Improvement in Mechanical Properties of 3D-Printed PEEK Structure by Nonsolvent Vapor Annealing.

The broad applications of 3D-printed poly-ether-ether-ketone (3D-PEEK) structures are largely hampered by their inadequate mechanical properties that can be improved by post treatments. At present, thermal annealing is generally used to improve the mechanical properties of 3D-PEEK. However, it cannot simultaneously improve strength and ductility. Here, a cost-effective postprocessing method is developed to improve the mechanical properties of 3D-PEEK, based on annealing in nonsolvent vapor at room temperature. The annealing in nonsolvent vapor at room temperature simultaneously improves the strength, ductility, and fracture energy of as-printed 3D-PEEK by 22.6%, 151.3%, and 109.1%, respectively. The improved mechanical properties are attributed to enhanced interfacial bonding, increased crystallinity, decreased pinhole defects, and stress relaxation in the 3D-PEEK. Moreover, the annealing in both polar solvents (such as acetone and chloroform) and nonpolar solvents (such as n-hexane) are demonstrated to be effective for improving the mechanical properties of 3D-PEEK. The nonsolvent vapor-annealed 3D-PEEK can thus have potential applications in the fields of medical implants, automotive, aerospace, and more.

Adhesion Enhancement of Micropillar Array by Combining the Adhesive Design from Gecko and Tree Frog.

It has long been demonstrated the gecko-inspired micropillar array with T-shape tips possesses the best adhesion performance of a given material. The further enhancement of the adhesion performances of T-shape micropillars can offer redundant adhesion to compensate for the inevitable improper contacts. Here, the array of T-shape polydimethylsiloxane (PDMS) micropillars is incorporated with gradient dispersed calcium carbonate nanoparticles in the micropillar stalk, termed as T-shape gradient micropillars (TG), possessing the modulus gradient with stiff tip and soft root. The gradient modulus in TG facilitates the contact formation and regulates the stress at the detaching interface, resulting in a 4.6 times adhesion and 2.4 times friction as compared with the pure PDMS T-shape micropillar arrays. The study here provides a new design strategy for the super-strong structured dry adhesives.

Switchable Adhesion of Micropillar Adhesive on Rough Surfaces.

Switchable structured adhesion on rough surfaces is highly desired for a wide range of applications. Combing the advantages of gecko seta and creeper root, a switchable fibrillar adhesive composed of polyurethane (PU) as the backing layer and graphene/shape memory polymer (GSMP) as the pillar array is developed. The photothermal effect of graphene (under UV irradiation) changes GSMP micropillars into the viscoelastic state, allowing easy and intimate contact on surfaces with a wide range of roughness. By controlling the phase state of GSMP via UV irradiation during detachment, the GSMP micropillar array can be switched between the robust-adhesion state (UV off) and low-adhesion state (UV on). The state of GSMP micropillars determines the adhesion force capacity and the stress distribution at the detaching interface, and therefore the adhesion performance. The PU-GSMP adhesive achieves large adhesion strength (278 kPa), high switching ratio (29), and fast switching (10 s) at the same time. The results suggest a design principle for bioinspired structured adhesives, especially for reversible adhesion on surfaces with a wide range of roughness.

Continuous Gradient Nanoporous Film Enabled by Delayed Directional Diffusion of Solvent and Selective Swelling.

Nature-inspired porous structures are highly desired in the fields of new materials, sustainable energy, biological and chemical science, and so forth. Here, a new strategy for the fabrication of continuous, gradient nanoporous polystyrene- block-poly(2-vinylpyridine) (PS- b-P2VP) film is established. The continuous nanopore gradient along the direction of film thickness (∼120 µm) is achieved via delayed directional diffusion of dynamic binary solvent of ethanol/water and selective swelling of P2VP domains. Ethanol in binary solvent diffuses into the film from one side to another, which is retarded by the water gate as water is concentrated at the film surface. The delayed diffusion matches the swelling rate of P2VP domains, forming the continuous nanopore gradient normal to the film surface.

[Effect of Xinling Wan in treatment of stable angina pectoris: a randomized, double-blinded, placebo parallel-controlled, multicenter trial].

