A coaxial antenna with miniaturized choke for minimally invasive interstitial heating

We present a new coaxial antenna for microwave interstitial coagulative therapy, working at 2450 MHz and endowed with a miniaturized sleeve choke in order to reduce back heating effects and make the system response less dependent on the antenna insertion depth into the tissue; the way the choke is implemented makes the overall transversal size minimum and allows small adjustments of the choke section length even during operation. We describe the main technical features of the antenna and show experimental results clearly proving the choke effectiveness. Numerical simulations well agree with experimental data, confirming the suitability of the proposed device for minimally invasive medical applications.     

Bioinspired Nanocomposites: Ordered 2D Materials Within a 3D Lattice

Composites, materials composed of two or more materials—metallic, organic, or inorganic—usually exhibit the combined physical properties of their component materials. The result is a material that is superior to conventional monolithic materials. Advanced composites are used in a variety of industrial applications and therefore attract much scientific interest. Here the formation of novel carbon‐based nanocomposites is described via incorporation of graphene oxide (GO) into the crystal lattice of single crystals of calcite. Incorporation of a 2D organic material into single‐crystal lattices has never before been reported. To characterize the resulting nanocomposites, high‐resolution synchrotron powder X‐ray diffraction, electron microscopy, transmission electron microscopy, fluorescence microscopy and nanoindentation tests are employed. A detailed analysis reveals a layered distribution of GO sheets incorporated within the calcite host. Moreover, the optical and mechanical properties of the calcite host are altered when a carbon‐based nanomaterial is introduced into its lattice. Compared to pure calcite, the composite GO/calcite crystals exhibits lower elastic modulus and higher hardness. The results of this study show that the incorporation of a 2D material within a 3D crystal lattice is not only feasible but also can lead to the formation of hybrid crystals exhibiting new properties.     

CMOS Integrated Lock-in Readout Circuit for FET Terahertz Detectors

In this paper, a switched-capacitor readout circuit topology integrated with a THz antenna and field-effect transistor detector is analyzed, designed, and fabricated in a 0.13-μm standard CMOS technology. The main objective is to perform amplification and filtering of the signal, as well as subtraction of background in case of modulated source, in order to avoid the need for an external lock-in amplifier, in a compact implementation. A maximum responsivity of 139.7 kV/W, and a corresponding minimum NEP of 2.2 nW/√Hz, was obtained with a two-stage readout circuit at 1 kHz modulation frequency. The presented switched-capacitor circuit is suitable for implementation in pixel arrays due to its compact size and power consumption (0.014 mm² and 36 μW).     

Identification and Rejuvenation of NBTI-Critical Logic Paths in Nanoscale Circuits

The Negative Bias Temperature Instability (NBTI) phenomenon is agreed to be one of the main reliability concerns in nanoscale circuits. It increases the threshold voltage of pMOS transistors, thus, slows down signal propagation along logic paths between flip-flops. NBTI may cause intermittent faults and, ultimately, the circuit’s permanent functional failures. In this paper, we propose an innovative NBTI mitigation approach by rejuvenating the nanoscale logic along NBTI-critical paths. The method is based on hierarchical identification of NBTI-critical paths and the generation of rejuvenation stimuli using an Evolutionary Algorithm. A new, fast, yet accurate model for computation of NBTI-induced delays at gate-level is developed. This model is based on intensive SPICE simulations of individual gates. The generated rejuvenation stimuli are used to drive those pMOS transistors to the recovery phase, which are the most critical for the NBTI-induced path delay. It is intended to apply the rejuvenation procedure to the circuit, as an execution overhead, periodically. Experimental results performed on a set of designs demonstrate reduction of NBTI-induced delays by up to two times with an execution overhead of 0.1 % or less. The proposed approach is aimed at extending the reliable lifetime of nanoelectronics.     

Studies about the influence of self-organization of colloidal magnetic nanoparticles on the magnetic Néel relaxation time

The monodomain magnetic nanoparticle-based colloids are mainly used in biomedical applications. In this type of colloids, there is a tendency of agglomeration even in the absence of external magnetic field. So, the Néel magnetic relaxation time of the system is affected by that tendency. In this paper, we propose a model to study how the nanoparticle tendency to agglomerate in the nanofluid affects the Néel relaxation time of the system. For simulating the self-organization of colloidal nanoparticles, we apply a Monte Carlo method, and the Néel magnetic relaxation time is assessed through the adaptation and solution of Coffey equations in oblique magnetic field, adapted to the local magnetic field on a nanoparticle.     

