Survey, Analysis and Comparison of Radar Technologies for Embedded Vital Sign Monitoring.

Contactless vital sign monitoring systems are becoming increasing in demand for a wide range of biomedical applications. Millimetre-wave radars and embedded signal processing are the most promising technologies to enable non-contact vital signs monitoring. In this work, the challenging task of heart rate estimation from radar data has been addressed. Three different radar systems from Infineon, Texas Instruments and Acconeer, and four algorithms, FFT, Median-FFT, STFT and Median-STFT, have been analysed and compared against a reference sensor. Accuracy, as well as power figures, have been reported for all the radar systems. A dataset of 16 volunteers has been acquired, yielding a total of 400 minutes of radar-recorded vital sign data. The accuracy of the four investigated algorithms has been reported on average and per subject for every radar. The algorithm exploiting the Short Time Fourier Transform (STFT) is able to achieve an error as low as 0.02% on a single person and of 6.4% in heart rate estimation on average across the whole dataset.

Direct Mechanocatalysis: Palladium as Milling Media and Catalyst in the Mechanochemical Suzuki Polymerization.

The milling ball is the catalyst. We introduce a palladium-catalyzed reaction inside a ball mill, which makes catalyst powders, ligands, and solvents obsolete. We present a facile and highly sustainable synthesis concept for palladium-catalyzed C-C coupling reactions, exemplarily showcased for the Suzuki polymerization of 4-bromo or 4-iodophenylboronic acid giving poly(para-phenylene). Surprisingly, we observe one of the highest degrees of polymerization (199) reported so far.

On the Bending and Stretching of Liquid Metal Receive Coils for Magnetic Resonance Imaging.

The eGaIn coil on neoprene demonstrated in this paper presents a stretchable radio frequency receive coil for magnetic resonance imaging (MRI). The coil with dimensions [Formula: see text] is tuned to resonate at 128 MHz for 3 T MRI. We investigate the effect of stretching (up to 40% strain) and bending (50 mm radius of curvature) of the coil on the coil's resistance and resonance frequency. Measurements and simulations show a decrease in resonance frequency of 2.5 MHz per 10% strain. The higher resistivity of liquid metal compared to copper reduces the SNR of MRI scans by 34%; therefore, a tradeoff between flexibility and performance remains. Nevertheless, we have successfully performed MRI scans with the liquid metal coil.

Automatic Resonance Frequency Retuning of Stretchable Liquid Metal Receive Coil for Magnetic Resonance Imaging.

Stretchable magnetic resonance (MR) receive coils show shifts in their resonance frequency when stretched. An in-field receiver measures the frequency response of a stretchable coil. The receiver and coil are designed to operate at 128 MHz for a 3T MR scanner. Based on the measured frequency response, we are able to detect the changes of the resonance frequency of the coil. We show a proportional-integral-derivative controller that tracks the changes in resonance frequency and retunes the stretchable coil. The settling time of the control loop is less than 3.8ms. The retuning system reduces the loss in signal-to-noise ratio of phantom images from 1.6 dB to 0.3 dB, when the coil is stretched by 40% and the coil is retuned to 128 MHz.

Metal-Halide Perovskites for Gate Dielectrics in Field-Effect Transistors and Photodetectors Enabled by PMMA Lift-Off Process.

Metal-halide perovskites have emerged as promising materials for optoelectronics applications, such as photovoltaics, light-emitting diodes, and photodetectors due to their excellent photoconversion efficiencies. However, their instability in aqueous solutions and most organic solvents has complicated their micropatterning procedures, which are needed for dense device integration, for example, in displays or cameras. In this work, a lift-off process based on poly(methyl methacrylate) and deep ultraviolet lithography on flexible plastic foils is presented. This technique comprises simultaneous patterning of the metal-halide perovskite with a top electrode, which results in microscale vertical device architectures with high spatial resolution and alignment properties. Hence, thin-film transistors (TFTs) with methyl-ammonium lead iodide (MAPbI3 ) gate dielectrics are demonstrated for the first time. The giant dielectric constant of MAPbI3 (>1000) leads to excellent low-voltage TFT switching capabilities with subthreshold swings ≈80 mV decade-1 over ≈5 orders of drain current magnitude. Furthermore, vertically stacked low-power Au-MAPbI3 -Au photodetectors with close-to-ideal linear response (R2 = 0.9997) are created. The mechanical stability down to a tensile radius of 6 mm is demonstrated for the TFTs and photodetectors, simultaneously realized on the same flexible plastic substrate. These results open the way for flexible low-power integrated (opto-)electronic systems based on metal-halide perovskites.

