners think shareholder-initiated corporate governance proposals promote value-maximizing policies. These proposals are regarded as serving an important role in the governance of public corporations. Our findings, however, do not support this view. Shareholder-initiated corporate governance resolutions tend to target poorly performing firms, as measured by market-to-book ratio, operating return, and recent sales growth. This suggests that their sponsors seek improvements. We find little evidence, however, that proposals increase share values or spur performance improvements. The average wealth effects associated with shareholder-initiated corporate governance proposals are not significantly different from zero. Sales growth subsequently declines for firms receiving proposals relative to sales growth for control firms. And changes in operating return on sales are not significantly larger for proposal firms than their controls. We also find little evidence that shareholder proposals are associated with significant changes in firm policy. Turnover among chief executive officers is not significantly higher among firms that previously attracted proposals than for other firms matched by industry and size. We find that some of the firms attracting successful proposals changed managers or restructured operations, but such changes typically were motivated by external control threats, not the shareholder proposals. Even proposals receiving a majority of share votes are not associated systematically with significant changes in target firms' policies or stock values.

NMR reveals the surface functionalisation of Ti3C2 MXene

Abstract: 1H and 19F NMR experiments have identified and quantified the internal surface terminations of Ti3C2Tx MXene. –F and –OH terminations are shown to be intimately mixed and there are found to be significantly fewer –OH terminations than –F and –O, with the proportions highly dependent on the synthesis method.

Carbide‐Derived Carbons – From Porous Networks to Nanotubes and Graphene

Abstract: Carbide-derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of resulting carbon structures and their tunability enables a wide range of applications, from tribological coatings for ceramics, or selective sorbents, to gas and electrical energy storage. In particular, the application of CDC in supercapacitors has recently attracted much attention. This review paper summarizes key aspects of CDC synthesis, properties, and applications. It is shown that the CDC structure and properties are sensitive to changes of the synthesis parameters. Understanding of processing–structure–properties relationships facilitates tuning of the carbon material to the requirements of a certain application.

Protein synthesis and neurotrophin-dependent structural plasticity of single dendritic spines.

Abstract: Long-term potentiation (LTP) at glutamatergic synapses is considered to underlie learning and memory and is associated with the enlargement of dendritic spines. Because the consolidation of memory and LTP require protein synthesis, it is important to clarify how protein synthesis affects spine enlargement. In rat brain slices, the repetitive pairing of postsynaptic spikes and two-photon uncaging of glutamate at single spines (a spike-timing protocol) produced both immediate and gradual phases of spine enlargement in CA1 pyramidal neurons. The gradual enlargement was strongly dependent on protein synthesis and brain-derived neurotrophic factor (BDNF) action, often associated with spine twitching, and was induced specifically at the spines that were immediately enlarged by the synaptic stimulation. Thus, this spike-timing protocol is an efficient trigger for BDNF secretion and induces protein synthesis-dependent long-term enlargement at the level of single spines.

Additive-free MXene inks and direct printing of micro-supercapacitors

Abstract: Direct printing of functional inks is critical for applications in diverse areas including electrochemical energy storage, smart electronics and healthcare. However, the available printable ink formulations are far from ideal. Either surfactants/additives are typically involved or the ink concentration is low, which add complexity to the manufacturing and compromises the printing resolution. Here, we demonstrate two types of two-dimensional titanium carbide (Ti3C2Tx) MXene inks, aqueous and organic in the absence of any additive or binary-solvent systems, for extrusion printing and inkjet printing, respectively. We show examples of all-MXene-printed structures, such as micro-supercapacitors, conductive tracks and ohmic resistors on untreated plastic and paper substrates, with high printing resolution and spatial uniformity. The volumetric capacitance and energy density of the all-MXene-printed micro-supercapacitors are orders of magnitude greater than existing inkjet/extrusion-printed active materials. The versatile direct-ink-printing technique highlights the promise of additive-free MXene inks for scalable fabrication of easy-to-integrate components of printable electronics.