Multifunctional Liquid Metal-Bridged Graphite Nanoplatelets/Aramid Nanofiber Film for Thermal Management.

Miniaturization of modern micro-electronic devices urges the development of multi-functional thermal management materials. Traditional polymer composite-based thermal management materials are promising candidates, but they suffer from single functionality, high cost, and low fire-resistance. Herein, a multifunctional liquid metal (LM)-bridged graphite nanoplatelets (GNPs)/ aramid nanofibers (ANFs) film is fabricated via a facile vacuum-assisted self-assembly approach followed by compression. ANFs serve as interfacial binders to link LM and GNPs together via hydrogen bondings and π-π interactions, while LM bridges the adjacent layer of GNPs to endow a fast thermal transport by phonons and electrons. The resultant composite films exhibit a high bidirectional thermal conductivity (In-plane: 29.5 W m-1 K-1 and through-plane: 5.3 W m-1 K-1 ), offering a reliable and effective cooling. Moreover, the as-fabricated composite films exhibit superior flame-retardance (peak of heat release rate of 4000J g-1 ), outstanding Joule heating performance (200 °C at supplied voltage of 3.5 V), and excellent electromagnetic interference shielding effectiveness (EMI SE of 62 dB). This work provides an efficient avenue to fabricate multifuntional thermal management materials for micro-electronic devices, battery thermal management, and artificial intelligence.

Multifunctional MoSe2 @MXene Heterostructure-Decorated Cellulose Fabric for Wearable Thermal Therapy.

A booming demand for wearable electronic devices urges the development of multifunctional smart fabrics. However, it is still facing a challenge to fabricate multifunctional smart fabrics with satisfactory mechanical property, excellent Joule heating performance, highly efficient photothermal conversion, outstanding electromagnetic shielding effectiveness, and superior anti-bacterial capability. Here, a MoSe2 @MXene heterostructure-based multifunctional cellulose fabric is fabricated by depositing MXene nanosheets onto cellulose fabric followed by a facile hydrothermal method to grow MoSe2 nanoflakes on MXene layers. A low-voltage Joule heating therapy platform with rapid Joule heating response (up to 230 °C in 25 s at a supplied voltage of 4 V) and stable performance under repeated bending cycles (up to 1000 cycles) is realized. Besides, the multifunctional fabric also exhibits excellent photothermal performance (up to 130 °C upon irradiation for 25 s with a light intensity of 400 mW cm-2 ), outstanding electromagnetic interference shielding effectiveness (37 dB), and excellent antibacterial performances (>90% anti-bacterial rate toward Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). This work offers an efficient avenue to fabricate multifunctional wearable thermal therapy devices for mobile healthcare and personal thermal management.

Soft Organic Thermoelectric Materials: Principles, Current State of the Art and Applications.

The enormous demand for waste heat utilization and burgeoning eco-friendly wearable materials has triggered huge interest in the development of thermoelectric materials that can harvest low-cost energy resources by converting waste heat to electricity efficiently. In particular, due to their high flexibility, nontoxicity, cost-effectivity, and promising applicability in various fields, organic thermoelectric materials are drawing more attention compared with their toxic, expensive, heavy, and brittle inorganic counterparts. Organic thermoelectric materials are approaching the figure of merit of the inorganic ones via the construction and optimization of unique transport pathways and device geometries. This review presents the recent development of the interdependence and decoupling principles of the thermoelectric efficiency parameters as well as the new achievements of high performance organic thermoelectric materials. Moreover, this review also discusses the advances in the thermoelectric devices with emphasis on their energy-related applications. It is believed that organic thermoelectric materials are emerging as green energy alternatives rivaling their conventional inorganic counterparts in the efficient and pure electricity harvesting from waste heat and solar thermal energy.

Lithium Bonds Enable Small Biomass Molecule-Based Ionoelastomers with Multiple Functions for Soft Intelligent Electronics.