Closed-loop laser polishing using in-process surface finish metrology.

This paper lays out the trail onto a closed-loop polishing process of optical elements enabling the application of the optimum polishing time needed. To that aim, an in-process testing method for monitoring an inclusive microsurface quality (e.g., comprising surface roughness and scratch-and-dig) within the polishing spot is analyzed, and its applicability to closed-loop polishing for classical loose-abrasive full-aperture polishing as well as for computer-controlled laser polishing is experimentally tested and verified. This enables the determination of the optimum local dwell time resulting in stable and cost-optimized polishing.

Adsorbed Eutectic GaIn Structures on a Neoprene Foam for Stretchable MRI Coils.

Stretchable conductors based on eutectic gallium-indium (eGaIn) alloy are patterned on a polychloroprene substrate (neoprene foam) using stencil printing. By tuning the amount of eGaIn on the neoprene substrate, different strain-sensitivity of electrical resistance is achieved. Conductors with a layer of eGaIn, which adsorbs to the walls of 60-100 µm wide neoprene cells, change their electrical resistance for 5% at 100% strain. When the amount of eGaIn is increased, the cells are filled with eGaIn and the strain-sensitivity of the electrical resistance rises to 300% at 100% strain. The developed conductors are patterned as stretchable on-body coils for receiving magnetic signals in a clinical magnetic resonance imaging setup. First images with a stretchable coil are acquired on an orange and compared to the images that are recorded using a rigid copper coil of the same size.

Buckled Thin-Film Transistors and Circuits on Soft Elastomers for Stretchable Electronics.

Although recent progress in the field of flexible electronics has allowed the realization of biocompatible and conformable electronics, systematic approaches which combine high bendability (<3 mm bending radius), high stretchability (>3-4%), and low complexity in the fabrication process are still missing. Here, we show a technique to induce randomly oriented and customized wrinkles on the surface of a biocompatible elastomeric substrate, where Thin-Film Transistors (TFTs) and circuits (inverter and logic NAND gates) based on amorphous-IGZO are fabricated. By tuning the wavelength and the amplitude of the wrinkles, the devices are fully operational while bent to 13 µm bending radii as well as while stretched up to 5%, keeping unchanged electrical properties. Moreover, a flexible rectifier is also realized, showing no degradation in the performances while flat or wrapped on an artificial human wrist. As proof of concept, transparent TFTs are also fabricated, presenting comparable electrical performances to the nontransparent ones. The extension of the buckling approach from our TFTs to circuits demonstrates the scalability of the process, prospecting applications in wireless stretchable electronics to be worn or implanted.

Transfer of skills and comparison of performance between king vision® video laryngoscope and macintosh blade following an AHA airway management course.

BACKGROUND: To potentially optimize intubation skill teaching in an American Heart Association® Airway Management Course® for novices, we investigated the transfer of skills from video laryngoscopy to direct laryngoscopy and vice versa using King Vision® and Macintosh blade laryngoscopes respectively. METHODS: Ninety volunteers (medical students, residents and staff physicians) without prior intubation experience were randomized into three groups to receive intubation training with either King Vision® or Macintosh blade or both. Afterwards they attempted intubation on two human cadavers with both tools. The primary outcome was skill transfer from video laryngoscopy to direct laryngoscopy assessed by first attempt success rates within 60 s. Secondary outcomes were skill transfer in the opposite direction, the efficacy of teaching both tools, and the success rates and esophageal intubation rates of Macintosh blade versus King Vision®. RESULTS: Performance with the Macintosh blade was identical following training with either Macintosh blade or King Vision® (unadjusted odds ratio [OR] 1.09, 95% confidence interval [95% CI] 0.5-2.6). Performance with the King Vision® was significantly better in the group that was trained on it (OR 2.7, 95% CI 1.2-5.9). Success rate within 60 s with Macintosh blade was 48% compared to 52% with King Vision® (OR 0.85, 95% CI 0.4-2.0). Rate of esophageal intubations with Macintosh blade was significantly higher (17% versus 4%, OR 5.0, 95% CI 1.1-23). CONCLUSIONS: We found better skill transfer from King Vision® to Macintosh blade than vice versa and fewer esophageal intubations with video laryngoscopy. For global skill improvement in an airway management course for novices, teaching only video laryngoscopy may be sufficient. However, success rates were low for both devices.