To evaluate the effectiveness and safety of Xinling Wan on patients with stable angina pectoris, a randomized, double-blinded, placebo parallel-controlled, multicenter clinical trial was conducted. A total of 232 subjects were enrolled and randomly divided into experiment group and placebo group. The experiment group was treated with Xinling Wan (two pills each time, three times daily) for 4 weeks, and the placebo group was treated with placebo. The effectiveness evaluation showed that Xinling Wan could significantly increase the total duration of treadmill exercise among patients with stable angina pectoris. FAS analysis showed that the difference value of the total exercise duration was between experiment group (72.11±139.32) s and placebo group (31.25±108.32) s. Xinling Wan could remarkably increase the total effective rate of angina pectoris symptom score, and the analysis showed that the total effective rate was 78.95% in experiment group and 42.61% in placebo group. The reduction of nitroglycerin dose was (2.45±2.41) tablets in experiment group and (0.50±2.24) tablets in placebo group on the basis of FAS analysis. The decrease of symptom integral was (4.68±3.49) in experiment group and (3.19±3.31) in placebo group based on FAS analysis. Besides, Xinling Wan could decrease the weekly attack time and the duration of angina pectoris. PPS analysis results were similar to those of FAS analysis. In conclusion, Xinling Wan has an obvious therapeutic effect in treating stable angina pectoris, with a good safety and a low incidence of adverse event and adverse reaction in experiment group.

Cryptosporidium Contamination and Attributed Risks in Yunlong Lake in Xuzhou, China.

Swimming in surface water bodies (e.g., lakes, rivers) can expose the human body to substantial risk of infection by Cryptosporidium. These findings are from a one-year investigation on the occurrence and distribution of the protozoan parasite Cryptosporidium in Yunlong Lake, Xuzhou, China. Cryptosporidium oocysts were detected by immunofluorescence microscopy. From January to November of 2015, 180 samples (120 water samples and 60 sediment samples) were collected and analyzed. Among them, 42 (35%) water samples and 28 (47%) sediment samples tested positive for Cryptosporidium. The concentration of Cryptosporidium oocysts in the water samples was 0-8/10 L and 0-260/g in sediment samples. Results revealed that July was the highest risk period for both swimming and diving with an estimated probability of infection from swimming of greater than 18 per 10,000 swim sessions. It was concluded that swimming or diving in Yunlong Lake has a higher risk of Cryptosporidium infection than the acceptable risk level set by the United States Environmental Protection Agency. Thus, regular monitoring of water quality in recreation water bodies is strongly recommended.

[Effects of intensive antiplatelet therapy for patients with high on-treatment platelet reactivity after coronary stent implantation].

OBJECTIVE: To explore the effects of intensive antiplatelet therapy for patients with high on-treatment platelet reactivity (HPR) after coronary stent implantation. METHODS: Between March 2009 and February 2011, a total of 3316 consecutive acute coronary syndrome patients undergoing drug-eluting stent implanting from 3 hospitals were enrolled. Among them, 840 patients (25.3%) were identified as HPR (defined as 20 µmol/L adenosine diphosphate induced platelet aggregation of ≥ 55% at 24 hours after administration of 300 mg clopidogrel loading dose and 300 mg aspirin). The HPR patients were randomly assigned to receive standard (aspirin 300 mg/d and clopidogrel 75 mg/d, n = 280) or intensified (n = 560) antiplatelet therapy by the ratio of 1:2. Patients in the intensive group were initially treated with a double maintenance dose of clopidogrel (150 mg/d) and aspirin (300 mg/d). After 3 days, patients with unsolved HPR received additional cilostazol treatment (50 - 100 mg, bid). The reversion rate of HPR and clinical events were observed. RESULTS: In the intensive group, HPR reversed in 304 out of 560 patients (54.3%) at 3 days post therapy and the remaining 256 patients with HPR were treated with additional cilostazol regimen for another 3 days and the total reversion rate of HPR was 81.1% (454/560). The reversion rate of HPR at 30 days in the intensified group was significantly higher than that of the standard group (69.9% vs. 55.7%, P = 0.000). At 30 days after percutaneous coronary intervention, 1 patient suffered from subacute stent thrombosis (0.2%) in intensified group and no stent thrombosis was observed in standard group (P = 1.000). There were no death, major or minor bleeding in both two groups. Minimal bleeding was also similar in the two groups (intensive: 4.28% vs. standard: 2.14%, P = 0.166). CONCLUSIONS: The intensified antiplatelet therapy regimens could significantly increase the reversion rate of HPR in acute coronary syndrome patients undergoing coronary stenting without increasing the risk of bleeding. The clinic impact of this strategy needs to be elucidated by long term follow-up outcome studies.

Is vitamin D deficiency a risk factor for all-cause mortality and rehospitalization in heart failure patients?: A systematic review and meta-analysis.

