Hierarchically ordered montmorillonite block copolymer brushes

We report the phase behavior of a new class of polymer nanocomposites, montmorillonite (MMT) block copolymer brushes (MBBs). MBBs are comprised of discrete MMT particles encapsulated with block copolymer brushes synthesized via surface initiated atom transfer radical polymerization. Polystyrene-b-poly(n-butyl acrylate) MBBs of varying composition and total Mn = 80--250 kDa were compared with bulk block copolymers via electron microscopy and a host of mechanical tests. MBBs were found to self assemble into single grain morphologies across incredibly large areas (\u3e 3 um). Perhaps most promising is that MBBs maintain similar melt state properties to bulk block copolymers and are thus amenable to current processing techniques

Influence of Graft Density on Kinetics of Surface-Initiated ATRP of Polystyrene from Montmorillonite

Here we report the kinetics of the surface-initiated atom transfer radical polymerization (ATRP) of styrene from the surface of functionalized montmorillonite clay as a function of graft density. Compared with analogous ATRP reactions with free initiator, we observe a seven-fold increase in the polymerization rate at the highest graft density, 1 chain/nm2, whereas bulk kinetics are recovered as the graft density is reduced. We hypothesize that this phenomenon is a consequence of local concentration heterogeneities that shift the ATRP equilibrium in favor of the active state and present a simple phenomenological kinetic model that accounts for our data. These findings present an important consideration relevant to the design of precisely defined molecular architectures from surfaces via surface-initiated ATRP

IgM Multiple Myeloma: A Rare Clinical Entity and Diagnostic Dilemma

IgM multiple myeloma is a rare disease that shares many common features with Waldenström macroglobulinemia and lymphoplasmacytic lymphoma. It has been described in the literature as having unique diagnostic findings that separate it from the more common IgG and IgA myelomas. It is important for physicians to be able to differentiate between IgM multiple myeloma, Waldenström macroglobulinemia and lymphoplasmacytic lymphoma as their treatments vastly differ. This case report describes the clinical presentation of a patient with IgM lambda multiple myeloma and highlights the pathologic and clinical findings that are specific to this rare entity. We aim to provide further evidence for the previously reported diagnostic criteria for IgM multiple myeloma

Updated site compilation of the Latin American Pollen Database

Flantua, Suzette G A et al.The updated inventory of the Latin American Pollen Database (LAPD) offers a wide range of new insights. This paper presents a systematic compilation of palynological research in Latin America. A comprehensive inventory of publications in peer-reviewed and grey literature shows a major expansion of studies over the last decades. The inventory includes 1379 cores and sections with paleoecological data and more than 4800 modern samples from throughout the continent. Through the years, pollen datasets extend over increasing spans of time and show improved taxonomic and temporal resolution. Currently, these datasets are from 12 modern biomes and 30 countries, covering an altitudinal range of 0 to 6300. m asl. The most densely sampled regions are the Colombian Andes, the southeast coast of Brazil, and Patagonia. Underrepresented biomes are the warm temperate mixed forest (3%), dry forests (3%), and warm temperate rainforest (1%); whereas steppe, tropical rainforest, and cool grass shrublands, such as the páramos, are generally well represented (all >. 17%). There are 126 records that span the late Pleistocene to the Last Glacial Maximum transition (21,000. cal. yr BP), and >. 20% of the records cover the Younger Dryas interval and the Pleistocene/Holocene transition. Reanalysis of numerous sites using multiproxy tools emphasize the informative value of this approach in paleoenvironmental reconstruction. We make suggestions for several pollen sites and regions to be visited again; similarly we identify some key research questions that have yet to be answered. The updated LAPD now provides the platform to support an exciting new phase of global palynological research in which multi-site data are being integrated to address current cutting-edge research questions. The LAPD compilation of sites and the literature database will be available through the Neotoma Paleoecology Database website and a new LAPD website by the end of 2015We thank the Netherlands Organization for Scientific Research (NWO, grant 2012/13248/ALW) for financial support of this project.Peer reviewe

Prolonged hemophagocytic lymphohistiocytosis syndrome as an initial presentation of Hodgkin lymphoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hemophagocytic lymphohistiocytosis is an immune-mediated syndrome that typically has a rapidly progressive course that can result in pancytopenia, coagulopathy, multi-system organ failure and death.</p> <p>Case presentation</p> <p>A 57-year-old Caucasian woman was referred in fulminant hemophagocytic lymphohistiocytosis, with fever, pancytopenia, splenomegaly, mental status changes and respiratory failure. She was found to have stage IV classical Hodgkin lymphoma, in addition to Epstein-Barr virus and cytomegalovirus viremia. Her presentation was preceded by a 3-year prodrome consisting of cytopenia and fever that were partially controlled by steroids and azathioprine.</p> <p>Conclusion</p> <p>Fulminant hemophagocytic lymphohistiocytosis may follow a prodromal phase that possesses features suggestive of a chronic form of hemophagocytic lymphohistiocytosis, but which may also resemble immune cytopenias of other causes. A diagnosis of hemophagocytic lymphohistiocytosis should be considered in the setting of chronic pancytopenia.</p

Hierarchically Ordered Montmorillonite Block Copolymer Brushes

Block copolymers (BCPs) have been known for decades to offer an easily tunable method for producing self-assembled structures with length scales on the order of nanometers. More recently, the community has shown significant interest in exploiting the properties of BCP self-assembly to tailor the spatial and orientational distribution of nanoscale filler materials, with targeted applications ranging from high-density storage devices, to organic electronics, to optical devices, and to separation devices/catalytic membranes.Reprinted with permission from Macromolecules 43 (2010): 2111–2114, doi:10.1021/ma902357s. Copyright 2010 American Chemical Society</p

Cerebral Phaeohyphomycosis in a Patient with Neurosarcoidosis on Chronic Steroid Therapy Secondary to Recreational Marijuana Usage

Cerebral phaeohyphomycosis is often a fatal disease that typically takes a hematogenous spread after inhalation or accidental skin inoculation of pathogens. We present a patient with a history of heavy marijuana smoking while being on chronic steroid therapy for treatment of neurosarcoidosis who was found to have multiple brain abscesses from Curvularia sp. This is a ubiquitous soil-dwelling dematiaceous fungus that is generally thought to affect solely plants, but there is increasing evidence in the literature of it affecting humans and animals. We review the radiographic findings of neurosarcoidosis and cerebral phaeohyphomycosis as well as the pathophysiology of dematiaceous fungi infections

Influence of Graft Density on Kinetics of Surface-Initiated ATRP of Polystyrene from Montmorillonite

Here we report the kinetics of the surface-initiated atom transfer radical polymerization (ATRP) of styrene from the surface of functionalized montmorillonite clay as a function of graft density. Compared with analogous ATRP reactions with free initiator, we observe a seven-fold increase in the polymerization rate at the highest graft density, 1 chain/nm2, whereas bulk kinetics are recovered as the graft density is reduced. We hypothesize that this phenomenon is a consequence of local concentration heterogeneities that shift the ATRP equilibrium in favor of the active state and present a simple phenomenological kinetic model that accounts for our data. These findings present an important consideration relevant to the design of precisely defined molecular architectures from surfaces via surface-initiated ATRP.Reprinted with permission from Macromolecules 42 (2009): 1867–1872, doi:10.1021/ma8024909. Copyright 2009 American Chemical Society.</p