Detection of DNA and Poly-L-Lysine using CVD Graphene-channel FET Biosensors

A graphene channel field-effect biosensor is demonstrated for detecting the binding of double-stranded DNA and poly-l-lysine. Sensors consist of CVD graphene transferred using a clean, etchant-free transfer method. The presence of DNA and poly-l-lysine are detected by the conductance change of the graphene transistor. A readily measured shift in the Dirac Voltage (the voltage at which the graphenes resistance peaks) is observed after the graphene channel is exposed to solutions containing DNA or poly-l-lysine. The Dirac voltage shift is attributed to the binding/unbinding of charged molecules on the graphene surface. The polarity of the response changes to positive direction with poly-l-lysine and negative direction with DNA. This response results in detection limits of 8 pM for 48.5 kbp DNA and 11 pM for poly-l-lysine. The biosensors are easy to fabricate, reusable and are promising as sensors of a wide variety of charged biomolecule

Low-power photothermal self-oscillation of bimetallic nanowires

We investigate the nonlinear mechanics of a bimetallic, optically absorbing SiN-Nb nanowire in the presence of incident laser light and a reflecting Si mirror. Situated in a standing wave of optical intensity and subject to photothermal forces, the nanowire undergoes self-induced oscillations at low incident light thresholds of $<1\, \rm{\mu W}$ due to engineered strong temperature-position ($T$-$z$) coupling. Along with inducing self-oscillation, laser light causes large changes to the mechanical resonant frequency $\omega_0$ and equilibrium position $z_0$ that cannot be neglected. We present experimental results and a theoretical model for the motion under laser illumination. In the model, we solve the governing nonlinear differential equations by perturbative means to show that self-oscillation amplitude is set by the competing effects of direct $T$-$z$ coupling and $2\omega_0$ parametric excitation due to $T$-$\omega_0$ coupling. We then study the linearized equations of motion to show that the optimal thermal time constant $\tau$ for photothermal feedback is $\tau \to \infty$ rather than the widely reported $\omega_0 \tau = 1$. Lastly, we demonstrate photothermal quality factor ($Q$) enhancement of driven motion as a means to counteract air damping. Understanding photothermal effects on micromechanical devices, as well as nonlinear aspects of optics-based motion detection, can enable new device applications as oscillators or other electronic elements with smaller device footprints and less stringent ambient vacuum requirements.Comment: New references adde

Gamification and online consumer decisions: Is the game over?

Consumption can be more than just a necessity; it can become a leisure activity. With the emergence of e-commerce and social media, products and services are just one click away; a trend that is further driven by gamified systems. This research aims to systematically analyze the most relevant academic literature on gamification, to establish if it influences online consumer decisions and, if so, which elements, mechanisms, and theories can explain it. After a thorough search from Web of Science and Scopus databases using SciMAT, 257 papers were analyzed. Twenty-nine (29) of the 36 papers found show empirical evidence that the inclusion of game elements in non-game activities has a significant influence on consumer engagement and online consumer decisions in digital contexts. Moreover, rewards and challenges were identified as the two most used mechanisms, with points, badges, and leaderboards being the most tested gamification elements. The Self- Determination Theory (SDT) and the Technology Acceptance Model (TAM) are the two most common theoretical explanations for why gamification works. Lastly, possible future studies to include thematic, methodological and theoretical agendas were discussed

Enhancement of Hydrolysis through the Formation of Mixed Heterometal Species: Al3+/CH3Sn3+ Mixtures

ABSTRACT: The hydrolysis of mixed-metal cations (Al3+/CH3Sn3+) was studied in aqueous solutions of NaNO3, at I = 1.00 ± 0.05 mol·dm−3 and T = 298.15 K, by potentiometric technique. Several hydrolytic mixed species are formed in this mixed system, namely, Alp(CH3Sn)q(OH)r with (p, q, r) = (1, 1, 4), (1, 1, 5), (1, 1, 6), (2, 1, 4), (1, 2, 5), (1, 4, 11), (1, 3, 8), and (7, 6, 32). The stability of these species, expressed by the equilibrium: pAl3+ + qCH3Sn3+ + rOH− = Alp(CH3Sn)q(OH)r 3(p+q)−r, βpqr OH, can be modeled by the empirical relationship: log βpqr OH = −3.34 + 2.67p + 9.23(q + r). By using the equilibrium constant Xpqr relative to the formation reaction: pAl(p+q)(OH)r + q(CH3Sn)(p+q)(OH)r = (p + q)Alp(CH3Sn)q(OH)r, it was found that the formation of heterometal mixed species is thermodynamically favored, and the extra stability can be expressed as a function of the difference in the stability of parent homometal species. This leads, in turn, to a significant enhancement of hydrolysis and solubility