Lipoic acid (LA), which originates from animals and plants, is a small biomass molecule and has recently shown great application value in soft conductors. However, the severe depolymerization of LA places a significant limitation on its utilization. A strategy of using Li-bonds as both depolymerization quenchers and dynamic mediators to melt transform LA into high-performance ionoelastomers (IEs) is proposed. They feature dry networks while simultaneously combining transparency, stretchability, conductivity, self-healing ability, non-corrosive property, re-mouldability, strain-sensitivity, recyclability, and degradability. Most of the existing soft conductors' drawbacks, such as the tedious synthesis, non-renewable polymer networks, limited functions, and single-use only, are successfully solved. In addition, the multi-functions allow IEs to be used as soft sensors in human-computer interactive games and wireless remote sports assistants. Notably, the recycled IE also provides an efficient conductive filler for transparent ionic papers, which can be used to design soft transparent triboelectric nanogenerators for energy harvesting and multidirectional motion sensing. This work creates a new direction for future research involving intelligent soft electronics.

Association between C-reactive protein levels and development of post-stroke depression: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Different prospective cohort studies have focused on the C-reactive protein (ie, a pentameric protein) biomarker as a predictor of post-stroke depression. In this review and meta-analysis, we will attempt to synthesize the evidence for the association between C-reactive protein and the development of post-stroke depression. METHODS: We systematically searched five academic databases for relevant studies according to the PRISMA guidelines. We evaluate the comparative levels of C-reactive protein in patients with stroke and/without depression, and analyzed the hazard ratio to evaluate the overall risk of C-reactive protein levels in patients with stroke. RESULTS: We selected eligible studies with 2534 patients (mean age: 65.2 ± 5.9 years) from the initial 10 926 studies in the databases. Increased C-reactive protein levels (Hedge's g, 0.84) in patients with stroke and depression as compared to patients with stroke without depression. Increased levels of C-reactive protein were associated with the onset of depression (Hazard's ratio, 1.6) in patients with stroke. CONCLUSION: Our findings provide an association of C-reactive protein with the development of post-stroke depression, and present higher levels than patients with stroke without depression. Additionally, our findings support the role of C-reactive protein levels as markers for predicting depression in patients with stroke.

Adsorption in Reversed Order of C2 Hydrocarbons on an Ultramicroporous Fluorinated Metal-Organic Framework.

Metal-organic frameworks have been widely studied in the separation of C2 hydrocarbons, which usually preferentially bind unsaturated hydrocarbons with the order of acetylene (C2 H2 )>ethylene (C2 H4 )>ethane (C2 H6 ). Herein, we report an ultramicroporous fluorinated metal-organic framework Zn-FBA (H2 FBA=4,4'-(hexafluoroisopropylidene)bis(benzoic acid)), shows a reversed adsorption order characteristic for C2 hydrocarbons, that the uptake for C2 hydrocarbons of the framework and the binding affinity between the guest molecule and the framework follows the order C2 H6 >C2 H4 >C2 H2 . Density-functional theory calculations confirm that the completely reversed adsorption order behavior is attributed to the close van der Waals interactions and multiple cooperative C-H⋅⋅⋅F hydrogen bonds between the framework and C2 H6 . Moreover, Zn-FBA exhibits a high selectivity of about 2.9 for C2 H6 over C2 H4 at 298 K and 1 bar. The experimental breakthrough studies show that the high-purity C2 H4 can be obtained from C2 H6 and C2 H4 mixtures in one step.

Highly Aligned Graphene Aerogels for Multifunctional Composites.

Stemming from the unique in-plane honeycomb lattice structure and the sp2 hybridized carbon atoms bonded by exceptionally strong carbon-carbon bonds, graphene exhibits remarkable anisotropic electrical, mechanical, and thermal properties. To maximize the utilization of graphene's in-plane properties, pre-constructed and aligned structures, such as oriented aerogels, films, and fibers, have been designed. The unique combination of aligned structure, high surface area, excellent electrical conductivity, mechanical stability, thermal conductivity, and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions, enabling advancements in diverse fields. This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites. It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively. The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties, showing enhanced electrical, mechanical, and thermal properties along the alignment at the sacrifice of the perpendicular direction. This review showcases remarkable properties and applications of aligned graphene aerogels and their composites, such as their suitability for electronics, environmental applications, thermal management, and energy storage. Challenges and potential opportunities are proposed to offer new insights into prospects of this material.

