Search

Background: While low back pain (LBP) is the leading cause of disability worldwide, its clinical objective assessment is currently limited. Part of this syndrome arises from the abnormal sensorimotor control of back muscles, involving increased muscle fatigability (i.e., assessed with the Biering–Sorensen test) and abnormal muscle activation patterns (i.e., the flexion–extension test). Surface electromyography (sEMG) provides objective measures of muscle fatigue development (median frequency drop, MDF) and activation patterns (RMS amplitude change). This study therefore assessed the sensitivity and validity of a novel and flexible sEMG system (NSS) based on PEVA electrodes and potentially embeddable in textiles, as a tool for objective clinical LBP assessment. Methods: Twelve participants wearing NSS and a commercial laboratory sEMG system (CSS) performed two clinical tests used in LBP assessment (Biering–Sorensen and flexion–extension). Erector spinae muscle activity was recorded at T12-L1 and L4-L5. Results: NSS showed sensitivity to sEMG changes associated with fatigue development and muscle activations during flexion–extension movements (p < 0.05) that were similar to CSS (p > 0.05). Raw signals showed moderate cross-correlations (MDF: 0.60–0.68; RMS: 0.53–0.62). Adding conductive gel to the PEVA electrodes did not influence sEMG signal interpretation (p > 0.05). Conclusions: This novel sEMG system is promising for assessing electrophysiological indicators of LBP during clinical tests. [ABSTRACT FROM AUTHOR]

Vibronic spectra of lutetium oxide (LuO) seeded in supersonic molecule beams are investigated with mass-analyzed threshold ionization (MATI) spectroscopy and second-order multiconfigurational quasi-degenerate perturbation (MCQDPT2) theory. Six states of LuO and four states of LuO+ are located by the MCQDPT2 calculations, and an a3Π(LuO+) ← C2Σ+ (LuΟ) transition is observed by the MATI measurement. The vibronic spectra show abnormal vibrational intervals for both the neural and cation excited states, and the abnormality is attributed to vibrational perturbations induced by interactions with neighboring states. [ABSTRACT FROM AUTHOR]

Smart sensors embedded into wearables and capable of monitoring vital signs have become an important research topic and the technology of interest for numerous commercial ventures. Monitoring respiratory rate is challenging due to the complexity and uniqueness of the musculoskeletal movements involved in the breathing process. At the same time, it is a critical factor in assessing patient health. Multi-material fibers exhibit the potential to be inter-woven into a textile and used in a wearable garment to measure respiration rate. This study compares the effectiveness of two types of flexible multi-material fibers, namely the polyethylene-co-vinyl acetate (PEVA) fiber and the polydimethylsiloxane elastomer (PDMS) fiber, in detecting respiratory rate using two principles, the Fiber Strain method and the Bioimpedance method. The study involved five experiments where ten volunteers’ respiratory rate was measured under different conditions: deep breathing, holding breath, deep breathing with exercise, relaxed breathing, and deep breathing with the fibers mounted onto a wearable. Overall, the PDMS fiber outperformed the PEVA fiber in detecting the breathing rate by providing better accuracy, greater signal to noise ratio (SNR), and more versatility. Although some studies have previously described the successful use of multi-material fibers in monitoring vital signs, e.g., electromyography, no reported research could be identified that examined the use of these multi-material fibers for respiratory rate measurement. [ABSTRACT FROM AUTHOR]

A flexible sinusoidal-shaped antenna sensor is introduced in this work, which is a modified half-wave dipole that can be used for strain sensing applications. The presented antenna is an improved extension of the previously introduced antenna sensor for respiration monitoring. The electrical and radiative characteristics of the sinusoidal antenna and the effects of the geometrical factors are studied. An approach is provided for designing the antenna, and equations are introduced to estimate the geometrical parameters based on desired electrical specifications. It is shown that the antenna sensor can be designed to have up to 5.5 times more sensitivity compared to the last generation of the antenna sensor previously introduced for respiration monitoring. The conductive polymer material used to fabricate the new antenna makes it more flexible and durable compared to the previous generation of antenna sensors made of glass-based material. Finally, a reference antenna made of copper and an antenna sensor made of the conductive polymer are fabricated, and their electrical characteristics are analyzed in free space and over the body. [ABSTRACT FROM AUTHOR]