A Fully Integrated Dual-Channel On-Coil CMOS Receiver for Array Coils in 1.5-10.5 T MRI.

Magnetic resonance imaging (MRI) is among the most important medical imaging modalities. Coil arrays and receivers with high channel counts (16 and more) have to be deployed to obtain the image quality and acquisition speed required by modern clinical protocols. In this paper, we report the theoretical analysis, the system-level design, and the circuit implementation of the first receiver IC (RXIC) for clinical MRI fully integrated in a modern CMOS technology. The dual-channel RXIC sits directly on the sensor coil, thus eliminating any RF cable otherwise required to transport the information out of the magnetic field. The first stage LNA was implemented using a noise-canceling architecture providing a highly reflective input used to decouple the individual channels of the array. Digitization is performed directly on-chip at base-band by means of a delta-sigma modulator, allowing the subsequent optical transmission of data. The presented receiver, implemented in a CMOS technology, is compatible with MRI scanners up to . It reaches sub- noise figure for MRI units and features a dynamic range up to at a power consumption below per channel, with an area occupation of . Mounted on a small-sized printed circuit board (PCB), the receiver IC has been employed in a commercial MRI scanner to acquire in-vivo images matching the quality of traditional systems, demonstrating the first step toward multichannel wearable MRI array coils.

The Bitter Chemodiversity of Hops (Humulus lupulus L.).

To map the chemodiversity of key bitter compounds in hops, a total of 75 different samples collected from the global hop market were analyzed for 117 key bitter tastants by means of a multiparametric HPLC-MS/MSMRM method. Among the compounds detected, 2'',3''-epoxyxanthohumol was detected for the first time in hops and iso¬xantho¬humol M was identified as a marker compound for varieties grown in Germany. Hop ageing experiments in the absence and presence of air oxygen, respectively, were conducted to address the stability of hop-derived compounds during long-term storage.

A wearable bluetooth LE sensor for patient monitoring during MRI scans.

This paper presents a working prototype of a wearable patient monitoring device capable of recording the heart rate, blood oxygen saturation, surface temperature and humidity during an magnetic resonance imaging (MRI) experiment. The measured values are transmitted via Bluetooth low energy (LE) and displayed in real time on a smartphone on the outside of the MRI room. During 7 MRI image acquisitions of at least 1 min and a total duration of 25 min no Bluetooth data packets were lost. The raw measurements of the light intensity for the photoplethysmogram based heart rate measurement shows an increased noise floor by 50LSB (least significant bit) during the MRI operation, whereas the temperature and humidity readings are unaffected. The device itself creates a magnetic resonance (MR) signal loss with a radius of 14 mm around the device surface and shows no significant increase in image noise of an acquired MRI image due to its radio frequency activity. This enables continuous and unobtrusive patient monitoring during MRI scans.

Design and simulation of a 800 Mbit/s data link for magnetic resonance imaging wearables.

This paper presents the optimization of electronic circuitry for operation in the harsh electro magnetic (EM) environment during a magnetic resonance imaging (MRI) scan. As demonstrator, a device small enough to be worn during the scan is optimized. Based on finite element method (FEM) simulations, the induced current densities due to magnetic field changes of 200 T s(-1) were reduced from 1 × 10(10) A m(-2) by one order of magnitude, predicting error-free operation of the 1.8V logic employed. The simulations were validated using a bit error rate test, which showed no bit errors during a MRI scan sequence. Therefore, neither the logic, nor the utilized 800 Mbit s(-1) low voltage differential swing (LVDS) data link of the optimized wearable device were significantly influenced by the EM interference. Next, the influence of ferro-magnetic components on the static magnetic field and consequently the image quality was simulated showing a MRI image loss with approximately 2 cm radius around a commercial integrated circuit of 1×1 cm(2). This was successively validated by a conventional MRI scan.

