Sensor-Location-Specific Joint Acquisition of Peripheral Artery Bioimpedance and Photoplethysmogram for Wearable Applications.

BACKGROUND: Cardiovascular diseases (CVDs), being the culprit for one-third of deaths globally, constitute a challenge for biomedical instrumentation development, especially for early disease detection. Pulsating arterial blood flow, providing access to cardiac-related parameters, involves the whole body. Unobtrusive and continuous acquisition of electrical bioimpedance (EBI) and photoplethysmography (PPG) constitute important techniques for monitoring the peripheral arteries, requiring novel approaches and clever means. METHODS: In this work, five peripheral arteries were selected for EBI and PPG signal acquisition. The acquisition sites were evaluated based on the signal morphological parameters. A small-data-based deep learning model, which increases the data by dividing them into cardiac periods, was proposed to evaluate the continuity of the signals. RESULTS: The highest sensitivity of EBI was gained for the carotid artery (0.86%), three times higher than that for the next best, the posterior tibial artery (0.27%). The excitation signal parameters affect the measured EBI, confirming the suitability of classical 100 kHz frequency (average probability of 52.35%). The continuity evaluation of the EBI signals confirmed the advantage of the carotid artery (59.4%), while the posterior tibial artery (49.26%) surpasses the radial artery (48.17%). The PPG signal, conversely, commends the location of the posterior tibial artery (97.87%). CONCLUSIONS: The peripheral arteries are highly suitable for non-invasive EBI and PPG signal acquisition. The posterior tibial artery constitutes a candidate for the joint acquisition of EBI and PPG signals in sensor-fusion-based wearable devices-an important finding of this research.

Analysis of Shock Wave Interaction with an Obstacle by Coupling Pressure Measurements and Visualization.

Small-scale experiments are a good means of carrying out explosion and shock wave measurements. Commonly, the shock wave is tracked thanks to pressure sensors and sometimes with a high-speed camera. In the present study, these methods were used to analyze the interaction of a shock wave with an obstacle of simple geometry. The primary aim of the study was to demonstrate the need to correlate these different methods in order to analyze certain phenomena related to the three-dimensional interaction of a shock wave with an object. The correlation between the overpressure and the visualization made it possible to carry out a complex analysis. The visualization was carried out simultaneously on two planes, from the front and top views, thanks to the optical setup. Shock wave characteristics were taken at ground level downstream of the obstacle with pressure gauges. The correlation of the images obtained allows the identification of the waves on the profile and their contribution in intensity.

Transcutaneous ventriculo-peritoneal shunt catheter extrusion with silent bowel perforation following digestive surgery: a case report.

This case report provides an account of transcutaneous ventriculo-peritoneal (VP) shunt extrusion with silent bowel perforation occurring 2 years post digestive surgery. A 22-year-old man treated since childhood for post-infectious hydrocephalus was referred to our neurosurgery department for an inflammatory wound to the right hypochondrium caused by an abandoned calcified VP shunt. This VP shunt was surgically removed without complications. The perforated bowel required no direct repair. Progress is favorable at 1 year follow-up.

Study of Electrode Locations for Joint Acquisition of Impedance- and Electro-cardiography Signals.

ICG (impedance cardiography) and ECG (electrocardiography) provide important indications about functioning of the heart and of overall cardiovascular system. Measuring ICG along with ECG using wearable devices will improve the quality of health monitoring, as ICG points to important hemodynamic parameters (such as time intervals, stroke volume, cardiac output, and their variability). In this work, various electrode locations (12 different setups) have been tested for possible joint ECG & ICG data acquisition (using the same electrodes) and signal quality has been evaluated for every setup. It is shown that, while typically ICG is acquired over the whole thorax, a wrist-based joint acquisition of ECG & ICG signals can achieve acceptable signal quality and therefore can be considered in wearable sensing.

Registrar performance in minimally invasive distal pancreatectomy and effects on postoperative outcomes.