A new wearable smart T-Shirt design for breathing rate monitoring using Received Signal Strength Indicator (RSSI) is proposed. This new design features three principal functions: a wireless sensor to monitor the breathing rate, a wireless power transfer system, and a user interface to analyze the collected breathing data. First, the breathing curves obtained from a breathing sensor incorporated in a smart T-shirt were presented. Then, the data analysis methods are applied for extracting the important parameters for medical diagnosis. To observe multiple breathing profiles, additional results are presented for different tests on male and female subjects using another design of a smart T-shirt system consisting of an array of six sensors. [ABSTRACT FROM AUTHOR]

The òE" ← X2A'2 spectrum of NO3 radical from 7550 cm-1 to 9750 cm-1 has been recorded and analyzed. Our spectrum differs from previously recorded spectra of this transition due to jet-cooling, which narrows the rotational contours and eliminates spectral interference from hot bands. Assignments of numerous vibronic features can be made based on both band contour and position including the previously unassigned 3¹0 band and several associated combination bands. We have analyzed our spectrum first with an independent anharmonic oscillator model and then by a quadratic Jahn-Teller vibronic coupling model. The fit achieved with the quadratic Jahn- Teller model is excellent, but the potential energy surface obtained with the fitted parameters is in only qualitative agreement with one obtained from ab initio calculations. [ABSTRACT FROM AUTHOR]

Group 3 metal-aniline complexes, M(aniline) (M = Sc, Y, and La), are produced in a pulsed laser-vaporization molecular beam source, identified by photoionization time-of-flight mass spectrometry, and investigated by pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy and quantum chemical calculations. Adiabatic ionization energies and several low-frequency vibrational modes are measured for the first time from the ZEKE spectra. Metal binding sites and electronic states are determined by combining the ZEKE measurements with the theoretical calculations. The ionization energies of the complexes decrease down the metal group. An out-of-plane ring deformation mode coupled with an asymmetric metal-carbon stretch is considerably anharmonic. Although aniline has various possible sites for metal coordination, the preferred site is the phenyl ring. The metal binding with the phenyl ring yields syn and anti conformers with the metal atom and amino hydrogens on the same and opposite sides of the ring, respectively. The anti conformer is determined to be the spectral carrier. The ground electronic state of the anti conformer of each neutral complex is a doublet with a metal-based electron configuration of nd2(n + 1)s1, and the ground electronic state of each ion is a singlet with a metal-based electron configuration of nd2. The formation of the neutral complexes requires the nd2(n + 1)s1 ← nd1(n + 1)s2 electron excitation in the metal atoms. [ABSTRACT FROM AUTHOR]

In this paper, we present the design and the validation of a new smart textile developed for real time monitoring of human breath. The smart textile is a wearable stretching T-shirt featuring an array of six contactless and non-invasive sensors placed on human’s thoraco-abdominal walls. The wireless sensors communicate quasi-simultaneously the data to a detection base station through Bluetooth protocol. The sensor is composed of a spiral shaped multi-material fiber antenna with a central frequency at 2.4 GHz connected to a compact Bluetooth transmitter. The sensors are integrated on the stretchable T-shirt without compromising the user’s comfort. The sensing mechanism of the system is based on the shift of the central frequency of the spiral fiber antenna induced by the deformation of the thorax and the abdomen during the breath. As a consequence, the breathing pattern is obtained through the received signal strength indicator recorded by a portable detection base station. With the sensor array integrated into a T-shirt, we demonstrate the feasibility assessment for monitoring breathing of seven volunteers in seating and standing positions. Using an array of sensors strategically placed on the T-shirt provides a more reliable approach to detect interpretable breathing patterns by sensing the movement of the abdomen and the thorax at the same time. Using a commercial spirometer as a standard reference, we assessed the validity of breathing parameters (ie; expiration and inspiration times, breathing period, and breathing rate) measured with the T-shirt. Based on Bland-Altman statistical analysis, a good agreement between textile-based sensors and the standard reference was obtained. We were able to show that the smart T-shirt could detect breathing patterns and pauses in breathing, which could be very useful to monitor sleep apnea and clinical monitoring of patients. [ABSTRACT FROM AUTHOR]

