Implantable Flexible Sensors for Health Monitoring.

Flexible sensors, as a significant component of flexible electronics, have attracted great interest the realms of human-computer interaction and health monitoring due to their high conformability, adjustable sensitivity, and excellent durability. In comparison to wearable sensor-based in vitro health monitoring, the use of implantable flexible sensors (IFSs) for in vivo health monitoring offers more accurate and reliable vital sign information due to their ability to adapt and directly integrate with human tissue. IFSs show tremendous promise in the field of health monitoring, with unique advantages such as robust signal reading capabilities, lightweight design, flexibility, and biocompatibility. Herein, a review of IFSs for vital signs monitoring is detailly provided, highlighting the essential conditions for in vivo applications. As the prerequisites of IFSs, the stretchability and wireless self-powered properties of the sensor are discussed, with a special attention paid to the sensing materials which can maintain prominent biosafety (i.e., biocompatibility, biodegradability, bioresorbability). Furthermore, the applications of IFSs monitoring various parts of the body are described in detail, with a summary in brain monitoring, eye monitoring, and blood monitoring. Finally, the challenges as well as opportunities in the development of next-generation IFSs are presented.

AI-assisted accelerated MRI of the ankle: clinical practice assessment.

BACKGROUND: High-spatial resolution magnetic resonance imaging (MRI) is essential for imaging ankle joints. However, the clinical application of fast spin-echo sequences remains limited by their lengthy acquisition time. Artificial intelligence-assisted compressed sensing (ACS) technology has been recently introduced as an integrative acceleration solution. We compared ACS-accelerated 3-T ankle MRI to conventional methods of compressed sensing (CS) and parallel imaging (PI) . METHODS: We prospectively included 2 healthy volunteers and 105 patients with ankle pain. ACS acceleration factors for ankle protocol of T1-, T2-, and proton density (PD)-weighted sequences were optimized in a pilot study on healthy volunteers (acceleration factor 3.2-3.3×). Images of patients acquired using ACS and conventional acceleration methods were compared in terms of acquisition times, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, and diagnostic agreement. Shapiro-Wilk test, Cohen κ, intraclass correlation coefficient, and one-way ANOVA with post hoc tests (Tukey or Dunn) were used. RESULTS: ACS acceleration reduced the acquisition times of T1-, T2-, and PD-weighted sequences by 32-43%, compared with conventional CS and PI, while maintaining image quality (mostly higher SNR with p < 0.004 and higher CNR with p < 0.047). The diagnostic agreement between ACS and conventional sequences was rated excellent (κ = 1.00). CONCLUSIONS: The optimum ACS acceleration factors for ankle MRI were found to be 3.2-3.3× protocol. The ACS allows faster imaging, yielding similar image quality and diagnostic performance. RELEVANCE STATEMENT: AI-assisted compressed sensing significantly accelerates ankle MRI times while preserving image quality and diagnostic precision, potentially expediting patient diagnoses and improving clinical workflows. KEY POINTS: • AI-assisted compressed sensing (ACS) significantly reduced scan duration for ankle MRI. • Similar image quality achieved by ACS compared to conventional acceleration methods. • A high agreement by three acceleration methods in the diagnosis of ankle lesions was observed.

Assessment of Blood Volume in Liposuction Fluids Using Colorimetry.

OBJECTIVE: The possibility of using a color contrast method to evaluate blood loss during liposuction was assessed. A color chart of blood-lipid content associated with different blood volumes was developed. METHODS: Three color cards with different concentrations of blood were developed based on clinical parameters. The color cards were used to evaluate the volume of blood present in liposuction solutions obtained from 60 clinical liposuction patients. The red blood cell count also was evaluated for each patient. The data obtained using each evaluation method were compared and statistically analyzed to determine the most accurate calculation formula. RESULTS: The red blood cell counts were compared to the color card results. The paired t test results for the calculated values for the 3:1, 2:1, and 1:1 color cards and the red blood cell count values were comparable (44.3 ± 22.1 ml vs. 53.6 ± 25.0 ml, t = 10.5; 45.4 ± 19.0 ml vs. 55.2 ± 20.7 ml, t = 18.1; 41.9 ± 25.6 ml vs. 52.8 ± 28.3 ml, t = 14.0). The P values were < 0.05, and the difference between the two groups was statistically significant. The average standard error of the mean was 0.90, 0.54, and 0.77, respectively. Sixty samples were evaluated in a scatter diagram using the two detection methods. Trend analysis revealed that the two results demonstrated a linear increase (y = 5.6 + 1.1x), R2 = 0.989, indicating that the two inspection methods were highly correlated with only small errors. CONCLUSION: The colorimetric card protocol developed in this study could quickly, accurately, and conveniently calculate blood volumes in liposuction fluids, which has considerable clinical significance. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Integrated Assessment of Computational Coronary Physiology From a Single Angiographic View in Patients Undergoing TAVI.