Effects of inbreeding on mouthpart deformities of Chironomus riparius under sublethal pesticide exposure.

Mouthpart deformities in chironomids have been reported to indicate adverse effects of environmental pollutants. The authors assessed rates of mouthpart deformities in tributyltin-exposed, inbred, and outcrossed Chironomus riparius larvae over multiple generations. The authors found that the occurrence of mouthpart deformities was significantly correlated with inbreeding, whereas no correlation was found with the tributyltin exposure. The present study confirms the strong effect of high inbreeding rates on developmental deformities in chironomids.

Impact of genetic diversity and inbreeding on the life-history of Chironomus midges over consecutive generations.

We report results of a multigenerational experiment with Chironomus riparius. Two strains with a high and a low level of genetic variability were exposed to a low, environmentally relevant TBT concentration of 80 µg Sn kg(-1)sedimentdw nominally (time weighted mean, based on measured concentrations: 4.5 µg Sn kg(-1)sedimentdw), and various life history traits as well as genetic diversity were monitored for eleven consecutive generations. While TBT effects are hardly visible in the outbred and genetically diverse strain, the inbred and genetically impoverished strain shows a clearly reduced population growth rate compared to the control. Moreover, the impoverished strain shows an increase in fitness over time. Analyses of variation at five microsatellite loci revealed that the level of genetic variation is strongly reduced in the inbred compared to the outbred strain. Moreover, genetic diversity increases over time in the inbred strain. This finding explains the observed increase in fitness in both inbred lineages (control and TBT exposed). The results document that inbreeding and the level of genetic diversity might be of crucial importance in populations under pollution stress. Furthermore, ecotoxicological bioassays have to consider genetic diversity if results between laboratories should be comparable. Our data provides evidence that genetic diversity strongly contributes to the survival of a population exposed to chemical pollution.

Sediment contact test with Potamopyrgus antipodarum in effect-directed analyses-challenges and opportunities.

BACKGROUND AND SCOPE: Effect-directed analysis is increasingly used for the identification of key toxicants in environmental samples and there is a growing need for in vivo biotests as diagnostic tools. Within this study, we performed an in vivo sediment contact test, applicable on both native field samples and their extracts or fractions, in order to be able to compare the results from both field and laboratory studies. MATERIAL AND METHODS: A sediment contact test with the prosobranch snail, Potamopyrgus antipodarum, was carried out on extracts and fractions of field sediments from three European river basins. The results were compared with previous results of the native field samples. RESULTS: In contrast to the native sediments, the extracts of the samples led to an overall decrease in reproduction. Even the chosen reference sites had an adverse effect on the snails' reproduction. It appeared that a higher bioavailability in the organic extracts, together with a changing composition of compounds could have lead to this change in effects. The fractionation of the extracts partly led to a more differentiated picture, but the resolution was not high enough to see any distinct effects on the snails' reproduction. DISCUSSION AND CONCLUSION: Our results highlight the importance of the use of in vivo biotests and point out the relevance of bioavailability in native sediments. For further fractionation studies, a more realistic extraction procedure, together with a higher resolution fractionation, would be appropriate in order to separate individual bioavailable compounds more efficient.

Clopidogrel improves endothelial function and NO bioavailability by sensitizing adenylyl cyclase in rats with congestive heart failure.

