Irisin attenuates angiotensin II-induced atrial fibrillation and atrial fibrosis via LOXL2 and TGFß1/Smad2/3 signaling pathways.

Objectives: Irisin was reported as a cardioprotective and anti-oxidative effector, while the effect on atrial fibrosis is unknown. The current research examined irisin's function in atrial fibrillation (AF); atrial fibrosis brought on by Ang II can be suppressed, thus lessening the risk of developing AF. Materials and Methods: 246 individuals were enrolled in the present case-control study. Chinese AF patients (n=126), 83 of whom were paroxysmal AF (PAF), 43 patients with persistent AF (PeAF), and 120 healthy controls. Saline or Ang II (2.0 mg/kg/day) was subcutaneously injected into healthy male C57BL/6 mice for four weeks. Once daily for four weeks, intraperitoneal injections of exogenous irisin (500 g/kg/day) were administered. Results: In comparison to PAF patients and healthy controls (all P<0.05), PeAF patients had significantly higher rates of heart failure (HF), large left atrial size (LAD), hypertrophic protein B-type natriuretic peptide (BNP), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-terminal telopeptide of type I collagen (CTX-I), and transforming growth factor beta-1 (TGF-ß1), while superoxide dismutase (SOD) level was low. Expression of irisin was decreased in AF patients' serum and Ang II-infused mice. Exogenous irisin dramatically reduced apoptosis, atrial fibrosis, atrial inflammation, and the susceptibility to AF caused by Ang II. In the atrial tissue, irisin inhibited Ang II-induced fibroblast transdifferentiation, LOXL2, TGF-ß1, collagen production, and phosphorylation of Smad2/3. Conclusion: The study results speculated that irisin could be a potential AF target, and it inhibited atrial fibrosis and significantly impaired increased AF susceptibility through inactivation of LOXL2 and the TGF-ß/Smad pathway.

Effectiveness and electrophysiological mechanisms of focal vibration on upper limb motor dysfunction in patients with subacute stroke: A randomized controlled trial.

Upper limb motor dysfunction is a common complication after stroke, which has a negative impact on the daily life of the patients. Focal vibration (FV) has been used to improve upper limb motor function in acute and chronic stroke patients, but its application in subacute stroke patients has not been extensively explored. Therefore, the purpose of this study was to explore the therapeutic effect of FV on upper limb motor function in subacute stroke patients and its underlying electrophysiological mechanism. Twenty-nine patients were enrolled and randomized into two groups: a control group and a vibration group. The control group were treated with conventional therapy including passive and active physical activity training, standing and sitting balance exercises, muscle strength training, hand extension and grasping exercises. The vibration group were given conventional rehabilitation and vibration therapy. A deep muscle stimulator (DMS) with a frequency of 60 Hz and an amplitude of 6 mm was used to provide vibration stimulation, which was sequentially applied along the biceps muscle to the flexor radialis of the affected limb for 10 min, once a day, and 6 times a week. Both groups received treatments for 4 consecutive weeks. In the vibration group, the motor evoked potential (MEP) latency and the somatosensory evoked potential (SEP) latency were significantly shortened (P < 0.05) immediately and 30 min after vibration; the SEP amplitude and MEP amplitude were significantly increased (P < 0.05) immediately and 30 min after vibration. The MEP latency (P = 0.001) and SEP N20 latency (P = 0.001) were shortened, and the MEP amplitude (P = 0.011) and SEP N20 amplitude (P = 0.017) were significantly increased after 4 weeks in the vibration group. After 4 consecutive weeks, the vibration group showed significant improvements in Modified Ashworth Scale (MAS) (P = 0.037), Brunnstrom stage for upper extremity (BS-UE) (P = 0.020), Fugl-Meyer assessment for upper extremity (FMA-UE) (P = 0.029), Modified Barthel Index (MBI) (P = 0.024), and SEP N20 (P = 0.046) compared to the control group. The Brunnstrom stage for hand (BS-H) (P = 0.451) did not show significant differences between the two groups. This study showed that FV was effective in improving upper limb motor function in subacute stroke patients. The underlying mechanism of FV may be that it enhances the efficacy of sensory pathways and induces plastic changes in the sensorimotor cortex.

[Clinical analysis of severe/critical 2019 novel coronavirus Omicron variant infection combined with atrial fibrillation].

