Response to geometrical visual illusions in non-human animals: a meta-analysis.

Visual illusions have been studied in many non-human species, spanning a wide range of biological and methodological variables. While early reviews have proved useful in providing an overview of the field, they have not been accompanied by quantitative analysis to systematically evaluate the contribution of biological and methodological moderators on the proportion of illusory choice. In the current meta-analytical study, we confirm that geometrical visual illusion perception is a general phenomenon among non-human animals. Additionally, we found that studies testing birds report stronger illusion perception compared to other classes, as do those on animals with lateral-positioned eyes compared to animals with forward-facing eyes. In terms of methodological choices, we found a positive correlation between the number of trials during training or testing and the effect sizes, while studies with larger samples report smaller effect sizes. Despite studies that trained animals with artificial stimuli showing larger effect sizes compared with those using spontaneous testing with naturalistic stimuli, like food, we found more recent studies prefer spontaneous choice over training. We discuss the challenges and bottlenecks in this area of study, which, if addressed, could lead to more successful advances in the future.

Conceptual DFT, machine learning and molecular docking as tools for predicting LD50 toxicity of organothiophosphates.

CONTEXT: Several descriptors from conceptual density functional theory (cDFT) and the quantum theory of atoms in molecules (QTAIM) were utilized in Random Forest (RF), LASSO, Ridge, Elastic Net (EN), and Support Vector Machines (SVM) methods to predict the toxicity (LD50) of sixty-two organothiophosphate compounds. The A-RF-G1 and A-RF-G2 models were obtained using the RF method, yielding statistically significant parameters with good performance, as indicated by R2 values for the training set (R2Train) and R2 values for the test set (R2Test), around 0.90. METHODS: The molecular structure of all organothiophosphates was optimized via the range-separated hybrid functional ωB97XD with the 6-311 + + G** basis set. Seven hundred and eighty-seven descriptors have been processed using a variety of machine learning algorithms: RF LASSO, Ridge, EN and SVM to generate a predictive model. The properties were obtained with Multiwfn, AIMALL and VMD programs. Docking simulations were performed by using AutoDock 4.2 and LigPlot + programs. All the calculations in this work are carried out in Gaussian 16 program package.

A single hole spin with enhanced coherence in natural silicon.

Semiconductor spin qubits based on spin-orbit states are responsive to electric field excitations, allowing for practical, fast and potentially scalable qubit control. Spin electric susceptibility, however, renders these qubits generally vulnerable to electrical noise, which limits their coherence time. Here we report on a spin-orbit qubit consisting of a single hole electrostatically confined in a natural silicon metal-oxide-semiconductor device. By varying the magnetic field orientation, we reveal the existence of operation sweet spots where the impact of charge noise is minimized while preserving an efficient electric-dipole spin control. We correspondingly observe an extension of the Hahn-echo coherence time up to 88 µs, exceeding by an order of magnitude existing values reported for hole spin qubits, and approaching the state-of-the-art for electron spin qubits with synthetic spin-orbit coupling in isotopically purified silicon. Our finding enhances the prospects of silicon-based hole spin qubits for scalable quantum information processing.

Coherent Control and Spectroscopy of a Semiconductor Quantum Dot Wigner Molecule.

Semiconductor quantum dots containing more than one electron have found wide application in qubits, where they enable readout and enhance polarizability. However, coherent control in such dots has typically been restricted to only the lowest two levels, and such control in the strongly interacting regime has not been realized. Here we report quantum control of eight different transitions in a silicon-based quantum dot. We use qubit readout to perform spectroscopy, revealing a dense set of energy levels with characteristic spacing far smaller than the single-particle energy. By comparing with full configuration interaction calculations, we argue that the dense set of levels arises from Wigner-molecule physics.

Topical Antibiotic Elution in a Collagen-Rich Hydrogel Successfully Inhibits Bacterial Growth and Biofilm Formation In Vitro.

