Polydimethylsiloxane (PDMS)-assisted non-destructive transient thermoreflectance characterizations.

The conventional pump-probe thermoreflectance (pump-probe TR) techniques are routinely performed on a thin (typically <100 nm) metal transducer deposited on samples, ensuring the most fundamental principle of thermoreflectance: the reflectance change (∆R/R) of the sample surface is directly and linearly related to the temperature change (∆T) within a finite temperature range. However, general metal coating methods may damage the sample by forming a mixed layer with the sample. In this article, we present a non-destructive pump-probe transient thermoreflectance (TTR) characterization using the polydimethylsiloxane (PDMS)-assisted metal transfer technique. Our method utilizes PDMS dry transfer to transfer common transducer metals (Au and Al) to the target substrate. This method effectively avoids impurities and damage to the sample. In particular, we have utilized Au as a transition layer to study the application of Al transfer in TTR measurements. The substrate thermal conductivity measurement results show that they can all be used for TTR measurement, and the thermal boundary conductance results show that the transferred metals have low bonding to the substrate. In addition, Al/Au can be transferred over a large area at room temperature compared to Au. After measurement, the samples can be restored to their original state by a simple cleaning method. This method provides a simple and reliable way to characterize samples without metal coating for TTR.

Screening Selection of Hydrogen Evolution-Inhibiting and Zincphilic Alloy Anode for Aqueous Zn Battery.

The hydrogen evolution reaction (HER) and Zn dendrites growth are two entangled detrimental effects hindering the application of aqueous Zn batteries. The alloying strategy is studied to be a convenient avenue to stabilize Zn anodes, but there still lacks global understanding when selecting reliable alloy elements. Herein, it is proposed to evaluate the Zn alloying elements in a holistic way by considering their effects on HER, zincphilicity, price, and environmental-friendliness. Screening selection sequence is established through the theoretical evaluation of 17 common alloying elements according to their effects on hydrogen evolution and Zn nucleation thermodynamics. Two alloy electrodes with opposite predicted effects are prepared for experimental demonstration, i.e., HER-inhibiting Bi and HER-exacerbating Ni. Impressively, the optimum ZnBi alloy anode exhibits one order of magnitude lower hydrogen evolution rate than that of the pure Zn, leading to an ultra-long plating/stripping cycling life for more than 11 000 cycles at a high current density of 20 mA cm-2 and 81% capacity retention for 170 cycles in a Zn-V2O5 pouch cell. The study not only proposes a holistic alloy selection principle for Zn anode but also identifies a practically effective alloy element.

Low temperature and facile synthesis of nitrogen-doped hierarchical porous carbon derived from waste polyethylene terephthalate for efficient CO2 capture.

Waste polyethylene terephthalate (PET) with high carbon content (>60 wt%) has shown great potential in the field of synthesizing carbon materials for CO2 capture, attracting increasing attention. Herein, an innovative strategy was proposed to synthesize nitrogen-doped hierarchical porous carbon (PC) for CO2 capture using PET as precursor and sodium amide (NaNH2) as both nitrogen dopant and low-temperature activator. As-synthesized N-doped PC exhibited a significantly high micropore volume of 0.755 cm3/g and a rich content of N- and O-containing functional groups, offering ample active sites for CO2 molecules. Further, the adsorbents demonstrated excellent CO2 capture capacity, achieving 5.7 mmol/g (0 °C) and 3.3 mmol/g (25 °C) at 1 bar, respectively. This was primarily attributed to the synergistic effect of narrow micropores filling and electrostatic interactions. Moreover, as-synthesized PC exhibited rapid CO2 adsorption capability, and its dynamic adsorption process was effectively described using a pseudo-second-order kinetic model. After five consecutive cycles, PET-derived PC still maintained ~100 % of adsorption capacity. They also possessed good CO2/N2 selectivity and reasonable isosteric heat of adsorption. Therefore, as-synthesized nitrogen-doped PC is a promising CO2 adsorbent through low-temperature activation of carbonized PET with NaNH2. Such findings have substantial implications for waste plastic recycling and mitigating the greenhouse effect.

Skin irritation assessment and potential mechanism of Capparis spinosa L. fruits.

