scholarly journals Acoustofluidic localization of sparse particles on a piezoelectric resonant sensor for nanogram-scale mass measurements

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jingui Qian ◽  
Habiba Begum ◽  
Joshua E.-Y. Lee
Keyword(s):  
Mass Measurement ◽  
Label Free ◽  
Mass Measurements ◽  
Mass Sensing ◽  
Microelectromechanical System ◽  
Mems Sensor ◽  
Low Concentrations ◽  
Particle Localization ◽  
Analysis Platform ◽  
First Time

AbstractThe ability to weigh microsubstances present in low concentrations is an important tool for environmental monitoring and chemical analysis. For instance, developing a rapid analysis platform that identifies the material type of microplastics in seawater would help evaluate the potential toxicity to marine organisms. In this study, we demonstrate the integration of two different techniques that bring together the functions of sparse particle localization and miniaturized mass sensing on a microelectromechanical system (MEMS) chip for enhanced detection and minimization of negative measurements. The droplet sample for analysis is loaded onto the MEMS chip containing a resonant mass sensor. Through the coupling of a surface acoustic wave (SAW) from a SAW transducer into the chip, the initially dispersed microparticles in the droplet are localized over the detection area of the MEMS sensor, which is only 200 µm wide. The accreted mass of the particles is then calibrated against the resulting shift in resonant frequency of the sensor. The SAW device and MEMS chip are detachable after use, allowing the reuse of the SAW device part of the setup instead of the disposal of both parts. Our platform maintains the strengths of noncontact and label-free dual-chip acoustofluidic devices, demonstrating for the first time an integrated microparticle manipulation and real-time mass measurement platform useful for the analysis of sparse microsubstances.

scholarly journals Modifications of the PAMONO-Sensor Help to Size and Quantify Low Number of Individual Biological and Non-Biological Nano-Particles

2021 ◽  
Vol 6 (1) ◽  
pp. 26
Author(s):  
Rahat Morad Talukder ◽  
Al Shahriar Hossain Rakib ◽  
Julija Skolnik ◽  
Zohair Usfoor ◽  
Katharina Kaufmann ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Nano Particles ◽  
Label Free ◽  
Specific Detection ◽  
Virus Like Particles ◽  
Low Concentrations ◽  
Challenging Tasks ◽  
Image Area

In a series of recently published works, we demonstrated that the plasmon-assisted microscopy of nano-objects (PAMONO) technique can be successfully employed for the sizing and quantification of single viruses, virus-like particles, microvesicles and charged non-biological particles. This approach enables label-free, but specific detection of biological nano-vesicles. Hence, the sensor, which was built up utilizing plasmon-assisted microscopy, possesses relative versatility and it can be used as a platform for cell-based assays. However, one of the challenging tasks for such a sensor was the ability to reach a homogeneous illumination of the whole surface of the gold sensor slide. Moreover, in order to enable the detection of even relatively low concentrations of nano-particles, the focused image area had to be expanded. Both tasks were solved via modifications of previously described PAMONO-sensor set ups. Taken together, our latest findings can help to develop a research and diagnostic platform based on the principles of the surface plasmon resonance (SPR)-assisted microscopy of nano-objects.

scholarly journals Nuclear mass measurements with radioactive ion beams

2019 ◽  
Vol 28 (04) ◽  
pp. 1930005 ◽  
Author(s):  
Michael A. Famiano
Keyword(s):  
Mass Measurement ◽  
Measurement Techniques ◽  
Nuclear Mass ◽  
Mass Measurements ◽  
Future Directions ◽  
Advantages And Disadvantages ◽  
Nuclear Masses ◽  
Under Construction ◽  
Very High ◽  
Practical Constraints

Nuclear masses are the most fundamental of all nuclear properties, yet they can provide a wealth of knowledge, including information on astrophysical sites, constraints on existing theory, and fundamental symmetries. In nearly all applications, it is necessary to measure nuclear masses with very high precision. As mass measurements push to more short-lived and more massive nuclei, the practical constraints on mass measurement techniques become more exacting. Various techniques used to measure nuclear masses, including their advantages and disadvantages are described. Descriptions of some of the world facilities at which the nuclear mass measurements are performed are given, and brief summaries of planned facilities are presented. Future directions are mentioned, and conclusions are presented which provide a possible outlook and emphasis on upcoming plans for nuclear mass measurements at existing facilities, those under construction, and those being planned.

scholarly journals Nanoscale chromatin imaging and analysis platform bridges 4D chromatin organization with molecular function