Chronic wounds are a prominent concern, accounting for $25 billion of health care costs annually. Biofilms have been implicated in delayed wound closure, but they are susceptible to developing antibiotic resistance and treatment options continue to be limited. A novel collagen-rich hydrogel derived from human extracellular matrix presents an avenue for treating chronic wounds by providing appropriate extracellular proteins for healing and promoting neovascularization. Using the hydrogel as a delivery system for localized secretion of a therapeutic dosage of antibiotics presents an attractive means of maximizing delivery while minimizing systemic side effects. We hypothesize that the hydrogel can provide controlled elution of antibiotics leading to inhibition of bacterial growth and disruption of biofilm formation. The rate of antibiotic elution from the collagen-rich hydrogel and the efficacy of biofilm disruption was assessed with Pseudomonas aeruginosa Bacterial growth inhibition, biofilm disruption, and mammalian cell cytotoxicity were quantified using in vitro models. The antibiotic-loaded hydrogel showed sustained release of antibiotics for up to 24 h at therapeutic levels. The treatment inhibited bacterial growth and disrupted biofilm formation at multiple time points. The hydrogel was capable of accommodating various classes of antibiotics and did not result in cytotoxicity in mammalian fibroblasts or adipose stem cells. The antibiotic-loaded collagen-rich hydrogel is capable of controlled antibiotic release effective for bacteria cell death without native cell death. A human-derived hydrogel that is capable of eluting therapeutic levels of antibiotic is an exciting prospect in the field of chronic wound healing.

Enhancing the dipolar coupling of a S-T0 qubit with a transverse sweet spot.

A fundamental challenge for quantum dot spin qubits is to extend the strength and range of qubit interactions while suppressing their coupling to the environment, since both effects have electrical origins. Key tools include the ability to take advantage of physical resources in different regimes, and to access optimal working points, sweet spots, where dephasing is minimized. Here, we explore an important resource for singlet-triplet qubits: a transverse sweet spot (TSS) that enables transitions between qubit states, a strong dipolar coupling, and leading-order protection from electrical fluctuations. Of particular interest is the possibility of transitioning between the TSS and symmetric operating points while remaining continuously protected. This arrangement is ideal for coupling qubits to a microwave cavity, because it combines tunability of the coupling with noise insensitivity. We perform simulations with [Formula: see text]-type electrical noise, demonstrating that two-qubit gates mediated by a resonator can achieve fidelities >99% under realistic conditions.

Virtual-photon-mediated spin-qubit-transmon coupling.

Spin qubits and superconducting qubits are among the promising candidates for realizing a solid state quantum computer. For the implementation of a hybrid architecture which can profit from the advantages of either approach, a coherent link is necessary that integrates and controllably couples both qubit types on the same chip over a distance that is several orders of magnitude longer than the physical size of the spin qubit. We realize such a link with a frequency-tunable high impedance SQUID array resonator. The spin qubit is a resonant exchange qubit hosted in a GaAs triple quantum dot. It can be operated at zero magnetic field, allowing it to coexist with superconducting qubits on the same chip. We spectroscopically observe coherent interaction between the resonant exchange qubit and a transmon qubit in both resonant and dispersive regimes, where the interaction is mediated either by real or virtual resonator photons.

Copper-Catalyzed Click Reaction on/in Live Cells.

We demonstrated that copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction could be performed inside live mammalian cells without using a chelating azide. Under optimized conditions, the reaction was performed in human ovary cancer cell line OVCAR5 in which newly synthesized proteins were metabolically modified with homopropargylglycine (HPG). This model system allowed us to estimate the efficiency of the reaction on the cell membranes and in the cytosol using mass spectrometry. We found that the reaction was greatly promoted by a tris(triazolylmethyl)amine CuI ligand tethering a cell-penetrating peptide. Uptake of the ligand, copper, and a biotin-tagged azide in the cells was determined to be 69 ± 2, 163 ± 3 and 1.3 ± 0.1 µM, respectively. After 10 minutes of reaction, the product yields on the membrane and cytosolic proteins were higher than 18% and 0.8%, respectively, while 75% cells remained viable. By reducing the biothiols in the system by scraping or treatment with N-ethylmalemide, the reaction yield on the cytosolic proteins was greatly improved to ~9% and ~14%, respectively, while the yield on the membrane proteins remained unchanged. The results indicate that out of many possibilities, deactivation of the current copper catalysts by biothiols is the major reason for the low yield of CuAAC reaction in the cytosol. Overall, we have improved the efficiency for CuAAC reaction on live cells by 3-fold. Despite the low yielding inside live cells, the products that strongly bind to the intracellular targets can be detected by mass spectrometry. Hence, the in situ CuAAC reaction can be potentially used for screening of cell-specific enzyme inhibitors or biomarkers containing 1,4-substituted 1,2,3-triazoles.

Interface effects on acceptor qubits in silicon and germanium.

Dopant-based quantum computing implementations often require the dopants to be situated close to an interface to facilitate qubit manipulation with local gates. Interfaces not only modify the energies of the bound states but also affect their symmetry. Making use of the successful effective mass theory we study the energy spectra of acceptors in Si or Ge taking into account the quantum confinement, the dielectric mismatch and the central cell effects. The presence of an interface puts constraints to the allowed symmetries and leads to the splitting of the ground state in two Kramers doublets (Mol et al 2015 Appl. Phys. Lett. 106 203110). Inversion symmetry breaking also implies parity mixing which affects the allowed optical transitions. Consequences for acceptor qubits are discussed.