ETHNOPHARMACOLOGICAL RELEVANCE: In China, Capparis spinosa L. fruits (CSF) are often used topically in Uyghur folk medicine in treating rheumatic diseases with remarkable efficacy. However, it has noticed severe skin irritation after a short time application with high dose of CSF, which limited long-term clinical use. To date, there is almost no research related to skin irritation of CSF. AIM OF THE STUDY: This study was intended to perform the first systematic assessment of morphological and histological changes in skin after stimulation with CSF. Furthermore, potential irritant components in CSF and related mechanisms were explored by in vitro transdermal techniques, network pharmacology, molecular docking, and experimental validation. MATERIALS AND METHODS: Skin changes after single and multiple stimulations with CSF were observed and subjected to skin irritation response scoring, irritation strength assessment, and histopathological analysis. In addition, in vitro transdermal technology, liquid chromatography-mass spectrometry (LC-MS) method, network pharmacology, molecular docking, and experimental validation were used to further exploit underlying skin irritant components and possible mechanisms of action. RESULTS: CSF induced significant morphological (erythema and edema) and histological (epidermal thickening and inflammatory infiltration) changes in skin of mice, which were similar to the clinical presentation of irritation contact dermatitis (ICD). The ethyl acetate fraction of CSF (CFEAF) was the main source of CSF-induced skin irritation. Kaempferol, flazin, and gallic acid were potential major irritant compounds. Moreover, CFEAF, kaempferol, flazin, and gallic acid could increase the levels of pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and interleukin-17A (IL-17A) to promote skin inflammation. The potential mechanism of CSF-induced skin irritation may be activation of the nuclear factor kappa-B (NF-κB) signaling pathway, including phosphorylation of NF-κB p65 (p65) and nuclear factor-kappa B inhibitor alpha (IκBα). CONCLUSION: Kaempferol, flazin, and gallic acid are potential skin irritant components from CSF. Altogether, they induce skin irritation responses through promoting the release of the inflammatory factors TNF-α and ICAM-1, as well as activating the NF-κB signaling pathway. In addition, IL-17A may be an important pro-inflammatory factor in skin irritation.

The cluster digging behavior of larvae confers trophic benefits to fitness in insects.

Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans. Fly larvae tend to cluster and form coordinated digging groups under crowded conditions, yet understanding the rules governing this behavior is in its infancy. We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior. Here, we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging. Subsequently, we investigated relative factors, including larval stage, population density, and food stiffness and quality, that affect the cluster digging behavior. Remarkably, oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters. More importantly, we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth, cross-section area, and food volume. We found that cluster digging behavior approximately increases 2.2 fold depth, 1.7-fold cross-section area, and 1.9 fold volume than control groups, respectively. Amplification of food sources significantly facilitates survival, larval development, and reproductive success of Drosophila challenged with competition for limited food resources, thereby conferring trophic benefits to fitness in insects. Overall, our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity, advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.

Clean energy transitions and health.

Clean energy can lead to significant health benefits. Making it accessible throughout the world can address many ills. We delve deeply into one example-the transition toward clean residential heating and its relationship to health benefits-in China. We find that the health benefits can outweigh costs from energy expenses in northern provinces. Low-income households enjoy larger health benefits but also experience a higher expense increase, suggesting that extra subsidies or stimuli are needed to help them benefit from clean energy. Our findings suggest that clean energy transitions should be promoted in developing economies due to improved social health, lessened medical costs, and significant environmental improvements.

Understanding the migration mechanism of hydrogen atom from the α-Fe matrix into nano-precipitates via DFT calculations.

The service of high-strength steel suffers from the threat of hydrogen embrittlement and introducing nano-precipitates is an effective avenue to mitigate it. How hydrogen atoms migrate into nano-precipitates is an important question that needs to be clarified. In this study, NEB-based DFT calculations have clearly constructed the energy evolution profiles of the whole process for hydrogen atoms diffusing from α-Fe through the α-Fe/MC (M = V, Ti, Nb) coherent interfaces and finally into the nano-precipitates. The calculation results indicate that a hydrogen atom migrates with difficulty through the α-Fe/MC coherent interfaces and the diffusions in nano-precipitates follow two-step pathways. The C atom vacancy is easier to form in MC nano-precipitates. When introducing a C atom or metallic atom vacancy into the α-Fe/MC interface, the C atom vacancy is the hydrogen trapping site, while the metallic atom vacancy reduces the migration barrier. In addition, once a C atom or metallic atom vacancy is formed in the nano-precipitate, the vacancy will behave as an irreversible trapping site. Finally, electronic structure analyses and distortion energy calculations clearly reveal the effects of the local atomic environment on hydrogen diffusion from α-Fe into nano-precipitates.