BACKGROUND: Angiography-derived computational physiology is an appealing alternative to pressure-wire coronary physiology assessment. However, little is known about its reliability in the setting of severe aortic stenosis. This study sought to provide an integrated assessment of epicardial and microvascular coronary circulation by means of single-view angiography-derived physiology in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). METHODS: Pre-TAVI angiographic projections of 198 stenotic coronary arteries (123 patients) were analyzed by means of Murray's law-based quantitative flow ratio and angiography microvascular resistance. Wire-based reference measurements were available for comparison: fractional flow reserve (FFR) in all cases, instantaneous wave-free ratio in 148, and index of microvascular resistance in 42 arteries. RESULTS: No difference in terms of the number of ischemia-causing stenoses was detected between FFR ≤0.80 and Murray's law-based quantitative flow ratio ≤0.80 (19.7% versus 19.2%; P=0.899), while this was significantly higher when instantaneous wave-free ratio ≤0.89 (44.6%; P=0.001) was used. The accuracy of Murray's law-based quantitative flow ratio ≤0.80 in predicting pre-TAVI FFR ≤0.80 was significantly higher than the accuracy of instantaneous wave-free ratio ≤0.89 (93.4% versus 77.0%; P=0.001), driven by a higher positive predictive value (86.9% versus 50%). Similar findings were observed when considering post-TAVI FFR ≤0.80 as reference. In 82 cases with post-TAVI angiographic projections, Murray's law-based quantitative flow ratio values remained stable, with a low rate of reclassification of stenosis significance (9.9%), similar to FFR and instantaneous wave-free ratio. Angiography microvascular resistance demonstrated a significant correlation (Rho=0.458; P=0.002) with index of microvascular resistance, showing an area under the curve of 0.887 (95% CI, 0.752-0.964) in predicting index of microvascular resistance ≥25. CONCLUSIONS: Angiography-derived physiology provides a valid, reliable, and systematic assessment of the coronary circulation in a complex scenario, such as severe aortic stenosis.

Comprehensive Approach to Assessment of Liver Viability During Normothermic Machine Perfusion.

Liver transplantation is the most effective treatment of advanced liver disease, and the use of extended criteria donor organs has broadened the source of available livers. Although normothermic machine perfusion (NMP) has become a useful tool in liver transplantation, there are no consistent criteria that can be used to evaluate the viability of livers during NMP. This review summarizes the criteria, indicators, and methods used to evaluate liver viability during NMP. The shape, appearance, and hemodynamics of the liver can be analyzed at a macroscopic level, while markers of liver injury, indicators of liver and bile duct function, and other relevant indicators can be evaluated by biochemical analysis. The liver can also be assessed by tissue biopsy at the microscopic level. Novel methods for assessment of liver viability are introduced. The limitations of evaluating liver viability during NMP are discussed and suggestions for future clinical practice are provided.

Wafer-Scale and Cost-Effective Manufacturing of Controllable Nanogap Arrays for Highly Sensitive SERS Sensing.

The metallic nanogap has been proved as an efficient architecture for surface-enhanced Raman scattering (SERS) applications. Although a lot of nanogap fabrication methods have been proposed in the last few decades, the economical and high-yield manufacturing of sub-10 nm gaps remains a challenge. Here, we present a convenient and cost-effective fabrication method for wafer-scale patterning of metallic nanogaps, which simply combines photolithographic metal patterning, swelling-induced nanocracking, and superimposition metal sputtering without requiring expensive nanofabrication equipment. By controlling the swelling time and metal deposition thickness, the gap size can be precisely defined, down to the sub-10 nm scale. Furthermore, we demonstrate that the fabricated nanogap array can be used as an excellent SERS substrate for molecule measurements and shows a high Raman enhancement factor of ∼108 and a high sensitivity for the detection of rhodamine 6G (R6G) molecules, even down to 10-14 M, indicating an extraordinary capability for single-molecule detection. Due to its high controllability and wafer-scale fabrication capability, this nanogap fabrication method offers a promising route for highly sensitive and economical SERS detections.

