A skin-interfaced, miniaturized platform for triggered induction, capture and colorimetric multicomponent analysis of microliter volumes of sweat

Eccrine sweat can serve as a source of biomarkers for assessing physiological health and nutritional balance, for tracking loss of essential species from the body and for evaluating exposure to hazardous substances. The growing interest in this relatively underexplored class of biofluid arises in part from its non-invasive ability for capture and analysis. The simplest devices, and the only ones that are commercially available, exploit soft microfluidic constructs and colorimetric assays with purely passive modes of operation. The most sophisticated platforms exploit batteries, electronic components and radio hardware for inducing sweat, for electrochemical evaluation of its content and for wireless transmission of this information. The work reported here introduces a technology that combines the advantages of these two different approaches, in the form of a cost-effective, easy-to-use device that supports on-demand evaluation of multiple biomarkers in sweat. This flexible, skin-interfaced, miniaturized system incorporates a hydrogel that contains an approved drug to activate eccrine sweat glands, electrodes and a simple circuit and battery to delivery this drug by iontophoresis through the surface of the skin, microfluidic channels and microreservoirs to capture the induced sweat, and multiple colorimetric assays to evaluate the concentrations of chloride, zinc, and iron. As demonstrated in healthy human participants monitored before and after a meal, such devices yield results that match those of traditional laboratory analysis techniques. Clinical studies that involve cystic fibrosis pediatric patients illustrate the use of this technology as a simple, painless, and reliable alternative to traditional hospital systems for measurements of sweat chloride.

A wireless, implantable bioelectronic system for monitoring urinary bladder function following surgical recovery

Partial cystectomy procedures for urinary bladder-related dysfunction involve long recovery periods, during which urodynamic studies (UDS) intermittently assess lower urinary tract function. However, UDS are not patient-friendly, they exhibit user-to-user variability, and they amount to snapshots in time, limiting the ability to collect continuous, longitudinal data. These procedures also pose the risk of catheter-associated urinary tract infections, which can progress to ascending pyelonephritis due to prolonged lower tract manipulation in high-risk patients. Here, we introduce a fully bladder-implantable platform that allows for continuous, real-time measurements of changes in mechanical strain associated with bladder filling and emptying via wireless telemetry, including a wireless bioresorbable strain gauge validated in a benchtop partial cystectomy model. We demonstrate that this system can reproducibly measure real-time changes in a rodent model up to 30 d postimplantation with minimal foreign body response. Studies in a nonhuman primate partial cystectomy model demonstrate concordance of pressure measurements up to 8 wk compared with traditional UDS. These results suggest that our system can be used as a suitable alternative to UDS for long-term postoperative bladder recovery monitoring.

Functional bio-inspired hybrid fliers with separated ring and leading edge vortices

Recent advances in passive flying systems inspired by wind-dispersed seeds contribute to increasing interest in their use for remote sensing applications across large spatial domains in the Lagrangian frame of reference. These concepts create possibilities for developing and studying structures with performance characteristics and operating mechanisms that lie beyond those found in nature. Here, we demonstrate a hybrid flier system, fabricated through a process of controlled buckling, to yield unusual geometries optimized for flight. Specifically, these constructs simultaneously exploit distinct fluid phenomena, including separated vortex rings from features that resemble those of dandelion seeds and the leading-edge vortices derived from behaviors of maple seeds. Advanced experimental measurements and computational simulations of the aerodynamics and induced flow physics of these hybrid fliers establish a concise, scalable analytical framework for understanding their flight mechanisms. Demonstrations with functional payloads in various forms, including bioresorbable, colorimetric, gas-sensing, and light-emitting platforms, illustrate examples with diverse capabilities in sensing and tracking.

Materials and Device Designs for Wireless Monitoring of Temperature and Thermal Transport Properties of Wound Beds during Healing

Chronic wounds represent a major health risk for diabetic patients. Regeneration of such wounds requires regular medical treatments over periods that can extend for several months or more. Schemes for monitoring the healing process can provide important feedback to the patient and caregiver. Although qualitative indicators such as malodor or fever can provide some indirect information, quantitative measurements of the wound bed have the potential to yield important insights. The work presented here introduces materials and engineering designs for a wireless system that captures spatio-temporal temperature and thermal transport information across the wound continuously throughout the healing process. Systematic experimental and computational studies establish the materials aspects and basic capabilities of this technology. In vivo studies reveal that both the temperature and the changes in this quantity offer information on wound status, with indications of initial exothermic reactions and mechanisms of scar tissue formation. Bioresorbable materials serve as the foundations for versions of this device that create possibilities for monitoring on and within the wound site, in a way that bypasses the risks of physical removal.

High-Performing and Capacitive-Matched Triboelectric Implants Driven by Ultrasound

In implantable bioelectronics, which aim for semipermanent use of devices, biosafe energy sources and packaging materials to protect devices are essential elements. However, research so far has been conducted in a direction where they cannot coexist. Here, the development of capacitance-matched triboelectric implants driven is reported by ultrasound under 500 mW cm-2 safe intensity and realize a battery-free, miniatured, and wireless neurostimulator with full titanium (Ti) packaging. The triboelectric implant with high dielectric composite, which has ultralow output impedance, can efficiently deliver sufficient power to generate the stimulation pulse without an energy-storing battery, despite ultrasound attenuation due to the Ti, and has the highest energy transmission efficiency among those reported so far. In vivo study using a rat model demonstrated that the proposed device system is an effective solution for relieving urinary symptoms. These achievements provide a significant step toward permanently implantable devices for controlling human organs and treating various diseases.