"Click" immobilization of a VEGF-mimetic peptide on decellularized endothelial extracellular matrix to enhance angiogenesis.

We show that coating of decellularized extracellular matrix (DC-ECM) on substrate surfaces is an efficient way to generate a platform mimicking the native ECM environment. Moreover, the DC-ECM can be modified with a peptide (QK) mimicking vascular endothelial growth factor without apparently compromising its integrity. The modification was achieved through metabolic incorporation of a "clickable" handle to DC-ECM followed by rapid attachment of the QK peptide with an azido tag using copper-catalyzed click reaction. The attachment of the QK peptide on to DC-ECM in this way further enhanced the angiogenic responses (formation of branched tubular networks) of endothelial cells.

Stability, antimicrobial activity, and cytotoxicity of poly(amidoamine) dendrimers on titanium substrates.

In this article, we present the first report on the antibacterial activity and cytotoxicity of poly(amidoamine) (PAMAM) dendrimers immobilized on three types of titanium-based substrates with and without calcium phosphate coating. We show that the amino-terminated PAMAM dendrimers modified with various percentages (0-60%) of poly(ethylene glycol) (PEG) strongly adsorbed on the titanium-based substrates. The resultant dendrimer films effectively inhibited the colonization of the Gram-negative bacteria Pseudomonas aeruginosa (strain PAO1) and, to a lesser extent, the Gram-positive bacteria Staphylococcus aureus (SA). The antibacterial activity of the films was maintained even after storage of the samples in PBS for up to 30 days. In addition, the dendrimer films had a low cytotoxicity to human bone mesenchymal stem cells (hMSCs) and did not alter the osteoblast gene expression promoted by the calcium phosphate coating.

Biofunctionalization on alkylated silicon substrate surfaces via "click" chemistry.

Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the nonoxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, a "click" reaction) were reported. However, yields of the CuAAC reactions on these monolayer platforms were low. Also, the nonspecific adsorption of proteins on the resultant surfaces remained a major obstacle for many potential biological applications. Herein, we report a new type of "clickable" monolayers grown by selective, photoactivated surface hydrosilylation of α,ω-alkenynes, where the alkynyl terminal is protected with a trimethylgermanyl (TMG) group, on hydrogen-terminated silicon substrates. The TMG groups on the film are readily removed in aqueous solutions in the presence of Cu(I). Significantly, the degermanylation and the subsequent CuAAC reaction with various azides could be combined into a single step in good yields. Thus, oligo(ethylene glycol) (OEG) with an azido tag was attached to the TMG-alkyne surfaces, leading to OEG-terminated surfaces that reduced the nonspecific adsorption of protein (fibrinogen) by >98%. The CuAAC reaction could be performed in microarray format to generate arrays of mannose and biotin with varied densities on the protein-resistant OEG background. We also demonstrated that the monolayer platform could be functionalized with mannose for highly specific capturing of living targets (Escherichia coli expressing fimbriae) onto the silicon substrates.

"Clickable", polymerized liposomes as a versatile and stable platform for rapid optimization of their peripheral compositions.

A versatile and stable liposomal platform is developed for rapid optimization of its peripheral composition. The platform is based on polydiacetylene lipids terminated with alkynyl groups. Conditions for copper-catalyzed azide-alkyne cycloaddition (a "click" reaction) are optimized for rapid attachment of azides with controlled composition onto the liposomes.

[Dermatophytes isolated in our clinics. 5-year-study in Zaragoza]. / Dermatófitos aislados en muestras clínicas. Estudio de 5 años en Zaragoza.

BACKGROUND: This review summarizes the different species of dermatophytes isolates in our laboratory between 1991 and 1995. We describe the clinical forms and establish the distribution over this period of time. METHODS: Retrospective survey of samples from outpatients of the Dermatology Service in Miguel Servet Hospital where mycologic cultures are required. The extraction of samples is made by scrapes with a carpet or scalpel and they are cultured on Saboureaud agar with chloramphenicol and dermatophytes agar for 3 weeks. All plates were incubated at 28 degrees C. The identification of isolated strains is made by means of morphologic and physiologic criteria; the doubtful strains were identified in national referral center of Majadahonda CNMVISS. RESULTS: 4004 samples were analyzed from 3934 patients and 543 strains of dermatophytes were isolated. The frequencies were as follow: Microsporum canis (44%), Trichophyton mentagrophytes (31.4%), Trichophyton rubrum (18.6%), Epidermophyton floccosum (2.6%), Microsporum gypseum (1.4%), Trichophyton tonsurans (0.7%), Trichophyton verrucosum (0.7%), Trichophyton violaceum (0.2%) y Microsporum audouinii (0.2%). The most frequently observed dermatophytoses were Tinea corporis (54.8%), followed by Tinea unguium (12.6%), Tinea capitis (12.5%), Tinea pedis (8.3%), Tinea manuum (6.3%), Tinea cruris (4.7%) and Tinea barbae (0.7%). CONCLUSIONS: The zoophylic species are the most prevalent in our area and we have observed a raise of Microsporum canis in recent years. It is important to perform mycologic survey in every suspected lesion in older to determinate the true incidence of human dermatophytoses.