Experimental psycholinguistics as an approach to the study of lexical creation

Aquest article presenta una metodologia psicolingüística experimental innovadora per explorar la neologia i la creació lèxica, crucial per caracteritzar la neologia tant en dominis de llenguatge generals com especialitzats. Utilitzant tasques de presa de decisions lèxiques juntament amb electroencefalografia i seguiment ocular, capturem els processos cognitius implicats en la formació de paraules en temps real i en la interacció dinàmica entre la creativitat lingüística, l’accés lèxic i l’atenció visual, i oferim valuosos coneixements sobre els mecanismes subjacents a la formació de noves unitats lèxiques.This paper presents an innovative experimental psycholinguistic methodology for the exploration of neology and lexical creation, which may prove crucial for characterising neology in both general and specialised language domains. Utilising lexical decision tasks alongside electroencephalography and eye tracking, we grasp the cognitive processes involved in real-time word formation and in the dynamic interplay between linguistic creativity, lexical access, and visual attention, offering valuable insights into the mechanisms underlying the formation of new lexical units

The York map as a Shanmugadhasan canonical transformation in tetrad gravity and the role of non-inertial frames in the geometrical view of the gravitational field

A new parametrization of the 3-metric allows to find explicitly a York map in canonical ADM tetrad gravity, the two pairs of physical tidal degrees of freedom and 14 gauge variables. These gauge quantities (generalized inertial effects) are all configurational except the trace ${}^3K(\tau ,\vec \sigma)$ of the extrinsic curvature of the instantaneous 3-spaces $\Sigma_{\tau}$ (clock synchronization convention) of a non-inertial frame. The Dirac hamiltonian is the sum of the weak ADM energy $E_{ADM} = \int d^3\sigma {\cal E}_{ADM}(\tau ,\vec \sigma)$ (whose density is coordinate-dependent due to the inertial potentials) and of the first-class constraints. Then: i) The explicit form of the Hamilton equations for the two tidal degrees of freedom in an arbitrary gauge: a deterministic evolution can be defined only in a completely fixed gauge, i.e. in a non-inertial frame with its pattern of inertial forces. ii) A general solution of the super-momentum constraints, which shows the existence of a generalized Gribov ambiguity associated to the 3-diffeomorphism gauge group. It influences: a) the explicit form of the weak ADM energy and of the super-momentum constraint; b) the determination of the shift functions and then of the lapse one. iii) The dependence of the Hamilton equations for the two pairs of dynamical gravitational degrees of freedom (the generalized tidal effects) and for the matter, written in a completely fixed 3-orthogonal Schwinger time gauge, upon the gauge variable ${}^3K(\tau ,\vec \sigma)$, determining the convention of clock synchronization. Therefore it should be possible (for instance in the weak field limit but with relativistic motion) to try to check whether in Einstein's theory the {\it dark matter} is a gauge relativistic inertial effect induced by ${}^3K(\tau ,\vec \sigma)$.Comment: 90 page

Using bacterial inclusion bodies to screen for amyloid aggregation inhibitors

Background: The amyloid-β peptide (Aβ42) is the main component of the inter-neuronal amyloid plaques characteristic of Alzheimer's disease (AD). The mechanism by which Aβ42 and other amyloid peptides assemble into insoluble neurotoxic deposits is still not completely understood and multiple factors have been reported to trigger their formation. In particular, the presence of endogenous metal ions has been linked to the pathogenesis of AD and other neurodegenerative disorders. Results: Here we describe a rapid and high-throughput screening method to identify molecules able to modulate amyloid aggregation. The approach exploits the inclusion bodies (IBs) formed by Aβ42 when expressed in bacteria. We have shown previously that these aggregates retain amyloid structural and functional properties. In the present work, we demonstrate that their in vitro refolding is selectively sensitive to the presence of aggregation-promoting metal ions, allowing the detection of inhibitors of metal-promoted amyloid aggregation with potential therapeutic interest. Conclusions: Because IBs can be produced at high levels and easily purified, the method overcomes one of the main limitations in screens to detect amyloid modulators: the use of expensive and usually highly insoluble synthetic peptides

Effects of Orange Pulp Conservation Methods (Dehydrated or Ensiled Sun-Dried) on the Nutritional Value for Finishing Pigs and Implications on Potential Gaseous Emissions from Slurry