In this work, we have extended our previous high resolution study of the vacuum ultraviolet emission spectrum of the D2 molecule [M. Roudjane, et al. J. Chem. Phys. 125, 214305 (2006)] up to 124.2 nm in order to investigate the B′ 1Σu+→X 1Σg+ band system. The analysis of the spectrum has been carried out by means of a complex spectrum visual identification code IDEN [V. I. Azarov, Phys. Scr. 44, 528 (1991); 48, 656, (1993)] and supported by theoretical calculations using ab initio data [L. Wolniewicz, J. Chem. Phys. 103, 1792 (1995); 99, 1851 (1993); G. Staszewska and L. Wolniewicz, J. Mol. Spectrosc. 212, 208 (2002); L. Wolniewicz and G. Staszewska, 220, 45 (2003)] which provided level energies and transition probabilities. More than 1480 new emission lines have been observed and 109 bands belonging to the B′ 1Σu+→X 1Σg+ system have been identified between 84.1 and 121.6 nm. Except for the υ′-0 bands that were reported in absorption [I. Dabrowski and G. Herzberg, Can. J. Phys. 52, 1110 (1974)], all the υ′-υ″ bands are reported here for the first time. The analysis led to the determination of 111 rovibronic energy levels in the B′ 1Σu+ state, of which 31 with higher rotational numbers J are new. Observed perturbations are accounted for through a set of coupled equations involving the four excited electronic states B 1Σu+, B′ 1Σu+, C 1Πu, and D 1Πu and including nonadiabatic couplings. The solution of this set provides the percent contribution of these four states to each of the observed rovibronic level. [ABSTRACT FROM AUTHOR]

The emission spectrum of the D2 molecule has been studied at high resolution in the vacuum ultraviolet region 78.5–102.7 nm. A detailed analysis of the two D 1Πu→X 1Σg+ and D′ 1Πu-→X 1Σg+ electronic band systems is reported. New and improved values of the level energies of the two upper states have been derived with the help of the program IDEN [V. I. Azarov, Phys. Scr. 44, 528 (1991); 48, 656 (1993)], originally developed for atomic spectral analysis. A detailed comparison is made between the observed energy levels and solutions of coupled equations using the newest ab initio potentials by Wolniewicz and co-workers [J. Chem. Phys. 103, 1792 (1995); 99, 1851 (1993); J. Mol. Spectros. 212, 208 (2002); 220, 45 (2003)] taking into account the nonadiabatic coupling terms for the D 1Πu state with the lowest electronic states B 1Σu+, C 1Πu, and B′ 1Σu+. A satisfactory agreement has been found for most of the level energies belonging to the D and D′ states. The remaining differences between observation and theory are probably due to nonadiabatic couplings with other higher electronic states which were neglected in the calculations. [ABSTRACT FROM AUTHOR]

A new non-invasive and flexible sensor was fabricated to monitor the muscular activity of upper body muscles. It consists of a dry electrode made of multimaterial metal-polymer-glass hollow-core fiber electrodes connected to a custom made signal acquisition platform. This fiber electrode only adds a negligible contribution to the recording system’s internal noise ($7.626~\mu \text{V}$ peak-to-peak and $1.234~\mu \text{V}$ RMS; recording system noise: $6.901~\mu \text{V}$ peak-to-peak and $1.205~\mu \text{V}$ RMS). Surface electromyograms (sEMGs) of the biceps bracci and trapezius muscles were recorded during maximal voluntary contractions using the new sensor and compared to that obtained with medical grade commercial sensors. Frequency content and time domain analysis show that the new flexible sensor performs similarly to commercial devices in terms of sEMG signal amplitude discrimination and frequency shift evaluation during the development of muscle fatigue. The advantage of the new sensor is the high flexibility of the fibers allowing their easy integration into stretchable garments without compromising the user’s comfort. This will lead to the development of a new generation of smart textile with large application for telemedicine and assistive devices. [ABSTRACT FROM AUTHOR]

