Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins

Electronic skins (e-skins) with high sensitivity to multidirectional mechanical stimuli are crucial for healthcare monitoring devices, robotics, and wearable sensors. In this study, we present piezoresistive e-skins with tunable force sensitivity and selectivity to multidirectional forces through the engineered microstructure geometries (i.e., dome, pyramid, and pillar). Depending on the microstructure geometry, distinct variations in contact area and localized stress distribution are observed under different mechanical forces (i.e., normal, shear, stretching, and bending), which critically affect the force sensitivity, selectivity, response/relaxation time, and mechanical stability of e-skins. Microdome structures present the best force sensitivities for normal, tensile, and bending stresses. In particular, microdome structures exhibit extremely high pressure sensitivities over broad pressure ranges (47,062 kPa(-1) in the range of < 1 kPa, 90,657 kPa(-1) in the range of 1-10 kPa, and 30,214 kPa(-1) in the range of 10-26 kPa). On the other hand, for shear stress, micropillar structures exhibit the highest sensitivity. As proof-of-concept applications in healthcare monitoring devices, we show that our e-skins can precisely monitor acoustic waves, breathing, and human artery/carotid pulse pressures. Unveiling the relationship between the microstructure geometry of e-skins and their sensing capability would provide a platform for future development of high-performance microstructured e-skins

30 inch Roll-Based Production of High-Quality Graphene Films for Flexible Transparent Electrodes

We report that 30-inch scale multiple roll-to-roll transfer and wet chemical doping considerably enhance the electrical properties of the graphene films grown on roll-type Cu substrates by chemical vapor deposition. The resulting graphene films shows a sheet resistance as low as ~30 Ohm/sq at ~90 % transparency which is superior to commercial transparent electrodes such as indium tin oxides (ITO). The monolayer of graphene shows sheet resistances as low as ~125 Ohm/sq with 97.4% optical transmittance and half-integer quantum Hall effect, indicating the high-quality of these graphene films. As a practical application, we also fabricated a touch screen panel device based on the graphene transparent electrodes, showing extraordinary mechanical and electrical performances

Lack of correlation of stem cell markers in breast cancer stem cells

BACKGROUND: Various markers are used to identify the unique sub-population of breast cancer cells with stem cell properties. Whether these markers are expressed in all breast cancers, identify the same population of cells, or equate to therapeutic response is controversial. METHODS: We investigated the expression of multiple cancer stem cell markers in human breast cancer samples and cell lines in vitro and in vivo, comparing across and within samples and relating expression with growth and therapeutic response to doxorubicin, docetaxol and radiotherapy. RESULTS: CD24, CD44, ALDH and SOX2 expression, the ability to form mammospheres and side-population cells are variably present in human cancers and cell lines. Each marker identifies a unique rather than common population of cancer cells. In vivo, cells expressing these markers are not specifically localized to the presumptive stem cell niche at the tumour/stroma interface. Repeated therapy does not consistently enrich cells expressing these markers, although ER-negative cells accumulate. CONCLUSIONS: Commonly employed methods identify different cancer cell sub-populations with no consistent therapeutic implications, rather than a single population of cells. The relationships of breast cancer stem cells to clinical parameters will require identification of specific markers or panels for the individual cancer

Cognitive reserve in granulin-related frontotemporal dementia: from preclinical to clinical stages

OBJECTIVE Consistent with the cognitive reserve hypothesis, higher education and occupation attainments may help persons with neurodegenerative dementias to better withstand neuropathology before developing cognitive impairment. We tested here the cognitive reserve hypothesis in patients with frontotemporal dementia (FTD), with or without pathogenetic granulin mutations (GRN+ and GRN-), and in presymptomatic GRN mutation carriers (aGRN+). METHODS Education and occupation attainments were assessed and combined to define Reserve Index (RI) in 32 FTD patients, i.e. 12 GRN+ and 20 GRN-, and in 17 aGRN+. Changes in functional connectivity were estimated by resting state fMRI, focusing on the salience network (SN), executive network (EN) and bilateral frontoparietal networks (FPNs). Cognitive status was measured by FTD-modified Clinical Dementia Rating Scale. RESULTS In FTD patients higher level of premorbid cognitive reserve was associated with reduced connectivity within the SN and the EN. EN was more involved in FTD patients without GRN mutations, while SN was more affected in GRN pathology. In aGRN+, cognitive reserve was associated with reduced SN. CONCLUSIONS This study suggests that cognitive reserve modulates functional connectivity in patients with FTD, even in monogenic disease. In GRN inherited FTD, cognitive reserve mechanisms operate even in presymptomatic to clinical stages