OBJECTIVE: The association of low 25-hydroxyvitamin D level with mortality and rehospitalization remains inconsistent in patients with heart failure. This systematic review and meta-analysis aimed to evaluate the value of blood 25-hydroxyvitamin D level in predicting all-cause mortality and hospitalization in heart failure patients. METHODS: Two reviewers independently search the articles indexed in PubMed and Embase databases until November 30, 2021. Only the prospective or retrospective cohort studies evaluating the association of blood 25-hydroxyvitamin D level with all-cause mortality and rehospitalization in heart failure patients were selected. The predictive value of 25-hydroxyvitamin D level was summarized by pooling multivariable adjusted risk estimates for the bottom versus reference top 25-hydroxyvitamin D level. RESULTS: Seven studies with a total of 5941 patients with heart failure were identified. The pooled adjusted risk ratio (RR) of all-cause mortality was 1.37 (95% confidence interval [CI] 1.13-1.66), with significant heterogeneity (I2 = 70.5%; P = 0.002). However, there was no clear association between low 25-hydroxyvitamin D level and all-cause rehospitalization risk (RR 1.38; 95% CI 0.87-2.19). CONCLUSIONS: Low blood level of 25-hydroxyvitamin D may be an independent risk factor for all-cause mortality in patients with heart failure. Serum 25-hydroxyvitamin D level may provide prognostic information in heart failure patients. Additional randomized controlled trials are required to explore whether treatment of 25-hydroxyvitamin D deficiency by supplementation of vitamin D can improve survival in heart failure patients.

Efficacy of add-on Danhong injection in patients with unstable angina pectoris: A double-blind, randomized, placebo-controlled, multicenter clinical trial.

ETHNOPHARMACOLOGICAL RELEVANCE: Danhong injection (DHI)，which is extracted from Salviae miltiorrhizae and Flos carthami，has been widely prescribed to patients with unstable angina pectoris (UAP) in China. However, a high quality clinical trial is needed. AIM OF THE STUDY: To determine whether DHI can relieve symptoms of transient myocardial ischemia in patients with unstable angina pectoris. MATERIALS AND METHODS: A double-blind, placebo-controlled, randomized clinical trial was conducted in nine hospitals in China. Inpatients with UAP with blood stasis syndrome (BSS) were randomized 1:1 to receive DHI or placebo. The primary outcome was improvement rate in the quantification score of angina pectoris. Secondary outcomes included blood stasis syndrome scale, nitrates use, electrocardiogram recordings, PCI procedures, Seattle Angina Questionnaire (SAQ) and biochemical indexes. RESULTS: 160 participants were enrolled and 159 were analyzed. There was no significant difference in primary outcome as compared with control group at the end of 7-day treatment, but significant difference at 28-day follow up (70.53% [95% CI, 59.97-81.09%] and 54.34% [95% CI, 42.68-65.99%]; P = 0.0423). The BSS score was significantly lower in the DHI group than that in the control group at day 28 (6.49 [6.96] vs 10.53 [9.07], P = 0.0034). In addition, DHI was significantly superior to placebo in the angina stability score of SAQ (91.10 [17.37] versus 78.21 [22.08], P < 0.001). There were no significant differences in other secondary outcome measures. CONCLUSIONS: A small decrease in the total effective rate and an increase in the angina stability score were observed 28 days after implementation of DHI in UAP with a total blood stasis syndrome score decrease, but the efficacy was not observed at day 7. The findings support that DHI may potentially relieve clinical symptoms and can benefit angina stability. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02007187.

Internal Forces Analysis of Prestressed Concrete Box Girder Bridge by Using Structural Stressing State Theory.

This paper analyzes the working behavior characteristics of a prestressed concrete transverse large cantilever continuous (PCTLCC) box girder bridge model based on structural stressing state theory and the numerical shape function (NSF) method. At first, the normalized generalized strain energy density (GSED) is established to model the stressing state of the bridge model. Subsequently, the Mann Kendall (M-K) criterion is applied to detect three characteristic loads, respectively, elastic-plastic branch load P (200 kN), failure load Q (300 kN), and progressive failure load H (340 kN), and the failure load Q is found to be the starting load of the damage process of the bridge model, rather than the ultimate load where the structure has been destroyed. Finally, the NSF method is adopted to interpolate the test data, and a detailed analysis for the variation characteristics of the working behavior of the bridge model under loads is performed based on the interpolation results. The characteristic load detection method and experimental data extension method for PCTLCC box girder bridge established in this study can provide valuable references for the design and analysis of such bridges.

Programmable Local Orientation of Micropores by Mold-Assisted Ice Templating.

Pore geometry plays a crucial role in determining the properties and functions of porous materials. Various methods have been developed to prepare porous materials that have randomly distributed or well-aligned pores. However, a technique capable of fine regulation of local pore orientation is still highly desired but difficult to attain. A technique, termed mold-assisted ice templating (MIT), is reported to control and program the local orientation of micropores. MIT employs a copper mold of a particular shape (for instance a circle, square, hexagon, or star) and a cold finger to regulate the 3D orientation of a local temperature gradient, which directs the growth of ice crystals; this approach results in the formation of finely regulated patterns of lamellar pore structures. Moreover, the lamellar thickness and spacing can be tuned by controlling the solution concentration.

Reversible Structure Engineering of Bioinspired Anisotropic Surface for Droplet Recognition and Transportation.