An on-demand bioresorbable neurostimulator

Bioresorbable bioelectronics, with their natural degradation properties, hold significant potential to eliminate the need for surgical removal. Despite notable achievements, two major challenges hinder their practical application in medical settings. First, they necessitate sustainable energy solutions with biodegradable components via biosafe powering mechanisms. More importantly, reliability in their function is undermined by unpredictable device lifetimes due to the complex polymer degradation kinetics. Here, we propose an on-demand bioresorbable neurostimulator to address these issues, thus allowing for clinical operations to be manipulated using biosafe ultrasound sources. Our ultrasound-mediated transient mechanism enables (1) electrical stimulation through transcutaneous ultrasound-driven triboelectricity and (2) rapid device elimination using high-intensity ultrasound without adverse health effects. Furthermore, we perform neurophysiological analyses to show that our neurostimulator provides therapeutic benefits for both compression peripheral nerve injury and hereditary peripheral neuropathy. We anticipate that the on-demand bioresorbable neurostimulator will prove useful in the development of medical implants to treat peripheral neuropathy.

Differentiation between Chondrosarcoma and Synovial Chondromatosis of the Temporomandibular Joint Using CT and MR Imaging

BACKGROUND AND PURPOSE

Chondrosarcoma and synovial chondromatosis of the temporomandibular joint share overlapping clinical and histopathologic features. We aimed to identify CT and MR imaging features to differentiate chondrosarcoma from synovial chondromatosis of the temporomandibular joint.

MATERIALS AND METHODS

The CT and MR images of 12 and 35 patients with histopathologically confirmed chondrosarcoma and synovial chondromatosis of the temporomandibular joint, respectively, were retrospectively reviewed. Imaging features including lesion size, center, enhancement, destruction/sclerosis of surrounding bone, infiltration into the tendon of the lateral pterygoid muscle, calcification, periosteal reaction, and osteophyte formation were assessed. A comparison between chondrosarcoma and synovial chondromatosis was performed with a Student t test for quantitative variables and the Fisher exact test or linear-by-linear association test for qualitative variables. Receiver operating characteristic analysis was performed to determine the diagnostic performance for differentiation of chondrosarcoma and synovial chondromatosis based on a composite score obtained by assigning 1 point for each of 9 imaging features.

RESULTS

High-risk imaging features for chondrosarcoma were the following: lesion centered on the mandibular condyle, destruction of the mandibular condyle, no destruction/sclerosis of the articular eminence/glenoid fossa, infiltration into the tendon of the lateral pterygoid muscle, absent or stippled calcification, periosteal reaction, internal enhancement, and size of ≥30.5 mm. The best cutoff value to discriminate chondrosarcoma from synovial chondromatosis was the presence of any 4 of these high-risk imaging features, with an area under the curve of 0.986 and an accuracy of 95.8%.

CONCLUSIONS

CT and MR imaging features can distinguish chondrosarcoma from synovial chondromatosis of the temporomandibular joint with improved diagnostic performance when a subcombination of 9 imaging features is used.

Self-powered, light-controlled, bioresorbable platforms for programmed drug delivery

Degradable polymer matrices and porous scaffolds provide powerful mechanisms for passive, sustained release of drugs relevant to the treatment of a broad range of diseases and conditions. Growing interest is in active control of pharmacokinetics tailored to the needs of the patient via programmable engineering platforms that include power sources, delivery mechanisms, communication hardware, and associated electronics, most typically in forms that require surgical extraction after a period of use. Here we report a light-controlled, self-powered technology that bypasses key disadvantages of these systems, in an overall design that is bioresorbable. Programmability relies on the use of an external light source to illuminate an implanted, wavelength-sensitive phototransistor to trigger a short circuit in an electrochemical cell structure that includes a metal gate valve as its anode. Consequent electrochemical corrosion eliminates the gate, thereby opening an underlying reservoir to release a dose of drugs by passive diffusion into surrounding tissue. A wavelength-division multiplexing strategy allows release to be programmed from any one or any arbitrary combination of a collection of reservoirs built into an integrated device. Studies of various bioresorbable electrode materials define the key considerations and guide optimized choices in designs. In vivo demonstrations of programmed release of lidocaine adjacent the sciatic nerves in rat models illustrate the functionality in the context of pain management, an essential aspect of patient care that could benefit from the results presented here.

Bioresorbable, wireless, and battery-free system for electrotherapy and impedance sensing at wound sites

Chronic wounds, particularly those associated with diabetes mellitus, represent a growing threat to public health, with additional notable economic impacts. Inflammation associated with these wounds leads to abnormalities in endogenous electrical signals that impede the migration of keratinocytes needed to support the healing process. This observation motivates the treatment of chronic wounds with electrical stimulation therapy, but practical engineering challenges, difficulties in removing stimulation hardware from the wound site, and absence of means to monitor the healing process create barriers to widespread clinical use. Here, we demonstrate a miniaturized wireless, battery-free bioresorbable electrotherapy system that overcomes these challenges. Studies based on a splinted diabetic mouse wound model confirm the efficacy for accelerated wound closure by guiding epithelial migration, modulating inflammation, and promoting vasculogenesis. Changes in the impedance provide means for tracking the healing process. The results demonstrate a simple and effective platform for wound site electrotherapy.

Biodegradable, three-dimensional colorimetric fliers for environmental monitoring

Recently reported winged microelectronic systems offer passive flight mechanisms as a dispersal strategy for purposes in environmental monitoring, population surveillance, pathogen tracking, and other applications. Initial studies indicate potential for technologies of this type, but advances in structural and responsive materials and in aerodynamically optimized geometries are necessary to improve the functionality and expand the modes of operation. Here, we introduce environmentally degradable materials as the basis of 3D fliers that allow remote, colorimetric assessments of multiple environmental parameters-pH, heavy metal concentrations, and ultraviolet exposure, along with humidity levels and temperature. Experimental and theoretical investigations of the aerodynamics of these systems reveal design considerations that include not only the geometries of the structures but also their mass distributions across a range of bioinspired designs. Preliminary field studies that rely on drones for deployment and for remote colorimetric analysis by machine learning interpretation of digital images illustrate scenarios for practical use.

