Singular Dimensions of the¶N= 2 Superconformal Algebras. I

Verma modules of superconfomal algebras can have singular vector spaces with dimensions greater than 1. Following a method developed for the Virasoro algebra by Kent, we introduce the concept of adapted orderings on superconformal algebras. We prove several general results on the ordering kernels associated to the adapted orderings and show that the size of an ordering kernel implies an upper limit for the dimension of a singular vector space. We apply this method to the topological N= 2 algebra and obtain the maximal dimensions of the singular vector spaces in the topological Verma modules: 0, 1, 2 or 3 depending on the type of Verma module and the type of singular vector. As a consequence we prove the conjecture of Gato-Rivera and Rosado on the possible existing types of topological singular vectors (4 in chiral Verma modules and 29 in complete Verma modules). Interestingly, we have found two-dimensional spaces of singular vectors at level 1. Finally, by using the topological twists and the spectral flows, we also obtain the maximal dimensions of the singular vector spaces for the Neveu–Schwarz N= 2 algebra (0, 1 or 2) and for the Ramond N= 2 algebra (0, 1, 2 or 3). Received: 19 August 1998 / Accepted: 15 March 1999     

Automatic Identification of Myeloperoxidase Natural Inhibitors in Plant Extracts

The aim of this study is the development of an automated method for myeloperoxidase activity evaluation and its application in testing the inhibitory action of different plant extracts on the activity of the enzyme. This enzyme has its concentration increased in inflammatory and infectious processes, so it is a possible target to limit these processes. Therefore, an automatic sequential in-jection analysis (SIA) system was optimized and demonstrated that it is possible to obtain results with satisfactory accuracy and precision. With the developed method, plant extracts were studied, as promising candidates for MPO inhibition. In the group of selected plant extracts, IC50 values from 0.029 ± 0.002 mg/mL to 35.4 ± 3.5 mg/mL were obtained. Arbutus unedo L. proved to be the most inhibitory extract for MPO based on its phenolic compound content. The coupling of an automatic SIA method to MPO inhibition assays is a good alternative to other conventional methods, due to its simplicity and speed. This work also supports the pharmacological use of these species that inhibit MPO, and exhibit activity that may be related to the treatment of infection and inflammation.     

Analysis of Accelerometer and GPS Data for Cattle Behaviour Identification and Anomalous Events Detection

In this paper, a method to classify behavioural patterns of cattle on farms is presented. Animals were equipped with low-cost 3-D accelerometers and GPS sensors, embedded in a commercial device attached to the neck. Accelerometer signals were sampled at 10 Hz, and data from each axis was independently processed to extract 108 features in the time and frequency domains. A total of 238 activity patterns, corresponding to four different classes (grazing, ruminating, laying and steady standing), with duration ranging from few seconds to several minutes, were recorded on video and matched to accelerometer raw data to train a random forest machine learning classifier. GPS location was sampled every 5 min, to reduce battery consumption, and analysed via the k-medoids unsupervised machine learning algorithm to track location and spatial scatter of herds. Results indicate good accuracy for classification from accelerometer records, with best accuracy (0.93) for grazing. The complementary application of both methods to monitor activities of interest, such as sustainable pasture consumption in small and mid-size farms, and to detect anomalous events is also explored. Results encourage replicating the experiment in other farms, to consolidate the proposed strategy.     

Chemical CdS Thin-Film Deposition Influenced by External Electric and Magnetic Fields

Cadmium sulfide polycrystalline thin films were grown on glass substrates by the chemical-bath deposition technique (CBD) under application of both a pulsating direct electric and a dc magnetic field acting on the Cd- and S-ions during growth in an aqueous solution which contains CdCl₂ and thiourea as source material for the cadmium and sulfur components, respectively. The field orientation in each case of deposition was chosen perpendicular as well as parallel to the growing CdS-film interface. Two different values of the magnetic field strength were applied. Various properties of the films were studied, such as optical transmission and reflection, surface morphology, X-ray diffraction, and dark electrical resistivity, as a function of the applied field configurations, which reveal a clear effect of the field presence during growth.     

