A new approach to micropatterning: application of potential-assisted ion transfer at the liquid-liquid interface for the local metal deposition

A new approach to micropatterning is demonstrated. The approach is based on driving an electrochemical process at the solid-liquid interface through the formation of a flux of ions from a micropipet that is held in close proximity to the surface. The flux of ions is generated by the so-called potential assisted ion transfer at the interface between two immiscible electrolyte solutions (ITIES). As a model system, the local deposition of silver was examined. Specifically, a constant potential, which was applied to a micropipet filled with an aqueous solution of silver ions, caused the transfer of Ag(+) into the outer nitrobenzene (NB) solution that consisted of an electrolyte, tetrabutylammonium tetrakis[4-chlorophenyl]borate (TBATPBCl). To facilitate the transfer of silver ions a macrocyclic ligand, that is, dibenzo-24-crown-8 (DB24C8), was added to the organic phase. The Faradaic current of this micro-ITIES was used as a means of controlling the tip-surface distance in scanning electrochemical microscopy (SECM) and depositing silver microstructures on a gold substrate.     

A peptide-derived strategy for specifically targeting the mitochondria and ER of cancer cells: a new approach in fighting cancer

An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance. Here, we present a new approach in cancer therapy that specifically targets the mitochondria and ER of cancer cells. We developed a peptide derived from the flexible and transmembrane domains of the human protein NAF-1/CISD2. This peptide (NAF-1^44-67) specifically permeates through the plasma membranes of human epithelial breast cancer cells, abolishes their mitochondria and ER, and triggers cell death with characteristics of apoptosis, ferroptosis and necroptosis. In vivo analysis revealed that the peptide significantly decreases tumor growth in mice carrying xenograft human tumors. Computational simulations of cancer vs. normal cell membranes reveal that the specificity of the peptide to cancer cells is due to its selective recognition of their membrane composition. NAF-1^44-67 represents a promising anti-cancer lead compound that acts via a unique mechanism.

An effective anti-cancer therapy should exclusively target cancer cells and trigger in them a broad spectrum of cell death pathways that will prevent avoidance.     

Applying the Voice Handicap Index (VHI) to Dysphonic and Nondysphonic Hebrew Speakers

OBJECTIVE: To evaluate a translated version of the Voice Handicap Index (VHI) as a diagnostic tool for people with and without a laryngeal pathology, among Hebrew speakers. STUDY DESIGN: Parallel group design. METHODS: The VHI was translated and adapted to Hebrew. The translated version was, then, administered to a group of 182 patients with various laryngeal pathologies and a control group of 171 people with no laryngeal pathology. Based on the participants' responses to the VHI, statistical analyses were, initially, performed to assess validity and reliability, and then to evaluate group differences between the pathological and control groups and among the different pathological groups included in the study. RESULTS: Statistical analyses showed high reliability values of the Hebrew version of the VHI (overall Cronbach's alpha r = 0.976). Participants' scores were not affected by their age (P = 0.156) or gender (P = 0.261). The participants in the control group obtained significantly lower scores on the overall VHI score, as well as on all three subscale scores, in comparison with the pathological group (P < 0.001). In addition, within the pathological group, patients with neurogenic pathologies received higher scores than all other pathological groups, whereas patients with laryngeal inflammation received lower scores than all other pathological groups (P < 0.05). CONCLUSION: The VHI is a powerful tool for quantifying patients' perceptions of their voice handicaps, and it maintained its power across translation. The VHI was shown to be valuable for the assessment of speakers with, as well as without laryngeal pathologies.     

High Charge Delocalization and Conjugation in Oligofuran Molecular Wires

The extent of charge delocalization and of conjugation in oligofurans and oligothiophenes was studied by using mixed valence systems comprising oligofurans and oligothiophenes capped at both ends by ferrocenyl redox units. Using electrochemical, spectral, and computational tools, we find strong charge delocalization in ferrocene‐capped oligofurans which was stronger than in the corresponding oligothiophene systems. Spectroscopic studies suggest that the electronic coupling integral (H_ab) is roughly 30–50 % greater for oligofuran‐bridged systems, indicating better energy matching between ferrocene units and oligofurans. The distance decay constant (damping factor), β, is similar for oligofurans (0.066 A^?1) and oligothiophenes (0.070 A^?1), which suggests a similar extent of delocalization in the bridge, despite the higher HOMO–LUMO gap in oligofurans. Computational studies indicate a slightly larger extent of delocalization in furan‐bridged systems compared with thiophene‐bridged systems, which is consistent with oligofurans being significantly more rigid and less aromatic than oligothiophenes. High charge delocalization in oligofurans, combined with the previously reported strong fluorescence, high mobility, and high rigidity of oligofuran‐based materials makes them attractive candidates for organic electronic applications.     