A bioresorbable peripheral nerve stimulator for electronic pain block

Local electrical stimulation of peripheral nerves can block the propagation of action potentials, as an attractive alternative to pharmacological agents for the treatment of acute pain. Traditional hardware for such purposes, however, involves interfaces that can damage nerve tissue and, when used for temporary pain relief, that impose costs and risks due to requirements for surgical extraction after a period of need. Here, we introduce a bioresorbable nerve stimulator that enables electrical nerve block and associated pain mitigation without these drawbacks. This platform combines a collection of bioresorbable materials in architectures that support stable blocking with minimal adverse mechanical, electrical, or biochemical effects. Optimized designs ensure that the device disappears harmlessly in the body after a desired period of use. Studies in live animal models illustrate capabilities for complete nerve block and other key features of the technology. In certain clinically relevant scenarios, such approaches may reduce or eliminate the need for use of highly addictive drugs such as opioids.

Skin-Integrated Devices with Soft, Holey Architectures for Wireless Physiological Monitoring, With Applications in the Neonatal Intensive Care Unit

Continuous monitoring of vital signs is an essential aspect of operations in neonatal and pediatric intensive care units (NICUs and PICUs), of particular importance to extremely premature and/or critically ill patients. Current approaches require multiple sensors taped to the skin and connected via hard-wired interfaces to external data acquisition electronics. The adhesives can cause iatrogenic injuries to fragile, underdeveloped skin, and the wires can complicate even the most routine tasks in patient care. Here, materials strategies and design concepts are introduced that significantly improve these platforms through the use of optimized materials, open (i.e., "holey") layouts and precurved designs. These schemes 1) reduce the stresses at the skin interface, 2) facilitate release of interfacial moisture from transepidermal water loss, 3) allow visual inspection of the skin for rashes or other forms of irritation, 4) enable triggered reduction of adhesion to reduce the probability for injuries that can result from device removal. A combination of systematic benchtop testing and computational modeling identifies the essential mechanisms and key considerations. Demonstrations on adult volunteers and on a neonate in an operating NICUs illustrate a broad range of capabilities in continuous, clinical-grade monitoring of conventional vital signs, and unconventional indicators of health status.

Fully implantable and bioresorbable cardiac pacemakers without leads or batteries

Temporary cardiac pacemakers used in periods of need during surgical recovery involve percutaneous leads and externalized hardware that carry risks of infection, constrain patient mobility and may damage the heart during lead removal. Here we report a leadless, battery-free, fully implantable cardiac pacemaker for postoperative control of cardiac rate and rhythm that undergoes complete dissolution and clearance by natural biological processes after a defined operating timeframe. We show that these devices provide effective pacing of hearts of various sizes in mouse, rat, rabbit, canine and human cardiac models, with tailored geometries and operation timescales, powered by wireless energy transfer. This approach overcomes key disadvantages of traditional temporary pacing devices and may serve as the basis for the next generation of postoperative temporary pacing technology.

Triboelectrification induced self-powered microbial disinfection using nanowire-enhanced localized electric field

Air-transmitted pathogens may cause severe epidemics showing huge threats to public health. Microbial inactivation in the air is essential, whereas the feasibility of existing air disinfection technologies meets challenges including only achieving physical separation but no inactivation, obvious pressure drops, and energy intensiveness. Here we report a rapid disinfection method toward air-transmitted bacteria and viruses using the nanowire-enhanced localized electric field to damage the outer structures of microbes. This air disinfection system is driven by a triboelectric nanogenerator that converts mechanical vibration to electricity effectively and achieves self-powered. Assisted by a rational design for the accelerated charging and trapping of microbes, this air disinfection system promotes microbial transport and achieves high performance: >99.99% microbial inactivation within 0.025 s in a fast airflow (2 m/s) while only causing low pressure drops (<24 Pa). This rapid, self-powered air disinfection method may fill the urgent need for air-transmitted microbial inactivation to protect public health.

Transparent, Compliant 3D Mesostructures for Precise Evaluation of Mechanical Characteristics of Organoids

Recently developed methods for transforming 2D patterns of thin-film materials into 3D mesostructures create many interesting opportunities in microsystems design. A growing area of interest is in multifunctional thermal, electrical, chemical, and optical interfaces to biological tissues, particularly 3D multicellular, millimeter-scale constructs, such as spheroids, assembloids, and organoids. Herein, examples of 3D mechanical interfaces are presented, in which thin ribbons of parylene-C form the basis of transparent, highly compliant frameworks that can be reversibly opened and closed to capture, envelop, and mechanically restrain fragile 3D tissues in a gentle, nondestructive manner, for precise measurements of viscoelastic properties using techniques in nanoindentation. Finite element analysis serves as a design tool to guide selection of geometries and material parameters for shape-matching 3D architectures tailored to organoids of interest. These computational approaches also quantitate all aspects of deformations during the processes of opening and closing the structures and of forces imparted by them onto the surfaces of enclosed soft tissues. Studies of cerebral organoids by nanoindentation show effective Young's moduli in the range from 1.5 to 2.5 kPa depending on the age of the organoid. This collection of results suggests broad utility of compliant 3D mesostructures in noninvasive mechanical measurements of millimeter-scale, soft biological tissues.

