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Conducting polymer poly(3-hexylthiophene) (P3HT) and a graft copolymer of P3HT with poly(acrylic acid) (P3HT-g-PAA) were synthesized. The structure and molecular dynamics of P3HT and P3HT-g-PAA were investigated by solid-state NMR (SSNMR), Fourier transform infrared (FTIR), Raman, UV–vis, and fluorescence spectroscopies and X-ray diffraction (XRD) technique. The spectroscopic data confirmed the grafting of the PAA chains from the P3HT backbone at the molar ratio of ≈3:1 and significant changes in molecular dynamics in the grafted sample. XRD results suggested that overall grafting introduced the structural order in P3HT-g-PAA due to steric effects probably caused by charged polyanionic side chains. Solution NMR indicates the prevalence of the head-to-tail, HT-HT sequence in P3HT-g-PAA. The spin–lattice relaxation time constant, T1(13C), for the thiophene rings in P3HT-g-PAA (13.5 s) is approximately an order of magnitude longer than T1(13C) for the thiophene rings in P3HT (1.8 s). The rotating-frame relaxation time constants T1ρ(1H) for the thiophene ring carbons in P3HT were 2.2 and 3.2 (0.5) and 26.1 (0.5) ms for P3HT-g-PAA s, respectively. The longer component of the cross-polarization time TCHin P3HT (5.3 ms) becomes ca.5 times shorter for P3HT-g-PAA (1.1 ms). The carbon rotating-frame relaxation time constants T1ρ(13C) were 13.3 and 29.1 ms for the thiophene ring carbons in P3HT and P3HT-g-PAA, respectively. The T1ρ(1H), T1(13C), and T1ρ(13C) for the side chains in P3HT and P3HT-g-PAA were measured in the aliphatic spectral region. T1ρ(1H) constants were 2.9 and 27.0 ms for P3HT and P3HT-g-PAA, respectively. T1(13C) values were 0.4 for P3HT and 0.5 (0.65) and 5.6 (0.35) ms for P3HT-g-PAA. T1ρ(13C) values were 7.0 (0.45) and 1.1 (0.55) ms for P3HT and 19.0 (0.75) and 0.9 (0.25) ms for P3HT-g-PAA. The data imply significant changes in structural order and molecular dynamics after grafting the PAA polyelectrolyte side chains.

Objective: Walking is a key component of daily-life mobility. We examined associations between laboratory-measured gait quality and daily-life mobility through Actigraphy and Global Positioning System (GPS). We also assessed the relationship between two modalities of daily-life mobility i.e., Actigraphy and GPS. Methods: In community-dwelling older adults (N = 121, age = 77±5 years, 70% female, 90% white), we obtained gait quality from a 4-m instrumented walkway (gait speed, walk-ratio, variability) and accelerometry during 6-Minute Walk (adaptability, similarity, smoothness, power, and regularity). Physical activity measures of step-count and intensity were captured from an Actigraph. Time out-of-home, vehicular time, activity-space, and circularity were quantified using GPS. Partial Spearman correlations between laboratory gait quality and daily-life mobility were calculated. Linear regression was used to model step-count as a function of gait quality. ANCOVA and Tukey analysis compared GPS measures across activity groups [high, medium, low] based on step-count. Age, BMI, and sex were used as covariates. Results: Greater gait speed, adaptability, smoothness, power, and lower regularity were associated with higher step-counts (0.20<|ρp| < 0.26, p < .05). Age(β = −0.37), BMI(β = −0.30), speed(β = 0.14), adaptability(β = 0.20), and power(β = 0.18), explained 41.2% variance in step-count. Gait characteristics were not related to GPS measures. Participants with high (>4800 steps) compared to low activity (steps<3100) spent more time out-of-home (23 vs 15%), more vehicular travel (66 vs 38 minutes), and larger activity-space (5.18 vs 1.88 km2), all p < .05. Conclusions: Gait quality beyond speed contributes to physical activity. Physical activity and GPS-derived measures capture distinct aspects of daily-life mobility. Wearable-derived measures should be considered in gait and mobility-related interventions.

Background: Physical activity can improve function and decrease healthcare spending among overweight and obese older adults. Although unstructured physical activity has been related to cardiometabolic improvements, the relationship between unstructured activity and movement quality is unclear. Aims: This study aimed to evaluate the association of amount of unstructured free-living moderate-vigorous physical activity (MVPA) with measures of movement quality in overweight and obese older adults. Methods: The association of MVPA with movement quality was assessed in 165 overweight and obese older adults (Age: 77.0(8.0) years; Body mass index (BMI): 29.2(5.3) kg/m2). Participants performed overground walking, the Figure of 8 Walk test, and the Five-Times Sit to Stand. Weekly physical activity was measured using a waist-worn Actigraph activity monitor. Results: Movement quality during straight path [gait speed (ρ = 0.30, p< 0.01), stride length (ρ = 0.33, p< 0.01), double-limb support time (ρ = −0.26, p< 0.01), and gait symmetry (ρ = 0.17, p= 0.02)] and curved path [F8W time (ρ = −0.22, p< 0.01) and steps (ρ = −0.22, p< 0.01)] walking were associated with weekly minutes of MVPA after controlling for age. Five-Times Sit to Stand performance was not significantly associated with weekly minutes of MVPA (ρ = −0.10, p= 0.13). Conclusions: Older adults with high BMIs who are less active also demonstrate poorer movement quality, independent of age. Physical activity engagement and task-specific training should be targeted in interventions to promote healthy aging, decrease falls, and delay disability development. Future work should consider the interconnected nature of movement quality with physical activity engagement and investigate if targeting one influences the other.