OBJECTIVE: To investigate the clinical characteristics and prognosis of coronavirus disease 2019 (COVID-19) patients with Omicron variant combined with atrial fibrillation (AF). METHODS: From March 23, 2022 to May 15, 2022, 2 675 aged ≥ 50 years old COVID-19 patients with AF were admitted to Zhoupu Hospital, the designated hospital for COVID-19 in Shanghai. Patients were divided into mild symptoms group, normal group, and serious/critical group according to the symptoms. The clinical data, imaging examination and laboratory results and prognosis of the three group patients were compared. RESULTS: The median age of 2 675 COVID-19 patients was 69.0 (60.0, 81.0) years old, the incidence of AF was 5.05% (135/2 675), the age range of AF patients were from 55 to 101 years old, with a median age of 84.0 (74.0, 89.0), and the number of mild symptoms, normal, serious/critical patients were 68, 30, 37, respectively, including 9 of serious and 28 of critical patients. In the serious/critical patients, aged 55-75 years old accounted for 43.2%, the rate of 2019 novel coronavirus vaccination was 32.4%. The identified new-onset AF was the highest among the three groups, but the rate of persistent AF was the highest in the mild symptoms group (58.8%). The severe/critical group complicated with fever (29.7%), hepatic insufficiency (13.5%), renal insufficiency (46.0%), type 2 diabetes (46.0%), and heart failure were higher in NYHA classification [compared with the mild symptoms and normal group (score): 1.8±1.1 vs. 1.1±0.8, 1.2±0.7, respectively, all P < 0.05]. In term of laboratory examinations, C-reactive protein (CRP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were significantly higher in serious/critical patients compared to the mild symptoms and normal groups [CRP (mg/L): 27.2 (6.0, 60.8) vs. 7.6 (3.1, 19.3), 12.8 (4.9, 26.3), ALT (U/L): 31.3±15.4 vs. 15.4±9.3, 19.3±11.7, AST (U/L): 78.0±21.7 vs. 34.7±15.6, 38.1±24.4, all P < 0.05]. The hemoglobin (Hb) and albumin (ALB) levels were significantly lower than those in the mild symptoms and normal groups [Hb (g/L): 105.3±22.5 vs. 125.8±25.4, 123.0±20.4, ALB (g/L): 33.7±6.0 vs. 39.0±5.5 and 39.6±13.1, all P < 0.05]. In addition, MB isoenzyme of creatine kinase (CK-MB) was significantly higher in the serious/critical group than that in the mild symptoms group [µg/L: 2.5 (1.5, 3.4) vs. 2.2 (1.2, 2.8), P < 0.05]. In terms of the treatment, the percentage of antiplatelet agents and low-molecular heparin ratio compared among the three groups were statistically significant, with the serious/critical group using the lowest percentage of antiplatelet agents (27.0%) and a higher percentage of low-molecular heparin usage than that in mild symptoms group [81.1% (30/37) vs. 51.5% (35/68), P < 0.05]. In terms of prognosis, the mortality of patients with AF was 18.5% (25/135), all of whom were critical ill, including 32.0% (8/25) with cerebral embolism, pulmonary embolism and cerebral hemorrhage. Among them, 40.0% (10/25) died of multiple organ failure (40.0% combined with gastrointestinal hemorrhage), 20.0% (5/25) died of heart failure, and 12.0% (3/25) died of respiratory failure; while there were no death cases recorded in the mild symptoms, normal group and 9 serious patients. CONCLUSIONS: The serious/critical patients infected with COVID-19 Omicron variant with AF, have a worse prognosis and high mortality. Multiple organ failure, heart failure, sudden cardiac death, respiratory failure and embolic disease are the major causes of death.

LOXL2 silencing suppresses angiotensin II-induced cardiac hypertrophy through the EMT process and TGF-ß1/Smad3/NF-κB pathway.

Objectives: Atrial fibrillation (AF) is a common arrhythmia with atrial myocyte hypertrophy linked with stroke, heart failure, and increased mortality. Lysyl oxidase-like 2 (LOXL2) involves the cross-linking of collagen in the extracellular matrix (ECM). In the present study, we investigated the roles and underlying mechanisms of LOXL2 on cardiomyocyte hypertrophy. Materials and Methods: The expression of LOXL2 mRNA and protein were detected in angiotensin II (Ang II) treated rat cardiomyocytes H9c2 by RT-qPCR and western blot. Small interfering RNA (siRNA) mediated LOXL2 gene silencing was used to evaluate cardiac hypertrophy and related markers. Also, the protein expression of EMT markers and Smad3/NF-κB pathway was determined by western blot. Results: Ang II significantly increased mRNA and protein expressions of LOXL2 and increased mRNA levels of myocardial hypertrophy markers, including ANP, BNP, and ß-MHC in H9c2 cells. Silencing of LOXL2 significantly suppressed Ang II-induced hypertrophy and reversed the increase in ANP, BNP, and ß-MHC mRNA levels. Also, EMT markers' expressions, as evidenced by increased E-cadherin and decreased vimentin, α-smooth muscle actin (α-SMA), fibroblast-specific protein (FSP), and collagen 1A1. Mechanistically, we found that LOXL2 silencing suppressed protein expressions of TGF-ß1, p-Smad3, and p-NF-κB in Ang II-stimulated H9c2 cells. LOXL2 silencing also attenuated Ang II-induced increased expression and content of proinflammatory cytokines IL-1ß (H) and TNF-α. Conclusion: Our data speculated that LOXL2 might be a potential contributing factor to Ang II-induced cardiac hypertrophy, and TGF-ß1/Smad3/NF-κB is involved in a signal axis and might be a potential strategy in treating cardiac hypertrophy.

Percutaneous Retrieval of Left Atrial Appendage Closure Devices in Patients With Atrial Fibrillation: A Case Report.