Bioresorbable Multilayer Photonic Cavities as Temporary Implants for Tether-Free Measurements of Regional Tissue Temperatures

Objective and Impact Statement. Real-time monitoring of the temperatures of regional tissue microenvironments can serve as the diagnostic basis for treating various health conditions and diseases. Introduction. Traditional thermal sensors allow measurements at surfaces or at near-surface regions of the skin or of certain body cavities. Evaluations at depth require implanted devices connected to external readout electronics via physical interfaces that lead to risks for infection and movement constraints for the patient. Also, surgical extraction procedures after a period of need can introduce additional risks and costs. Methods. Here, we report a wireless, bioresorbable class of temperature sensor that exploits multilayer photonic cavities, for continuous optical measurements of regional, deep-tissue microenvironments over a timeframe of interest followed by complete clearance via natural body processes. Results. The designs decouple the influence of detection angle from temperature on the reflection spectra, to enable high accuracy in sensing, as supported by in vitro experiments and optical simulations. Studies with devices implanted into subcutaneous tissues of both awake, freely moving and asleep animal models illustrate the applicability of this technology for in vivo measurements. Conclusion. The results demonstrate the use of bioresorbable materials in advanced photonic structures with unique capabilities in tracking of thermal signatures of tissue microenvironments, with potential relevance to human healthcare.

Stretchable, dynamic covalent polymers for soft, long-lived bioresorbable electronic stimulators designed to facilitate neuromuscular regeneration

Bioresorbable electronic stimulators are of rapidly growing interest as unusual therapeutic platforms, i.e., bioelectronic medicines, for treating disease states, accelerating wound healing processes and eliminating infections. Here, we present advanced materials that support operation in these systems over clinically relevant timeframes, ultimately bioresorbing harmlessly to benign products without residues, to eliminate the need for surgical extraction. Our findings overcome key challenges of bioresorbable electronic devices by realizing lifetimes that match clinical needs. The devices exploit a bioresorbable dynamic covalent polymer that facilitates tight bonding to itself and other surfaces, as a soft, elastic substrate and encapsulation coating for wireless electronic components. We describe the underlying features and chemical design considerations for this polymer, and the biocompatibility of its constituent materials. In devices with optimized, wireless designs, these polymers enable stable, long-lived operation as distal stimulators in a rat model of peripheral nerve injuries, thereby demonstrating the potential of programmable long-term electrical stimulation for maintaining muscle receptivity and enhancing functional recovery.

Aim high energy conversion efficiency in triboelectric nanogenerators

Triboelectric nanogenerators (TENGs) that enable the conversion of a given mechanical energy into electrical energy at high efficiency have been very important in practice. Since the given mechanical energy is involuntarily converted to secondary energy sources (light, heat, and sound during triboelectrification), the significant amount of energy being converted is lost. Various studies have thus been continuously carried out to overcome this issue. Since the first TENGs found in 2012, various developments in TENGs have been made: (1) the mechanical-electrical energy conversion characteristics of potential organic/inorganic material groups have been introduced, (2) the integration into the device structure considering the diversity of mechanical energy, and (3) user friendly and industrial application platforms have been aggressively studied. Despite the remarkable progress and improvement of TENGs, their mechanical-electrical conversion efficiency is still quite low. We therefore need to discover and develop materials that can be converted to improve efficiency. Here, we outline the recent progress made in a group of high polarity triboelectric materials that exploit surface charge density and charge transfer properties. We also review the recent boosting powering TENGs. The aim of this work is to provide insight into the future direction and strategies for highly enhanced powering TENGs through material research.

P1526Pre-dialysis left atrial function assessed by two-dimensional speckle tracking echocardiography as a predictor of upcoming heart failure in hemodialysis patients

Background

Left atrial global longitudinal strain (LA GLS) by 2-dimensional speckle tracking echocardiography is a useful tool to assess LA function and left ventricular (LV) diastolic function. The authors assessed prognostic value of LA GLS, and other diastolic functional parameters in patients undergoing hemodialysis.

Methods

A total of 78 (49 male) patients undergoing hemodialysis who checked echocardiography due to heart failure (HF) symptoms were included for this analysis. Echocardiography wasperformed at the same day of, and before hemodialysis session. Besides conventional echocardiographic measurements, GLS of the LA and the LV were checked and compared. Incidence of rehospitalization due to HF symptoms during mean follow up duration of 381.4±197.5 days was investigated and echocardiographic parameters were compared between patients who experienced rehospitalization and who did not.

Results

16 (20.1%) patients experienced rehospitalization due to HF. HF rehospitalization group had significantly low baseline LV ejection fraction (55.7±7.2 vs. 61.3±7.1%, p=0.006) and LV GLS (14.7±3.4 vs. 18.2±3.9%, p=0.002), while LV geometry (LV end-diastolic volume index and LV wall thickness) did not show significant differences. In HF rehospitalization group, baseline LA function and diastolic function were significantly impaired as reflected by LA GLS (18.8±2.6 vs. 23.8±3.6%, p<0.001), E/E' ratio (20.8±3.3 vs. 15.8±4.6%, p<0.001), and right ventricular systolic pressure (61.4±9.6 vs. 53.4±12.8%, p=0.022). LA end-systolic volume index was not significantly different between the 2 groups. Among various echocardiographic parameters, receiver operation characteristic curve analysis revealed that LA GLS had the strongest power (cutoff value 20.6%, sensitivity 0.813 and specificity 0.790, area under curve 0.849) in prediction of future rehospitalization due to HF.

Predictor of future HF: ROC analysis

Conclusions

The present study demonstrated that functional changes of the LA as measured by LA GLS before hemodialysis session can be used as an echocardiographic parameter to predict future rehospitalization due to HF. Further studies are required to evaluate prognostic value of LA function in predicting other cardiovascular events in hemodialysis patients.

P688Cardiac dysfunction as a predictor of hepatic sinusoidal obstruction syndrome after hematopoietic cell transplantation

Background

Hepatic sinusoidal obstruction syndrome (HSOS) is a well-known fatal complication of hematopoietic cell transplantation (HCT), but the impact of cardiac abnormalities on the occurrence of HSOS has been poorly evaluated. Therefore, the authors investigated whether the structural changes or dysfunction of the heart before HCT is associated with the future occurrence of HSOS.