BACKGROUND: Minimally invasive distal pancreatectomy (MIDP) is nowadays an established standard procedure for non-locally advanced pancreatic lesions without celio-mesenteric vascular invasion. However, little is known about how the involvement of junior surgeons in MIDP affects postoperative outcomes. We performed a retrospective case series study in order to determine whether registrar involvement in MIDP is associated with adverse outcomes. METHODS: Data were analyzed from a prospectively created database of consecutive patients undergoing MIDP. Only data from 91 patients who underwent MIDP for non-PDAC lesions were included. Patients were divided in 3 groups: Consultant P1 (first 20 MIDP, n=20), Consultant P2 (after 20 MIDP, n=44), and Registrar group (n=27). Conversion rates and 90-day postoperative outcomes were compared. RESULTS: Conversion rates were 5%, 0%, and 14% in Consultant P1 and P2 and Registrar groups, respectively (P1 vs. P2, p = 0.312 and P1 vs. Registrar, p=0.376). Only Comprehensive Complication Index was higher in Registrar group compared to Consultant P1 group (13 vs. 3.7; p = 0.041). Comparison between Consultant P2 and Registrar groups resulted in a significant higher conversion rate (0 vs. 14%, p = 0.029), increased blood loss (77 vs. 263 ml, p = 0.018), and longer surgery duration (156 vs. 212 min, p=0.001) for registrars MIDP. However, no differences were found in clinically relevant postoperative pancreatic fistula (CR-POPF) (16 vs. 7.5%, p=0.282), Clavien-Dindo severe complication ≥3 score (11 vs. 4%, p=0.396), or length of hospital stay (9 vs. 9 days; p=0.614) between the consultant and registrar cohorts. CONCLUSIONS: With all the limitations of a retrospective study with a small sample size, junior surgeons' involvement in MIDP for non-PDAC lesions resulted in higher conversion rate, blood loss and duration of surgery without statistically significant difference on clinical outcomes compared to a consultant.

Efficient production of a functional G protein-coupled receptor in E. coli for structural studies.

G protein-coupled receptors (GPCRs) are transmembrane signal transducers which regulate many key physiological process. Since their discovery, their analysis has been limited by difficulties in obtaining sufficient amounts of the receptors in high-quality, functional form from heterologous expression hosts. Albeit highly attractive because of its simplicity and the ease of isotope labeling for NMR studies, heterologous expression of functional GPCRs in E. coli has proven particularly challenging due to the absence of the more evolved protein expression and folding machinery of higher eukaryotic hosts. Here we first give an overview on the previous strategies for GPCR E. coli expression and then describe the development of an optimized robust protocol for the E. coli expression and purification of two mutants of the turkey ß1-adrenergic receptor (ß1AR) uniformly or selectively labeled in 15N or 2H,15N. These mutants had been previously optimized for thermal stability using insect cell expression and used successfully in crystallographic and NMR studies. The same sequences were then used for E. coli expression. Optimization of E. coli expression was achieved by a quantitative analysis of losses of receptor material at each step of the solubilization and purification procedure. Final yields are 0.2-0.3 mg receptor per liter culture. Whereas both expressed mutants are well folded and competent for orthosteric ligand binding, the less stable YY-ß1AR mutant also comprises the two native tyrosines Y5.58 and Y7.53, which enable G protein binding. High-quality 1H-15N TROSY spectra were obtained for E. coli-expressed YY-ß1AR in three different functional states (antagonist, agonist, and agonist + G protein-mimicking nanobody-bound), which are identical to spectra obtained of the same forms of the receptor expressed in insect cells. NdeI and AgeI restriction sites introduced into the expression plasmid allow for the easy replacement of the receptor gene by other GPCR genes of interest, and the provided quantitative workflow analysis may guide the respective adaptation of the purification protocol.

Scion genotypes exert long distance control over rootstock transcriptome responses to low phosphate in grafted grapevine.