Systematic Analysis of Monoallelic Gene Expression and Chromatin Accessibility Across Multiple Tissues in Hybrid Mice.

In diploid eukaryotic organisms, both alleles of each autosomal gene are usually assumed to be simultaneously expressed at similar levels. However, some genes can be expressed preferentially or strictly from a single allele, a process known as monoallelic expression. Classic monoallelic expression of X-chromosome-linked genes, olfactory receptor genes and developmentally imprinted genes is the result of epigenetic modifications. Genetic-origin-dependent monoallelic expression, however, is caused by cis-regulatory differences between the alleles. There is a paucity of systematic study to investigate these phenomena across multiple tissues, and the mechanisms underlying such monoallelic expression are not yet fully understood. Here we provide a detailed portrait of monoallelic gene expression across multiple tissues/cell lines in a hybrid mouse cross between the Mus musculus strain C57BL/6J and the Mus spretus strain SPRET/EiJ. We observed pervasive tissue-dependent allele-specific gene expression: in total, 1,839 genes exhibited monoallelic expression in at least one tissue, and 410 genes in at least two tissues. Among these 88 are monoallelic genes with different active alleles between tissues, probably representing genetic-origin-dependent monoallelic expression. We also identified six autosomal monoallelic genes with the active allele being identical in all eight tissues, which are likely novel candidates of imprinted genes. To depict the underlying regulatory mechanisms at the chromatin layer, we performed ATAC-seq in two different cell lines derived from the F1 mouse. Consistent with the global expression pattern, cell-type dependent monoallelic peaks were found, and a higher proportion of C57BL/6J-active peaks were observed in both cell types, implying possible species-specific regulation. Finally, only a small part of monoallelic gene expression could be explained by allelic differences in chromatin organization in promoter regions, suggesting that other distal elements may play important roles in shaping the patterns of allelic gene expression across tissues.

Static magnetic field of 0.2-0.4 T promotes the recovery of hindlimb unloading-induced bone loss in mice.

PURPOSE: Bone loss is one of the most serious medical problem associated with prolonged weightlessness in long-term spaceflight mission. Skeletal reloading after prolonged spaceflight have indicated incomplete recovery of lost bone, which may lead to an increased risk of fractures in astronauts when returning to Earth. Substantial studies have revealed the capacity of static magnetic fields (SMFs) on treating various bone disorders, whereas it is unknown whether SMFs have the potential regulatory effects on bone quality in unloaded mice during unloading. This study was conducted to investigate the potential effects of whole-body SMF exposure with 0.2-0.4 T on the recovery of unloading-induced bone loss. MATERIALS AND METHODS: Eight-week-old male C57BL/6J mice were subjected to hindlimb unloading (HLU) for 4 weeks, following the mice were reloaded for 4 weeks under geomagnetic field (GMF) and SMF of 0.2-0.4 T. Bone quality indexes, including bone mineral density (BMD) and bone mineral content (BMC), bone microarchitecture, and bone mechanical properties were examined by the measurement of dual energy X-ray absorptiometry (DEXA), micro-computed tomography (Micro-CT), and 3-point bending. Bone turnover was evaluated by bone histomorphometric and serum biochemical assay. RESULTS: We found that SMF exposure for 4 weeks significantly promoted the recovery in HLU-induced decrease of BMD and BMC, deterioration of bone microarchitecture, and reduction of bone strength. The results from bone turnover determination revealed that SMF exposure for 4 weeks induced lower osteoclast number of trabecular bone and serum TRAP-5b levels in reloaded mice, whereas SMF showed no significant alteration in skeletal osteoblast number and serum osteocalcin levels. CONCLUSIONS: Together, our findings suggest that SMF of 0.2-0.4 T facilitated the recovery of unloading-induced bone loss by inhibiting the increase of bone resorption in reloaded mice, and indicate that SMF might become a promising biophysical countermeasure for maintaining bone health in astronauts after landing.