Artificial intelligence and machine learning techniques have progressed dramatically and become powerful tools required to solve complicated tasks, such as computer vision, speech recognition, and natural language processing. Since these techniques have provided promising and evident results in these fields, they emerged as valuable methods for applications in human physiology and healthcare. General physiological recordings are time-related expressions of bodily processes associated with health or morbidity. Sequence classification, anomaly detection, decision making, and future status prediction drive the learning algorithms to focus on the temporal pattern and model the nonstationary dynamics of the human body. These practical requirements give birth to the use of recurrent neural networks (RNNs), which offer a tractable solution in dealing with physiological time series and provide a way to understand complex time variations and dependencies. The primary objective of this article is to provide an overview of current applications of RNNs in the area of human physiology for automated prediction and diagnosis within different fields. Finally, we highlight some pathways of future RNN developments for human physiology.

Accelerometers provide an opportunity to expand standing balance assessments outside of the laboratory. The purpose of this narrative review is to show that accelerometers are accurate, objective, and accessible tools for balance assessment. Accelerometry has been validated against current gold standard technology, such as optical motion capture systems and force plates. Many studies have been conducted to show how accelerometers can be useful for clinical examinations. Recent studies have begun to apply classification algorithms to accelerometry balance measures to discriminate populations at risk for falls. In addition to healthy older adults, accelerometry can monitor balance in patient populations such as Parkinson’s disease, multiple sclerosis, and traumatic brain injury. The lack of software packages or easy-to-use applications have hindered the shift into the clinical space. Lack of consensus on outcome metrics has also slowed the clinical adoption of accelerometer-based balance assessments. Future studies should focus on metrics that are most helpful to evaluate balance in specific populations and protocols that are clinically efficacious.

Patients with occlusion myocardial infarction (OMI) and no ST-elevation on presenting electrocardiogram (ECG) are increasing in numbers. These patients have a poor prognosis and would benefit from immediate reperfusion therapy, but, currently, there are no accurate tools to identify them during initial triage. Here we report, to our knowledge, the first observational cohort study to develop machine learning models for the ECG diagnosis of OMI. Using 7,313 consecutive patients from multiple clinical sites, we derived and externally validated an intelligent model that outperformed practicing clinicians and other widely used commercial interpretation systems, substantially boosting both precision and sensitivity. Our derived OMI risk score provided enhanced rule-in and rule-out accuracy relevant to routine care, and, when combined with the clinical judgment of trained emergency personnel, it helped correctly reclassify one in three patients with chest pain. ECG features driving our models were validated by clinical experts, providing plausible mechanistic links to myocardial injury.

Dysphagia occurs secondary to a variety of underlying etiologies and can contribute to increased risk of adverse events such as aspiration pneumonia and premature mortality. Dysphagia is primarily diagnosed and characterized by instrumental swallowing exams such as videofluoroscopic swallowing studies. videofluoroscopic swallowing studies involve the inspection of a series of radiographic images for signs of swallowing dysfunction. Though effective, videofluoroscopic swallowing studies are only available in certain clinical settings and are not always desirable or feasible for certain patients. Because of the limitations of current instrumental swallow exams, research studies have explored the use of acceleration signals collected from neck sensors and demonstrated their potential in providing comparable radiation-free diagnostic value as videofluoroscopic swallowing studies. In this study, we used a hybrid deep convolutional recurrent neural network that can perform multi-level feature extraction (localized and across time) to annotate swallow segments automatically via multi-channel swallowing acceleration signals. In total, we used signals and videofluoroscopic swallowing study images of 3144 swallows from 248 patients with suspected dysphagia. Compared to other deep network variants, our network was superior at detecting swallow segments with an average area under the receiver operating characteristic curve value of 0.82 (95% confidence interval: 0.807-0.841), and was in agreement with up to 90% of the gold standard-labeled segments.

Ischemic electrocardiogram (ECG) changes are subtle and transient in patients with suspected non-ST-segment elevation (NSTE)-acute coronary syndrome. However, the out-of-hospital ECG is not routinely used during subsequent evaluation at the emergency department. Therefore, we sought to compare the diagnostic performance of out-of-hospital and ED ECG and evaluate the incremental gain of artificial intelligence-augmented ECG analysis.

OBJECTIVE--To investigate the effects of inflammation on perfusion regulation and brain volumes in type 2 diabetes. RESEARCH DESIGN AND METHODS--A total of 147 subjects (71 diabetic and 76 nondiabetic, aged [...]

