Controlling Protein Enrichment in Lipid Sponge Phase Droplets using SNAP-Tag Bioconjugation

All cells use organized lipid compartments to facilitate specific biological functions. Membrane-bound organelles create defined spatial environments that favor unique chemical reactions while isolating incompatible biological processes. Despite the fundamental role of cellular organelles, there is a scarcity of methods for preparing functional artificial lipid-based compartments. Here, we demonstrate a robust bioconjugation system for sequestering proteins into zwitterionic lipid sponge phase droplets. Incorporation of benzylguanine (BG)-modified phospholipids that form stable covalent linkages with an O⁶-methylguanine DNA methyltransferase (SNAP-tag) fusion protein enables programmable control of protein capture. We show that this methodology can be used to anchor hydrophilic proteins at the lipid-aqueous interface, concentrating them within an accessible but protected chemical environment. SNAP-tag technology enables the integration of proteins that regulate complex biological functions in lipid sponge phase droplets, and should facilitate the development of advanced lipid-based artificial organelles.     

Structure-Based Virtual Screening and in vitro and in vivo Analyses Revealed Potent Methyltransferase G9a Inhibitors as Prospective Anti-Alzheimer's Agents

G9a is a lysine methyltransferase able to di-methylate lysine 9 of histone H3, promoting the repression of genes involved in learning and memory. Novel strategies based on synthesizing epigenetic drugs could regulate gene expression through histone post-translational modifications and effectively treat neurodegenerative diseases, like Alzheimer's disease (AD). Here, potential G9a inhibitors were identified using a structure-based virtual screening against G9a, followed by in vitro and in vivo screenings. First, screening methods with the AD transgenic Caenorhabditis elegans strain CL2006, showed that the toxicity/function range was safe and recovered age-dependent paralysis. Likewise, we demonstrated that the best candidates direct target G9a by reducing H3 K9me2 in the CL2006 strain. Further characterization of these compounds involved the assessment of the blood-brain barrier-permeability and impact on amyloid-β aggregation, showing promising results. Thus, we present a G9a inhibitor candidate, F , with a novel and potent structure, providing both leads in G9a inhibitor design and demonstrating their participation in reducing AD pathology.     

Effect of Mismatch on the Reliability of ON/OFF-Programmable CNNs

In this paper, the reliability of computation of ON/OFF-programmable cellular nonlinear networks (CNNs) is analyzed. This paper redefines the classical concept of robustness (tolerance to physical imperfections) in ON/OFF-programmable CNNs so that it can be used to predict the computation reliability of a physical realization. Also, a systematic approach to improve robustness is described, and guidelines for optimizing reliability with the given resources are given. Random mismatch is identified as the main source of errors in a physical realization. At the presence of random mismatch, we describe the probability of a cell producing an error with specific inputs and the error probability when processing random data. In addition, we show how the error probability could be defined in case the cell needs to work correctly with all possible input combinations.     

Multitarget‐Directed Tricyclic Pyridazinones as G Protein‐Coupled Receptor Ligands and Cholinesterase Inhibitors

By following a multitarget ligand design approach, a library of 47 compounds was prepared, and they were tested as binders of selected G protein‐coupled receptors (GPCRs) and inhibitors of acetyl and/or butyryl cholinesterase. The newly designed ligands feature pyridazinone‐based tricyclic scaffolds connected through alkyl chains of variable length to proper amine moieties (e.g., substituted piperazines or piperidines) for GPCR and cholinesterase (ChE) molecular recognition. The compounds were tested at three different GPCRs, namely serotoninergic 5‐HT_1A, adrenergic α_1A, and dopaminergic D₂ receptors. Our main goal was the discovery of compounds that exhibit, in addition to ChE inhibition, antagonist activity at 5‐HT_1A because of its involvement in neuronal deficits typical of Alzheimer’s and other neurodegenerative diseases. Ligands with nanomolar affinity for the tested GPCRs were discovered, but most of them behaved as dual antagonists of α_1A and 5‐HT_1A receptors. Nevertheless, several compounds displaying this GPCR affinity profile also showed moderate to good inhibition of AChE and BChE, thus deserving further investigations to exploit the therapeutic potential of such unusual biological profiles.     

Split and shift methodology on cellular processor arrays: area saving versus time penalty

This paper addresses the so‐called split and shift methodology. This methodology deals with the implementation of kernels of sizes that go above the physically implemented resources (local connections and weighting circuits) on synchronous cellular processor arrays (CPA), including the realization of large neighborhood operations and/or the reduction of the available hardware in order to drop the area consumption. Two main goals are pursued in the development of the methodology, namely: (1) minimum penalty at processing time and (2) absolutely no penalty at functional level. The paper presents different techniques and guidelines for the methodology application and introduces a Figure of Merit to evaluate them by relating area gains with time penalty. This, along with a kernel shape analysis, led us to propose more adequate configurations of weighting circuits and to justify the classical choice of North‐East‐West‐South connectivity. To validate the methodology, we realize several estimates over actual physical implementations, and we propose the realization over CPAs of the spin filters, scale invariant feature transform and speeded‐up robust features algorithms. A more in‐depth trade‐off analysis is realized over the implementation of the pixel level snakes algorithm. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis, 3D‐QSAR,and Structural Modeling of Benzolactam Derivatives with Binding Affinity for the D2 and D3 Receptors