Methods

A total of 92 patients who underwent HCT were divided into 2 groups; HSOS group (n=11, 6 males, 53.8±15.9 years) vs no HSOS group (n=81, 51 males, 48.6±14.7 years). According to the modified Seattle criteria, HSOS was defined as otherwise unexplained occurrence of 2 or more of the following events within 20 days of HCT; serum total bilirubin >2 mg/dL, hepatomegaly or right upper quadrant pain, sudden weight gain due to fluid accumulation (>2% of baseline body weight). Echocardiography examinations were performed 1 month before HCT, and echocardiographic findings were compared between the groups.

Results

HSOS was developed in 11 patients (12.0%). HSOS group had significantly larger left ventricular end-diastolic volume index (LVEDVI) (65.2±4.9 vs 53.2±6.9 ml/m2, p<0.001) and relatively worse systolic function than no HSOS group (LV ejection fraction: 56.4±3.4 vs 65.1±5.9%, p<0.001, LV global longitudinal strain: −17.9±1.4 vs −20.1±2.0%, p=0.001). LV diastolic functional parameters were also significantly worse in HSOS group than in no HSOS group (E/E' ratio: 11.3±1.8 vs 9.1±2.0, p=0.002, left atrial global longitudinal strain: 27.7±3.3 vs 34.9±5.9%, p<0.001). However, left atrial volume index was not different between the groups (30.8±2.8 vs 29.0±3.3 ml/m2, p=0.078). By receiver operation characteristic curve analysis, among significantly different variables, LVEDVI was the most powerful predictor for HSOS, and the optimal cutoff value was 59.25 mL/m2. (81.8% sensitivity and 77.8% specificity, AUC 0.909).

Predictor of HSOS: ROC analysis

Conclusions

The present study demonstrated that structural changes or dysfunction of the heart are more prevalent in patients with HSOS after HCT and larger LVEDVI, among them, can be a useful predictor of upcoming HSOS. Routine echocardiographic study before HCT would be useful to identify high risk group for HSOS, and the development of HSOS should be carefully monitored in HCT patients with cardiac structural changes or dysfunction on echocardiography.

P671Impacts of echocardiography-defined pulmonary hypertension on clinical outcome in patients with multiple myeloma

Background

Pulmonary hypertension (PH) is a rarely reported complication of multiple myeloma (MM). PH of MM is usually mild to moderate and can be secondary to a variety of conditions, including left ventricular dysfunction, diastolic dysfunction, chronic heart failure, treatment-related toxicity, thrombophilic condition and precapillary involvement. However, only few reports regarding PH in MM incidence and prognosis exist up to now.

Purpose

The purpose of this study was to investigate the risk factors of transthoracic echocardiography-defined PH and its impact on clinical outcome in patients with MM.

Methods

A total of 277 MM patients was included and divided into 2 groups–those non-pulmonary hypertension (PH) or those with PH, based on the results of the transthoracic echocardiography (TTE); PH group (n=143, 60.9±9.2 years, 68 males) versus non-PH group (n=134, 55.9±11.5 years, 72 males). We analyzed propensity score matching and multiple imputation method were used to deal with the missing data in echocardiographic characteristics.

Results

During the follow-up period (median 618 days), all-cause death occurred in 79 (28.5%) patients and 41 patients (14.8%) died from cardiovascular causes (including acute decompensated heart failure, fatal MI, sudden cardiac arrest). In the Kaplan-Meier survival analysis of crude population and propensity-matched population, cumulative overall survival and cardiovascular death (CVD)-free survival were significantly lower in the PH group than in the non-PH group (p<0.001). In propensity-matched population, estimated pulmonary artery pressure >35mmHg in TTE, congestive heart failure, and DM were significant independent predictors of all-cause death.

KM curves in MM stratified by PH

Conclusion

This study demonstrates that the presence of PH, congestive heart failure, and DM is an independent prognostic factor for all-cause death in MM patients with MM. These results highlight the risk associated cardiovascular disease in MM patients and emphasize that management strategies that prevent deterioration of cardiac function are essential.

Transcutaneous ultrasound energy harvesting using capacitive triboelectric technology

A major challenge for implantable medical systems is the inclusion or reliable delivery of electrical power. We use ultrasound to deliver mechanical energy through skin and liquids and demonstrate a thin implantable vibrating triboelectric generator able to effectively harvest it. The ultrasound can induce micrometer-scale displacement of a polymer thin membrane to generate electrical energy through contact electrification. We recharge a lithium-ion battery at a rate of 166 microcoulombs per second in water. The voltage and current generated ex vivo by ultrasound energy transfer reached 2.4 volts and 156 microamps under porcine tissue. These findings show that a capacitive triboelectric electret is the first technology able to compete with piezoelectricity to harvest ultrasound in vivo and to power medical implants.

Hybrid Energy Harvesters: Toward Sustainable Energy Harvesting

Recently, sustainable green energy harvesting systems have been receiving great attention for their potential use in self-powered smart wireless sensor network (WSN) systems. In particular, though the developed WSN systems are able to advance public good, very high and long-term budgets will be required in order to use them to supply electrical energy through temporary batteries or connecting power cables. This report summarizes recent significant progress in the development of hybrid nanogenerators for a sustainable energy harvesting system that use natural and artificial energies such as solar, wind, wave, heat, machine vibration, and automobile noise. It starts with a brief introduction of energy harvesting systems, and then summarizes the different hybrid energy harvesting systems: integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. In terms of the reported hybrid nanogenerators, a systematic summary of their structures, working mechanisms, and output performances is provided. Specifically, electromagnetic induction, triboelectric, piezoelectric, photovoltaic, thermoelectric, and pyroelectric effects are reviewed on the basis of the individual and hybrid power performances of hybrid nanogenerators and their practical applications with various device designs. Finally, the perspectives on and challenges in developing high performance and sustainable hybrid nanogenerator systems are presented.

Factors associated with HIV/AIDS-related stigma and discrimination by medical professionals in Korea: A survey of infectious disease specialists in Korea

Objectives

This study sought to identify factors associated with this discrimination by medical professionals in Korea.