2021 ◽  
Vol 7 (1) ◽  
pp. eabe4310
Author(s):  
Yue Li ◽  
Adam Eshein ◽  
Ranya K.A. Virk ◽  
Aya Eid ◽  
Wenli Wu ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Super Resolution ◽  
Population Level ◽  
Average Diameter ◽  
Live Cells ◽  
Molecular Function ◽  
Label Free ◽  
Multiple Length Scales ◽  
Chromatin Packing ◽  
Analysis Platform

Extending across multiple length scales, dynamic chromatin structure is linked to transcription through the regulation of genome organization. However, no individual technique can fully elucidate this structure and its relation to molecular function at all length and time scales at both a single-cell level and a population level. Here, we present a multitechnique nanoscale chromatin imaging and analysis (nano-ChIA) platform that consolidates electron tomography of the primary chromatin fiber, optical super-resolution imaging of transcription processes, and label-free nano-sensing of chromatin packing and its dynamics in live cells. Using nano-ChIA, we observed that chromatin is localized into spatially separable packing domains, with an average diameter of around 200 nanometers, sub-megabase genomic size, and an internal fractal structure. The chromatin packing behavior of these domains exhibits a complex bidirectional relationship with active gene transcription. Furthermore, we found that properties of PDs are correlated among progenitor and progeny cells across cell division.

scholarly journals Measuring Thiols in Single Cultivar South African Red Wines Using 4,4-Dithiodipyridine (DTDP) Derivatization and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry

Foods ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 138 ◽  
Author(s):  
Mpho Mafata ◽  
Maria Stander ◽  
Baptiste Thomachot ◽  
Astrid Buica
Keyword(s):  
South African ◽  
Red Wine ◽  
High Sensitivity ◽  
White Wine ◽  
Wine Aroma ◽  
Low Concentrations ◽  
Varietal Thiols ◽  
Cultivar Differentiation ◽  
First Time ◽  
Ionization Methods

Wine varietal thiols are important contributors to wine aroma. The chemical nature of thiols makes them difficult to measure due to low concentrations, high sensitivity to oxidation, and low ionization. Methods for the measurement of thiols usually consist of multiple steps of sample preparation followed by instrumental measurement. Studies have collected large datasets of thiols in white wine but not in red wine, due to the lack of availability of suitable methods. In this study, for the first time, convergence chromatography was used to measure thiols in red wine at ultratrace levels with improved sensitivity compared to previous methods. Performance parameters (selectivity, linearity, limits of detection, precision, accuracy) were tested to demonstrate the suitability of the method for the proposed application. Red wine thiols were measured in South African Pinotage, Shiraz, and Cabernet Sauvignon wines (n = 16 each). Cultivar differentiation using the thiol profile was demonstrated.

scholarly journals Reducing the Hygroscopic Swelling in MEMS Sensor using Different Mold Materials

2020 ◽  
Vol 10 (1) ◽  
pp. 494
Author(s):  
Pinki Kumari ◽  
Kuldeep Singh ◽  
Anuj Singal
Keyword(s):  
Performance Analysis ◽  
Pressure Sensor ◽  
Ceramic Mold ◽  
Mems Devices ◽  
Challenging Problem ◽  
Microelectromechanical System ◽  
Saturation Concentration ◽  
Mems Sensor ◽  
Hygroscopic Swelling

Today, Hygroscopic swelling is one of the biggest challenging problem of Epoxy mold compound (EMC) in packaging with Microelectromechanical system (MEMS) devices. To overcome this hygroscopic swelling problem of EMC and guard the devices, MEMS devices are molded in this paper with different Mold Compound (MC) i.e. titanium and ceramic etc. during their interconnection with the board. Also, a comparatively performance analysis of this various mold compound with MEMS pressure sensor has been studied in this paper at 60% humidity, 140 mol/m<sup>3</sup> saturation concentration and 25 <sup>o</sup>C. It was observed that hygroscopic swelling does not take place in the titanium mold compound. But, titanium is very costly so we have to consider something cheaper material i.e. ceramic in this paper. The Hygroscopic swelling in Ceramic Mold Compound after 1 year is nearly 0.05mm which is very less than epoxy.

scholarly journals Nanoscale mapping of newly-synthesised phospholipid molecules in a biological cell using tip-enhanced Raman spectroscopy

2017 ◽  
Vol 53 (16) ◽  
pp. 2451-2454 ◽  
Author(s):  
Naresh Kumar ◽  
Marek M. Drozdz ◽  
Haibo Jiang ◽  
Daniela M. Santos ◽  
David J. Vaux
Keyword(s):  
Raman Spectroscopy ◽  
Biological Cell ◽  
Label Free ◽  
Tip Enhanced Raman Spectroscopy ◽  
First Time ◽  
Non Destructive

Non-destructive & label-free nanoscale mapping of newly-synthesised phospholipid molecules inside a biological cell is demonstrated using tip-enhanced Raman spectroscopy for the first time.