Icariin ameliorates streptozocin-induced diabetic nephropathy through suppressing the TLR4/NF-κB signal pathway.

Diabetic nephropathy (DN) is one of the complex and severe complications of diabetes mellitus (DM). Icariin (ICA) is a flavonoid extracted from the leaves and stems of Herba epimedii with a wide range of pharmacological effects, such as anti-osteoporosis, anti-fibrosis, anti-aging, anti-inflammation and antioxidation. The purpose of our study was to explore the renal protective effect of ICA on DN in mice and its possible mechanisms. ICR mice were exposed to STZ-induced DN. The kidney organ coefficient of mice was computed. 24 h UP in urine was measured. Serum FBG, Cr and BUN were detected. The content of MDA and the activities of SOD, CAT and GSH-Px in renal tissues were tested. HE staining, PAS staining, PASM staining and transmission electron microscopy were used to observe renal pathological changes. Furthermore, TLR4, p-NF-κB p65, TNF-α and IL-6 of renal tissues were assayed by immunohistochemistry and western blotting. Our results indicated that ICA observably optimized the renal organ coefficient, reduced the level of 24 h UP in urine, decreased the content of Cr, BUN in serum and MDA in renal tissues, promoted the activities of SOD, CAT and GSH-Px in renal tissues, and ameliorated pathological lesions of kidneys noticeably. Besides, ICA inhibited the expressions of TLR4, p-NF-κB p65, TNF-α and IL-6 remarkably in renal tissues. ICA, which might lighten the renal inflammatory response by suppressing the TLR4/NF-κB signal pathway, played a protective role in kidneys of STZ-induced DN mice.

Organoarsenic conversion to As(III) in subcritical hydrothermal reaction of livestock manure.

Liquid phase produced by the subcritical hydrothermal liquefaction (HTL) of livestock manure is extensively used in agronomic and environmental applications, but the potential risks caused by inherent pollutants (e.g., roxarsone, ROX) of the livestock manure have not been considered. This study shows that less toxic ROX is completely converted into highly toxic As(III) and As(V) in the HTL reaction with temperature more than 240 °C. Moreover, more than 81.5% of As is distributed in the liquid phase generated by the livestock manure HTL reaction. Notably, the hydrothermal products of livestock manure facilitate the conversion of As(V) to As(III). The resulting hydrochar and aldehydes act as electron donors for As(V) reduction, thus resulting in the formation of As(III). Furthermore, the dissociated As promotes the depolymerization and deoxygenation of the macromolecular compounds to produce more small oxygen-containing compounds such as aldehydes, further boosting the As(V) reduction to As(III). These results indicate that the liquid phase of the livestock manure has potential risks in applications as a fertilizer. Such findings have substantial implications in biomass utilization and redox reactions of envirotechnical and biogeochemical relevance.

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy.

With the aim to develop optimized biochar with minimal contaminants, it is important significance to broaden the understanding of biochar. Here, we disclose for the first time, a highly toxic substance (metal cyanide, MCN, such as KCN or NaCN) in biochar. The cyanide ion (CN-) content in biochar can be up to 85,870 mg/kg, which is determined by the inherent metal content and type in the biomass with K and Na increasing and Ca, Mg and Fe decreasing its formation. Density functional theory (DFT) analysis shows that unstable alkali oxygen-containing metal salts such as K2CO3 can induce an N rearrangement reaction to produce for example, KOCN. The strong reducing character of the carbon matrix further converts KOCN to KCN, thus resulting biochar with high risk. However, the stable Mg, Ca and Fe salts in biomass cannot induce an N rearrangement reaction due to their high binding energies. We therefore propose that high valent metal chloride salts such as FeCl3 and MgCl2 could be used to inhibit the production of cyanide via metal interactive reaction. These findings open a new point of view on the potential risk of biochar and provide a mitigation solution for biochar's sustainable application.

Phosphorus and nitrogen transformation in antibiotic mycelial residue derived hydrochar and activated pyrolyzed samples: Effect on Pb (II) immobilization.

