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Nature Communications Aug 2018Label-free single-molecule detection has been achieved so far by funnelling a large number of ligands into a sequence of single-binding events with few recognition...
Label-free single-molecule detection has been achieved so far by funnelling a large number of ligands into a sequence of single-binding events with few recognition elements host on nanometric transducers. Such approaches are inherently unable to sense a cue in a bulk milieu. Conceptualizing cells' ability to sense at the physical limit by means of highly-packed recognition elements, a millimetric sized field-effect-transistor is used to detect a single molecule. To this end, the gate is bio-functionalized with a self-assembled-monolayer of 10 capturing anti-Immunoglobulin-G and is endowed with a hydrogen-bonding network enabling cooperative interactions. The selective and label-free single molecule IgG detection is strikingly demonstrated in diluted saliva while 15 IgGs are assayed in whole serum. The suggested sensing mechanism, triggered by the affinity binding event, involves a work-function change that is assumed to propagate in the gating-field through the electrostatic hydrogen-bonding network. The proposed immunoassay platform is general and can revolutionize the current approach to protein detection.
Topics: Animals; Blood Proteins; Cattle; Electrolytes; Female; Humans; Single Molecule Imaging; Staining and Labeling; Transistors, Electronic
PubMed: 30104563
DOI: 10.1038/s41467-018-05235-z -
Journal of Microscopy Aug 2008Transport networks are vital components of multi-cellular organisms, distributing nutrients and removing waste products. Animal cardiovascular and respiratory systems,... (Review)
Review
Transport networks are vital components of multi-cellular organisms, distributing nutrients and removing waste products. Animal cardiovascular and respiratory systems, and plant vasculature, are branching trees whose architecture is thought to determine universal scaling laws in these organisms. In contrast, the transport systems of many multi-cellular fungi do not fit into this conceptual framework, as they have evolved to explore a patchy environment in search of new resources, rather than ramify through a three-dimensional organism. These fungi grow as a foraging mycelium, formed by the branching and fusion of threadlike hyphae, that gives rise to a complex network. To function efficiently, the mycelial network must both transport nutrients between spatially separated source and sink regions and also maintain its integrity in the face of continuous attack by mycophagous insects or random damage. Here we review the development of novel imaging approaches and software tools that we have used to characterise nutrient transport and network formation in foraging mycelia over a range of spatial scales. On a millimetre scale, we have used a combination of time-lapse confocal imaging and fluorescence recovery after photobleaching to quantify the rate of diffusive transport through the unique vacuole system in individual hyphae. These data then form the basis of a simulation model to predict the impact of such diffusion-based movement on a scale of several millimetres. On a centimetre scale, we have used novel photon-counting scintillation imaging techniques to visualize radiolabel movement in small microcosms. This approach has revealed novel N-transport phenomena, including rapid, preferential N-resource allocation to C-rich sinks, induction of simultaneous bi-directional transport, abrupt switching between different pre-existing transport routes, and a strong pulsatile component to transport in some species. Analysis of the pulsatile transport component using Fourier techniques shows that as the colony forms, it self-organizes into well demarcated domains that are identifiable by differences in the phase relationship of the pulses. On the centimetre to metre scale, we have begun to use techniques borrowed from graph theory to characterize the development and dynamics of the network, and used these abstracted network models to predict the transport characteristics, resilience, and cost of the network.
Topics: Food; Fungi; Image Processing, Computer-Assisted; Microscopy, Confocal; Microscopy, Fluorescence; Microscopy, Video; Mycelium
PubMed: 18778429
DOI: 10.1111/j.1365-2818.2008.02043.x -
Nature Feb 2018Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable...
Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly, in bioengineering such as single-cell manipulation and biosensing, and in healthcare such as targeted drug delivery and minimally invasive surgery. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.
Topics: Biomimetics; Elasticity; Equipment Design; Locomotion; Robotics; Rotation; Swimming; Walking
PubMed: 29364873
DOI: 10.1038/nature25443 -
Nanomaterials (Basel, Switzerland) Mar 2021Nanomaterials science is becoming the foundation stone of high-frequency applications. The downscaling of electronic devices and components allows shrinking chip's... (Review)
Review
Nanomaterials science is becoming the foundation stone of high-frequency applications. The downscaling of electronic devices and components allows shrinking chip's dimensions at a more-than-Moore rate. Many theoretical limits and manufacturing constraints are yet to be taken into account. A promising path towards nanoelectronics is represented by atomic-scale materials. In this manuscript, we offer a perspective on a specific class of devices, namely switches designed and fabricated using two-dimensional or nanoscale materials, like graphene, molybdenum disulphide, hexagonal boron nitride and ultra-thin oxides for high-frequency applications. An overview is provided about three main types of microwave and millimeter-wave switch: filament memristors, nano-ionic memristors and ferroelectric junctions. The physical principles that govern each switch are presented, together with advantages and disadvantages. In the last part we focus on zirconium-doped hafnium oxide ferroelectrics (HfZrO) tunneling junctions (FTJ), which are likely to boost the research in the domain of atomic-scale materials applied in engineering sciences. Thanks to their Complementary Metal-Oxide Semiconductor (CMOS) compatibility and low-voltage tunability (among other unique physical properties), HfZrO compounds have the potential for large-scale applicability. As a practical case of study, we present a 10 GHz transceiver in which the switches are FTJs, which guarantee excellent isolation and ultra-fast switching time.