New Carbon Materials for Multifunctional Soft Electronics.

Soft electronics are garnering significant attention due to their wide-ranging applications in artificial skin, health monitoring, human-machine interaction, artificial intelligence, and the Internet of Things. Various soft physical sensors such as mechanical sensors, temperature sensors, and humidity sensors are the fundamental building blocks for soft electronics. While the fast growth and widespread utilization of electronic devices have elevated life quality, the consequential electromagnetic interference (EMI) and radiation pose potential threats to device precision and human health. Another substantial concern pertains to overheating issues that occur during prolonged operation. Therefore, the design of multifunctional soft electronics exhibiting excellent capabilities in sensing, EMI shielding, and thermal management is of paramount importance. Because of the prominent advantages in chemical stability, electrical and thermal conductivity, and easy functionalization, new carbon materials including carbon nanotubes, graphene and its derivatives, graphdiyne, and sustainable natural-biomass-derived carbon are particularly promising candidates for multifunctional soft electronics. This review summarizes the latest advancements in multifunctional soft electronics based on new carbon materials across a range of performance aspects, mainly focusing on the structure or composite design, and fabrication method on the physical signals monitoring, EMI shielding, and thermal management. Furthermore, the device integration strategies and corresponding intriguing applications are highlighted. Finally, this review presents prospects aimed at overcoming current barriers and advancing the development of state-of-the-art multifunctional soft electronics.

Production of Martian fiber by in-situ resource utilization strategy.

Many countries and commercial organizations have shown great interest in constructing a Martian base. In situ resource utilization (ISRU) provides a cost-effective way to achieve this ambitious goal. In this article, we proposed to use Martian soil simulant to produce a fiber to satisfy material requirement for the construction of Martian base. The composition, melting behavior, and fiber forming process of the soil simulant was studied, and continuous fiber with maximum strength of 1320 MPa and elastic modulus of 99 GPa was obtained on a spinning facility. The findings of this study demonstrate the feasibility of ISRU to prepare Martian fiber from the soil on the Mars, offering a new way to obtain key materials for the construction of a Martian base.

Ratio of procalcitonin/Simpson's dominance index predicted the short-term prognosis of patients with severe bacterial pneumonia.

Objective: The aim of this study was to explore the predictive value of the ratio of procalcitonin (PCT) in serum to Simpson's dominance index (SDI) in bronchoalveolar lavage fluid (BALF), in short-term prognosis of patients with severe bacterial pneumonia (SBP). Methods: This is a retrospective review of case materials of 110 patients with SBP who selected BALF metagenomic next-generation sequencing technique in the intensive care unit (ICU) of the Affiliated Hospital of Yangzhou University from January 2019 and July 2022. Based on the acute physiology and chronic health status score II, within 24 h after admission to the ICU, patients were divided into a non-critical group (n = 40) and a critical group (n = 70). Taking death caused by bacterial pneumonia as the endpoint event, the 28-day prognosis was recorded, and the patients were divided into a survival group (n = 76) and a death group (n = 34). The SDI, PCT, C-reactive protein (CRP), PCT/SDI, and CRP/SDI were compared and analyzed. Results: Compared with the non-critical group, the critical group had a higher PCT level, a greater PCT/SDI ratio, a longer ventilator-assisted ventilation time (VAVT), and more deaths in 28 days. Compared with the survivors, the death group had a higher PCT level, a lower SDI level, and a greater PCT/SDI ratio. The SDI level was significantly negatively correlated with the VAVT (r = -0.675, p < 0.05), while the PCT level, ratio of PCT/SDI, and ratio of CRP/SDI were remarkably positively correlated with VAVT (r = 0.669, 0.749, and 0.718, respectively, p < 0.05). The receiver operating characteristic (ROC) curves analysis showed that the area under ROC curves of PCT/SDI predicting patient death within 28 days was 0.851, followed by PCT + SDI, PCT, SDI, and CRP/SDI (0.845, 0.811, 0.778, and 0.720, respectively). The sensitivity and specificity of PCT/SDI for predicting death were 94.1% and 65.8%, respectively, at the optimal value (11.56). Cox regression analysis displayed that PCT/SDI (HR = 1.562; 95% CI: 1.271 to 1.920; p = 0.039) and PCT (HR = 1.148; 95% CI: 1.105 to 1.314; p = 0.015) were independent predictors of death in patients. Conclusion: The ratio of PCT/SDI was a more valuable marker in predicting the 28-day prognosis in patients with SBP.