In this study, lincomycin residue (LR, a type of antibiotic mycelial residue) derived hydrochar samples (LR-HCs) were obtained from hydrothermal carbonization (HTC), and pyrolysis applied to these LR-HCs to produce activated pyrolyzed samples (LR-APs). Transformation of phosphorus (P) and nitrogen (N) species during HTC and pyrolysis was of primary interest and characterized by several techniques. Nitrogen content of dry LR was calculated by elemental analysis, being 7.91 wt. %, decreasing to 2.51 after HTC and 1.12 wt. % after concesutive HTC and pyrolysis. FT-IR analysis provided evidence for amine groups in LR samples. XPS analysis described N species (Pyridinic-N, Amine-N, Protein-N, Pyrrolic-N, and Quaternary-N) and P species (ortho-P/pyro-P and Ar-P) in LR samples, effectively. Sequential extraction showed that the HTC and pyrolysis changed the proportion of the P species from labile (P-NaHCO3 and P-NaOH) to stable ones (P-residue). Utilization and suitability of as-prepared LR-HCs and LR-APs for heavy metal Pb (II) immobilization show promising results. To help understand immobilization process, kinetic (pseudo-1st-order and pseudo-2nd-order) and isotherm (Freundlich) models were tested and verified. Results confirmed that P and N species were transformed during HTC and pyrolysis and that these processes lead to an advantageous effect on Pb (II) removal from solution.

Heterojunction α-Co(OH)2/α-Ni(OH)2 nanorods arrays on Ni foam with high utilization rate and excellent structure stability for high-performance supercapacitor.

The practical implementation of supercapacitors is hindered by low utilization and poor structural stability of electrode materials. Herein, to surmount these critical challenges, a three-dimensional hierarchical α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods are built in situ on Ni foam through a mild two-step growth reaction. The unique lamellar crystal structure and abundant intercalated anions of α-M(OH)2 (M = Co or Ni) and the ideal electronic conductivity of α-Co(OH)2 construct numerous cross-linked ion and electron transport paths in heterojunction nanorods. The deformation stresses exerted by α-Co(OH)2 and α-Ni(OH)2 on each other guarantee the excellent structural stability of this heterojunction nanorods. Using nickel foam with a three-dimensional network conductive framework as the template ensures the rapidly transfer of electrons between this heterojunction nanorods and current collector. Three-dimensional hierarchical structure of α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods provides a large liquid interface area. These result together in the high utilization rate and excellent structure stability of the α-Co(OH)2/α-Ni(OH)2 heterojunction nanorods. And the capacitance retention rate is up to 93.4% at 1 A g-1 from three-electrode system to two-electrode system. The α-Co(OH)2/α-Ni(OH)2//AC device also present a long cycle life (the capacitance retention rate is 123.6% at 5 A g-1 for 10000 cycles), a high specific capacitance (207.2 F g-1 at 1 A g-1), and high energy density and power density (72.6 Wh kg-1 at 196.4 W kg-1 and 40.9 Wh kg-1 at 3491.8 W kg-1), exhibiting a fascinating potential for supercapacitor in large-scale applications.

Conversion of phosphorus and nitrogen in lincomycin residue during microwave-assisted hydrothermal liquefaction and its application for Pb2+ removal.

Treatment of antibiotic fermentative residue (AFR) produced from pharmaceutical industries and their application in the environment has been gaining researchers' interest. In this study, lincomycin residue (LMR, the type of AFR) was treated with microwave-assisted hydrothermal liquefaction (MW-HTL) in a temperature range 120-210 °C, transforming effect of phosphorus (P) and nitrogen (N) functional groups in LMR samples was characterized with elemental analysis, XRD, XPS, FT-IR, and P-extraction, and utilized LMR samples for Pb2+ removal from aqueous solutions. The temperature had a significant impact on P and N functional groups conversion justified by characterization techniques and also responsible for Pb2+ adsorption. LMR hydrochar produced at 210 °C was accounted highest Pb2+ adsorption capacity (57.4 mg g-1), higher four folds than raw LMR (13.8 mg g-1). To understand the mechanism and rate defining phase of adsorption equilibrium isotherm and kinetic models were applied systematically. Adsorption results of LMR and its derived hydrochar samples found connectivity with Langmuir and pseudo-first-order isotherm models. Adsorption mainly occurred as ion-exchange dependent on the substitution of metal ions (Pb2+) to Ca2+ ions present in P-materials, and surface adsorption dependent on surface functional groups of LMR samples. Better operation feasibility of MW-HTL treated LMR, elaboration of P and N conversion behavior and high sorption of Pb2+ ions could make LMR a frontrunner for heavy metals immobilization.