Beta-Amyloid (Aβ1-42) Increases the Expression of NKCC1 in the Mouse Hippocampus

Alzheimer’s disease (AD) is a neurodegenerative disorder with an increasing need for developing disease-modifying treatments as current therapies only provide marginal symptomatic relief. Recent evidence suggests the γ-aminobutyric acid (GABA) neurotransmitter system undergoes remodeling in AD, disrupting the excitatory/inhibitory (E/I) balance in the brain. Altered expression levels of K-Cl-2 (KCC2) and N-K-Cl-1 (NKCC1), which are cation–chloride cotransporters (CCCs), have been implicated in disrupting GABAergic activity by regulating GABA_A receptor signaling polarity in several neurological disorders, but these have not yet been explored in AD. NKCC1 and KCC2 regulate intracellular chloride [Cl⁻]_i by accumulating and extruding Cl⁻, respectively. Increased NKCC1 expression in mature neurons has been reported in these disease conditions, and bumetanide, an NKCC1 inhibitor, is suggested to show potential therapeutic benefits. This study used primary mouse hippocampal neurons to explore if KCC2 and NKCC1 expression levels are altered following beta-amyloid (Aβ_1-42) treatment and the potential neuroprotective effects of bumetanide. KCC2 and NKCC1 expression levels were also examined in 18-months-old male C57BL/6 mice following bilateral hippocampal Aβ_1-42 stereotaxic injection. No change in KCC2 and NKCC1 expression levels were observed in mouse hippocampal neurons treated with 1 nM Aβ_1-42, but NKCC1 expression increased 30-days post-Aβ_1-42-injection in the CA1 region of the mouse hippocampus. Primary mouse hippocampal cultures were treated with 1 nM Aβ_1-42 alone or with various concentrations of bumetanide (1 µM, 10 µM, 100 µM, 1 mM) to investigate the effect of the drug on cell viability. Aβ_1-42 produced 53.1 ± 1.4% cell death after 5 days, and the addition of bumetanide did not reduce this. However, the drug at all concentrations significantly reduced cell viability, suggesting bumetanide is highly neurotoxic. In summary, these results suggest that chronic exposure to Aβ_1-42 alters the balance of KCC2 and NKCC1 expression in a region-and layer-specific manner in mouse hippocampal tissue; therefore, this process most likely contributes to altered hippocampal E/I balance in this model. Furthermore, bumetanide induces hippocampal neurotoxicity, thus questioning its suitability for AD therapy. Further investigations are required to examine the effects of Aβ_1-42 on KCC2 and NKCC1 expression and whether targeting CCCs might offer a therapeutic approach for AD.     

Proposal to Test a Transient Deviation from Quantum Mechanics’ Predictions for Bell’s Experiment

Quantum mechanics predicts correlations between measurements performed in distant regions of a spatially spread entangled state to be higher than allowed by intuitive concepts of Locality and Realism. These high correlations forbid the use of nonlinear operators of evolution (which would be desirable for several reasons), for they may allow faster-than-light signaling. As a way out of this situation, it has been hypothesized that the high quantum correlations develop only after a time longer than L/c has elapsed (where L is the spread of the entangled state and c is the velocity of light). In shorter times, correlations compatible with Locality and Realism would be observed instead. A simple hidden variables model following this hypothesis is described. It is based on a modified Wheeler–Feynman theory of radiation. This hypothesis has not been disproved by any of the experiments performed to date. A test achievable with accessible means is proposed and described. It involves a pulsed source of entangled states and stroboscopic record of particle detection during the pulses. Data recorded in similar but incomplete optical experiments are analyzed, and found consistent with the proposed model. However, it is not claimed, in any sense, that the hypothesis has been validated. On the contrary, it is stressed that a complete, specific test is absolutely needed.     