PubMed: 33802404
DOI: 10.3390/nano11030625 -
Sensors (Basel, Switzerland) Oct 2019This study proposes a novel piezoelectric micromachined ultrasonic transducer (PMUT), fabricated on a metal foil. Using a bottom-up, cost-effective micromachining...
This study proposes a novel piezoelectric micromachined ultrasonic transducer (PMUT), fabricated on a metal foil. Using a bottom-up, cost-effective micromachining technique, the PMUTs made of electrodes, a piezoelectric film, or electrode-sandwiched structures with versatile patterns were implemented on a large-area foil thinner rather than regular paper. The proposed microfabrication facilitated the PMUT to be able to generate ultrasonic waves with fundamental and harmonic resonances. The fourth-order resonances of the fabricated PMUT functionally operated at an ultrasonic spectrum of approximately 30 kHz as an ultrasonic emitter. The developed PMUT was paired with a microelectromechanical system (MEMS) microphone module for range-finding applications in the range of several tens of millimeters. A signal-processing scheme was developed to extract the representative pattern from the acquired signals that were emitted and received. The pattern enabled finding the distance between the PMUT and the microphone using time-of-flight and strength-variation technology. The developed PMUT-microphone pair demonstrated its range-finding performance, displaying an error of less than 0.7% using the time-of-flight method.
PubMed: 31671739
DOI: 10.3390/s19214696 -
Nanomaterials (Basel, Switzerland) Mar 2018While high-aspect-ratio metal nanowires are essential for producing nanowire-based electrodes of good performance used in electronics and electrocatalysis, the synthesis...
While high-aspect-ratio metal nanowires are essential for producing nanowire-based electrodes of good performance used in electronics and electrocatalysis, the synthesis of millimeter-long Cu nanowires remains a challenge. This work demonstrates an oleylamine-mediated hydrothermal method for synthesis of Cu nanowires with an average diameter of ~80 nm and a length up to several millimeters. An investigation on the role of oleylamine in nanowire formation by mass spectroscopy, small angle X-ray diffraction and transmission electron microscopy reveals that oleylamine serves as a mild reducing agent for slow reduction of Cu(II) to Cu, a complexing agent to form Cu(II)-oleylamine complex for guiding the nanowire growth, as well as a surfactant to generate lamellar phase structure for the formation of nanowire bundles. The growth mechanism of these millimeter-long Cu nanowire bundles is proposed based on the experimental observations. Electrochemical measurements by linear sweep voltammetry indicate that the self-supported nanowire electrode prepared from as-formed Cu nanowire bundles shows high catalytic activity for electroreduction of nitrate in water.
PubMed: 29584646
DOI: 10.3390/nano8040192 -
Optica Jun 2022Optical coherence tomography (OCT) has seen widespread success as an in vivo clinical diagnostic 3D imaging modality, impacting areas including ophthalmology,...
Optical coherence tomography (OCT) has seen widespread success as an in vivo clinical diagnostic 3D imaging modality, impacting areas including ophthalmology, cardiology, and gastroenterology. Despite its many advantages, such as high sensitivity, speed, and depth penetration, OCT suffers from several shortcomings that ultimately limit its utility as a 3D microscopy tool, such as its pervasive coherent speckle noise and poor lateral resolution required to maintain millimeter-scale imaging depths. Here, we present 3D optical coherence refraction tomography (OCRT), a computational extension of OCT which synthesizes an incoherent contrast mechanism by combining multiple OCT volumes, acquired across two rotation axes, to form a resolution-enhanced, speckle-reduced, refraction-corrected 3D reconstruction. Our label-free computational 3D microscope features a novel optical design incorporating a parabolic mirror to enable the capture of 5D plenoptic datasets, consisting of millimetric 3D fields of view over up to ±75° without moving the sample. We demonstrate that 3D OCRT reveals 3D features unobserved by conventional OCT in fruit fly, zebrafish, and mouse samples.