BACKGROUND: Grafting is widely used in horticulture and rootstocks are known to modify scion growth and adaptation to soil conditions. However, the role of scion genotype in regulating rootstock development and functioning has remained largely unexplored. In this study, reciprocal grafts of two grapevine genotypes were produced as well as the corresponding homo-graft controls. These plants were subjected to a low phosphate (LP) treatment and transcriptome profiling by RNA sequencing was done on root samples collected 27 h after the onset of the LP treatment. RESULTS: A set of transcripts responsive to the LP treatment in all scion/rootstock combinations was identified. Gene expression patterns associated with genetic variation in response to LP were identified by comparing the response of the two homo-grafts. In addition, the scion was shown to modify root transcriptome responses to LP in a rootstock dependent manner. A weighted gene co-expression network analysis identified modules of correlated genes; the analysis of the association of these modules with the phosphate treatment, and the scion and rootstock genotype identified potential hub genes. CONCLUSIONS: This study provides insights into the response of grafted grapevine to phosphate supply and identifies potential shoot-to-root signals that could vary between different grapevine genotypes.

Merging genotypes: graft union formation and scion-rootstock interactions.

Grafting has been utilised for at least the past 7000 years. Historically, grafting has been developed by growers without particular interest beyond the agronomical and ornamental effects, and thus knowledge about grafting has remained largely empirical. Much of the commercial production of fruit, and increasingly vegetables, relies upon grafting with rootstocks to provide resistance to soil-borne pathogens and abiotic stresses as well as to influence scion growth and performance. Although there is considerable agronomic knowledge about the use and selection of rootstocks for many species, we know little of the molecular mechanisms underlying rootstock adaptation to different soil environments and rootstock-conferred modifications of scion phenotypes. Furthermore, the processes involved in the formation of the graft union and graft compatibility are poorly understood despite over a hundred years of scientific study. In this paper, we provide an overview of what is known about grafting and the mechanisms underlying rootstock-scion interactions. We highlight recent studies that have advanced our understanding of graft union formation and outline subjects that require further development.

Phosphorus acquisition efficiency and phosphorus remobilization mediate genotype-specific differences in shoot phosphorus content in grapevine.

Crop productivity is limited by phosphorus (P) and this will probably increase in the future. Rootstocks offer a means to increase the sustainability and nutrient efficiency of agriculture. It is known that rootstocks alter petiole P concentrations in grapevine. The objective of this work was to determine which functional processes are involved in genotype-specific differences in scion P content by quantifying P uptake, P remobilization from the reserves in the cutting and P allocation within the plant in three grapevine genotypes. Cuttings of two American rootstocks and one European scion variety were grown in sand and irrigated with a nutrient solution containing either high P (0.6 mM) or low P (0 mM). The high P solution was labelled with 32P throughout the experiment. The grapevine genotypes studied show variation in the inhibition of shoot and root biomass in response to low P supply, and P supply also affected shoot, but not root, P concentrations. Genotype-specific differences in total P content were related to differences in P acquisition and utilization efficiencies (PAE and PUE, respectively). Phosphorus allocation within the plant was not affected by genotype or P supply. The rootstock genotype known to confer high petiole P content in the vineyard was associated with a high PAE under high P, and a high PUE under low P. This suggests that the petiole P concentrations in the vineyard are related to genotype-specific differences in PAE and PUE, and that these traits could be used for rootstock selection programmes in the future.

An Efficient Multilinear Optimization Framework for Hypergraph Matching.

Hypergraph matching has recently become a popular approach for solving correspondence problems in computer vision as it allows the use of higher-order geometric information. Hypergraph matching can be formulated as a third-order optimization problem subject to assignment constraints which turns out to be NP-hard. In recent work, we have proposed an algorithm for hypergraph matching which first lifts the third-order problem to a fourth-order problem and then solves the fourth-order problem via optimization of the corresponding multilinear form. This leads to a tensor block coordinate ascent scheme which has the guarantee of providing monotonic ascent in the original matching score function and leads to state-of-the-art performance both in terms of achieved matching score and accuracy. In this paper we show that the lifting step to a fourth-order problem can be avoided yielding a third-order scheme with the same guarantees and performance but being two times faster. Moreover, we introduce a homotopy type method which further improves the performance.