Steric and Electronic Effects on an Antibody‐Catalyzed Diels–Alder Reaction

A series of substituted thiophene dioxides was tested as diene substrates for the antibody 1E9, which was elicited with a hexachloronorbornene derivative and normally catalyzes the inverse electron‐demand Diels–Alder reaction between 2,3,4,5‐tetrachlorothiophene dioxide (TCTD) and N‐ethylmaleimide (NEM). Previous structural and computational studies had suggested that the catalytic efficiency of this system derives in part from a very snug fit between the apolar active site and the transition state of this reaction. Nevertheless, replacing all the Cl‐atoms in the hapten with Br‐atoms leads to no loss in affinity (K_d=0.1 nM ), indicating substantial conformational flexibility in the residues that line the binding pocket. Consistent with this observation, the 2,3,4,5‐tetrabromothiophene dioxide is a good substrate for the antibody (k_cat=1.8 min^?1, K_NEM=14 μM ), despite being considerably larger than TCTD. In contrast, normal electron‐demand Diels–Alder reactions between NEM and unsubstituted thiophene dioxide or 2,3,4,5‐tetramethylthiophene dioxide, which are much smaller or nearly isosteric with TCTD, respectively, are not detectably accelerated. These results show that the electronic properties of the 1E9 active site are optimized to a remarkable degree for the inverse electron‐demand Diels–Alder reaction for which it was designed. Indeed, they appear to play a more important role in catalysis than simple proximity effects.     

Crystal engineering of metalloporphyrin assemblies. New supramolecular architectures mediated by bipyridyl ligands

Targeted synthesis of new supramolecular motifs of metalloporphyrins in crystals by a concerted mechanism of molecular recognition in three dimensions, aided by organic ligands, is presented; it involves induced assembly of [tetrakis(4-hydroxyphenyl)porphyrinato]zinc species by a combination of axial coordination through bridging bipyridyls and of lateral hydrogen bonding.     

Soy addition improves the texture of microwavable par-baked pocket-type flat doughs

Microwavable baked goods are used frequently by the food industry to enrobe meat, vegetable, and sweet items for convenient meal delivery but suffer from poor texture upon microwave re-heating. Par-baking the dough prior to the reheating stage provides an opportunity to supply fresh baked goods with a simple baking stage at retail locations. Nonetheless, reheating conditions significantly affect texture of reheated par-baked products, resulting in shrinkage, porosity reduction, and crust softening. Appropriate formula modifications have been shown to reduce microwave-induced toughness of reheated bread by virtue of water-binding agents and lipids. The objective of this study was, therefore, to assess the effect of soy addition on the water state of microwavable par-baked doughs. Four dough formulations were developed by substituting wheat flour with increasing amounts of a soy blend. Addition of soy at 20 and 26% levels improved textural properties of microwaved products, resulting in a softer and less chewy texture. Thermogravimetric analysis (TG) showed increased water binding in soy formulations 20 and 26% with a broadening of the main peak (attributed to water loss) that shifted from 40 to 80 °C. Differential scanning calorimetry (DSC) depicted a transition in the −25/−10 °C range, attributed to soy lipids melting, which broadened at high soy addition. This change in water dynamics was confirmed by proton nuclear magnetic resonance (¹H NMR) relaxation tests, T ₁ and T ₂, having lower values in soy products, and therefore, depicting a more solid-like matrix. Soy addition above 20% significantly improved the texture of microwave reheated par-baked flat doughs.     

C−C Bond Formation of Benzyl Alcohols and Alkynes Using a Catalytic Amount of KOtBu: Unusual Regioselectivity through a Radical Mechanism

We report a C?C bond‐forming reaction between benzyl alcohols and alkynes in the presence of a catalytic amount of KO^tBu to form α‐alkylated ketones in which the C=O group is located on the side derived from the alcohol. The reaction proceeds under thermal conditions (125 °C) and produces no waste, making the reaction highly atom efficient, environmentally benign, and sustainable. Based on our mechanistic investigations, we propose that the reaction proceeds through radical pathways.