Tuning the Negative Thermal Expansion Behavior of the Metal-Organic Framework CuBTC by Retrofitting.

The modular building principle of metal-organic frameworks (MOFs) presents an excellent platform to explore and establish structure-property relations that tie microscopic to macroscopic properties. Negative thermal expansion (NTE) is a common phenomenon in MOFs and is often ascribed to collective motions that can move through the structure at sufficiently low energies. Here, we show that the introduction of additional linkages in a parent framework, retrofitting, is an effective approach to access lattice dynamics experimentally, in turn providing researchers with a tool to alter the NTE behavior in MOFs.

Mechanical properties of the ferroelectric metal-free perovskite [MDABCO](NH)I.

The metal-free hybrid organic-inorganic perovskite [MDABCO](NH)I (with MDABCO = N-methyl-1,4-diazabicyclo[2.2.2]octane) was recently discovered to exhibit an excellent ferroelectric performance, challenging established ceramic ferroelectrics.

A hybrid imidazolylidene/imidazolium nickel NHC complex: an isolated intermediate.

Macrocyclic ligand systems with a variety of (different) donor sites oftentimes give rise to very exciting and unexpected multinuclear metal complexes. We report herein the structure of a trinuclear mixed imidazolylidene/imidazolium nickel N-heterocyclic carbene (NHC) complex, namely di-μ-chlorido-bis{μ-calix[2]imidazolium[2]imidazolylidene[2]pyrazolate}trinickel(II) tetrakis(hexafluoridophosphate) acetonitrile tetrasolvate, [Ni(CHN)Cl](PF)·4CHCN or [Ni(L)Cl](PF)·4CHCN, that can be understood as a trapped reaction intermediate during the synthesis of the respective [NiL](PF) product. The structure not only contains protonated next to deprotonated imidazole heterocycles, but also Ni ions with fundamentally different coordination modes within one molecule.

Incontinentia pigmenti (Bloch-Sulzberger syndrome): a systemic disorder.

Incontinentia pigmenti (IP) is a rare inherited multisystem disorder characterized by a distinctive swirling pattern of the skin; defects of teeth, hair, and nails; and ophthalmic, central nervous system, and musculoskeletal abnormalities. It progresses through several well-defined stages. IP is transmitted as a dominant X-linked trait with variable expressivity, but many--if not most--cases are sporadic.

Update on dermal substitutes.

Tissue-engineered biological dressings offer promise in the treatment of burns, chronic ulcers, donor site and other surgical wounds, and a variety of dermatologic conditions. Despite this promise, cellular tissue-engineered products such a Dermagraft and Apligraf have suffered setbacks in recent years with a lower market share than the commercial promoters of these products anticipated. AlloDerm acellular dermal matrix, an older technology than these cell-based products, has made strong progress in winning over clinicians in various disciplines.

Tissue-engineered temporary wound coverings. Important options for the clinician.

Finding an ideal temporary wound dressing is challenging. Although TransCyte, built on Biobrane, offers many of the characteristics of the ideal wound dressing, and may have added benefits from the delivery of extra-cellular matrix (ECM) and growth factors to the wound, the downside of high cost and less convenient storage and usage are considerable barriers to its broader adoption. The low cost and established clinical utility of Biobrane sets the bar high for new products.