Utility of Advanced DWI in the Detection of Spinal Cord Microstructural Alterations and Assessment of Neurologic Function in Cervical Spondylotic Myelopathy Patients.

BACKGROUND: Diffusion-weighted imaging (DWI) can quantify the microstructural changes in the spinal cord. It might be a substitute for T2 increased signal intensity (ISI) for cervical spondylotic myelopathy (CSM) evaluation and prognosis. PURPOSE: The purpose of the study is to investigate the relationship between DWI metrics and neurologic function of patients with CSM. STUDY TYPE: Retrospective. POPULATION: Forty-eight patients with CSM (18.8% females) and 36 healthy controls (HCs, 25.0% females). FIELD STRENGTH/SEQUENCE: 3 T; spin-echo echo-planar imaging-DWI; turbo spin-echo T1/T2; multi-echo gradient echo T2*. ASSESSMENT: For patients, conventional MRI indicators (presence and grades of T2 ISI), DWI indicators (neurite orientation dispersion and density imaging [NODDI]-derived isotropic volume fraction [ISOVF], intracellular volume fraction, and orientation dispersion index [ODI], diffusion tensor imaging [DTI]-derived fractional anisotropy [FA] and mean diffusivity [MD], and diffusion kurtosis imaging [DKI]-derived FA, MD, and mean kurtosis), clinical conditions, and modified Japanese Orthopaedic Association (mJOA) were recorded before the surgery. Neurologic function improvement was measured by the 3-month follow-up recovery rate (RR). For HCs, DWI, and mJOA were measured as baseline comparison. STATISTICAL TESTS: Continuous (categorical) variables were compared between patients and HCs using Student's t-tests or Mann-Whitney U tests (chi-square or Fisher exact tests). The relationships between DWI metrics/conventional MRI findings, and the pre-operative mJOA/RR were assessed using correlation and multivariate analysis. P < 0.05 was considered statistically significant. RESULTS: Among patients, grades of T2 ISI were not correlated with pre-surgical mJOA/RR (P = 0.717  and 0.175, respectively). NODDI ODI correlated with pre-operative mJOA (r = -0.31). DTI FA, DKI FA, and NODDI ISOVF were correlated with the recovery rate (r = 0.31, 0.41, and -0.34, respectively). In multivariate analysis, NODDI ODI (DTI FA, DKI FA, NODDI ISOVF) significantly contributed to the pre-operative mJOA (RR) after adjusting for age. DATA CONCLUSION: DTI FA, DKI FA, and NODDI ISOVF are predictors for prognosis in patients with CSM. NODDI ODI can be used to evaluate CSM severity. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 5.

Analysis of Health Service Utilization and its Influencing Factors among Patients with Pneumoconiosis in China.

Pneumoconiosis, an interstitial lung disease that occurs from breathing in certain kinds of damaging dust particles, is a major occupational disease in China. Patients diagnosed with occupational pneumoconiosis can avail of free medical treatment, whereas patients without a diagnosis of occupational diseases cannot not claim free medical treatment in most provinces from the government before 2019. This study aimed to analyze the priority of medical facility selection and its influencing factors among patients with pneumoconiosis. A total of 1,037 patients with pneumoconiosis from nine provinces in China were investigated. The health service institutions most frequently selected by the patients were county-level hospitals (37.5%). The main reason for the choice was these hospitals' close distance to the patients' homes (47.3%). The factors for the choice of health care institutions were living in the eastern region ( OR = 2.91), living in rural areas ( OR = 2.10), silicosis diagnosis ( OR = 2.44), employment in private enterprises ( OR = 2.91), smoking ( OR = 2.69), and quit smoking ( OR = 3.98). The diagnosis, treatment, and rehabilitation therapy of pneumoconiosis should be enhanced in primary medical institutions.

Geographical Environment Factors and Risk Assessment of Tick-Borne Encephalitis in Hulunbuir, Northeastern China.