A series of 37 benzolactam derivatives were synthesized, and their respective affinities for the dopamine D₂ and D₃ receptors evaluated. The relationships between structures and binding affinities were investigated using both ligand‐based (3D‐QSAR) and receptor‐based methods. The results revealed the importance of diverse structural features in explaining the differences in the observed affinities, such as the location of the benzolactam carbonyl oxygen, or the overall length of the compounds. The optimal values for such ligand properties are slightly different for the D₂ and D₃ receptors, even though the binding sites present a very high degree of homology. We explain these differences by the presence of a hydrogen bond network in the D₂ receptor which is absent in the D₃ receptor and limits the dimensions of the binding pocket, causing residues in helix 7 to become less accessible. The implications of these results for the design of more potent and selective benzolactam derivatives are presented and discussed.     

Gas gangrene due to Clostridium septicum in a patient with an occult colonic neoplasm. A case report and review of the literature

The study included 30 IHD patients with primary hypercholesterolemia (22 males and 8 females). 18 and 12 patients have received a single daily dose of fluvastatin 20 and 40 mg, respectively, in the evening for 12 weeks. The drug effect was assessed by changes in the clinical status, lipid spectrum, transport-metabolic and absorption-secretory functions of the liver. IHD patients with hypercholesterolemia were found to have dysfunction of the hepatobiliary system. Fluvastatin treatment reduced the level of total cholesterol (Ch), LDLP Ch, triglycerides. HDLP Ch levels remained unchanged. Atherogenic lipoproteins aggregation diminished. Positive changes occurred in hepatic metabolism: bilirubin concentrations lowered, serum albumin went up, absorption-secretory function of hepatocytes normalized, hepatic mono-oxidase system activated. Fluvastatin-related hepatic damage was not reported in the course of 12-month follow-up.     

Pulsed time‐of‐flight pixel with on‐chip 20 klux background light suppression in standard CMOS technology

A novel time‐of‐flight pixel designed in 0.18‐μm standard CMOS technology with an indirect pulsed technique is presented. This design is capable of operating in ambients with high levels of background light, since a novel in‐pixel background suppression circuit makes it robust up to 20 klux of ambient light. In addition to this, the pixel incorporates an adaptive number of accumulations circuit that selects the optimum number of accumulations for each situation at pixel level, avoiding saturation even under high illumination conditions.     

Dynamic joint model of capacitive charge pumps and on‐chip photovoltaic cells for CMOS micro‐energy harvesting

On‐chip energy harvesting by means of integrated photovoltaic cells in standard CMOS technology can be successfully used to recharge or power‐up integrated circuits with the use of charge pumps for voltage boosting. In this paper, a tool to facilitate the design of such structures is proposed consisting of an accurate model of the joint dynamics of the micro‐photovoltaic cell and a capacitive DC/DC converter in the slow‐switching limit regime. The model takes into account both the top and bottom parasitic capacitances of the flying capacitors. We assume a classical model for the photodiode whose photogenerated current is extracted from device‐level simulations. The joint model is verified by circuit‐level simulations achieving high accuracy and computation time savings of up to 1700×. The joint model shows that the voltage generated by an integrated photovoltaic cell connected to a capacitive DC/DC converter is not constant even under constant illumination. This phenomenon can only be reproduced through the joint model and failing to take it into account results in an error in the estimation of the time needed by the DC/DC converter to reach a given output voltage. We also demonstrate that the maximum output voltage reached by a DC/DC converter in the slow‐switching limit regime when a photovoltaic cell is used as energy transducer depends on the switching frequency. Finally, the applicability of the model is illustrated through the optimization of time response and charge efficiency for the Dickson, Fibonacci, and exponential topologies in the case of implantable devices. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient recovery of syngas from dry methane reforming product by a dual pressure swing adsorption process

In recent years, there has been growing interest in the dry reforming of methane (using CO₂ instead of H₂O) to obtain syngas, due to its economic and environmental advantages. In this reaction, to achieve conversions close to 100%, it is necessary to work at temperatures higher than 1000 °C. However, to attenuate the catalyst deactivation by sintering is convenient to work at lower temperatures, so that normally the syngas (mixture CO + H₂) is obtained mixed with unreacted CO₂ and CH₄. In this work a process has been simulated to recover the syngas from the product of a dry reforming reaction of methane at 700 °C by means of a Dual PSA (Dual Pressure Swing Adsorption) process with heavy reflux using BPL activated carbon as an adsorbent, operating at 25 °C. The process can recover syngas with purity and recovery higher than 99%. Unreacted CO₂ and CH₄ can be recycled to the reactor, leading to effective CO₂ and CH₄ conversions close to 100%. The process specific energy input (SEI) is 4.7 thermal kJ per L (STP) of syngas. The process can also be used to recover the syngas contained in the tail gas of a H₂ purification PSA from SMR-off gas.