The successful covalent attachment, via copper(I)-catalyzed azide alkyne cycloaddition (CuAAC), of alkyne-functionalized nickel(II) and copper(II) macrocyclic complexes onto azide (N3)-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) films on ITO-coated glass electrodes is reported. To investigate the surface attachment of the selected metal complexes, which are analogues of the cobalt-based complex previously reported to be a molecular catalyst for hydrogen evolution, first, three different PEDOT films were formed by electropolymerization of pure PEDOTor pure N3-PEDOT, and last, 1:2N3-PEDOT:PEDOTwere formed by co-polymerizing a 1:4 mixture of N3-EDOT:EDOT monomers. The successful surface immobilization of the complexes on the latter two azide-functionalized films, by CuAAC, was confirmed by X-ray photoelectron spectroscopy (XPS) and electrochemistry as well as by UV–vis–NIR and resonance Raman spectroelectrochemistry. The ratio between the N3groups, and hence, the number of surface-attached metal complexes after CuAAC functionalization, in pristine N3-PEDOTversus 1:2N3-PEDOT:PEDOTis expected to be 3:1 and seen to be 2.86:1 with a calculated surface coverage of 3.28 ± 1.04 and 1.15 ± 0.09 nmol/cm2, respectively. The conversion, to the metal complex attached films, was lower for the N3-PEDOTfilms (Ni 74%, Cu 76%) than for the copolymer 1:2N3-PEDOT:PEDOTfilms (Ni 83%, Cu 91%) due to the former being more sterically congested. The Raman and UV–vis–NIR results were simulated using density functional theory (DFT) and time-dependent DFT (TD-DFT), respectively, and showed good agreement with the experimental data. Importantly, the spectroelectrochemical behavior of both anchored metal complexes is analogous to that of the free metal complexes in solution. This proves that PEDOT films are promising conducting scaffolds for the covalent immobilization of metal complexes, as the existing electrochromic features of the complexes are preserved on immobilization, which is important for applications in electrocatalytic proton and carbon dioxide reduction, optoelectronics, and sensing.

There is a myth that people only use 10% of their brains, but science has proven this to be untrue. Another myth claims all brains work and learn the same. This is why so many schools teach all students the same way from classroom to classroom, year to year. [ABSTRACT FROM AUTHOR]

There is a significant and growing research interest in the isolation of extracellular vesicles (EVs) from large volumes of biological samples and their subsequent concentration into clean and small volumes of buffers, especially for applications in medical diagnostics. Materials that are easily incorporated into simple sampling devices and which allow the release of EVs without the need for auxiliary and hence contaminating reagents are particularly in demand. Herein, we report on the design and fabrication of a flexible, microporous, electrochemically switchable cloth that addresses the key challenges in diagnostic applications of EVs. We demonstrate the utility of our electrochemically switchable substrate for the fast, selective, nondestructive, and efficient capture and subsequent release of EVs. The substrate consists of an electrospun cloth, infused with a conducting polymer and decorated with gold particles. Utilizing gold–sulfur covalent bonding, the electrospun substrates may be functionalized with SH-terminated aptamer probes selective to EV surface proteins. We demonstrate that EVs derived from primary human dermal fibroblast (HDFa) and breast cancer (MCF-7) cell lines are selectively captured with low nonspecific adsorption using an aptamer specific to the CD63 protein expressed on the EV membranes. The specific aptamer–EV interactions enable easy removal of the nonspecifically bound material through washing steps. The conducting polymer component of the cloth provides a means for efficient (>92%) and fast (<5 min) electrochemical release of clean and intact captured EVs by cathodic cleavage of the Au–S bond. We demonstrate successful capture of diluted EVs from a large volume sample and their release into a small volume of clean phosphate-buffered saline buffer. The developed cloth can easily be incorporated into different designs for separation systems and would be adaptable to other biological entities including cells and other EVs. Furthermore, the capture/release capability holds great promise for liquid biopsies if used to targeted disease-specific markers.

Hydrogels are a popular substrate for cell culture due to their mechanical properties closely resembling natural tissue. Stimuli-responsive hydrogels are a good platform for studying cell response to dynamic stimuli. Poly(N-isopropylacrylamide) (pNIPAM) is a thermo-responsive polymer that undergoes a volume-phase transition when heated to 32 °C. Conducting polymers can be incorporated into hydrogels to introduce electrically responsive properties. The conducting polymer, polypyrrole (PPy), has been widely studied as electrochemical actuators due to its electrochemical stability, fast actuation and high strains. We determine the volume-phase transition temperature of pNIPAM hydrogels with PPy electropolymerised with different salts as a film within the hydrogel network. We also investigate the electro-mechanical properties at the transition temperature (32 °C) and physiological temperature (37 °C). We show statistically significant differences in the Young's modulus of the hybrid hydrogel at elevated temperatures upon electrochemical stimulation, with a 5 kPa difference at the transition temperature. Furthermore, we show a three-fold increase in actuation at transition temperature compared to room temperature and physiological temperature, attributed to the movement of ions in/out of the PPy film that induce the volume-phase transition of the pNIPAM hydrogel. Furthermore, cell adhesion to the hybrid hydrogel was demonstrated with mouse articular chondrocytes.

