'Kunbarat' and 'Kunleany' – full not half-siblings

Research Not

Cylindrical Zwitterionic Particles via Interpolyelectrolyte Complexation on Molecular Polymer Brushes

The fabrication of macromolecular architectures with high aspect ratio and well‐defined internal and external morphologies remains a challenge. The combination of template chemistry and self‐assembly concepts to construct peculiar polymer architectures via a bottom‐up approach is an emerging approach. In this study, a cylindrical template—namely a core–shell molecular polymer brush—and linear diblock copolymers (DBCP) associate to produce high aspect ratio polymer particles via interpolyelectrolyte complexation. Induced, morphological changes are studied using cryogenic transmission electron and atomic force microscopy, while the complexation is further followed by isothermal titration calorimetry and ξ‐potential measurements. Depending on the nature of the complexing DBCP, distinct morphological differences can be achieved. While polymers with a non‐ionic block lead to internal compartmentalization, polymers featuring zwitterionic domains lead to a wrapping of the brush template

A Regenerable Biosensing Platform for Bacterial Toxins

Waterborne diarrheal diseases such as travelers’ diarrhea and cholera remain a threat to public health in many countries. Rapid diagnosis of an infectious disease is critical in preventing the escalation of a disease outbreak into an epidemic. Many of the diagnostic tools for infectious diseases employed today are time-consuming and require specialized laboratory settings and trained personnel. There is hence a pressing need for fit-for-purpose point-of-care diagnostic tools with emphasis in sensitivity, specificity, portability, and low cost. We report work toward thermally reversible biosensors for detection of the carbohydrate-binding domain of the Escherichia coli heat-labile enterotoxin (LTB), a toxin produced by enterotoxigenic E. coli strains, which causes travelers’ diarrhea. The biosensing platform is a hybrid of two materials, combining the optical properties of porous silicon (pSi) interferometric transducers and a thermoresponsive multivalent glycopolymer, to enable recognition of LTB. Analytical performance of our biosensors allows us to detect, using a label-free format, sub-micromolar concentrations of LTB in solution as low as 0.135 μM. Furthermore, our platform shows a temperature-mediated “catch-and-release” behavior, an exciting feature with potential for selective protein capture, multiple readouts, and regeneration of the sensor over consecutive cycles of use

Localized Deformation in Ni-Mn-Ga Single Crystals

The magnetomechanical behavior of ferromagnetic shape memory alloys such as Ni-Mn-Ga, and hence the relationship between structure and nanoscale magnetomechanical properties, is of interest for their potential applications in actuators. Furthermore, due to its crystal structure, the behavior of Ni-Mn-Ga is anisotropic. Accordingly, nanoindentation and magnetic force microscopy were used to probe the nanoscale mechanical and magnetic properties of electropolished single crystalline 10M martensitic Ni-Mn-Ga as a function of the crystallographic c-axis (easy magnetization) direction relative to the indentation surface (i.e., c-axis in-plane versus out-of-plane). Load-displacement curves from 5–10 mN indentations on in-plane regions exhibited pop-in during loading, whereas this phenomenon was absent in out-of-plane regions. Additionally, the reduced elastic modulus measured for the c-axis out-of-plane orientation was ∼50% greater than for in-plane. Although heating above the transition temperature to the austenitic phase followed by cooling to the room temperature martensitic phase led to partial recovery of the indentation deformation, the magnitude and direction of recovery depended on the original relative orientation of the crystallographic c-axis: positive recovery for the in-plane orientation versus negative recovery (i.e., increased indent depth) for out-of-plane. Moreover, the c-axis orientation for out-of-plane regions switched to in-plane upon thermal cycling, whereas the number of twins in the in-plane regions increased. We hypothesize that dislocation plasticity contributes to the permanent deformation, while pseudoelastic twinning causes pop-in during loading and large recovery during unloading in the c-axis in-plane case. Minimization of indent strain energy accounts for the observed changes in twin orientation and number following thermal cycling

A parametric study of the acoustic properties of thermal cladding systems

Thermal cladding systems have developed and modernised since the first systems were implemented, and predictions of single figure sound insulation improvement, ΔRW, based on the natural frequency, f0, of the spring-mass covering may no longer be reliable. To identify aspects of the compound acoustic behaviour due to multiple power flow paths of the thermal insulating system, a statistical energy analysis (SEA) based prediction model was developed. A simplified calculation of sound insulation improvement, ΔR, is described, allowing the high frequency (f > f0) behaviour of thermal cladding systems to be predicted. A parametric study in which the impact of different construction materials in the model is discussed; the damping constants, elastic properties of the interlayer and fixings, number of fixings, thickness and material properties (including bending stiffness) of the weatherproof outer layer and the heavyweight wall are assessed. While agreement within 4.0 dB (mean absolute differences) between calculated and measured results for thick render (≥8.0 mm) and curtain wall systems can be obtained at high frequencies (f > f0) using the simplified methodology, this approach was not successful at predicting single figure values. This is because single figure values are weighted towards the low frequencies. Correlation of calculated f0 with measured ΔRW is slightly improved (r.m.s. differences of 2.62 compared with 3.21 using the f0 calculation methodology in EN ISO12354 Annex D) when a modified method to calculate the combined stiffness is used. To improve predictions further, a methodology must be developed to obtain the transfer function, Ytr, used to calculate non-resonant coupling loss factor due to the spring-mass resonance of thermal cladding on the heavyweight wall. The mobility of the connections, Yc, should also be accurately characterised to ensure accurate predictions at high frequencies