PubMed: 37719785
DOI: 10.1364/optica.454860 -
The Angle Orthodontist Apr 1976Latex elastics and synthetic elastomers have certain similarities and differences. In the fracture tests the latex elastics showed a greater amount of loss in strength... (Comparative Study)
Comparative Study
Latex elastics and synthetic elastomers have certain similarities and differences. In the fracture tests the latex elastics showed a greater amount of loss in strength than plastic elastomers when stretched over a 21 day period. There is a great variability, as much as 50%, in the tensile strength of the plastic materials taken from the same batch and stretched under the same conditions. The Ormco Power Chain was more resilient than the Unitek AlastiK chain. The Unitek AlastiKs had more force and stretched less. The force decay of synthetic elastomers, stretched over a specific length and time, exhibited a great loss in force. This loss could be as great as 73% during the first day. The decay of force continued at a slower rate during the rest of the 21 day period. Unitek AlastiK C2 double links, when stretched 17 millimeters, had a higher initial force averaging 641 grams (22.5 ounces) than the Ormco Power Chain which averages 342 grams (12.0 ounces). In one day the force was reduced to 171 grams (6.0 ounces) for both materials. The elastic materials within the same batch showed a great variation in the modulus of elasticity under different test conditions. The approximate force generated when stretched dry, within the elastic limit, was 22 grams per millimeter for 3/16 inches heavy latex elastics. The Unitek AlastiK C2 gave a force of 89 grams per millimeter, while the Ormco Power Chain had a value of 46 grams per millimeter. The modulus of elasticity of all of the materials was much lower after immersion in the water bath. The force decay under constant force application to latex, elastic, polymer chains, and tied loops showed that the greatest amount of force decay occurred during the first three hours in the water bath. The forces remained relatively the same throughout the rest of the test period. The elastic materials undergo permanent deformation in shape. The synthetic elastomers exhibited plastic deformation when the elastomers were stretched 17 millimeters for 21 days. In the dry condition the force decay was 63% for the Unitek chains and 42% for the Ormco Power Chain. The synthetic elastomers should be prestretched before being placed in the mouth. The elastomers should be used within their resilient ranges. Clinical treatment procedures should take into consideration the rapid initial force decay of elastic materials that occurs during the first day and the residual forces remaining.
Topics: Elasticity; Orthodontic Appliances; Polyurethanes; Rubber; Silicone Elastomers; Stress, Mechanical
PubMed: 1064346
DOI: 10.1043/0003-3219(1976)046<0196:OEM>2.0.CO;2 -
Mymensingh Medical Journal : MMJ Jan 2023The most common presentation of the most common gynaecological malignancy (Endometrial Cancer) is abnormal PV bleeding. Transvaginal sonography (TVS) is the first line... (Review)
Review
The most common presentation of the most common gynaecological malignancy (Endometrial Cancer) is abnormal PV bleeding. Transvaginal sonography (TVS) is the first line investigation to assess the endometrial nature. Four to five (4-5) millimetre endometrial thicknesses is considered as the normal cut off in post menopausal women. But endometrial cancer can be present while endometrial thickness is less than 4mm. The author describes three cases of isolated endometrial cancer in Glangwili General Hospital in Wales, UK that was diagnosed despite endometrial thickness being less than 4mm and a brief review of the literature on its prevalence, risk factors, clinical presentation, diagnosis and therapeutic approach.
Topics: Female; Humans; Uterine Hemorrhage; Ultrasonography; Endometrial Neoplasms; Endometrium
PubMed: 36594328
DOI: No ID Found -
Electroencephalography and Clinical... Sep 1995Subdural recordings from 8 patients and depth recordings from 3 patients via rows of electrodes with 5-10 mm spacing were searched for signs of significant local... (Comparative Study)
Comparative Study
Subdural recordings from 8 patients and depth recordings from 3 patients via rows of electrodes with 5-10 mm spacing were searched for signs of significant local differentiation of coherence calculated between all possible pairs of loci. EEG samples of 2-4 min were taken during 4 states: alertness, stage 2-3 sleep, light surgical anesthesia permitting the patient to respond to questions and electrical seizures. Coherence was computed for all frequencies from 1 to 50 Hz or 0.3-100 Hz; for comparisons the mean coherence over each of 6 or 7 narrower bands between 2 and 70 Hz was used. Whereas the literature supports the view that EEG coherence is usually substantial over many centimeters, the hypothesis here tested--and found to be well above stochastic expectations--is that significant structure occurs in the millimeter domain for EEG recorded subdurally or within the brain. In both the subdural surface samples and those from temporal lobe depth electrode arrays coherence declines with distance between electrodes of the pair, on the average quite severely in millimeters. This is nearly the same for all frequency bands. For middle bands like 8-13 and 13-20 Hz, mean coherence typically declines most steeply in the first 10 mm, from values indistinguishable from 1.0 at < 0.5 mm distance to 0.5 at 5-10 mm and to 0.25 in another 10-20 mm in the subdural surface data. Temporal lobe depth estimates decline about half as fast; coherence > or = 0.5 extends for 9-20 mm and > or = 0.25 for another 20-35mm. Low frequency bands (1-5, 5-8 Hz) usually fall slightly more slowly than high frequency bands (20-35, 35-50 Hz but the difference is small and variance large. The steepness of decline with distance in humans is significantly but only slightly smaller than that we reported earlier for the rabbit and rat, averaging less than one half. Local coherence, for individual pairs of loci, shows differentiation in the millimeter range, i.e., nearest neighbor pairs may be locally well above or below average and this is sustained over minutes. Local highs and lows tend to be similar for widely different frequency bands. Coherence varies quite independently of power, although they are sometimes correlated. Regional differentiation is statistically significant in average coherence among pairs of loci on temporal vs frontal cortex or lateral frontal vs. subfrontal strips in the same patient, but such differences are usually small.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Brain Mapping; Electroencephalography; Epilepsy; Hippocampus; Humans; Sleep; Subdural Space
PubMed: 7555907
DOI: 10.1016/0013-4694(95)93347-a