As transient electronics continue to advance, the demand for new materials has given rise to the exploration of conducting polymer (CP)-based electronic materials. The big challenge lies in balancing conductivity while introducing controlled degradable properties into CP-based transient materials. In response to this, we present in this work a concept of using conducting polymers attached to an enzymatically biodegradable biopolymer to create transient polymer electronics materials. Specifically, poly(3-hexyl thiophene) (P3HT) is covalently grafted onto biopolymer gelatin, affording graft copolymer gelatin-graft-poly(3-hexyl thiophene) (termed Gel-g-P3HT). The thin films of Gel-g-P3HT that were produced by optimized processing solvent (THF/H2O cosolvent) showed enhanced p–p stacking domains of P3HT, resulting in semiconducting thin films with good electroactivity. Due to the presence of amide bonds in the gelatin backbone, Gel-g-P3HT underwent degradation over a period of 5 days, resulting in the formation of amphiphilic micellar nanoparticles that are biocompatible and nontoxic. The potential of these conductive and degradable graft copolymers was demonstrated in a pressure sensor. This research paves the way for developing biocompatible and enzymatically degradable polymer materials based on P3HT, enabling the next generation of transient polymer electronics for diverse applications, such as skin, implantable, and environmental electronics.

Carbon nanotube-based field-effect transistors (NTFETs) are ideal sensor devices as they provide rich information regarding carbon nanotube interactions with target analytes and have potential for miniaturization in diverse applications in medical, safety, environmental, and energy sectors. Herein, we investigate chemical detection with cross-sensitive NTFETs sensor arrays comprised of metal nanoparticle-decorated single-walled carbon nanotubes (SWCNTs). By combining analysis of NTFET device characteristics with supervised machine-learning algorithms, we have successfully discriminated among five selected purine compounds, adenine, guanine, xanthine, uric acid, and caffeine. Interactions of purine compounds with metal nanoparticle-decorated SWCNTs were corroborated by density functional theory calculations. Furthermore, by testing a variety of prepared as well as commercial solutions with and without caffeine, our approach accurately discerns the presence of caffeine in 95% of the samples with 48 features using a linear discriminant analysis and in 93.4% of the samples with only 11 features when using a support vector machine analysis. We also performed recursive feature elimination and identified three NTFET parameters, transconductance, threshold voltage, and minimum conductance, as the most crucial features to analyte prediction accuracy.

Carbon nanomaterials possess superb properties and have contributed considerably to the advancement of integrated point-of-care chemical and biological sensing devices. Graphene has been widely researched as a signal transducing and sensing material. Here, a grass-like laser-scribed graphene (LSG) was synthesized by direct laser induction on common polyimide plastics. The resulting LSG grass was employed as a disposable electrochemical sensor for the detection of three neurotransmitters, dopamine (DA), epinephrine (EP), and norepinephrine (NE), and in the presence of uric acid and ascorbic acid as potential interferants, using differential pulse voltammetry and cyclic voltammetry. The LSG grass sensor achieved sensitivities of 0.243, 0.067, and 0.110 μA μM–1for DA, EP, and NE, respectively, whereas the limits of detection were 0.43, 1.1, and 1.3 μM, respectively. The selectivity of LSG grass was excellent for competing biomarkers with high structural similarity (EP vs NE and EP vs DA). The exceptional performance of LSG grass for DA, EP, and NE detection holds a promising future for carbon nanomaterial sensors with unique surface morphologies.

Direct writing is an effective and versatile technique for three-dimensional (3D) fabrication of conducting polymer (CP) structures. It is precisely localized and highly controllable, thus providing great opportunities for incorporating CPs into microelectronic array devices. Herein we demonstrate 3D writing and characterization of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT:PSS) pillars in an array format, by using an in-house-constructed variant of scanning ion conductance microscopy (SICM). CP pillars with different aspect ratios were successfully fabricated by optimizing the writing parameters: pulling speed, pulling time, concentration of the polymer solution, and the micropipette tip diameter. Especially, super high aspect ratio pillars of around 7 μm in diameter and 5000 μm in height were fabricated, indicating a good capability of this direct writing technique. Additions of an organic solvent and a cross-linking agent contribute to a significantly enhanced water stability of the pillars, critical if the arrays were to be used in biologically relevant applications. Surface morphologies and structural analysis of CP pillars were characterized by scanning electron microscopy and Raman spectroscopy, respectively. Electrochemical properties of the individual pillars of different heights were examined by cyclic voltammetry using a double-barrel micropipette as an electrochemical cell. Exceptional mechanical properties of the pillars, such as high flexibility and robustness, were observed when bent by applying a force. The 3D pillar arrays are expected to provide versatile substrates for functionalized and integrated biological sensing and electrically addressable array devices.

Research on balance and mobility in older adults has been conducted primarily in lab-based settings in individuals who live in the community. Although they are at greater risk of falls, residents of long-term care facilities, specifically residential care communities (RCCs), have been investigated much less frequently. We sought to determine the feasibility of using portable technology-based measures of balance and muscle strength (i.e., an accelerometer and a load cell) that can be used in any RCC facility. Twenty-nine subjects (age 87 ± 6 years) living in RCCs participated. An accelerometer placed on the back of the subjects measured body sway during different standing conditions. Sway in antero-posterior and mediolateral directions was calculated. Lower extremity strength was measured with a portable load cell and the within-visit reliability was determined. Assessments of grip strength, gait speed, frailty, and comorbidity were also examined. A significant increase in postural sway in both the AP and ML directions occurred as the balance conditions became more difficult due to alteration of sensory feedback (p< 0.001) or reducing the base of support (p< 0.001). There was an association between increased sway and increased frailty, more comorbidities and slower gait speed. All strength measurements were highly reliable (ICC = 0.93–0.99). An increase in lower extremity strength was associated with increased grip strength and gait speed. The portable instruments provide inexpensive ways for measuring balance and strength in the understudied RCC population, but additional studies are needed to examine their relationship with functional outcomes.

