Nanopore sensors detect individual species passing through a nanoscale pore. This experimental paradigm suffers from long analysis times at low analyte concentration and non-specific signals in ...complex media. These limit effectiveness of nanopore sensors for quantitative analysis. Here, we address these challenges using antibody-modified magnetic nanoparticles ((anti-PSA)-MNPs) that diffuse at zero magnetic field to capture the analyte, prostate-specific antigen (PSA). The (anti-PSA)-MNPs are magnetically driven to block an array of nanopores rather than translocate through the nanopore. Specificity is obtained by modifying nanopores with anti-PSA antibodies such that PSA molecules captured by (anti-PSA)-MNPs form an immunosandwich in the nanopore. Reversing the magnetic field removes (anti-PSA)-MNPs that have not captured PSA, limiting non-specific effects. The combined features allow detecting PSA in whole blood with a 0.8 fM detection limit. Our 'magnetic nanoparticle, nanopore blockade' concept points towards a strategy to improving nanopore biosensors for quantitative analysis of various protein and nucleic acid species.
Communication in a doctor-patient relationship constitutes a crucial aspect in medicine, and its multiple dimensions encompass a wide variety of ethical issues. Communication is particularly relevant ...in oncology, because it requires continually dealing with sensitive topics in one of the most highly vulnerable situations as a human: illness and proximity to death. Sexuality is one of these topics because it constitutes an area that is frequently affected by cancer and cancer treatment, which may include causing significant distress, the reinforcement of a negative self-image, relationship conflicts and a permanent memory of having cancer. The objective of this research is to describe the perception of knowledge and communications practices used by oncology doctors with respect to sexual health in the care of their patients, as well as the barriers found when it comes to confronting the topic.
An exploratory quantitative, descriptive and cross-sectional study was carried out, in which a self-administered questionnaire was given to oncology doctors who practise in Chile. This questionnaire had 41 closed questions with answers on a Likert scale and was previously validated by being reviewed and applied to a pilot group of five professionals (one medical bioethics expert and four doctors in the field of oncology). The data were analysed with the SPSS statistical program v. 20, using descriptive statistics.
The main results show that the surveyed doctors consider sexuality to be an important part of patients' quality of life. However, this finding does not align with the practices given for including it as part of clinical care. The professionals refer as the main barriers those that are attributed to the structural functioning of the institution, giving little value to those barriers related to personal aspects or those associated with patient characteristics and/or behaviors.
The results of this study show that, despite oncology doctors seeing sexuality as an important aspect of the quality of life of their patients, they do not include the topic in clinical care. Given that one of the main barriers is obstacles relating to the institution, it is necessary to create political institutions that create the conditions for including this area as a relevant part of cancer patient care.
Two-dimensional (2D) electronic systems can exhibit dramatic drops in resistivity, rhoxx, as the temperature Tarrow right0, which has renewed debate as to whether 2D systems may have a metallic ...ground state. The metallic behaviour is only observed in low-disorder systems, where interactions between the carriers are strong. However, the strength of the metallic behaviour is not universal, with decreases in resistivity ranging from a few per cent to an order of magnitude as Tarrow right0. Here, we compare the metallic behaviour in 2D systems dominated by long- and short-range disorder. We thereby highlight the pivotal role played by the type of disorder in determining the strength of metallic behaviour in these systems. In doing so, we resolve recent confusion in the literature that has arisen from the application of interaction-based theories of metallic behaviour to 2D systems whose disorder environments are inconsistent with the assumptions made by these theories. PUBLICATION ABSTRACT
We report the observation of Kondo physics in a spin-3/2 hole quantum dot. The dot is formed close to pinch-off in a hole quantum wire defined in an undoped AlGaAs/GaAs heterostructure. We clearly ...observe two distinctive hallmarks of quantum dot Kondo physics. First, the Zeeman spin splitting of the zero-bias peak in the differential conductance is independent of the gate voltage. Second, this splitting is twice as large as the splitting for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.
We have studied the Zeeman splitting in ballistic hole quantum wires formed in a (311)A quantum well by surface gate confinement. Transport measurements clearly show lifting of the spin degeneracy ...and crossings of the subbands when an in-plane magnetic field B is applied parallel to the wire. When B is oriented perpendicular to the wire, no spin splitting is discernible up to B = 8.8 T. The observed large Zeeman splitting anisotropy in our hole quantum wires demonstrates the importance of quantum confinement for spin splitting in nanostructures with strong spin-orbit coupling.
Replying to: K. Jones-Smith & H. Mathur replyOur use of the term 'fractal' is consistent with that by the research community. In dismissing Pollock's fractals because of their limited magnification ...range, Jones-Smith and Mathur would also dismiss half the published investigations of physical fractals. On the basis of previous debates on limited-range fractals, a fractal description is particularly appropriate for Pollock's patterns because it is physically reasonable and because it is useful for condensing the description of a complex geometry, as we now describe.
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