[EN] Utilization of local by-products in pig nutrition can reduce the environmental impact of feeds and contribute to the sustainable development of the livestock sector. Orange pulp (OP) is the most abundant citrus by-product worldwide, but its seasonal production and perishable nature requires storage and drying procedures that might affect its nutritive value. Conservation process by fuel drying is expensive and can impair feed sustainability. Instead, in the Mediterranean countries, OP is sun-dried in the open-air. This procedure often implies a previous silage (during storage) which occurs naturally, because OP has a high level of sugars available for fermentation. Orange pulp is also rich in soluble fiber, which is highly fermentable at the pig's caecum and may reduce gas emissions from slurry. In this study, the nutritive value of conventional fuel-dehydrated (DOP) or ensiled-sun dried (ESDOP) was determined for pig diets. Sugars fermentation during ensiling increases fiber level in ESDOP and decreases energy digestibility compared to DOP, but both OP have an appreciable digestible energy content for pigs, around 87 and 94% that of barley, respectively. In addition, they do not differ in the amount of slurry excreted and contribute to reduce potential derived ammonia and methane emissions. The inclusion of orange pulp (OP) in pig diets may promote the circular economy, but drying procedures might influence its nutritional value and environmental impact. The purpose of this study was to determine the energy value and nutrient digestibility of dehydrated (DOP) and ensiled sun dried (ESDOP) orange pulp. The potential ammonia (NH3) and methane (CH4) emissions derived from slurry were also measured. Digestible energies of 14.2 and 13.2 MJ/kg DM for DOP and ESDOP, respectively, were estimated by difference after a 500 g/kg substitution of a basal diet with OPs. A high fiber digestion efficiency was observed for both OPs. Pigs fed the basal diet showed a higher intake and a greater excretion of urine N than pigs fed with OP, but fecal N excretion did not differ among diets. A higher benzoic and hippuric acid content in urine was observed in OP than in basal diet. Altogether, these findings explained a lower pH in slurry of OP diets and a reduction of potential NH3 emissions. The biochemical CH4 potential also decreased, especially with ESDOP. Overall, both OP are relevant sources of energy for pig diets. Their inclusion in feeds generate favorable changes of slurry characteristics that reduce potential NH3 and CH4 emissions.This work was supported by the Spanish Ministry of Science, Innovation and Universities (AGL2014-56653 and RTI2018-095246).Ferrer, P.; García-Rebollar, P.; Calvet, S.; De Blas, C.; Piquer, O.; Rodríguez, CA.; Cerisuelo, A. (2021). Effects of Orange Pulp Conservation Methods (Dehydrated or Ensiled Sun-Dried) on the Nutritional Value for Finishing Pigs and Implications on Potential Gaseous Emissions from Slurry. Animals. 11(2):1-13. https://doi.org/10.3390/ani11020387S11311

Anatomical aspects and phytochemical potential of Caryocar villosum (Aubl.) Pers. (pequiá)/ Aspectos anatômicos e potencial fitoquímico de Caryocar villosum (Aubl.) Pers. (pequiá)

The knowledge of anatomical and phytochemical structures of many species has drawn the attention of researchers in several areas, because these species are characterized by the production of chemical compounds, mainly fixed and essential oils, which are of great industrial interest. The “pequiá” tree is a majestic tree from primary forest and represents huge economic potential. This work aimed to study the anatomical aspects, extraction and characterization of the fixed oil present in the fruit and the seed of Caryocar villosum. There were used fifty fruits of pequiá collected from the municipality of Tartarugalzinho (Amapá). The identification of species was made by comparison with exsiccates available in the Amapá Herbarium – HAMAB. For anatomical and phytochemical analyses, conventional methodology was used. The result in the macerate of the mesocarp corresponds to a yellow mass impregnated by lipids; in the endocarp there were registered trichomes which secret these lipids, forming an arc in all its extension. In the solvent-based phytochemical analyses of the mass of pericarp, mesocarp and fixed oil seed, favorable and satisfactory oil yields were obtained. The analyses of the acidity, saponification, ester and peroxide indexes are parameters that are related to the quality of the oil, therefore, the values obtained meet the Anvisa/2015 Resolution. It is thus concluded that the fixed oil obtained from the mesocarp/seed of C. villosum is indicated for alimentary purposes, with potential to reduce total cholesterol and LDL cholesterol, as well as in cosmetic industry. Therefore, anatomical analyses help phytochemical studies (CNPq/IEPA)