Tick-borne encephalitis (TBE) is one of natural foci diseases transmitted by ticks. Its distribution and transmission are closely related to geographic and environmental factors. Identification of environmental determinates of TBE is of great importance to understanding the general distribution of existing and potential TBE natural foci. Hulunbuir, one of the most severe endemic areas of the disease, is selected as the study area. Statistical analysis, global and local spatial autocorrelation analysis, and regression methods were applied to detect the spatiotemporal characteristics, compare the impact degree of associated factors, and model the risk distribution using the heterogeneity. The statistical analysis of gridded geographic and environmental factors and TBE incidence show that the TBE patients mainly occurred during spring and summer and that there is a significant positive spatial autocorrelation between the distribution of TBE cases and environmental characteristics. The impact degree of these factors on TBE risks has the following descending order: temperature, relative humidity, vegetation coverage, precipitation and topography. A high-risk area with a triangle shape was determined in the central part of Hulunbuir; the low-risk area is located in the two belts next to the outside edge of the central triangle. The TBE risk distribution revealed that the impact of the geographic factors changed depending on the heterogeneity.

Soft-Etching Copper and Silver Electrodes for Significant Device Performance Improvement toward Facile, Cost-Effective, Bottom-Contacted, Organic Field-Effect Transistors.

Poor charge injection and transport at the electrode/semiconductor contacts has been so far a severe performance hurdle for bottom-contact bottom-gate (BCBG) organic field-effect transistors (OFETs). Here, we have developed a simple, economic, and effective method to improve the carrier injection efficiency and obtained high-performance devices with low cost and widely used source/drain (S/D) electrodes (Ag/Cu). Through the simple electrode etching process, the work function of the electrodes is more aligned with the semiconductors, which reduces the energy barrier and facilitates the charge injection. Besides, the formation of the thinned electrode edge with desirable micro/nanostructures not only leads to the enlarged contact side area beneficial for the carrier injection but also is in favor of the molecular self-organization for continuous crystal growth at the contact/active channel interface, which is better for the charge injection and transport. These effects give rise to the great reduction of contact resistance and the amazing improvement of the low-cost bottom-contact configuration OFETs performance.

An integrated stroke model with a consistent penumbra for the assessment of neuroprotective interventions.

BACKGROUND/AIM: A longer period of vessel occlusion reduces the coefficient of variation of the infarct lesion size ['infarct variation coefficient' (IVC)] due to a gradual expansion of the lesion within a limited territory defined by the vascular anatomy, but it increases the mortality rate. A crucial issue in the induction of experimental focal cerebral ischemia has been to achieve a low IVC value and a low mortality rate. We attempted to improve IVC and mortality using the 3-vessel occlusion model. METHODS: We introduced a new, transtemporal fascia approach to expose the zygomatic arch, in which the fascia of the temporal muscle is cut and retracted dorsally together with the facial nerve and the vein en bloc. RESULTS/CONCLUSION: The approach avoided traumatic venous bleeding around the zygomatic arch. We established a bloodless model of focal ischemia that can produce a consistent degree of reduction in the regional cerebral blood flow within the ischemic penumbra. The model, characterized by a 15-min ischemia, an IVC of 15-21%, and low mortality after ischemia, is expected to produce reliable preclinical evidence in the assessment of neuroprotective interventions for ischemic stroke. The entire procedure is presented in the online supplementary video (www. karger.com/doi/10.1159/000356048).

Regulação autonômica das propriedades mecânicas em bioprótese valvar porcina / Autonomic regulation of mechanical properties in porcine mitral valve cusps / Regulación autonómica de las propiedades mecánicas en bioprótesis valvular porcina

FUNDAMENTO: A presença de nervos nas válvulas cardíacas foi demonstrada pela primeira vez há décadas e identificadas em subpopulações: simpáticas e parassimpáticas, e, portanto, é esperado que as válvulas sejam grandemente afetadas pelos nervos autônomos. Entretanto, poucos estudos têm se concentrado na regulação de válvulas cardíacas pelo sistema nervoso autônomo. OBJETIVO: Buscamos identificar o papel do sistema nervoso autônomo na regulação das propriedades mecânicas dos tecidos de válvulas mitrais porcinas. MÉTODOS: As propriedades mecânicas dos folhetos de válvulas mitrais porcinas foram avaliados em resposta à norepinefrina (NE) e acetilcolina (ACH), os principais neurotransmissores. Ao mesmo tempo, fentolamina (FENT), metoprolol (Metop), atropina (Atrop) e desnudamento endotelial foram adicionados ao sistema reativo. RESULTADOS: Sob condições fisiológicas, a rigidez não foi afetada pelo desnudamento endotelial (p > 0,05). A NE significantemente aumentou a rigidez valvar por aumento de 10 vezes na concentração (10-6 vs 10-7, p < 0,05; 10-5 vs 10-6, p < 0,05). Essa resposta foi amenizada por FENT, Metop ou desnudamento endotelial (p < 0,05); entretanto, manteve-se aumentada de maneira significante quando comparada aos Controles (p < 0,05). A ACH causou uma diminuição na rigidez acompanhada por um aumento em sua concentração (alteração significante na rigidez por aumento de 10 vezes na concentração de ACH, 10-6 vs Controle, p < 0,05; 10-5 vs 10-6, p < 0,05), que foi revertida pelo desnudamento endotelial e Atrop (p > 0,05 vs Controle). CONCLUSÃO: Esses achados ressaltam o papel do sistema nervoso autônomo na regulação das propriedades mecânicas das cúspides de válvula mitral porcina, o que reforça a importância do estado nervoso autônomo no funcionamento ideal da válvula.