Investigation of a Mesoporous Silicon Based Ferromagnetic Nanocomposite

A semiconductor/metal nanocomposite is composed of a porosified silicon wafer and embedded ferromagnetic nanostructures. The obtained hybrid system possesses the electronic properties of silicon together with the magnetic properties of the incorporated ferromagnetic metal. On the one hand, a transition metal is electrochemically deposited from a metal salt solution into the nanostructured silicon skeleton, on the other hand magnetic particles of a few nanometres in size, fabricated in solution, are incorporated by immersion. The electrochemically deposited nanostructures can be tuned in size, shape and their spatial distribution by the process parameters, and thus specimens with desired ferromagnetic properties can be fabricated. Using magnetite nanoparticles for infiltration into porous silicon is of interest not only because of the magnetic properties of the composite material due to the possible modification of the ferromagnetic/superparamagnetic transition but also because of the biocompatibility of the system caused by the low toxicity of both materials. Thus, it is a promising candidate for biomedical applications as drug delivery or biomedical targeting

A computationally efficient method for hand–eye calibration

Purpose: Surgical robots with cooperative control and semiautonomous features have shown increasing clinical potential, particularly for repetitive tasks under imaging and vision guidance. Effective performance of an autonomous task requires accurate hand–eye calibration so that the transformation between the robot coordinate frame and the camera coordinates is well defined. In practice, due to changes in surgical instruments, online hand–eye calibration must be performed regularly. In order to ensure seamless execution of the surgical procedure without affecting the normal surgical workflow, it is important to derive fast and efficient hand–eye calibration methods. Methods: We present a computationally efficient iterative method for hand–eye calibration. In this method, dual quaternion is introduced to represent the rigid transformation, and a two-step iterative method is proposed to recover the real and dual parts of the dual quaternion simultaneously, and thus the estimation of rotation and translation of the transformation. Results: The proposed method was applied to determine the rigid transformation between the stereo laparoscope and the robot manipulator. Promising experimental and simulation results have shown significant convergence speed improvement to 3 iterations from larger than 30 with regard to standard optimization method, which illustrates the effectiveness and efficiency of the proposed method

Routes for breaching and protecting genetic privacy

We are entering the era of ubiquitous genetic information for research, clinical care, and personal curiosity. Sharing these datasets is vital for rapid progress in understanding the genetic basis of human diseases. However, one growing concern is the ability to protect the genetic privacy of the data originators. Here, we technically map threats to genetic privacy and discuss potential mitigation strategies for privacy-preserving dissemination of genetic data.Comment: Draft for comment

Ontogeny of the circadian system during embryogenesis in rainbow trout (Oncorhynchus mykiss) and the effect of prolonged exposure to continuous illumination on daily rhythms of per1, clock, and aanat2 expression

It is widely held that the development of the circadian system during embryogenesis is important for future survival of an organism. Work in teleosts has been, to date, limited to zebrafish, which provides little insight into the diversity of this system within such a large vertebrate class. In this study, we analyzed the diel expression of per1, clock, and aanat2 in unfertilized rainbow trout oocytes and embryos maintained under either a 12:12 light:dark (LD) cycle or continuous illumination (LL) from fertilization. 24-h profiles in expression were measured at fertilization as well as 8, 21 42, and 57 days postfertilization (dpf). Both per1 and clock were expressed in unfertilized oocytes and all embryonic stages, while aanat2 expression was only measureable from 8 dpf. A reduction in both per1 and clock mean expression level between unfertilized oocytes/0-1dpf embryos and 8-9dpf embryos was suggestive of a transition from maternal RNA to endogenous mRNA expression. While aanat2 expression was not clearly associated with photic conditions, photoperiod treatment did alter the expression of per1 and clock expression/rhythmicity from as early as 8 dpf (per1), which could suggest the presence and functionality of an as yet unidentified “photoreceptor”. As a whole, this work demonstrates that clock systems are present and functional during embryonic development in rainbow trout. Further studies of their expression and regulation will help understand how the environment interacts with embryonic development in the species