Expression of NAMPT is associated with breast invasive ductal carcinoma development and prognosis.

Nicotinamide phosphoribosyltransferase (NAMPT) possesses various functions in human cells, and altered NAMPT expression is associated with human carcinogenesis. The present study detected the expression of NAMPT in normal and cancerous breast tissues from 83 patients using immunohistochemistry, and analyzed its association with the clinicopathological and survival data of the patients. NAMPT was significantly overexpressed in the breast invasive ductal carcinoma tissues compared with adjacent normal mammary gland tissues. Upregulated NAMPT expression was associated with a larger tumor size, lymph node metastasis, advanced clinical tumor-node-metastasis stages, and estrogen receptor and progesterone receptor expression. Furthermore, NAMPT expression was associated with poor overall and disease-free survival in patients with breast cancer. In conclusion, NAMPT increased protein expression in tumor cells may contribute to the development and progression of breast invasive ductal carcinoma. Thus, detection of NAMPT expression might be useful as a biomarker for the early detection and prognosis prediction of breast cancer.

Development of high-utilization honeycomb-like α-Ni(OH)2 for asymmetric supercapacitors with excellent capacitance.

The low utilization rate of active materials has been a critical obstacle for the industrialization of ultracapacitors. In this study, a thin layer of cross-structured ultrathin α-Ni(OH)2 nanosheets was successfully grown in situ on the surface of a nickel foam as a high-conductivity framework by a vibratory water bath route under a low temperature (80 °C) and mild conditions. Combining the ultrathin α-Ni(OH)2 nanosheets and ultrashort electron transport, the strategy of a perfect intercalation structure of α-Ni(OH)2 and a thin layer of active material on a continuous conductive framework resulted in a high utilization rate of active material, which further achieved high specific capacitance of 213.55 F g-1 at 1 A g-1 in a two-electrode system and high capacitance retention from three to two electrode system (753.79 F g-1 at 1 A g-1 in the three-electrode system). Meanwhile, the device also achieved high energy density of 74.94 W h kg-1 at power density of 197.4 W kg-1 and still retained 24.87 W h kg-1 at power density of 3642 W kg-1.

Serum Dickkopf-1 expression level positively correlates with a poor prognosis in breast cancer.

BACKGROUND: The different expression level of Dickkopf-1 (DKK-1) in different cancers shows that the function of DKK-1 depends on the histological type of the cancer cells and the tissue microenvironment. To our knowledge, the serum expression level of DKK-1 in breast cancer is little known. METHODS: Blood samples from 125 consecutive patients diagnosed with breast cancer and 53 control subjects from March 2008 to August 2013 were investigated. Serum DKK-1 expression levels were measured by enzyme-linked immunosorbent assay (ELISA). The overall survival (OS) and relapse-free survival (RFS) analyzed by log-rank test, and survival curves were plotted according to Kaplan-Meier. RESULTS: The mean serum level of DKK-1 in patients with breast cancer was 4.99 ± 1.50 ng/mL, and was significantly higher than that in healthy individuals (1.88 ± 0.81 ng/mL, P < 0.001). DKK-1 level correlated significantly with TNM stage (P = 0.009), tumor grade (P = 0.02), lymph node metastasis (P = 0.001), and expression of HER2 (P = 0.002). The DKK-1 expression level was classified as high or low in relation to the median value, and patients with breast cancer (n = 125) were divided into a high expression group (n = 63) and a low expression group (n = 62). The Kaplan-Meier method for survival analysis showed that the patients with a high serum DKK-1 level had a poorer OS (48.7% vs. 81.3%, p = 0.01) and RFS (24.3% vs. 71.6%, p = 0.003) than those with a low expression level. The multivariate Cox regression analysis indicated that serum DKK-1 level was independent prognostic factors for OS and RFS. CONCLUSIONS: Serum DKK-1 level can be used as a noninvasive biomarker for the prognosis of breast cancer. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_161.