Surfaces with tunable liquid adhesion have aroused great attention in past years. However, it remains challenging to endow a surface with the capability of droplet recognition and transportation. Here, a bioinspired surface, termed as TMAS, is presented that is inspired by isotropic lotus leaves and anisotropic butterfly wings. The surface is prepared by simply growing a triangular micropillar array on the pre-stretched thin poly(dimethylsiloxane) (PDMS) film. The regulation of mechanical stress in the PDMS film allows the fine tuning of structural parameters of the micropillar array reversibly, which results in the instantaneous, in situ switching between isotropic and various degrees of anisotropic droplet adhesions, and between strong adhesion and directional sliding of water droplets. TMAS can thus be used for robust droplet transportation and recognition of acids, bases, and their pH strengths. The results here could inspire the design of robust sensor techniques.

Tree Frog-Inspired Micropillar Arrays with Nanopits on the Surface for Enhanced Adhesion under Wet Conditions.

Inspired by the nanoconcave top of epidermal cells on tree frogs' toe pads, an array of composite micropillars with nanopits on the surface (CPp) has been designed. Polystyrene (PS) nanoparticles are mixed with polydimethylsiloxane (PDMS) and serve as the template for nanopits on the PS/PDMS composite micropillars. CPp shows much larger wet adhesion compared to the arrays of micropillars without nanopits. Under a certain loading force, most of the liquid between CPp and the counterpart surface is squeezed out, so the liquid that remained in nanopits forms multiple nanoscale liquid bridges within the contact area of a single micropillar. Moreover, a large loading force could squeeze part of the liquid out of nanopits, resulting in the suction effect during the pull-off. The multiple liquid bridges, the suction effect, and the solid direct contact thus contribute to strong wet adhesion, which could be ∼36.5 times that of tree frogs' toe pads. The results suggest the function of nanoconcaves on the toe pad of tree frogs and offer a new design strategy for structured adhesives to gain strong wet adhesion.

Reversible Adhesion via Light-Regulated Conformations of Rubber Chains.

Bio-inspired reversible adhesives have attracted great attention because of their promising applications in the electronic, biomedical, and robotic fields. Here, to achieve in situ reversible adhesion, a new concept is demonstrated by modulating the conformations of polydimethylsiloxane (PDMS) chains. The new adhesive, termed BGPP, is composed of the graphene/PDMS composite (GP) as the backing layer and PDMS as the micropillar array. The photothermal effect of graphene under UV irradiation heats up the micropillars, resulting in an increase in the chain conformations of PDMS and thus the contact points with the counterpart surface. The more contact points together with the alignment of PDMS chains during the shearing result in an adhesion much higher than that without UV irradiation. The adhesion switching thus does not rely on the changing of the contact area, and so the macroscopic deformation of structures is avoided. The results suggest a new design principle for light-controllable structured adhesive, which could be conceptualized into other rubbery materials.

A Multicenter, Randomized, Double-Blind, and Placebo-Controlled Study of the Effects of Tongxinluo Capsules in Acute Coronary Syndrome Patients with High On-Treatment Platelet Reactivity.

BACKGROUND: High platelet reactivity (HPR) during clopidogrel treatment predicts postpercutaneous coronary intervention (PCI) ischemic events strongly and independently. Tongxinluo capsules (TCs) are a traditional Chinese medicine formulation used as antiplatelet treatment. However, its efficacy against HPR is not known. The aim of the present study was to evaluate the effects of TCs in acute coronary syndrome (ACS) patients with HPR. METHODS: This multicenter, randomized, double-blind, placebo-controlled study prospectively analyzed 136 ACS patients with HPR who underwent PCI. The patients were enrolled from November 2013 to May 2014 and randomized to receive placebo or TCs in addition to standard dual antiplatelet therapy (DAPT) with aspirin and clopidogrel. The primary end points were the prevalence of HPR at 30 days and the mean change in P2Y12reaction units (PRUs) between baseline and 30 days. Survival curves were constructed with Kaplan-Meier estimates and compared by log-rank tests between the two groups. RESULTS: Both groups had a significantly reduced prevalence of HPR at 30 days versus baseline, but the TC group, compared with the placebo group, had greater reduction (15.8% vs. 24.8%, P = 0.013), especially among patients with one cytochrome P450 2C19 loss of function (LOF) allele (χ2 = 2.931, P = 0.047). The TC group also had a lower prevalence of HPR (33.3% vs. 54.2%, t = 5.284, P = 0.022) and superior performance in light transmittance aggregometry and higher levels of high-sensitivity C-reactive protein (hsCRP), but the composite prevalence of ischemic events did not differ significantly (χ2 = 1.587, P = 0.208). CONCLUSIONS: In addition to standard DAPT with aspirin and clopidogrel, TCs further reduce PRU and hsCRP levels, especially in patients carrying only one LOF allele. The data suggest that TCs could be used in combination therapy for ACS patients with HPR undergoing PCI.