Tracking the Formation and Degradation of Fatty-Acid-Accumulated Mitochondria Using Label-Free Chemical Imaging

2020 ◽  
Author(s):  
Chi Zhang ◽  
Stephen Boppart
Keyword(s):  
Fatty Acid ◽  
Structural Features ◽  
Chemical Imaging ◽  
Live Cells ◽  
Label Free ◽  
Dynamic Changes ◽  
Regulatory Processes ◽  
Transport Chain ◽  
Anti Stokes ◽  
First Time

Abstract The mitochondrion is one of the key organelles for maintaining cellular homeostasis. External environmental stimuli and internal regulatory processes alter the metabolism and functions of mitochondria. To understand these activities of mitochondria, it is critical to probe the key metabolic molecules inside these organelles. In this study, we used label-free chemical imaging modalities including coherent anti-Stokes Raman scattering and multiphoton-excited autofluorescence to study the mitochondrial activities in living cancer cells. We found that hypothermia exposure tends to induce fatty-acid (FA) accumulation in some mitochondria of MIAPaCa-2 cells. Autofluorescence images show that the FA-accumulated mitochondria also have abnormal NADH and FAD metabolism, likely induced by the dysfunction of the electron transport chain. We also found that when the cells were re-warmed to physiological temperature after a period of hypothermia, the FA-accumulated mitochondria changed their structural features, likely caused by the mitophagy process. To the best of our knowledge, this is the first time that FA accumulation in mitochondria was observed in live cells. Our research also demonstrates that multimodal label-free chemical imaging is an attractive tool to discover abnormal functions of mitochondria at the single-organelle level and can be used to quantify the dynamic changes of this organelle under perturbative conditions.

scholarly journals Colocalized Sensing and Intelligent Computing in Micro-Sensors

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6346
Author(s):  
Mohammad H Hasan ◽  
Ali Al-Ramini ◽  
Eihab Abdel-Rahman ◽  
Roozbeh Jafari ◽  
Fadi Alsaleem
Keyword(s):  
Electrical Signal ◽  
Virtual Node ◽  
Noise Resistance ◽  
Microelectromechanical System ◽  
Analog To Digital ◽  
Intelligent Computing ◽  
Electrostatically Actuated ◽  
Digital To Analog Converters ◽  
Mems Sensor ◽  
Mems Device

This work presents an approach to delay-based reservoir computing (RC) at the sensor level without input modulation. It employs a time-multiplexed bias to maintain transience while utilizing either an electrical signal or an environmental signal (such as acceleration) as an unmodulated input signal. The proposed approach enables RC carried out by sufficiently nonlinear sensory elements, as we demonstrate using a single electrostatically actuated microelectromechanical system (MEMS) device. The MEMS sensor can perform colocalized sensing and computing with fewer electronics than traditional RC elements at the RC input (such as analog-to-digital and digital-to-analog converters). The performance of the MEMS RC is evaluated experimentally using a simple classification task, in which the MEMS device differentiates between the profiles of two signal waveforms. The signal waveforms are chosen to be either electrical waveforms or acceleration waveforms. The classification accuracy of the presented MEMS RC scheme is found to be over 99%. Furthermore, the scheme is found to enable flexible virtual node probing rates, allowing for up to 4× slower probing rates, which relaxes the requirements on the system for reservoir signal sampling. Finally, our experiments show a noise-resistance capability for our MEMS RC scheme.

Mode of Action of the Hypertrehalosaemic Peptides from the American Cockroach

1985 ◽  
Vol 40 (9-10) ◽  
pp. 670-676 ◽  
Author(s):  
Gerd Gäde
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mode Of Action ◽  
Glycogen Phosphorylase ◽  
Fat Body ◽  
American Cockroach ◽  
Dependent Manner ◽  
Low Concentrations ◽  
First Time ◽  
Dose Dependent

Abstract Although crude extracts of cockroach (Periplaneta amencana) corpora cardiaca have been shown previously to affect the activity of adenylate cyclase and phosphorylase, we demonstrate in the present study for the first time that low concentrations (0.5 to 5 pmol) of the synthetic myoactive peptides. M I and M II, also affect these systems; these myoactive peptides are identical to the hypertrehalosaemic hormones I and II, and cause an increase in the concentration of the second messenger cyclic AMP in the fat body.In addition, both octapeptides activate fat body glycogen phosphorylase and promote breakdown of fat body glycogen. Both peptides increase the levels to haemolymph carbohydrate in a dose-dependent manner.

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