IMPORTANCE: Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. OBJECTIVE: To determine whether a dual-task gait test is associated with incident dementia in MCI. DESIGN, SETTING, AND PARTICIPANTS: The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. MAIN OUTCOMES AND MEASURES: Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity – dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. RESULTS: Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (&lt;0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P = .05)while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. CONCLUSIONS AND RELEVANCE: Dual-task gait is associated with progression to dementia in patients with MCI. Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI. TRIAL REGISTRATION: clinicaltrials.gov: NCT03020381.

Transient electronics is a rapidly growing field that focuses on the development of electronic materials that are intentionally degraded to environmentally and physiologically safe byproducts after a well-defined period of operation. The limited time frame of these materials makes them potential candidates for use in areas such as biomedicine and wearable electronics as well as mitigating the growing problem of electronic waste. Polymer-based transient electronics is attracting increasing interest due to its many advantages, including extensive chemical modification capabilities for transience and functionality, biocompatibility, and flexible and stretchable formats for electronics. In this Perspective, we discuss recent advances in the field of transient polymer electronics, highlighting existing strategies for degradation: the use of composites of biodegradable polymers with conducting polymers, the synthesis of copolymers/block copolymers or graft copolymers of conducting polymers with biodegradable polymers, the synthesis of fully (bio)degradable conjugated polymers with degradable conjugated linkers, and transience via dissolution of the conjugated polymers. We then highlight the applications of transient electronics based on conducting polymers. Finally, we provide an outlook on the future prospects in the field of transient polymer electronics and the challenges that need to be overcome for transient electronics to fulfill its promise in future electronic devices.

Introduction:Women are less likely than men to be promptly diagnosed with acute coronary syndrome (ACS) and have worse post-ACS outcomes. These diagnostic failures are partially due to ACS findings on surface ECG manifesting differently in women, which may result in unnecessary delays in treatment. To narrow health disparities, we aim to investigate the sex-specific signatures of ACS as they appear on ECGs.Methods:This was a prospective observational cohort study of chest-pain patients evaluated for suspected ACS at 3 UPMC-affiliated tertiary care hospitals. After featurization, all ECG data were separately fed into 7 machine learning classifiers to predict ACS. We examined the results by sex. We also investigated two other methods: (1) building two independent models based respectively on the female and male subgroups and (2) building a model based on the initial total sample supplemented by the patients’ sex. We used Shapley values to explain the decision-making criteria of the models. We report the results for random forest, the best performing classifier.Results:Our sample consisted of 4132 patients (Age 59 ± 16; 47% female; 15% ACS). Machine learning models continue to disproportionately underperform in females across all classifiers evaluated. The sensitivity, specificity and false negative rate in the global model blinded to sex were 82.89%, 76.22% and 17.11% for men, and 67.39%, 74.16% and 32.61% for women (p<0.0001). This statistically significant gap could not be alleviated by building sex-specific models or feeding sex to the input of the model. Indeed, the rate of false negatives in sex-specific models and global models with sex as input were 14.67% and 18.42% for men, and 34.04% and 32.61% for women (p<0.0001). The explainability analysis of the sex-specific models revealed that STT configuration in lateral leads is most informative in women, whereas STT configuration in all leads and particularly in anterolateral leads most informative in men.Conclusions:Machine learning models display crucial sex differences in the ACS signatures on the ECG that consistently put women in a detrimental situation. The alternative methods investigated here are not adequate solutions for this disparity. Thus, further investigations should be conducted.

Cervical auscultation is the recording of sounds and vibrations caused by the human body from the throat during swallowing. While traditionally done by a trained clinician with a stethoscope, much work has been put toward developing more sensitive and clinically useful methods to characterize the data obtained with this technique. The eventual goal of the field is to improve the effectiveness of screening algorithms designed to predict the risk that swallowing disorders pose to individual patients’ health and safety. This paper provides an overview of these signal-processing techniques and summarizes recent advances made with digital transducers in hopes of organizing the highly varied research on cervical auscultation. It investigates where on the body these transducers are placed in order to record a signal as well as the collection of analog and digital filtering techniques used to further improve the signal quality. It also presents the wide array of methods and features used to characterize these signals, ranging from simply counting the number of swallows that occur over a period of time to calculating various descriptive features in the time, frequency, and phase space domains. Finally, this paper presents the algorithms that have been used to classify these data into “normal” and “abnormal” categories. Both linear as well as nonlinear techniques are presented in this regard.

Supplemental Digital Content is available in the text.

Für produzierende Unternehmen stellt der Produktionsanlauf oft eine erfolgskritische Phase dar, die es effizient zu planen und überwachen gilt. Im Allgemeinen können Prozesse und Aktivitäten anhand von Kennzahlen in einer quantitativ messbaren Form erfasst werden. Im vorliegenden Beitrag wird ein Vorgehen beschrieben, um Kennzahlen für die Überwachung zusätzlicher Produktionskapazitäten an neuen Standorten zu identifizieren.