Structure determination of α-helical membrane proteins by solution-state NMR: emphasis on retinal proteins.

The biochemical processes of living cells involve a numerous series of reactions that work with exceptional specificity and efficiency. The tight control of this intricate reaction network stems from the architecture of the proteins that drive the chemical reactions and mediate protein-protein interactions. Indeed, the structure of these proteins will determine both their function and interaction partners. A detailed understanding of the proximity and orientation of pivotal functional groups can reveal the molecular mechanistic basis for the activity of a protein. Together with X-ray crystallography and electron microscopy, NMR spectroscopy plays an important role in solving three-dimensional structures of proteins at atomic resolution. In the challenging field of membrane proteins, retinal-binding proteins are often employed as model systems and prototypes to develop biophysical techniques for the study of structural and functional mechanistic aspects. The recent determination of two 3D structures of seven-helical trans-membrane retinal proteins by solution-state NMR spectroscopy highlights the potential of solution NMR techniques in contributing to our understanding of membrane proteins. This review summarizes the multiple strategies available for expression of isotopically labeled membrane proteins. Different environments for mimicking lipid bilayers will be presented, along with the most important NMR methods and labeling schemes used to generate high-quality NMR spectra. The article concludes with an overview of types of conformational restraints used for generation of high-resolution structures of membrane proteins. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks.

Solution NMR studies of integral polytopic α-helical membrane proteins: the structure determination of the seven-helix transmembrane receptor sensory rhodopsin II, pSRII.

About 30% of the proteins encoded in the genome are expressed as membrane proteins but these represent <1% of all the structures solved today. In view of the physiological and pharmaceutical significance of membrane proteins it is clear that a better and more comprehensive understanding of their three-dimensional (3D) structures at atomic resolution is required. α-Helical integral membrane proteins are generally more difficult to work with than ß-barrel-type proteins and this has particularly been true for the polytopic members such as the large family of seven-helical proteins. In this chapter we describe the practical aspects of the solution-state NMR spectroscopy structure determination of the seven-helical transmembrane (7-TM) protein receptor sensory rhodopsin pSRII from the haloalkaliphilic archaeon Natronomonas pharaonis reconstituted in detergent micelles. This is the first time that a three-dimensional structure of a 7-TM protein has been determined by NMR.

Solution NMR studies of polytopic α-helical membrane proteins.

NMR spectroscopy has established itself as one of the main techniques for the structural study of integral membrane proteins. Remarkably, over the last few years, substantial progress has been achieved in the structure determination of increasingly complex polytopical α-helical membrane proteins, with their size approaching ∼100kDa. Such advances are the result of significant improvements in NMR methodology, sample preparation and powerful selective isotope labelling schemes. We review the requirements facilitating such work based on the more recent solution NMR studies of α-helical proteins. While the majority of such studies still use detergent-solubilized proteins, alternative more native-like lipid-based media are emerging. Recent interaction, dynamics and conformational studies are discussed that cast a promising light on the future role of NMR in this important and exciting area.

Structure determination of the seven-helix transmembrane receptor sensory rhodopsin II by solution NMR spectroscopy.

Seven-helix membrane proteins represent a challenge for structural biology. Here we report the first NMR structure determination of a detergent-solubilized seven-helix transmembrane (7TM) protein, the phototaxis receptor sensory rhodopsin II (pSRII) from Natronomonas pharaonis, as a proof of principle. The overall quality of the structure ensemble is good (backbone r.m.s. deviation of 0.48 A) and agrees well with previously determined X-ray structures. Furthermore, measurements in more native-like small phospholipid bicelles indicate that the protein structure is the same as in detergent micelles, suggesting that environment-specific effects are minimal when using mild detergents. We use our case study as a platform to discuss the feasibility of similar solution NMR studies for other 7TM proteins, including members of the family of G protein-coupled receptors.