Clopidogrel treatment in patients with coronary artery disease not only inhibits platelet activation but also improves endothelial function and nitric oxide (NO) bioavailability. Congestive heart failure (CHF) is associated with endothelial dysfunction and increased platelet activation. In rats with CHF following myocardial infarction (MI), we investigated whether treatment with clopidogrel modifies endothelial function. Eight weeks after coronary artery ligation, rats with CHF were randomized to placebo or the P2Y(12) receptor antagonist clopidogrel (5 mg/kg twice daily, given by gavage) for another 2 weeks. Afterwards, endothelial function was assessed in isolated aortic rings in organ bath experiments. Acetylcholine-induced, endothelium-dependent, nitric oxide-mediated vasorelaxation was significantly attenuated in CHF rats compared to sham-operated animals, and was significantly improved by treatment with clopidogrel. Adenosine-induced vasorelaxation via adenylyl cyclase stimulation was attenuated in CHF and significantly improved by clopidogrel. Increased vasoconstriction to phenylephrine was observed in CHF, particularly evident under cyclooxygenase inhibition, but prevented by clopidogrel treatment. Vasoconstriction by the P2Y(12) activator 2MeS-ADP was increased in CHF. Clopidogrel-treated CHF animals displayed enhanced phosphorylation of AKT and eNOS. In conclusion, clopidogrel improved endothelial function and NO bioavailability in heart failure. During CHF, sensitivity to P2Y(12) signaling was increased leading to impaired adenylyl cyclase-mediated signaling. Chronic P2Y(12)-blockade with clopidogrel improved adenylyl cyclase-mediated signaling including increased AKT- and eNOS-phosphorylation contributing to improved NO-mediated vasorelaxation.

Chemotaxis to the quorum-sensing signal AI-2 requires the Tsr chemoreceptor and the periplasmic LsrB AI-2-binding protein.

AI-2 is an autoinducer made by many bacteria. LsrB binds AI-2 in the periplasm, and Tsr is the l-serine chemoreceptor. We show that AI-2 strongly attracts Escherichia coli. Both LsrB and Tsr are necessary for sensing AI-2, but AI-2 uptake is not, suggesting that LsrB and Tsr interact directly in the periplasm.

In situ cage experiments with Potamopyrgus antipodarum--a novel tool for real life exposure assessment in freshwater ecosystems.

In situ experiments are an important tool within ecotoxicological research but there is a lack of suitable methodologies especially for freshwater invertebrate species. Within this study, a novel in situ methodology with Potamopyrgus antipodarum was developed. Snails were inserted into cages, made of Plexiglas measuring 7 × 9 × 7 cm(3) and fixed with stainless steel pins into the sediment at the relevant sampling sites. During the experiment physico-chemical properties of the water and concentrations of metals, PAHs and PCBs were measured in the sediment. The growth and survival of the snails was not affected, but the reproduction increased significantly at one of the most polluted sites. The increase in reproduction was neither correlated with physico-chemical parameters, nor with the concentrations of the different compounds, but maybe related to certain groups of estrogenic compounds. The study demonstrates the excellent applicability of this novel in situ test.

Increased cytochrome P4502E1 expression and altered hydroxyeicosatetraenoic acid formation mediate diabetic vascular dysfunction: rescue by guanylyl-cyclase activation.

OBJECTIVE: We investigated the mechanisms underlying vascular endothelial and contractile dysfunction in diabetes as well as the effect of HMR1766, a novel nitric oxide (NO)-independent activator of soluble guanylyl cyclase (sGC). RESEARCH DESIGN AND METHODS: Two weeks after induction of diabetes by streptozotocin, Wistar rats received either placebo or HMR1766 (10 mg/kg twice daily) for another 2 weeks; thereafter, vascular function was assessed. RESULTS: Endothelial function and contractile responses were significantly impaired, while vascular superoxide formation was increased in the aortae from diabetic versus healthy control rats. Using RNA microarrays, cytochrome P4502E1 (CYP2E1) was identified as the highest upregulated gene in diabetic aorta. CYP2E1 protein was significantly increased (16-fold) by diabetes, leading to a reduction in levels of the potent vasoconstrictor 20-hydroxy-eicosatetraenoic acid (20-HETE). Induction of CYP2E1 expression in healthy rats using isoniazide mimicked the diabetic noncontractile vascular response while preincubation of aortae from STZ-diabetic rats in vitro with 20-HETE rescued contractile function. Chronic treatment with the sGC activator HMR1766 improved NO sensitivity and endothelial function, reduced CYP2E1 expression and superoxide formation, enhanced 20-HETE levels, and reversed the contractile deficit observed in the diabetic rats that received placebo. CONCLUSIONS: Upregulation of CYP2E1 is essentially involved in diabetic vascular dysfunction. Chronic treatment with the sGC activator HMR1766 reduced oxidative stress, decreased CYP2E1 levels, and normalized vasomotor function in diabetic rats.