Identification of novel key markers that are induced during traumatic brain injury in mice.

Background: Traumatic brain injury (TBI) has emerged as an increasing public health problem but has not been well studied, particularly the mechanisms of brain cellular behaviors during TBI. Methods: In this study, we established an ischemia/reperfusion (I/R) brain injury mice model using transient middle cerebral artery occlusion (tMCAO) strategy. After then, RNA-sequencing of frontal lobes was performed to screen key inducers during TBI. To further verify the selected genes, we collected peripheral blood mononuclear cells (PBMCs) from TBI patients within 24 h who attended intensive care unit (ICU) in the Affiliated Hospital of Yangzhou University and analyzed the genes expression using RT-qPCR. Finally, the receiver operator characteristic (ROC) curves and co-expression with cellular senescence markers were applied to evaluate the predictive value of the genes. Results: A total of six genes were screened out from the RNA-sequencing based on their novelty in TBI and implications in apoptosis and cellular senescence signaling. RT-qPCR analysis of PBMCs from patients showed the six genes were all up-regulated during TBI after comparing with healthy volunteers who attended the hospital for physical examination. The area under ROC (AUC) curves were all >0.7, and the co-expression scores of the six genes with senescence markers were all significantly positive. We thus identified TGM1, TGM2, ATF3, RCN3, ORAI1 and ITPR3 as novel key markers that are induced during TBI, and these markers may also serve as potential predictors for the progression of TBI.

Baseline Serum Estradiol Level Is Associated with Acute Kidney Injury in Patients with Moderately Severe and Severe Acute Pancreatitis.

Background: Sexual dimorphism with critical diseases has been documented. However, the role of serum sex hormones for the presence of acute kidney injury (AKI) in moderately or severe acute pancreatitis (MSAP and SAP) patients remains controversial. Here we set out to evaluate whether early (first 48 h) serum estradiol level is associated with AKI in patients with MSAP and SAP. Patients and Methods. We retrospectively collected data from patients with preliminary diagnosis of MSAP and SAP from the Affiliated Hospital of Yangzhou University between January 2014 and June 2018. Serum sex hormones were extracted for further assessment within first 48 h following admission. Logistic regression analysis and the receiving operating characteristic (ROC) curve were applied to evaluate the association and correlation between serum sex hormones and AKI. Results: Data from a total of 122 patients with MSAP or SAP were enrolled in this study. There were no differences in the incidence of AKI between males and females. However, comparing with patients without AKI, those with AKI saw higher estradiol level (p ≤ 0.01) and slight higher progesterone level (p = 0.014) but similar testosterone level (p = 0.668). Interestingly, during both the manual selection and the stepwise backward logistic regression analysis, serum estradiol level was independently associated with AKI in patients with MSAP and SAP (OR 4.699, CI 1.783-12.386, and p = 0.002). Additionally, area under the curve of ROC (AUCROC) showed that serum estradiol level was a proper predictor for AKI (area under the curve 0.875). Specifically, the serum estradiol level of 223.15 pg/mL demonstrated a 92.3% sensitive and a 79.3% specificity in predicting AKI of MSAP and SAP patients, respectively. Conclusions: High baseline serum estradiol level appears to be an independent risk factor for AKI in patients with MSAP and SAP. It also tends to be an appropriate indicator for AKI.