Subjects and Methods

This study was a cross-sectional survey. We conducted web-based surveys against infectious disease specialists and infectious disease nurse. We evaluated the frequency of human immunodeficiency virus (HIV)/AIDS-related discrimination by medical professionals by health service type on the 5-point scale. We identified the association between several factors and HIV/AIDS-related stigma and discrimination by medical professionals on the 5-point scale.

Results

A total of 81 experts, 57 infectious disease specialists (approximately 27% of all infectious disease specialists in Korea) and 24 infectious disease nurse practitioners, participated in this study. The frequency of stigma and discrimination increased significantly when invasive treatment included both outpatient and inpatient services (both P < 0.05). Medical professional's preconceptions, fear of infection, and lack of knowledge have an association with HIV/AIDS-related stigma and discrimination by medical professionals.

Conclusion

HIV/AIDS-related stigma and discrimination by medical professionals in Korea might be associated with factors related to the fear of medical professionals.

Measurement of levels of fractional exhaled nitric oxide in patients with pulmonary tuberculosis

SETTING

The role of fractional exhaled nitric oxide (FeNO) in the diagnosis and treatment of pulmonary tuberculosis (PTB) is uncertain.

OBJECTIVE

To examine the value of FeNO as a biomarker for PTB.

DESIGN

Baseline FeNO levels were compared in 69 PTB patients and 118 healthy controls. The correlation between baseline FeNO levels and clinical variables of tuberculosis were studied. FeNO levels were checked twice in the PTB group, at diagnosis and after 2 months of anti-tuberculosis medication, and factors affecting changes in FeNO levels after treatment were analysed.

RESULTS

FeNO levels were not significantly different in the PTB group and controls (mean ± standard deviation 27.7 ± 17.6 parts per billion [ppb] vs. 27.0 ± 10.8 ppb, P = 0.531). In a multivariate regression analysis, no variable was shown to affect FeNO levels at diagnosis. FeNO levels did not significantly change after 2 months of treatment (26.8 ± 18.3 ppb vs. 24.0 ± 10.7 ppb, P = 0.257). Only PTB with a high FeNO level (>25 ppb) was related to a decline in FeNO levels after 2 months of treatment.

CONCLUSION

FeNO levels do not appear to be affected in PTB patients.

Reliable Piezoelectricity in Bilayer WSe2 for Piezoelectric Nanogenerators

Recently, piezoelectricity has been observed in 2D atomically thin materials, such as hexagonal-boron nitride, graphene, and transition metal dichalcogenides (TMDs). Specifically, exfoliated monolayer MoS₂ exhibits a high piezoelectricity that is comparable to that of traditional piezoelectric materials. However, monolayer TMD materials are not regarded as suitable for actual piezoelectric devices due to their insufficient mechanical durability for sustained operation while Bernal-stacked bilayer TMD materials lose noncentrosymmetry and consequently piezoelectricity. Here, it is shown that WSe₂ bilayers fabricated via turbostratic stacking have reliable piezoelectric properties that cannot be obtained from a mechanically exfoliated WSe₂ bilayer with Bernal stacking. Turbostratic stacking refers to the transfer of each chemical vapor deposition (CVD)-grown WSe₂ monolayer to allow for an increase in degrees of freedom in the bilayer symmetry, leading to noncentrosymmetry in the bilayers. In contrast, CVD-grown WSe₂ bilayers exhibit very weak piezoelectricity because of the energetics and crystallographic orientation. The flexible piezoelectric WSe₂ bilayers exhibit a prominent mechanical durability of up to 0.95% of strain as well as reliable energy harvesting performance, which is adequate to drive a small liquid crystal display without external energy sources, in contrast to monolayer WSe₂ for which the device performance becomes degraded above a strain of 0.63%.

The effect of low-volatile organic compounds, water-based paint on aggravation of allergic disease in schoolchildren

Whether indoor painting aggravates preexisting allergic diseases remains unclear. We aimed to evaluate the impact of new classroom painting on aggravation of asthma, allergic rhinitis (AR), and atopic dermatitis (AD) in children. Studied school was previously painted with conventional water-based paint 20 years ago and had natural ventilation system. We identified a total of 172 children aged 10-12 years with allergic diseases in 17 classrooms, which were allocated to newly painted rooms with low-volatile organic compounds (VOC), water-based paint, or existing rooms. After painting, there was no intervention or internal airflow to influence indoor air environment in both classrooms. We prospectively assessed the symptom severity and serious events of allergic diseases between both classrooms at baseline and after one and eight weeks after painting. At one and eight weeks, there were no significant changes in the Childhood Asthma Control Test scores, the fractional nitric oxide levels, lung function in asthmatic children in either classroom. There were also no significant changes in the severity score of AR or AD, or serious events in all allergic diseases. These findings suggest classroom painting with this new paint at the levels encountered in this study might not be a major aggravating factor for school-aged children with allergic diseases.

Control of Skin Potential by Triboelectrification with Ferroelectric Polymers

Negatively polarized ferroelectric polymer β-P(VDF-TrFE) shows higher positive triboelectric properties than skin, which could lead to new medical applications. Kelvin force microscope measurements and triboelectric nanogenerator characterizations are performed to demonstrate this new property. In addition, how many negative charges are exchanged by contact electrification between the negatively polarized β-P(VDF-TrFE) and the skin is estimated.