In this paper, we present a new mobile wireless communication platform for real-time monitoring of an individual’s breathing rate. The platform takes the form of a wearable stretching T-shirt featuring a sensor and a detection base station. The sensor is formed by a spiral-shaped antenna made from a multi-material fiber connected to a compact transmitter. Based on the resonance frequency of the antenna at approximately 2.4 GHz, the breathing sensor relies on its Bluetooth transmitter. The contactless and non-invasive sensor is designed without compromising the user’s comfort. The sensing mechanism of the system is based on the detection of the signal amplitude transmitted wirelessly by the sensor, which is found to be sensitive to strain. We demonstrate the capability of the platform to detect the breathing rates of four male volunteers who are not in movement. The breathing pattern is obtained through the received signal strength indicator (RSSI) which is filtered and analyzed with home-made algorithms in the portable system. Numerical simulations of human breath are performed to support the experimental detection, and both results are in a good agreement. Slow, fast, regular, irregular, and shallow breathing types are successfully recorded within a frequency interval of 0.16–1.2 Hz, leading to a breathing rate varying from 10 to 72 breaths per minute. [ABSTRACT FROM AUTHOR]

A VUV absorption spectroscopy facility designed for ultra-high spectral resolution is in operation as a dedicated branch on the DESIRS beamline at Synchrotron SOLEIL. This branch includes a unique VUV Fourier transform spectrometer (FTS) and a dedicated versatile gas sample chamber. The FTS instrument can cover a large UV-VUV spectral range from 4 to 30 eV, with an ultimate line width of 0.08 cm−1 on a large spectral window, Δ E/ E = 7%, over which all spectral features can be acquired in a multiplex way. The performance can be considered to be a middle ground between broadband moderate-resolution spectrometers based on gratings and ultra-high-spectral-resolution VUV tunable-laser-based techniques over very narrow spectral windows. The various available gaseous-sample-handling setups, which function over a wide range of pressures and temperatures, and the acquisition methodology are described. A selection of experimental results illustrates the performance and limitations of the FTS-based facility. [ABSTRACT FROM AUTHOR]

η2-Propadienylidenelanthanum[La(η2-CCCH2)] and deprotiolanthanacyclobutadiene[La(HCCCH)] of La(C3H2) are identified fromthe reaction mixture of neutral La atom activation of propyne in thegas phase. The two isomers are characterized with mass-analyzed thresholdionization spectroscopy combined with electronic structure calculationsand spectral simulations. La(η2-CCCH2)and La(HCCCH) are formed by concerted 1,3- and 3,3-dehydrogenation,respectively. Both isomers prefer a doublet ground state with a La6s-based unpaired electron, and La(η2-CCCH2) is slightly more stable than La(HCCCH). Ionization of the neutraldoublet state of either isomer produces a singlet ion state by removingthe La-based electron. The geometry change upon ionization resultsin the excitation of a symmetric metal–hydrocarbon stretchingmode in the ionic state, whereas thermal excitation leads to the observationof the same stretching mode in the neutral state. Although the Laatom is in a formal oxidation state of +2, the ionization energiesof these metal–hydrocarbon radicals are lower than that ofthe neutral La atom. Deuteration has a very small effect on the ionizationenergies of the two isomers and the metal–hydrocarbon stretchingmode of La(η2-CCCH2), but it reduces considerablythe metal–ligand stretching frequencies of La(HCCCH). [ABSTRACT FROM AUTHOR]