Recent Advances in Design Strategies and Multifunctionality of Flexible Electromagnetic Interference Shielding Materials.

With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for "green EMI shielding" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.

Effects of stage, intercalant species and expansion technique on exfoliation of graphite intercalation compound into graphene sheets.

Graphite is composed of a series of stacked parallel graphene layers bonded by weak van der Waals forces. Although the weak interactions that hold the graphene sheets together allow them to slide readily over each other, the numerous weak bonds make it difficult to separate the sheets. A graphene sheet is a two-dimensional platelet consisting of a few graphene layers with an overall thickness in nanometer scale. Graphene sheets can be obtained from intercalation and subsequent exfoliation of graphite. To realize the expansion and exfoliation behaviors of graphite, graphite intercalation compound (GIC) is produced using an electrochemical method and three important factors, namely stage structure of GIC, intercalant species and expansion techniques, are taken into account. Graphene sheets produced from a lower stage FeCl3-GIC display the best exfoliation behavior in terms of specific surface area, total pore volume and expansion volume. Microwave irradiation gives rise to a more explosive expansion than heating in a furnace.

Anisotropic conductive networks for multidimensional sensing.

In the past decade, flexible physical sensors have attracted great attention due to their wide applications in many emerging areas including health-monitoring, human-machine interfaces, smart robots, and entertainment. However, conventional sensors are typically designed to respond to a specific stimulus or a deformation along only one single axis, while directional tracking and accurate monitoring of complex multi-axis stimuli is more critical in practical applications. Multidimensional sensors with distinguishable signals for simultaneous detection of complex postures and movements in multiple directions are highly demanded for the development of wearable electronics. Recently, many efforts have been devoted to the design and fabrication of multidimensional sensors that are capable of distinguishing stimuli from different directions accurately. Benefiting from their unique decoupling mechanisms, anisotropic architectures have been proved to be promising structures for multidimensional sensing. This review summarizes the present state and advances of the design and preparation strategies for fabricating multidimensional sensors based on anisotropic conducting networks. The fabrication strategies of different anisotropic structures, the working mechanism of various types of multidimensional sensing and their corresponding unique applications are presented and discussed. The potential challenges faced by multidimensional sensors are revealed to provide an insightful outlook for the future development.

Anisotropic, Wrinkled, and Crack-Bridging Structure for Ultrasensitive, Highly Selective Multidirectional Strain Sensors.

Flexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications. Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities, existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity. Here, an ultrasensitive, highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers. The bilayer sensor consists of an aligned carbon nanotube (CNT) array assembled on top of a periodically wrinkled and cracked CNT-graphene oxide film. The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched, leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100% strain. The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3, to the benefit of accurate detection of loading directions by the multidirectional sensor. This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity, selectivity, and stretchability, demonstrating promising applications in full-range, multi-axis human motion detection for wearable electronics and smart robotics.

Flexible temperature sensors made of aligned electrospun carbon nanofiber films with outstanding sensitivity and selectivity towards temperature.

Continuous real-time measurement of body temperature using a wearable sensor is an essential part of human health monitoring. Electrospun aligned carbon nanofiber (ACNF) films are employed to assemble flexible temperature sensors. The temperature sensor prepared at a low carbonization temperature of 650 °C yields an outstanding sensitivity of 1.52% °C-1, high accuracy, good linearity, fast response time and excellent long-term durability. Moreover, it exhibits high discriminability towards temperature amidst other unwanted stimuli and maintains its original performance even after repeated stretch/release cycles because of highly-aligned structures. The correlation between the atomic structure and the temperature sensing performance of ACNF sensors is established. Contrary to conventional highly conductive temperature sensors, the ACNF sensor with a low electrical conductivity prepared at a low carbonization temperature ameliorates the temperature sensing performance. This anomaly is explained by (i) the smaller and more disordered sp2 carbon crystallites yielding a high negative temperature coefficient, (ii) a larger number of defects, and (iii) a higher pyridinic-N content generating abundant entrapped and localized electrons which are activated once sufficient thermal energy is available. Flexible ACNF sensor's overall performance is among the best-known carbon material-based flexible temperature sensors, demonstrating potential applications in emerging healthcare and flexible electronics technologies.

