An enumeration procedure for the assembly line balancing problem based on branching by non-decreasing idle time

In this article, we present a new exact algorithm for solving the simple assembly line balancing problem given a determined cycle time (SALBP-1). The algorithm is a station-oriented bidirectional branch-and-bound procedure based on a new enumeration strategy that explores the feasible solutions tree in a non-decreasing idle time order. The procedure uses several well-known lower bounds, dominance rules and a new logical test based on the assimilation of the feasibility problem for a given cycle time and number of stations (SALBP-F) to a maximum-flow problem.     

Synthesis of Azabicyclic Building Blocks for Daphniphyllum Alkaloid Intermediates Featuring N‐Trichloroacetyl Enamide 5‐endo‐trig Radical Cyclizations

A general procedure is reported for the synthesis of cis ring fused azapolycyclic compounds bearing an all‐carbon quaternary stereocenter at the ring fusion and an adequate functionalization for the assembly of new rings leading to advanced synthetic intermediates for Daphniphyllum alkaloid synthesis. The key carbon?carbon bond‐forming step in this approach is a radical cyclization of an N‐cycloalkenyl trichloroacetamide derivative involving a tetrasubstituted enamide to achieve polyfunctionalized lactams.     

Scaffolds for Sustained Release of Ambroxol Hydrochloride,a Pharmacological Chaperone That Increases the Activity of Misfolded β‐Glucocerebrosidase

Ambroxol is a pharmacological chaperone (PC) for Gaucher disease that increases lysosomal activity of misfolded β‐glucocerebrosidase (GCase) while displaying a safe toxicological profile. In this work, different poly(ε‐caprolactone) (PCL)‐based systems are developed to regulate the sustained release of small polar drugs in physiological environments. For this purpose, ambroxol is selected as test case since the encapsulation and release of PCs using polymeric scaffolds have not been explored yet. More specifically, ambroxol is successfully loaded in electrospun PCL microfibers, which are subsequently coated with additional PCL layers using dip‐coating or spin‐coating. The time needed to achieve 80% release of loaded ambroxol increases from ≈15 min for uncoated fibrous scaffolds to 3 days and 1 week for dip‐coated and spin‐coated systems, respectively. Furthermore, it is proven that the released drug maintains its bioactivity, protecting GCase against induced thermal denaturation.     

Coupling between an optical phonon and the Kondo effect

We explore the ultrafast optical response of Yb14MnSb11, providing further evidence that this compound is the first d-electron, ferromagnetic, underscreened Kondo lattice. These results also provide the first demonstration of coupling between an optical phonon mode and the Kondo effect.     

KDP/PEDOT:PSS mixture as a new alternative in the fabrication of pressure sensing devices

In this work we studied the mixture of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), a commercial polymer, with monobasic potassium phosphate (KDP), a piezoelectric salt, as a possible novel material in the fabrication of a low cost, easy-to-make, flexible pressure sensing device. The mixture between KDP and PEDOT:PSS was painted in a flexible polyester substrate and dried. Afterwards, I × V curves were carried out. The samples containing KDP presented higher values of current in smaller voltages than the PEDOT:PSS without KDP. This can mean a change in the chain arrays. Other results showed that the material responds to directly applied pressure to the sample that can be useful to sensors fabrication.     

Possible observation of Kondo screening cloud in Yb14MnSb11 *

ABSTRACT

Single crystals of the underscreened Kondo ferromagnet Yb₁₄MnSb₁₁ were investigated using polarised neutron diffraction and magnetisation measurements. The magnitude and direction of the magnetisation at each of the 9 distinct crystallographic sites was measured using polarised neutron diffraction. A large moment of close to 4.2?μ_B was found at the unique Mn site. A compensating antiferromagnetic moment of ≈?0.5?μ_B was found to be distributed uniformly among the remaining Yb and Sb sites, which was not expected from a previous theoretical calculation. The compensating magnetisation, however, is consistent both in size and magnitude with the expected Kondo screening cloud.     

Electronic Structure Modulation in an Exceptionally Stable Non‐Heme Nitrosyl Iron(II) Spin‐Crossover Complex

The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF₆)₂ (bztpen=N‐benzyl‐N,N′,N′‐tris(2‐pyridylmethyl)ethylenediamine) displays an S=1/2?S=3/2 spin crossover (SCO) behavior (T_1/2=370 K, ΔH=12.48 kJ mol^?1, ΔS=33 J K^?1 mol^?1) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0?S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120–420 K affording a detailed picture of how the electronic distribution of the t_2g–e_g orbitals modulates the structure of the {FeNO}⁷ bond, providing valuable magneto–structural and spectroscopic correlations and DFT analysis.     

The synthesis of 2-amino-4(3H)-quinazolinones and related heterocycles via a mild electrocyclization of aryl guanidines

A new method for the preparation of 2-amino-4(3H)-quinazolinones and similar fused heterocycles is described. Simply warming a mixture of an aryl guanidine and carbonyl diimidazole in acetonitrile results in formation of a putative N-amidinoisocyanate intermediate which undergoes a 6π-electron electrocyclic reaction with the aryl ring to generate the quinazolinone ring system. The mild conditions are compatible with a variety of functional groups, and the reaction is shown to be successful on multigram scale.     

Dynamic Covalent Identification of an Efficient Heparin Ligand

Despite heparin being the most widely used macromolecular drug, the design of small‐molecule ligands to modulate its effects has been hampered by the structural properties of this polyanionic polysaccharide. Now a dynamic covalent selection approach is used to identify a new ligand for heparin, assembled from extremely simple building blocks. The amplified molecule strongly binds to heparin (K_D in the low μm range, ITC) by a combination of electrostatic, hydrogen bonding, and CH–π interactions as shown by NMR and molecular modeling. Moreover, this ligand reverts the inhibitory effect of heparin within an enzymatic cascade reaction related to blood coagulation. This study demonstrates the power of dynamic covalent chemistry for the discovery of new modulators of biologically relevant glycosaminoglycans.     

Absolute configuration of a rare dibenzoylmethane derivative from Dahlstedtia glaziovii (Fabaceae)

Dibenzoylmethanes (DBMs) belong to a small group of flavonoids, known as β-hydroxychalcones, rarely found in nature. Despite their biological and chemotaxonomic importance, the absolute configuration of C-8 substituted DBMs has never been reported. Herein, the absolute stereochemistry of 2′-methoxy-8-(α-α-dimethylallyl)-[3′,4′:4″,5″]-furan-dibenzoylmethane is determined using the VCD exciton chirality method, which may be safely applied to other members of this class.