Recently we published [Liu etal. J. Chem. Phys.2013, 139, 154312] an analysis of the rotationalstructure of the B̃–X̃origin band spectrum of isopropoxy, which confirmed that the doublemethyl substitution of methoxy to yield the isopropoxy radical onlyslightly lifted the degeneracy of the former’s X̃2E state. Additionally the spectral results provided considerableinsight into the relativistic and nonrelativistic contributions tothe experimental splitting between the components of the 2E state. However, left unexplained was how the Jahn–Teller(JT) vibronic coupling terms within methoxy’s 2Estate manifest themselves as pseudo-Jahn–Teller (pJT) vibroniccoupling between the Ã2A″and X̃2A′ levels of isopropoxy.To cast additional light on this subject we have obtained new isopropoxyspectra and assigned a number of weak, “forbidden” vibronictransitions in the B̃–X̃spectrum using new electronic structure calculations and rotationalcontour analyses. The mechanisms that provide the nonzero probabilityfor these transitions shed considerable information on pJT, spin-orbit,and Coriolis coupling between the Ãand X̃states. We also report a novel mechanism causedby pJT coupling that yields excitation probability to the B̃state dependent upon the permanentdipole moments in the B̃and Ãor X̃states. By combining a new B̃–Ãand the earlier B̃–X̃rotational analyseswe determine a much improved value for the experimental ÖX̃separation. [ABSTRACT FROM AUTHOR]

Gadolinium (Gd) complexes of benzene (C6H6) and (1,3.5,7-cyclooctatetraene) (C8H8) were produced in a laser-vaporization supersonic molecular beam source and studied by single-photon pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy. Adiabatic ionization energies and metal--ligand stretching frequencies were measured for the first time from the ZEKE spectra. Metal--ligand bonding and electronic states of the neutral and cationic complexes were analyzed by combining the spectroscopic measurements with ab initio calculations. The ground states of Gd(C6H6) and [Gd(C6H6)]+ were determined as 11A2 and 10A2, respectively, with C6v, molecular symmetry. The ground states of Gd(C8H8) and [Gd(C8H8)]+ were identified as 9A2 and 8A2, respectively, with C8v, molecular symmetry. Although the metal--ligand bonding in Gd(C6H6) is dominated by the covalent interaction, the bonding in Gd( C8H8) is largely electrostatic. The bonding in the benzene complex is much weaker than that in the cyclooctatetraene species. The strong bonding in Gd(C8H8) arises from two-electron transfer from Gd to C8H8, which creates a strong charge--charge interaction and converts the tub-shaped ligand into a planar form. In both systems, Gd 4f orbitals are localized and play little role in the bonding, but they contribute to the high electron spin multiplicities. [ABSTRACT FROM AUTHOR]

Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Mo\ller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes. [ABSTRACT FROM AUTHOR]

Monobenzene complexes of yttrium (Y), lanthanum (La), and lutetium (Lu), M(C6H6) (M = Y, La, and Lu), were prepared in a laser-vaporization supersonic molecular beam source and studied by pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy and ab initio calculations. The calculations included the second-order perturbation, the coupled cluster with single, double, and perturbative triple excitation, and the complete active space self-consistent field methods. Adiabatic ionization energies and metal-benzene stretching frequencies of these complexes were measured for the first time from the ZEKE spectra. Electronic states of the neutral and ion complexes and benzene ring deformation were determined by combining the spectroscopic measurements with the theoretical calculations. The ionization energies of M(C6H6) are 5.0908 (6), 4.5651 (6), and 5.5106 (6) eV, and the metal-ligand stretching frequencies of [M(C6H6)]+ are 328, 295, and 270 cm-1 for M = Y, La, and Lu, respectively. The ground states of M(C6H6) and [M(C6H6)]+ are 2A1 and 1A1, respectively, and their molecular structures are in C2v point group with a bent benzene ring. The deformation of the benzene ring upon metal coordination is caused by the pseudo Jahn-Teller interaction of (12E2+12A1+22E2) x e2 at C6v symmetry. In addition, the study shows that spectroscopic behaviors of Y(C6H6) and La(C6H6) are similar to each other, but different from that of Lu(C6H6). [ABSTRACT FROM AUTHOR]