Molecular dynamics study of the effect of chemical functionalization on the elastic properties of graphene sheets.

In this study, the effects of chemical functionalization on the elastic properties of graphene sheets are investigated by using molecular dynamics (MD) and molecular mechanics (MM) simulations. The influences of the degree of functionalization, which is defined as the ratio of the number of the total sp3-hybridized atoms to the number of the total carbon atoms of the graphene sheet, the chirality of graphene sheets, the molecular structure and molecular weight of functional groups on Young's modulus are studied. The dependence of shear modulus and wrinkling properties on the functional groups are also investigated. The simulation results indicate that Young's modulus depends strongly on the degree of functionalization and the molecular structure of the functional groups, while the effects of chirality of the graphene sheets and the molecular weight of the functional groups are negligible. The chemical functionalization also reduces the shear modulus and critical strain, beyond which the wrinkling instability occurs.

Regulation of cellular senescence by microRNAs.

Cellular senescence is mainly characterized as a stable proliferation arrest and a senescence associated secretory phenotype (SASP). Senescence is triggered by diverse stimuli such as telomere shortening, oxidative stress, oncogene activation and DNA damage, and consequently contributes to multiple physiology and pathology outcomes, including embryonic development, wound healing and tumor suppression as well as aging or age-associated diseases. Interestingly, therapeutic clearance of senescent cells in tissues has recently been demonstrated to be beneficial for extending a healthy lifespan and for improving numerous age-related disorders. However the molecular mechanisms of senescence regulation remain partially understood. Theoretically, senescence is tightly regulated by a vast number of molecules, among which the p16 and p53 pathways are the most classical. In addition, intracellular cellular calcium signaling has emerged as a key regulator of senescence. In the last few decades, a growing number of studies have demonstrated that microRNAs (miRNAs, small non-coding RNAs) are strongly implicated in controlling senescence, especially at the transcriptional and post-transcriptional levels. In this review we will discuss the involvement of miRNAs in modulating senescence through the major p16, p53, SASP and calcium signaling pathways, thus aiming to reveal the mechanisms of how miRNAs regulate cellular senescence.

Elevated PCT at ICU discharge predicts poor prognosis in patients with severe traumatic brain injury: a retrospective cohort study.

PURPOSE: Disease severity and inflammatory response status are closely related to a poor prognosis and must be assessed in patients with severe traumatic brain injury (STBI) before intensive care unit (ICU) discharge. Whether elevated serum procalcitonin (PCT) levels can predict a poor prognosis in STBI patients before ICU discharge is unclear. METHODS: This retrospective observational cohort study enrolled 199 STBI patients who were in the ICU for at least 48 hours and survived after discharge. Based on serum PCT levels at discharge, patients were divided into the high-PCT group (PCT ≥ 0.25 ng/mL) and the low-PCT group (PCT < 0.25 ng/mL). We assessed the relationship between serum PCT levels and a poor prognosis. RESULTS: The high-PCT group had a higher rate of adverse outcomes compared with the low-PCT group. Multivariate logistic regression analysis showed that the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, Sequential Organ Failure Assessment (SOFA) score, white blood cell (WBC) count, C-reactive protein (CRP) level, and PCT level at discharge were significantly associated with adverse outcomes. CONCLUSIONS: Elevated PCT levels at ICU discharge were associated with a poor prognosis in STBI patients. The serum PCT level as a single indicator has limited value for clinical decision-making.