[Disseminated zygomycosis by Absidia corymbifera in 2 leukemic patients]. / Zigomicosis diseminada por Absidia corymbifera en 2 pacientes leucémicos.

AIM: The term zygomycosis comprise mycotic infections produced by mucorales and entomophtorales. Mucorales become pathogenic in some conditions, principally diabetes mellitus, immunosuppression, trauma or burn. METHODS: We describe two cases of leukaemic patients who developed disseminated zygomycosis by Absidia corymbifera during the aplastic phase by antineoplastic chemotherapy. RESULTS: In both cases, the first symptom was high fever unresponsive to broad spectrum antibiotics neither fluconazole. Initial sites of infection were sinonasal region in one case and bowel in the other one. The diagnosis was confirmed by culture of nasal swab and peritoneal fluid respectively. One patient was early diagnosed and he received prolonged amphotericin B therapy but no surgical debridement. The other one had a postmortem diagnosis at autopsy. None of them survived. Death was directly related to the fungal infection. CONCLUSIONS: Although this infection is infrequent, it must be suspected in high-risk patients because early diagnosis and quick combined therapy appear to improve the prognosis.

Molar quantification by flow cytometry of fatty acid binding to cells using dipyrrometheneboron difluoride derivatives.

Fatty acid analogs of a dipyrrometheneboron difluoride fluorophore (BDY-FA) have recently been developed. Relative to other fluorescent fatty acids, some of these have the advantages of excitation and emission spectra similar to those of fluorescein and of high quantum yield, which permits their use in conventional argon laser cytometry or microscopy. For the cytofluorimetric quantification of BDY-FA analogs, expressed as molecules bound per cell, we have compared the fluorescence of BDY-dodecanoic acid (BDY-C12) with that of fluorescein. Fluorescent beads with different amounts of bound fluorescein were used to calibrate a flow cytometer in order to correlate the fluorescence intensity with the number of fluorescein molecules per bead. In addition, starting from the basic equation defining the relationship between fluorescence and concentration, we have derived another equation which makes it possible to establish, for a given fluorescence, the relative molar concentration of both fluorochromes and, consequently, to express the fluorescence intensity emitted by the BDY-FA as the equivalent number of BDY-FA molecules. As an example of the potential application of this procedure, the time-course and concentration-dependent binding of BDY-C12 to quiescent and mitogen-activated human lymphocytes and to cultured human T-lymphoma cells have been studied. The method described is of general interest as it can also be applied to the flow cytometric or laser scanning microscopic quantification of other fluorescent dyes.

Expression of the alpha-fetoprotein gene in human breast cancer.

Recently, evidence was obtained that the ability to take up alpha-fetoprotein (alpha-FP), which is characteristic of fetal cells, may be required both in vivo and in vitro by different types of human and animal tumor cells via expression of specific alpha-FP receptors. Mammary gland carcinomas belong to this class of tumor. In some neoplasms, expression of alpha-FP receptors is concomitant with activation of the alpha-FP gene and synthesis of the protein, suggesting that an autocrine alpha-FP/alpha-FP-receptor pathway is operational in these tumors. In the present work, 18 human breast cancer biopsy specimens were subjected to in situ hybridization with a human alpha-FP cDNA probe. Positive labeling for alpha-FP mRNA transcripts was seen in 8 of the specimens. Surprisingly, strong positive signals were seen in stromal fibroblasts and lymphocytes infiltrating tumor nests and in adipocytes adjacent to tumor areas, while the malignant cells themselves were hardly labeled. This suggest paracrine stimulation of the alpha-FP gene, probably as a result of epithelial-mesenchymal interactions. Pathological implications arise from the ability of alpha-FP to regulate growth, either alone or synergistically with other growth factors, as well as its ability to enhance fatty acid entry into proliferating cells.