Well adjusted: Using expediting and cancelation to manage store replenishment inventory for a seasonal good

We consider an inventory problem that can be translated into a two-period newsvendor setting where the day prior to sales, the newsvendor places an initial preliminary order—a semi-binding forecast—with the publisher. At the beginning of the actual day of sales, the newsvendor has a better forecast for the day’s demand: based on knowing the actual content of the paper, he knows whether it will be a high-demand day due to breaking news or a low-demand day due to slow news. He then can revise the preliminary order quantity by expediting additional papers or canceling all or part of the order, but each of these activities has an associated cost.     

Synthetic studies towards the penicisulfuranols: Synthesis of an advanced spirocyclic diketopiperazine intermediate

The 2,5-diketopiperazine (DKP) moiety is a core feature of many natural products and medicinally relevant scaffolds. As part of our efforts directed towards a total synthesis of penicisulfuranol B, we have developed and report herein: (1) the preparation of an N-hydroxy diketopiperazine intermediate accessible via a molybdenum-mediated oxidation of a parent diketopiperazine, and (2) further synthetic studies leading to a novel spirocyclic dihydrobenzofuran-containing diketopiperazine.     

Combining selection valve and mixing chamber for nanoflow gradient generation: Toward developing a liquid chromatography cartridge coupled with mass spectrometer for protein and peptide analysis

Toward developing a micro HPLC cartridge, we have recently built a high-pressure electroosmotic pump (EOP). However, we do not recommend people to use this pump to deliver an organic solvent directly, because it often makes the pump rate unstable. We have experimented several approaches to address this issue, but none of them are satisfactory. Here, we develop an innovative approach to address this issue. We first create an abruption (a dead-volume) within a fluid conduit. We then utilize an EOP to withdraw, via a selection valve, a train of eluent solutions having decreasing eluting power into the fluid conduit. When these solutions are further aspirated through the dead-volume, these solutions are partially mixed, smoothening concentration transitions between two adjacent eluent solutions. As these solutions are pushed back, through the dead-volume again, a smooth gradient profile is formed. In this work, we characterize this scheme for gradient formation, and we incorporate this approach with a high-pressure EOP, a nanoliter injection valve, and a capillary column, yielding a micro HPLC system. We then couple this micro HPLC with an electrospray ionization – mass spectrometer for peptide and protein separations and identifications.     

Allostatic load as a complex clinical construct: A case‐based computational modeling approach

Allostatic load (AL) is a complex clinical construct, providing a unique window into the cumulative impact of stress. However, due to its inherent complexity, AL presents two major measurement challenges to conventional statistical modeling (the field's dominant methodology): it is comprised of a complex causal network of bioallostatic systems, represented by an even larger set of dynamic biomarkers; and, it is situated within a web of antecedent socioecological systems, linking AL to differences in health outcomes and disparities. To address these challenges, we employed case‐based computational modeling (CBM), which allowed us to make four advances: (1) we developed a multisystem, 7‐factor (20 biomarker) model of AL's network of allostatic systems; (2) used it to create a catalog of nine different clinical AL profiles (causal pathways); (3) linked each clinical profile to a typology of 23 health outcomes; and (4) explored our results (post hoc) as a function of gender, a key socioecological factor. In terms of highlights, (a) the Healthy clinical profile had few health risks; (b) the pro‐inflammatory profile linked to high blood pressure and diabetes; (c) Low Stress Hormones linked to heart disease, TIA/Stroke, diabetes, and circulation problems; and (d) high stress hormones linked to heart disease and high blood pressure. Post hoc analyses also found that males were overrepresented on the High Blood Pressure (61.2%), Metabolic Syndrome (63.2%), High Stress Hormones (66.4%), and High Blood Sugar (57.1%); while females were overrepresented on the Healthy (81.9%), Low Stress Hormones (66.3%), and Low Stress Antagonists (stress buffers) (95.4%) profiles. © 2015 Wiley Periodicals, Inc. Complexity 21: 291–306, 2016     

Gas Storage in Porous Molecular Materials

Molecules with permanent porosity in the solid state have been studied for decades. Porosity in these systems is governed by intrinsic pore space, as in cages or macrocycles, and extrinsic void space, created through loose, intermolecular solid-state packing. The development of permanently porous molecular materials, especially cages with organic or metal–organic composition, has seen increased interest over the past decade, and as such, incredibly high surface areas have been reported for these solids. Despite this, examples of these materials being explored for gas storage applications are relatively limited. This minireview outlines existing molecular systems that have been investigated for gas storage and highlights strategies that have been used to understand adsorption mechanisms in porous molecular materials.     

Synthesis and Study of a Sulfur Heterocycle Fused p-Phenylene Vinylene Conducting Polymer

Abstract

Poly(benzo[1,2-b:4,5-b′]dithiophene-4,8-diyl vinylene) (1) has been prepared by the pyrolysis of the precursor polymer 2 and studied. Quantum mechanical calculations on the aromatic and quinoid monomers, oligomers and polymers indicate that 1 is a planar aromatic polymer.     

Immobilization of [Pt2(μ-S)2(PPh3)4] on Polymeric Supports by Sulfide Alkylation and Phosphine Exchange Reactions

Abstract

The immobilization of the dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂ (PPh₃)₄] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt₂(μ-S)₂(PPh₃)₄] with molecular alkylating agents. The model complex [Pt₂(μ-S)(μ-SCH₂SiMe₃)(PPh₃)₄]PF₆ was prepared as the first molecular silicon-containing derivative of [Pt₂(μ-S)₂(PPh₃)₄] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph₂PCH₂OH].