Smart textiles and wearable antennas along with broadband mobile technologies have empowered the wearable sensors for significant impact on the future of digital health care. Despite the recent development in this field, challenges related to lack of accuracy, reliability, user's comfort, rigid form and challenges in data analysis and interpretation have limited their wide-scale application. Therefore, the necessity of developing a new reliable and user friendly approach to face these problems is more than urgent. In this paper, a new generation of wearable antenna is presented, and its potential use as a contactless and non-invasive sensor for human breath detection is demonstrated. The antenna is made from multimaterial fiber designed for short-range wireless network applications at 2.4 GHz frequency. The used composite metal-glass-polymer fibers permits their integration into a textile without compromising comfort or restricting movement of the user due to their high flexibility, and shield efficiently the antenna from the environmental perturbation. The multimaterial fiber approach provided a good radio-frequency emissive properties, while preserving the mechanical and cosmetic properties of the garments. With a smart textile featuring a spiral shape fiber antenna placed on a human chest, a significant shift of the operating frequency of the antenna was observed during the breathing process. The frequency shift is caused by the deformation of the antenna geometry due to the chest expansion, and to the modification of the dielectric properties of the chest during the breath. We demonstrate experimentally that the standard wireless networks, which measure the received signal strength indicator (RSSI) via standard Bluetooth protocol, can be used to reliably detect human breathing and estimate the breathing rate in real time. The mobile platform takes the form of a wearable stretching T-shirt featuring a sensor and a detection base station. The sensor is formed by a spiral-shaped antenna connected to a compact Bluetooth transmitter. Breathing patterns were recorded in the case of female and male volunteers. Although the chest anatomy of females and males is different compared, the sensor's flexibility allowed recording successfully a breathing rate of 0.3 Hz for the female and 0.5 Hz for the male, which corresponds to a breathing rate of 21 breaths per minutes (bpm) and 30 bpm, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we present a new FTIR-based microfluidic system for Glucose, Fructose and Sucrose detection. The proposed microfluidic system is based on a pseudo-continuous flow coupled to a microscope-FTIR instrument. The detection and characterization of sugar samples were performed by recording their absorption spectrum in the wavelength range 700–1000 cm − 1 of the Mid-IR region. The proposed pseudo-continuous flow system is designed to improve the uniformity of the sample distribution in the analyzed area versus conventional systems. The obtained results for different sugars concentrations, show a very low measurement error of 4.35% in the absorption peak intensity, which is ten times lower than the error obtained using the conventional measurements. [ABSTRACT FROM AUTHOR]

A new multi-material polymer fiber electrode has been developed for smart clothing applications. The conductive fiber is optimized for bipotential measurements such as surface electromyogram (sEMG) and electrocardiogram (ECG). The main benefit of this fiber is its flexibility and being a dry and non-obtrusive electrode. It can be directly integrated into a garment to make a smart textile for real time biopoten-tial monitoring. A customized wireless electronic system has been developed to acquire electrophysiological signal from the fiber. The receiver base station is connected to a PC host running Matlab. The multi-material polymer fiber electrode recording setting were first optimized in length and inter-electrode distance by recording different sEMG signals. The typical sEMG signal to noise ratio ranges from 19.1 dB to 33.9 dB depending on the geometry. These value are comparable with those obtained with Ag/AgCl electrodes and dry electrode-base commercial system such as Delsys Trigno. The frequency domain analysis obtained from the power spectral density reveals that the new flexible fiber-electrode enables high sEMG signals recording quality while being suitable for integration in smart clothing fabric. A muscle fatigue analysis and ECG recording are also presented in this study. The multi-material polymer fiber electrodes demonstrate a viable solution for sEMG and ECG data acquisition.

In this paper, we present a new FTIR-based microfluidic system for Glucose, Fructose and Sucrose detection. The proposed microfluidic system is based on a pseudo-continuous flow coupled to a microscope-FTIR instrument. The detection and characterization of sugar samples were performed by recording their absorption spectrum in the wavelength range 700⁻1000 cm - 1 of the Mid-IR region. The proposed pseudo-continuous flow system is designed to improve the uniformity of the sample distribution in the analyzed area versus conventional systems. The obtained results for different sugars concentrations, show a very low measurement error of 4.35% in the absorption peak intensity, which is ten times lower than the error obtained using the conventional measurements.