The Interplay between Strain,Sn Content,and Temperature on Spatially Dependent Bandgap in Ge1−x Sn x Microdisks

Germanium–tin (GeSn) microdisks are promising structures for complementary metal–oxide–semiconductor-compatible lasing. Their emission properties depend on Sn concentration, strain, and operating temperature. Critically, the band structure of the alloy varies along the disk due to different lattice deformations associated with mechanical constraints. An experimental and numerical study of Ge_1−x Sn _x microdisk with Sn concentration between 8.5 and 14 at% is reported. Combining finite element method calculations, micro-Raman and X-ray diffraction spectroscopy enables a comprehensive understanding of mechanical deformation, where computational predictions are experimentally validated, leading to a robust model and insight into the strain landscape. Through micro-photoluminescence experiments, the temperature dependence of the bandgap of Ge_1−x Sn _x is parametrized using the Varshni formula with respect to strain and Sn content. These results are the input for spatially dependent band structure calculations based on deformation potential theory. It is observed that Sn content and temperature have comparable effects on the bandgap, yielding a decrease of more than 20 meV for an increase of 1 at% or 100 K, respectively. The impact of the strain gradient is also analyzed. These findings correlate structural properties to emission wavelength and spectral width of microdisk lasers, thus demonstrating the importance of material-related consideration on the design of optoelectronic microstructures.     

New Method for Obtaining a Bioactive Essence Extracted from Iberian Ham Fat Rich in MUFA and Antioxidants

Iberian ham is one of the most representative Spanish products and presents an excellent nutritional and sensory quality. Iberian ham trimming fat is considered a by-product and to give a new use to this remaining part could represent a healthy and innovative option for obtaining sustainable foods. The purpose of this work was to obtain a new bioactive ingredient from Iberian ham trimming fat with the highest amount of antioxidants and monounsaturated fatty acids (MUFA), using a new non-invasive solvent-free method. To obtain the essence, two different extraction procedures were carried out. After fatty acid characterization, degree of acidity, peroxide index and a basic sensory analysis were performed. Antioxidant in vitro activity and total phenolic compounds (TPC) were also determined. This new ingredient showed a better sensory profile than raw ham fat, a lower degree of acidity, a higher content of MUFAs, and also showed a higher antioxidant capacity and an increase in phenolic compounds compared to the raw material. This bioactive essence could be used as a food, a cosmetic or a nutraceutical ingredient to prevent certain diseases related to oxidative stress and could also contribute to the maintenance of the circular economy.     

The Pharmaceutical Industry in 2021. An Analysis of FDA Drug Approvals from the Perspective of Molecules

Similar to last year, 2021 will be remembered for the COVID-19 pandemic. Although five vaccines have been approved by the two most important drug regulatory agencies, namely the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA), the pandemic has still not been brought under control. However, despite the context of a global pandemic, 2021 has been an excellent year with respect to drug approvals by the FDA. In 2021, 50 drugs have been authorized, making it the fourth-best year after 2018 (59 drugs) and 1996 and 2020 (53 each). Regarding biologics, 2021 has been the third-best year to date, with 14 approvals, and it has also witnessed the authorization of 36 small molecules. Of note, nine peptides, eight monoclonal antibodies, two antibody-drug conjugates, and two oligonucleotides have been approved this year. From them, five of the molecules are pegylated and three of them highly pegylated. The presence of nitrogen aromatic heterocycles and/or fluorine atoms are once again predominant among the so-called small molecules. This report analyzes the 50 new drugs approved in 2021 from a chemical perspective, as it did for those authorized in the previous five years. On the basis of chemical structure alone, the drugs that received approval in 2021 are classified as the following: biologics (antibodies, antibody-drug conjugates, enzymes, and pegylated proteins); TIDES (peptide and oligonucleotides); combined drugs; natural products; nitrogen aromatic heterocycles; fluorine-containing molecules; and other small molecules.