Polypyrrole nanotubes (PPy-NTs) were prepared by the oxidation of pyrrole with iron(III) chloride in the presence of a structure-guiding agent, methyl orange. Upon carbonization of the salt form of PPy-NTs, the conducting nitrogen-containing nanotubular carbonaceous material (C-PPy-NT) was obtained. The morphology, structure, and physicochemical properties of PPy-NTs in salt and base form as well as C-PPy-NTs were investigated by transmission electron microscopy, Fourier transform infrared and Raman spectroscopies, conductivity measurements, elemental microanalysis, inductively coupled plasma optical emission spectroscopy, X-ray photoelectron spectroscopy, and nitrogen physisorption. Results of the material characterization were linked to their electrochemical behavior. Specific capacitance of around 120 F g–1at low potential sweep rate of 5 mV s–1was observed for original PPy-NTs. However, when the potential sweep rate was increased to 100 mV s–1, PPy-NT salt retained the value of specific capacitance, while the capacitance of PPy-NT base decreased by 70%. Upon carbonization of PPy-NT salt, the specific capacitance was doubled and capacitance fade measured in the interval 5–100 mV s–1was determined to be around 45%. It is proposed that the absolute value of specific capacitance is determined by specific surface area and surface functional groups, while the capacitance fade is determined by the conductivity of the electrode material. In this manner, a linear relationship between the percent of capacitance fade and the logarithm of the conductivity was revealed. C-PPy-NTs were also tested as an electrocatalyst for the oxygen reduction reaction (ORR) in alkaline media. High ORR activity was observed, characterized by the onset potential of −0.1 V versus saturated calomel electrode and the apparent number of electrons consumed per oxygen molecule higher than 3. Appreciable ORR activity can be linked with a high fraction of mesopores and the presence of surface functional groups, especially pyridinic and pyrrolic nitrogens, and also with a high degree of structural disorder.

This study investigates the effect of the ionic liquid 1-butyl-3-methyl imidazolium chloride ([bmim]Cl) on the morphological, structural, and electronic properties of polyaniline (PANI) products synthesised by the falling-pH method. Products were characterised by SEM, FT-IR, UVVIS, N2-physisorption, and conductivity measurements. The [bmim]Cl addition strongly influenced the PANI morphology, specific surface area, porosity, and conductivity. Depending on the [bmim]Cl: ANI ratio and the synthesis pH, a wide range of PANI nanostructures could be prepared, with rod-like, and fibre-like elongated structures being the dominant morphology under most experimental conditions. Samples prepared in the presence of [bmim]Cl exhibit specific areas of ca 22–35 m2g−1. The conductivity of the final products depends on the [bmim]Cl: ANI ratio. Temperature dependence of conductivity in the temperature range from 77 K to 300 K was also studied.

Abstract

Low-energy platinum ions were implanted with 15 keV under normal incidence into synthesized conducting polymer films with the aim to improve film conductivity and to demonstrate the use of implanted platinum in a simple sensing design. Conductivity measurements, cyclic voltammetry, and Raman spectroscopy were performed on samples both before and following ion implantation. Results display an optimum fluence of ion implantation for which polypyrrole films implanted with 2 × 1016at. cm–2display and retain enhanced conductivity compared with nonimplanted samples. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope–energy-dispersive X-ray spectroscopy (SEM-EDS) confirmed that implanted platinum is present mainly as Pt0and indicated that the depth and amount of ion implantation are in agreement with a simulated implantation profile. Raman spectroscopy showed a surface-enhanced Raman spectroscopy (SERS) effect with platinum’s presence. The advantageous increase in conductivity can be rationalized by two chemical modifications to the polymer upon high-fluence implantation: (1) an increase in the number of charge carriers (dications) within the polymer and (2) the presence of elemental platinum metal and its synergistic effect on conductivity. A simple DNA sensor was constructed on the basis of polypyrrole/Pt0films where Pt0was able to serve as anchoring points for DNA attachment as well as an enhancer of the film’s conductivity. This enabled a DNA sensor capable of successful detection of cDNA, and a good discrimination of noncDNA, thus opening a way to direct electrochemical biosensing on the basis of ion implanted highly conducting polymer films.

Recent applications of the scanned pipette to materials science problems have included its quantification of the ion flux resulting from conducting polymer actuation. However, in order to correlate this flux with the precise height changes arising from actuation, a separate experiment must be carried out. Herein we propose a new design that may be capable of simultaneously determining both ion flux and topography, on the basis of subtle current density magnitude shifts and precisely chosen experimental positioning parameters. A simulation of the geometrical model - consisting of the pipette, conducting polymer film and electrodes - was setup and solved in 2D axi-symmetrical domain. The ion concentrations, voltage potentials and current densities were determined as a function of time, with three key parameters varied: the maximum ion flux value Jmax, conducting polymer swelling Tp and overall separation distance d between pipette and polymer. It was found that the separation Tp - d should be around 50 to 150 nm, roughly the same as the actuation itself. Furthermore, the current density component arising from geometrical changes due to actuation was on the order of a few percent, and was highly sensitive to Jmax levels.