Martin’s maximum revisited

We present several results relating the general theory of the stationary tower forcing developed by Woodin with forcing axioms. In particular we show that, in combination with class many Woodin cardinals, the forcing axiom MM⁺⁺ makes the \({\Pi_2}\)-fragment of the theory of \({H_{\aleph_2}}\) invariant with respect to stationary set preserving forcings that preserve BMM. We argue that this is a promising generalization to \({H_{\aleph_2}}\) of Woodin’s absoluteness results for \({L(\mathbb{R})}\). In due course of proving this, we shall give a new proof of some of these results of Woodin. Finally we relate our generic absoluteness results with the resurrection axioms introduced by Hamkins and Johnstone and with their unbounded versions introduced by Tsaprounis.     

Femtosecond Structural Dynamics of Proteins

Proteins are the workhorses of living cells, providing essential functions such as structural support, signal transduction, enzymatic catalysis, transport and storage of small ligands. Atomic-resolution structures obtained with conventional X-ray crystallography show proteins essentially as static. In reality, however, proteins move and their motion is crucial for functioning. Although the structure and dynamics of proteins are intimately related, they are not equally well understood. A very large number of protein structures have been determined, but only a few studies have been able to monitor experimentally the dynamics of proteins in real time. In the last two decades, the availability of short (~100 ps) and intense (~10⁹–10¹⁰ photons) X-ray pulses produced by third-generation synchrotrons have allowed the implementation of structural methods like time-resolved X-ray crystallography and time-resolved X-ray solution scattering that have allowed us to monitor protein motion in the nanosecond-to-millisecond timescale [1 K. Moffat, Chem. Rev. 101, 1569–1582 (2001).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–4 J. G. Kim, Acc. Chem. Res. 48, 2200–2208 (2015).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]]. Time-resolved X-ray crystallography has been used to monitor processes such as the migration of a ligand from the protein active site to the surrounding solvent [5 V. Srajer, Science 274, 1726–1729 (1996).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–7 D. Bourgeois, Proc. Natl. Acad. Sci. U. S. A. 100, 8704–8709 (2003).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] or tertiary structural changes associated with allosteric transitions [8 J. E. Knapp, Proc. Natl. Acad. Sci. 103, 7649–7654 (2006).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar], 9 J. G. Kim, Struct. Dyn. 3, 023610 (2016). [Google Scholar]]. On the other hand, time-resolved X-ray scattering in the so-called wide-angle X-ray scattering (WAXS) region [10 M. Cammarata, Nat. Methods 5, 881–886 (2008).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] has been used to track conformational changes corresponding to large-amplitude protein motions such as the quaternary R-T transition of human hemoglobin [11 M. Cammarata, J. Mol. Biol. 400, 951–962 (2010).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–13 A. Spilotros, Soft Matter 8, 6434–6437 (2012).[Crossref], [Web of Science ®] , [Google Scholar]], the relative motion of bacteriorhodopsin α-helices following retinal isomerization [14 M. Andersson, Structure 17, 1265–1275 (2009).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]], or the open-to-close transition in bacterial phytochromes [15 H. Takala, Nature 509, 245–8 (2014).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]].     

A Method for Detecting Circulating Tumor Cells Based on the Measurement of Single‐Cell Metabolism in Droplet‐Based Microfluidics

The number of circulating tumor cells (CTCs) in blood is strongly correlated with the progress of metastatic cancer. Current methods to detect CTCs are based on immunostaining or discrimination of physical properties. Herein, a label‐free method is presented exploiting the abnormal metabolic behavior of cancer cells. A single‐cell analysis technique is used to measure the secretion of acid from individual living tumor cells compartmentalized in microfluidically prepared, monodisperse, picoliter (pL) droplets. As few as 10 tumor cells can be detected in a background of 200 000 white blood cells and proof‐of‐concept data is shown on the detection of CTCs in the blood of metastatic patients.