Electrodeposition of CuGaSe2 and CuGaS2 thin films for photovoltaic applications

The final publication is available at Springer via http://dx.doi.org/10.1007/s10008-016-3237-0.Abstract CuGaSe2 and CuGaS2 polycrystalline thin film absorbers were prepared by one-step electrodeposition from an aqueous electrolyte containing CuCl2, GaCl3 and H2SeO3. The pH of the solution was adjusted to 2.3 by adding HCl and KOH. Annealing improved crystallinity of CuGaSe2 and further annealing in sulphur atmosphere was required to obtain CuGaS2 layers. The morphology, topography, chemical composition and crystal structure of the deposited thin films were analysed by scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy and X-ray diffraction, respectively. X-Ray diffraction showed that the asdeposited CuGaSe2 film exhibited poor crystallinity, but which improved dramatically when the layers were annealed in forming gas atmosphere for 40 min. Subsequent sulphurization of CuGaSe2 films was performed at 400 °C for 10 min in presence of molecular sulphur and under forming gas atmosphere. The effect of sulphurization was the conversion of CuGaSe2 into CuGaS2. The formation of CuGaS2 thin films was evidenced by the shift observed in the X-ray diffraction pattern and by the blue shift of the optical bandgap. The bandgap of CuGaSe2 was found to be 1.66 eV, while for CuGaS2 it raised up to 2.2 eV. A broad intermediate absorption band associated to Cr and centred at 1.63 eV was observed in Cr-doped CuGaS2 films.This work was supported by Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R) and Generalitat Valenciana (Prometeus 2014/044). One of the authors (S. Ullah) acknowledges the European Union (IDEAS-Call-3, Innovation and Design for Euro-Asian scholars) for its financial support.Ullah, S.; Mollar García, MA.; Marí, B. (2016). Electrodeposition of CuGaSe2 and CuGaS2 thin films for photovoltaic applications. Journal of Solid State Electrochemistry. 20(8):2251-2257. https://doi.org/10.1007/s10008-016-3237-0S22512257208Calixto ME, Sebastian PJ, Bhattacharya RN, Noufi (1999) Sol Energ Mat Sol C 59:75–84Mandati S, Sarada BV, Dey SR, Joshi SV (2015) J Power Sources 273:149–157Jacobsson TJ, Fjällström V, Edoff M, Edvinsson T (2015) Sol Energ Mat Sol C 134:185–193Carrete A, Placidi M, Shavel A, Pérez Rodríguez A, Cabot A (2015) Phys Stat Sol (a) 212:67–71Saji VS, Ik-Ho C, Lee CW (2011) Sol Energy 86:2666–2678Park MG, Ahn SJ, Yun JH, Gwak J, Cho A, Ahn SK, Shin K, Nam D, Cheong H, Yoon K (2012) J Alloy Compd 513:68–74Saji VS, Lee SM, Lee CW (2011) J Korean Electrochem Soc 14:61–70Donglin X, Jangzhuang L, Man X, Xiujian Z (2008) J Non-Cryst Solids 354:1447–1450Araujo J, Ortíz R, López-Rivera A, Ortega JM, Montilla M, Alarcón D (2007) J Solid State Electroch 11(Issue 3):407–412Palacios P, Sanchez K, Conesa JC, Fernandez JJ, Wahnon P (2007) Phys Stat Sol A 203:1395–1401Palacios P, Sanchez K, Conesa JC, Wahnon P (2006) Thin Solid Films 515:6280–6284Lee H, Lee J-H, Hwang Y-H, Kim Y (2014) Curr Appl Phys 14:18–22Kim D, Kwon Y, Lee D, Yoon S, Lee S, Yoo B (2015) J Electrochem Soc 162:D36–D41Hou WW, Bob B, Li S, Yang Y (2009) Thin Solid Films 517:6853–6856Lee J, Lee W, Shrestha NK, Lee DY, Lim I, Kang SH, Nah YC, Lee SH, Yi W, Han SH (2014) Mater Chem Phys 144:49–54Yang JY, Lee D, Huh K, Jung SJ, Lee JW, Lee HC, Baek DH, Kim BJ, Kim D, Nam J, Kim GY, Jo W (2015) RSC Adv 5:40719–407257Sall T, Nafidi A, Marí B, Mollar M, Hartiti B, Fahoume M (2014) J Semicond 35:0630021–0630025Lee JH, Song WC, Yi JS, Joonyang K, Han WD, Hawang J (2003) Thin Solid Films 431-432:349–353Prabukanthan P, Dhanasekaran R (2007) Cryst Growth Des 7:618–623Guillemoles JF, Cowache P, Lusson A, Fezzaa K, Boisivon F, Vedel J, Lincot D (1996) J Appl Phys 79:7293–7302Aguilera I, Palacios P, Wahon P (2010) Sol Energ Mat Sol C 94:1903–1906Palacios P, Aguilera I, Wahnón P, Conesa JC (2008) J Phys Chem C 112:9525–952