Renovation and innovation using thermal insulation lining systems - Acoustic performance

Retrofit and design of thermal cladding systems provide an opportunity to improve the acoustic properties of a building. However, the complexity of the calculation process to predict sound insulation improvement may inhibit rather than encourage novelty and innovation. This paper investigates whether it is realistic to calculate the frequency dependant sound insulation improvement due to modern thermal insulation wall lining systems with just a few input parameters. The calculation procedure is tested using measured results for one external thermal insulation composite system (ETICS) and three curtain wall systems. The accuracy of the procedure is examined using three factors: (1) precision of the measurement, (2) variation of some of the basic parameters of the calculation procedure, and (3) an estimation of the standard error of the calculation. For the ETICS, agreement within <6.0 dB is achieved across much of the frequency range and the trend of the extended dip due to the spring-mass action of the panel is corroborated. The case for using this methodology on curtain wall systems is adequate, however, the trend of calculated results is mostly outside of the 95% confidence limits of the measured results. Possible reasons for this include lack of airtightness of all curtain wall systems and additional transmission due to radiation into and out of the cavity, neither of which are included in the model. The assumption of radiating points or lines, rather than a radiating surface involving the whole panel, gave better agreement at high frequencies for three of the four measured systems (f ≥ 2500 Hz)

Meta-analysis of neural systems underlying placebo analgesia from individual participant fMRI data

The brain systems underlying placebo analgesia are insufficiently understood. Here we performed a systematic, participant-level meta-analysis of experimental functional neuroimaging studies of evoked pain under stimulus-intensity-matched placebo and control conditions, encompassing 603 healthy participants from 20 (out of 28 eligible) studies. We find that placebo vs. control treatments induce small, widespread reductions in pain-related activity, particularly in regions belonging to ventral attention (including mid-insula) and somatomotor networks (including posterior insula). Behavioral placebo analgesia correlates with reduced pain-related activity in these networks and the thalamus, habenula, mid-cingulate, and supplementary motor area. Placebo-associated activity increases occur mainly in frontoparietal regions, with high between-study heterogeneity. We conclude that placebo treatments affect pain-related activity in multiple brain areas, which may reflect changes in nociception and/or other affective and decision-making processes surrounding pain. Between-study heterogeneity suggests that placebo analgesia is a multi-faceted phenomenon involving multiple cerebral mechanisms that differ across studies

A large ungated TPC with GEM amplification

A Time Projection Chamber (TPC) is an ideal device for the detection of charged particle tracks in a large volume covering a solid angle of almost . The high density of hits on a given particle track facilitates the task of pattern recognition in a high-occupancy environment and in addition provides particle identification by measuring the specific energy loss for each track. For these reasons, TPCs with Multiwire Proportional Chamber (MWPC) amplification have been and are widely used in experiments recording heavy-ion collisions. A significant drawback, however, is the large dead time of the order of 1 ms per event generated by the use of a gating grid, which is mandatory to prevent ions created in the amplification region from drifting back into the drift volume, where they would severely distort the drift path of subsequent tracks. For experiments with higher event rates this concept of a conventional TPC operating with a triggered gating grid can therefore not be applied without a significant loss of data. A continuous readout of the signals is the more appropriate way of operation. This, however, constitutes a change of paradigm with considerable challenges to be met concerning the amplification region, the design and bandwidth of the readout electronics, and the data handling. A mandatory prerequisite for such an operation is a sufficiently good suppression of the ion backflow from the avalanche region, which otherwise limits the tracking and particle identification capabilities of such a detector. Gas Electron Multipliers (GEM) are a promising candidate to combine excellent spatial resolution with an intrinsic suppression of ions. In this paper we describe the design, construction and the commissioning of a large TPC with GEM amplification and without gating grid (GEM-TPC). The design requirements have driven innovations in the construction of a light-weight field-cage, a supporting media flange, the GEM amplification and the readout system, which are presented in this paper. We further describe the support infrastructure such as gas, cooling and slow control. Finally, we report on the operation of the GEM-TPC in the FOPI experiment, and describe the calibration procedures which are applied to achieve the design performance of the device.Peer reviewe