The limited toolbox for conducting polymer (CP) microscale fabrication and characterization hampers the development of applications such as sensors and actuators. To address this issue, a robust and integrated methodology is presented, capable of electrochemical fabrication and characterization of CPs in a highly localized manner, allowing for CP patterning and spatial mapping of voltammetric response. This is enabled by scanning probe microscopy (SPM) tipped with a single‐barreled micropipette to electrochemically polymerize CP microspot arrays, demonstrated for 3,4‐ethylenedioxythiophene and aniline monomers. Stationary electropolymerization produces individual microspots; lateral movement produces long microribbons; retraction produces extruded microstructures. Subsequently the same SPM setup is tipped with a double‐barreled micropipette to carry out localized cyclic voltammetry. The micropipettes are filled with saline solutions in contact with Ag/AgCl electrodes, forming a thin meniscus of solution at the micropipette tip, which enable an automated approach in air and subsequent contact with the surface. The flexibility of this novel technique is demonstrated by application to 2D poly(3,4‐ethylenedioxythiophene) (PEDOT) microspots, microribbons and nanowires, plus polyaniline (PANI) microstructures and self‐assembled thin films. Finally, setting up a dynamic electrochemical cell allowed for voltammetric–amperometric imaging, simultaneously mapping the morphology and current response of CPs. Future refinements towards the nanoscale through smaller‐tipped pipettes should open up new opportunities for voltammetric response mapping of individual CP nanostructures.

We demonstrate an electrochemical switching of conformation of surface-bound polymer brushes, by grafting environmentally sensitive polymer brushes from an electrochemically-active conducting polymer (ECP). Using atom transfer radical polymerization (ATRP), we grafted zwitterionic polymer brushes, poly(3-(methacryloylamino)propyl)- dimethyl(3-sulfopropyl)ammonium hydroxide) (MPDSAH), from a surface initiated poly(pyrrole-co-pyrrolyl butyric acid) film. The changes in ionic solution composition in electrical double layer at the surface resulting from oxidation and reduction of the ECP trigger a switch in conformation of surface-bound poly(MPDSAH), demonstrated here by electrochemical impedance spectroscopy (EIS). The switch is also dependent upon temperature. We speculate that the synergistic combination of properties embodied in these "smart" materials may find application in electrochemical control of surface wetting and of interaction with biomolecules and living cells.

Composite hollow microspheres consisting of polyaniline (PANI) and indomethacin (IND) are prepared through a self‐assembly process in a mixed methanol/water solutions. Different volume fractions of methanol to water and different aniline concentrations are investigated to obtain the optimal conditions for the formation of PANI/IND composite hollow microspheres. The morphologies of the PANI/IND composites are characterized, showing the inner hollow center of the microspheres. Spectroscopic characterizations reveal that the synthesized materials have many typical features of chemically synthesized PANI and confirm the presence of IND in the composites. A controlled release of IND is achieved by adjusting the pH value of the buffer solution.

A novel flexible strain sensor was developed using a conducting polymer coated on rubber for large strain measurements. A coating of the conducting polymer, polypyrrole, was deposited on a strip of natural rubber through the process of vapour phase polymerisation while the rubber is in a stretched state. This process involves depositing a layer of oxidant on the rubber surface, followed by exposure to pyrrole monomer vapours that polymerize on the oxidantcoated rubber to produce polypyrrole. The change in electrical resistance of the strain sensor was recorded while cyclic strain from 0% to 20% was exerted on it. The gauge factor of the strain sensor was calculated to be 1.86. From repeated electrical resistance-strain measurements, the repeatability of the strain sensor was studied. A hysteresis was observed in a single extensionretraction strain cycle. Further study showed that the observed hysteresis is dependent on the strain rate where lower strain rate resulted in higher hysteresis and vice versa for a higher strain rate. There is also an electrical resistance drift between consecutive extension-retraction cycles. Owing to the flexibility of the rubber, the strain sensor can be used in complex configurations. The strain sensor can also be mounted or attached directly on surfaces to provide low-profile installation where space constraint is an issue. These characteristics offer advantages over traditional strain sensors to be used in applications that were not previously possible.

[3-(Methacryloylamino) propyl) dimethyl (3-sulfopropyl) ammonium hydroxide] polymer, known as poly (MPDSAH), and the random copolymers based on methyl methacrylate (MMA), methacryloxyethyltrimethylammonium (METAC) and 3-sulfopropyl methacrylate potassium (SPMA) were synthesized via Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization technique. Solution properties of these (co) polymers in response to temperature and ionic strength have been studied using dynamic light scattering (DLS). For poly (MPDSAH), polymer size decreased from 500 nm to 10 nm (in diameter) when the polymer aqueous solution was heated up from 15°C to 60°C or added 20 mM sodium chloride. The solution behaviour of poly (METAC-stat-MMA-stat-SPMA) is opposite to that of poly (MPDSAH): the size of polymer increased from 10 nm to 20 nm (in diameter) depending upon the elevating temperature or the addition of salt.

Electrochemical DNA sensors can be constructed by understanding basic interfacial electron transfer between solid surface-electrolyte-DNA interfaces. The kinetics of this heterogeneous process can be significantly affected by the microstructure and roughness of the electrode surface. By understanding this concept, in this paper; we compared the performance of micro electrodes containing poly(Py-co-PAA) with macro electrode containing same copolymer, showing that micro electrodes are more sensitive than the macro electrodes for biosensor applications. Sensors based on the copolymer electropolymerised on both micro and macro electrodes were evaluated across a range of oligonucleotide concentrations. The interfacial electron charge transfer resistance between the solution and electrode surface was studied using electrochemical impedance spectroscopy (EIS).