The flavone eupatilin inhibits eotaxin expression in an NF-κB-dependent and STAT6-independent manner

The CC chemokine eotaxin contributes to epithelium-induced inflammation in airway diseases such as asthma. Eupatilin (5,7-dihydroxy-3',4',6'-trimethoxyflavone), a bioactive component of Artemisia asiatica Nakai (Asteraceae), is reported to inhibit the adhesion of eosinophils to bronchial epithelial cells. However, little is known about the molecular mechanism of eupatilin-induced attenuation of bronchial epithelium-induced inflammation. In this study, we investigated the effect of eupatilin on expression of eotaxin-1 (CCL11), a potent chemoattractant for eosinophils. Eupatilin significantly inhibited eotaxin expression in bronchial epithelial cells stimulated with TNF-α, while NF-κB and IκBα kinase (IKK) activities declined concurrently. Eupatilin also inhibited mitogen-activated protein kinase (MAPK) activity; however, all of these anti-inflammatory activities were reversed by MAPK overexpression. In contrast, eupatilin did not affect the signal transducer and activator of transcription 6 (STAT6) signalling in bronchial epithelial cells stimulated with IL-4. Furthermore, eupatilin significantly attenuated TNF-α-induced eosinophil migration. These results suggest that the eupatilin inhibits the signalling of MAPK, IKK, NF-κB and eotaxin-1 in bronchial epithelial cells, leading to inhibition of eosinophil migration.

Short communication: Physicochemical and antioxidant properties of milk supplemented with red ginseng extract

This study investigated the effect of red ginseng extract (RGE) on the physicochemical properties, sensory test, and antioxidant activity of milk. The milk samples with RGE added at 0.5, 1, 1.5, and 2% were analyzed during storage at 4°C. The physicochemical properties included composition of milk, pH, titratable acidity, and color. The antioxidant activity of milk samples was determined using the 2,2-diphenyl-1-picrylhydrazyl method, β-carotene bleaching assay, and ferric thiocyanate assay. An increase in the amount of RGE in milk resulted in an increase of lactose and total solids content, titratable acidity, and a* and b* values, whereas fat and protein contents remained unchanged. Also, pH and L* value decreased. The antioxidant activity of milk samples supplemented with RGE was higher than that of the control sample. Sensory evaluation was performed using a quantitative descriptive analysis. Two types of samples were used: (1) sterilized milk fortified with RGE (0.5, 1, 1.5, and 2%) and (2) 2% RGE, 2% RGE with oligosaccharide, and 2% RGE with oligosaccharide and cyclodextrin. The addition of oligosaccharide and cyclodextrin could effect an increase of sweetness, a decrease of bitterness and flavor of RGE, and aftertaste. Therefore, milk supplemented with RGE could be useful as a functional food.

Estimated long-term dietary exposure to lead, cadmium, and mercury in young Korean children

BACKGROUND

Controlling for day-to-day variation is a key issue in estimating long-term dietary exposure to heavy metals using 24-hour recall (24HR) data from a relatively small number of days.

OBJECTIVES

This study was conducted to estimate long-term dietary exposure to lead, cadmium and mercury among Korean children using the Iowa State University (ISU) method and to assess the contributions of different food groups to heavy metal intake.

METHODS

We analyzed 2 days of 24HR data from 457 children between 0 and 6 years of age in 2010. Using bootstrapped concentration data for 118 representative foods, 93.5% of total intake was included in the exposure estimates in this study. Using the 2-day exposure data, we estimated long-term exposure by controlling for within-individual variation using the ISU method.

RESULTS

The long-term dietary exposure estimates (mean±standard deviation) for lead, cadmium, and mercury were 0.47±0.14, 0.38±0.20, and 0.22±0.08 μg/kg bw/day, respectively. For lead and cadmium, the percentages of children whose exposure was greater than the reference value were 35 and 42%, respectively. Fruits were an important source of lead exposure, and cereal and fish and shellfish made the greatest contributions to the total cadmium and mercury exposure.

CONCLUSIONS

Our findings also suggest that the long-term exposure to lead and cadmium was somewhat greater than the reference values, whereas mercury exposure was well below than the reference value in this population. Further studies may be necessary to evaluate the food items contributing to heavy metal exposure, and continuous monitoring is needed to ensure the safety of food intake and dietary patterns among vulnerable groups in Korea.

Bacillus-derived poly-γ-glutamic acid attenuates allergic airway inflammation through a Toll-like receptor-4-dependent pathway in a murine model of asthma

BACKGROUND

Asthma is an inflammatory disease of the airways that is mediated by Th2 responses. Poly-γ-glutamic acid (γ-PGA) is an extracellular polymeric compound that is synthesized by Bacillus cells. Previously, we found that γ-PGA promoted Th1 cell development in a manner dependent on antigen-presenting cells, but inhibited Th2 cell development.

OBJECTIVE

To investigate the effect of γ-PGA on dendritic cells (DCs), and its potential for treating Th2-mediated allergic asthma.

METHODS

Wild-type, Toll-like receptor (TLR)-2 deficient, and TLR-4-defective mice were used. DCs derived from the bone marrow and extracted from the lung were stimulated with γ-PGA and assayed for the expression of signalling molecules, costimulatory molecules, and cytokines. Mice were sensitized and challenged with ovalbumin (OVA) to induce asthma. They were repeatedly injected intranasally with γ-PGA before and during the challenge period, and inflammation and structural remodelling of the airways were examined.

RESULTS

γ-PGA selectively signalled conventional DCs to activate NF-κB and mitogen-activated protein kinase, leading to the up-regulation of CD86, CD40, and IL-12, but not IL-10 and IL-6. These effects of γ-PGA were dependent on TLR-4 and independent of TLR-2. Importantly, the intranasal administration of γ-PGA to OVA-sensitized/challenged mice reduced the airway hyperresponsiveness and allergic inflammation such as leucocyte influx, goblet cell hyperplasia, eosinophilia, and Th2 cytokine production. In addition to lowered IgE titres, the treatment of mice with γ-PGA significantly reduced the multiplication and Th2 polarization of mediastinal lymph node T cells upon allergen-specific restimulation. These anti-asthmatic effects of γ-PGA were also abolished in TLR-4-defective mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data indicate that γ-PGA activates DCs to favour Th1 cell induction through a TLR-4-dependent pathway and alleviates pathologic symptoms in a Th2-biased asthmatic model. These findings highlight the potential of γ-PGA for the treatment of asthma and other allergic disease in which Th2 polarization plays an important role.