BACKGROUND: The presence of nerves in heart valves was first depicted decades ago and identified into subpopulations: sympathetic, parasympathetic. So valves are expected to be greatly affected by the autonomic nerves. However, few studies have focused on the regulation of heart valves by the autonomic nervous system. OBJECTIVE: We sought to identify the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve tissues. METHODS: Mechanical properties of porcine mitral valve leaflets were evaluated in response to norepinephrine (NE) and acetylcholine (ACH), the main neurotransmitters. At the same time, phentolamine (Phent), metoprolol (Metop), atropine (Atrop) and endothelial denudation were added to the reactive system. RESULTS: Under physiological conditions, the stiffness was not affected by endothelial denudation (p > 0.05). NE elevated the valve stiffness significantly per 10-fold increase in concentration (10-6 vs 10-7, p < 0.05; 10-5 vs 10-6, p < 0.05). This response was mitigated by Phent, Metop or endothelial denudation (p < 0.05), however, it was still increased significantly when compared to Controls (p < 0.05). ACH caused a decrease in stiffness accompanied by an increase in its concentration (significant change in stiffness per 10-fold increase in ACH concentration, 10-6 vs Control, p < 0.05; 10-5 vs 10-6, p < 0.05), which were reversed by endothelial denudation and Atrop (p > 0.05 vs Control). CONCLUSION: These findings highlight the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve cusps, which underline the importance of autonomic nervous status for optimal valve function.

FUNDAMENTO: La presencia de nervios en las válvulas cardíacas quedó demostrada por primera vez hace algunas décadas e identificadas en sub-poblaciones: simpáticas y parasimpáticas y por lo tanto, lo que se espera es que las válvulas reciban una gran afectación de los nervios autónomos. Sin embargo, pocos estudios se han concentrado en la regulación de válvulas cardíacas a través del sistema nervioso autónomo. OBJETIVO: Buscamos identificar el papel del sistema nervioso autónomo en la regulación de las propiedades mecánicas de los tejidos de las válvulas mitrales porcinas. MÉTODOS: Las propiedades mecánicas de las capas de válvulas mitrales porcinas fueron evaluadas en respuesta a la norepinefrina (NE) y a la acetilcolina (ACH), los principales neurotransmisores. Igualmente, la fentolamina (FENT), el metoprolol (Metop), la atropina (Atrop) y la denudación endotelial también se añadieron al sistema reactivo. RESULTADOS: Bajo condiciones fisiológicas, la rigidez no se afectó por el denudación endotelial (p > 0,05). La NE aumentó significativamente la rigidez valvular con un aumento de 10 veces en la concentración (10-6 vs 10-7, p < 0,05; 10-5 vs 10-6, p < 0,05). Esa respuesta fue amenizada por FENT, Metop o denudación endotelial (p < 0,05); pero se mantuvo aumentada de manera significativa cuando se le comparó con los Controles (p < 0,05). La ACH causó una disminución en la rigidez acompañada por un aumento en su concentración (alteración significativa en la rigidez por el aumento en 10 veces de la concentración de ACH, 10-6 vs Control, p < 0,05; 10-5 vs 10-6, p < 0,05), que fue revertida por la denudación endotelial y Atrop (p > 0,05 vs Control). CONCLUSIÓN: Esos hallazgos destacan el rol del sistema nervioso autónomo en la regulación de las propiedades mecánicas de las cúspides de la válvula mitral porcina, lo que refuerza la importancia del estado nervioso autónomo en el funcionamiento ideal de la válvula.