Many medical, forensic science, environmental and general scientific difficulties may be aided by the existence of suitable biosensors such as gene sensors, body fluid detection DNA sensors, disease detection DNA sensors etc. The sensor technology described here uses the conducting polymer polypyrrole (PPy) as both sensing element and transducer of sensing events. Stability and reproducibility are necessary characteristics of practical biosensors. The stability of polymers can be investigated using electrical impedance spectroscopy (EIS). This work discusses research focused towards creating a stable, reproducible sensor surface for oligonucleotide detection. The effect of electropolymerisation conditions (electropolymerisation method, solvent and electrolyte used), post-growth treatment (cycling and EIS experiments), and the sensing-environment conditions on sensor stability and applicability will be discussed.

Composite nanofibres of poly (lactic acid) (PLA) with polyaniline (PANI) or poly (aniline-co-m-aminobenzoic acid) (P (ANI-co-m-ABA)) were prepared by electrospinning. Thermal effects on the properties of the composite nanofibres were studied by means of DSC and TGA. TGA results show that the onset thermal degradation temperature of the composite fibres was slightly higher than that of pure PLA. The degree of the crystallinity of the nanofibres was determined from DSC data and compared to film with the same composition.

We discuss experimental issues associated with a novel operating mode of scanning ion conductance microscopy (SICM). This mode characterizes the ion fluxes that emanate from conducting polymers (CPs) as they actuate, important for understanding CP applications ranging from artificial muscles to micropumps. The CP studied is a thin film of poly (3,4-ethylenedioxythiophene) (PEDOT) actuated out of plane. We outline the design principles underpinning our CP ion flux measurements and discuss experimental complications that arose - most notably a baseline current that may be attributable to a spatially varying CP oxidation state. We discuss the dependence of this baseline ion flux current on the separation distance between SICM tip and CP film, substrate type and substrate area.

Polyanilines having two different morphologies (nanorods for NR-PANI and granular for G-PANI) were synthesized and subjected to thermal treatment. NR-PANI and G-PANI were thermally stable up to 300 and 250 ºC respectively. Upon thermal treatment, both the polyanilines exhibited suppressed conductivity and free radical scavenging capacity. The polyanilines also became completely amorphous after treatment above 200 ºC.

Three sheets to the wind: The self‐assembly of polyaniline nanostructures is strongly dependent on single oligoanilinic nanosheets that undergo subsequent interactions, such as stacking and rolling. Imaging and spectroscopy tools detailed the stacking of nanosheets to form thicker nanoflakes and subsequently serve as nucleation sites for polyaniline synthesis.

The co‐vaporization and simultaneous polymerization of EDOT and APTES on a FTS‐coated substrate resulting in a homogeneous PEDOT/ASSQ thin film is described. The physicochemical properties of the film, including surface hardness, solvent mechanical wear resistance, and resistance to scratch, were much better than those of pure PEDOT. A PEDOT/ASSQ hybrid film with homogeneous morphology resulted, as judged by AFM topography scans, surface roughness calculations, and SEM images. The ASSQ proportion in the hybrid films, as investigated by XPS and EDS, was strongly dependent on the content of FTS on the substrate. In addition, the simultaneous polymerization of a PEDOT/ASSQ hybrid film onto selective micropatterns was demonstrated and analyzed.

Summary:Hollow microspheres of PEDOT (poly(3,4‐ethylenedioxythiophene) ranging from 0.5 to 10 µm have been synthesized by chemically oxidative polymerization of EDOT(3,4‐ethylenedioxythiophene) using ammonium persulfate in a catanionic surfactant solution obtained by mixing cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzenesulfonate (SDBS). The effect of the molar ratio of CTAB to SDBS on the morphology of the PEDOT oxidation products has been investigated using SEM and TEM and by an analysis of the structural properties using UV‐visible, FTIR and Raman spectroscopies, elemental analysis and conductivity measurements. The electro‐catalytic activity of PEDOT hollow microspheres for the oxidation of ascorbic acid was investigated by cyclic voltammetry in a pH 6 citrate/phosphate buffer solution and compared to the activity of granular PEDOT particles formed in the absence of the catanionic surfactant.

Polypyrrole (PPY) film has been selected as a platform material for drug delivery due to its inherent conductivity, ease of preparation and apparent biocompatibility. PPY films were prepared containing the antipsychotic drug risperidone as a model compound. Drug release profiles could be altered by applying different electrical stimulation to these films. Atomic force microscopy was used to investigate changes in PPY film thickness when different stimuli were applied. The highest levels of drug release were observed when PPY was reduced; this was accompanied by expansion of the film. Technology such as this could be utilized for implantable drug delivery devices, where the dose could be adjusted by external signaling.

The identification and control of a critical stage of polyaniline “nanotube” self‐assembly is presented, namely the granular agglomeration or growth onto nanorod templates. When the synthesis pH is held above 2.5, smooth insulating nanorods exhibiting hydrogen bonding and containing phenazine structures are produced, while below pH 2.5, small 15–30 nm granular polyaniline nanoparticles appear to agglomerate onto the available nanorod surface, apparently improving conductivity of the resulting structures by three orders of magnitude. This finding affects both fundamental theories of polyaniline nanostructure self‐assembly and their practical applications.