Gardnerella vaginalis septicaemia with pyelonephritis, infective endocarditis and septic emboli in the kidney and brain of an adult male

Gardnerella vaginalis is typically associated with bacterial vaginosis in women. However, balanitis, urethritis, urinary tract infections and asymptomatic bacteraemia have also been described in men. Here we report a case of G. vaginalis septicaemia with infective endocarditis and septic emboli in the kidney and brain of an adult male.

Brillouin gain-coefficient measurement for bismuth-oxide-based photonic crystal fiber under significant beam reflection at splicing points

We investigate a six-air-hole bismuth-oxide-based photonic crystal fiber (Bi-PCF) in terms of Brillouin characteristics. One huge challenge in measuring the Brillouin properties of the Bi-PCF is the nonnegligible beam reflection at the splicing points, which can be attributed to the mirroring effect caused by different refractive indices of silica and bismuth fibers. To solve the problem we propose a method that is based on the combination of a pump-probe beat lock-in scheme and a normalized gain curve-fitting technique. Using this method, successful characterization of Brillouin properties for a 1.16-m-long Bi-PCF is experimentally demonstrated. With the measured Brillouin gain coefficient and the known chi((3)) nonlinearity parameters, the Kerr nonlinearity figure-of-merit (F(nl-SBS)), including the stimulated Brillouin scattering-caused pump-power limit, is also estimated for the Bi-PCF.

The effect of anesthetic method for prophylactic cervical cerclage on plasma oxytocin: a randomized trial

BACKGROUND

This study compared the changes in plasma oxytocin, intraoperative hemodynamics and postoperative uterine activity in patients who underwent elective Shirodkar cerclage for cervical incompetence with general or spinal anesthesia.

METHODS

Thirty-seven singleton pregnant patients were enrolled in this prospective, randomized, controlled comparison of general (n=17) and spinal anesthesia (n=20) for elective Shirodkar suture in the second trimester. Plasma oxytocin concentration was measured before, 1 h after, and 24 h after the procedure. Uterine activity was recorded by external tocography twice daily for 30 min over a three-day period.

RESULTS

Plasma oxytocin concentration did not change significantly after cerclage in either group. There were no significant differences between the two groups at any time. None of the patients reported painful contractions during study period. Two (11.8%) and four patients (20.0%) in the general and spinal groups, respectively (NS), showed increased uterine activity but these symptoms disappeared without treatment. The systolic blood pressure in the spinal group was significantly lower after anesthesia compared with the baseline and was significantly lower than in the general group during the procedure.

CONCLUSIONS

Anesthetic method used for elective Shirodkar procedure did not affect the perioperative changes in plasma oxytocin nor postoperative uterine activity.

Association between the Clara cell secretory protein (CC16) G38A polymorphism and the progression of IgA nephropathy

AIMS

Clara cell secretory protein (CC16) is a protein with anti-inflammatory and immunomodulatory properties. Moreover, both CC16 gene knockout and antisense-transgenic mouse models developed glomerulonephritis resembling IgA nephropathy (IgAN). In the present study, we evaluated the influence of the G38A polymorphism in the CC16 gene exon 1 on the development and progression of IgAN.

METHODS

Korean patients with biopsy-proven IgAN (n=267) with a minimal follow-up of 4 years (mean +/- SD 103.8 +/- 52.6 months) were recruited. Healthy normal subjects (n=315) were included as controls. The G38A polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

GG, GA and AA genotype frequencies were 36.3, 50.2 and 13.5% in IgAN patients, respectively, and 34.3, 50.2 and 15.5% in controls (chi2 = 0.596, p = 0.742). The G allele frequency was 0.614 in IgAN patients and 0.594 in controls (chi2 = 0.429, p = 0.512). Moreover, the GG genotype frequencies were 40.4% in patients showing stable disease course and 26.6% in those with progressive disease (chi2 = 4.029, p = 0.045). Patients with the GG genotype showed a better outcome by Kaplan-Meier analysis in terms of renal survival (p = 0.043). The CC16 polymorphism remained an independent risk factor for progression after multivariate analysis (Cox regression model, HR for CC16 AA genotype: 2.34, 95% CI 1.19-4.64, p = 0.014).

CONCLUSION

Our results suggest that CC 16 gene G38A polymorphism is not associated with the development of IgAN, but that it is an important marker of progression in IgAN.

Mortality risk factors of Acinetobacter baumannii bacteraemia

BACKGROUND

Acinetobacter baumannii is one of the most important nosocomial pathogens, and its multiple antibiotic resistance has emerged as an obstacle in the treatment of these infections worldwide.

AIMS

To identify risk factors of mortality for A. baumannii bacteraemia.

METHODS

A retrospective cohort study of 72 patients with significant A. baumannii bacteraemia was conducted to evaluate risk factors for mortality.

RESULTS

The median age of the 72 enrolled patients was 48 years, 96% of the cases were hospital-acquired, and the bacteraemia-related mortality rate was 29% (21 of 72 patients). Univariate analysis revealed that the risk factors for mortality included: an elevated acute physiology and chronic health evaluation (APACHE II) score, receipt of in vitro ineffective definitive antimicrobial therapy, in vitro A. baumannii resistance to cefoperazone/ sulbactam, neutropenia, and presentation with septic shock. Multivariate analysis reveals that the independent risk factors for mortality are neutropenia and elevated APACHE II scores.

CONCLUSION

Risk factors such as neutropenia and elevated APACHE II scores are found to be associated with higher mortality rates of A. baumannii bacteraemia. Further study is necessary for the determination of optimal strategies for both the prevention and treatment of these infections.