Left atrial appendage closure (LAAC) devices can be inadvertently released into unfavorable locations, which may allow them to migrate to a different position within the left atrial appendage or embolize from the heart into the aorta. In such instances, it can be challenging to remove the LAAC device. Here, we present two cases in which patients with atrial fibrillation experienced LAAC device exposure at an inappropriate site because of interventional operator error and device mismatch: (a) the LAAC device was dislodged into the aortic arch and retrieved percutaneously from the femoral artery route, and (b) in the left atrium, which was dislodged into the left atrium and retrieved via atrial transseptal puncture of the femoral vein.

Covalent-organic frameworks as adsorbent and matrix of SALDI-TOF MS for the enrichment and rapid determination of fluorochemicals.

An imine-linked two-dimensional covalent organic framework, via the condensation of 1, 3, 5-triformylbenzene and p-phenylenediamine (COF-LZU1) is used as both adsorbent and matrix of SALDI-TOF MS for the rapid analysis of fluorochemicals. COF-LZU1 can efficiently assist the laser desorption/ionization of fluorochemicals and function well in negative ion modes without background interference. COF-LZU1 with large surface area, high porosity and suitable hydrophobicity, also can enrich trace amounts of fluorochemicals from solution effectively and quickly through hydrophobic interaction. Therefore, COF-LZU1-solid-phase extraction (SPE) enrichment is combined with SALDI-TOF MS measurement to provide the rapid and high sensitive analysis of fluorochemicals in water samples. The LODs of fluorochemicals can reach ppt or subppt levels. Besides, this method shows robust anti-interference ability. With the assistance of COF-LZU1, trace levels of fluorochemicals could be quantitatively and sensitively analyzed from environmental water samples in a rapid, sensitive and convenient way.

Effect of Paired Associative Stimulation on Motor Cortex Excitability in Rats.

Paired associative stimulation (PAS), combining transcranial magnetic stimulation (TMS) with electrical peripheral nerve stimulation (PNS) in pairs with an optimal interstimulus interval (ISI) in between, has been shown to influence the excitability of the motor cortex (MC) in humans. However, the underlying mechanisms remain unclear. This study was designed to explore an optimal protocol of PAS, which can modulate the excitability of MC in rats, and to investigate the underlying mechanisms. The resting motor thresholds (RMTs) of TMS-elicited motor evoked potentials (MEPs) recorded from the gastrocnemius muscle and the latency of P1 component of somatosensory evoked potentials (SEPs) induced by electrical tibial nerve stimulation were determined in male Sprague-Dawley rats (n=10). Sixty rats were then randomly divided into 3 groups: a PAS group (further divided into 10 subgroups at various ISIs calculated by using the latency of P1, n=5, respectively), a TMS (only) group (n=5) and a PNS (only) group (n=5). Ninety repetitions of PAS, TMS and PNS were administered to the rats in the 3 groups, respectively, at the frequency of 0.05 Hz and the intensity of TMS at 120% RMT and that of PNS at 6 mA. RMTs and motor evoked potentials' amplitude (MEPamp) were recorded before and immediately after the interventions. It was found that the MEPamp significantly decreased after PAS at ISI of 5 ms (P<0.05), while the MEPamp significantly increased after PAS at ISI of 15 ms, as compared with those before the intervention (P<0.05). However, the RMT did not change significantly after PAS at ISI of 5 ms or 15 ms (P>0.05). PAS at other ISIs as well as the sole use of TMS and PNS induced no remarkable changes in MEPamp and RMT. In conclusion, PAS can influence motor cortex excitability in rats. Neither TMS alone nor PNS alone shows significant effect.

Effects of Repetitive Transcranial Magnetic Stimulation on Astrocytes Proliferation and nNOS Expression in Neuropathic Pain Rats.

This study investigated the effects of different frequencies of repetitive transcranial magnetic stimulation (rTMS) on chronic neuropathic pain in rats. The behavior of rats with experimental chronic neuropathic pain was observed, and the expression of neuronal nitric oxide synthase (nNOS) in the ipsilateral dorsal root ganglions (DRGs) and the activation and proliferation of astrocytes in the ipsilateral spinal dorsal horn were detected. Thirty-two male Sprague-Dawley rats were randomly divided into four groups: sham-operated group, sham-rTMS group, 1 Hz group and 20 Hz group (8 rats in each group). Chronic constriction nerve injury induced by sciatic nerve ligation was made to establish the models of the chronic neuropathic pain in rats except those in the sham-operated group. Then we applied different frequencies of rTMS to the primary motor cortex (Ml) contralateral to the pain side once daily for 10 consecutive days. Pain behavior scores were observed before and after treatment. Western blot analysis was used to detect the expression of nNOS in ipsilateral L4-6 DRGs. Double immunofluorescent labeling for glial fibrillary acidic protein (GFAP) and 5-bromo-2- deoxyuridine (BrdU) was employed to observe the activation and proliferation of astrocytes in the ipsilateral L4-6 spinal dorsal horn. After rTMS treatment, the spontaneous pain behavior scores were significantly lower in the 20 Hz group than those in the sham-rTMS group (P<0.05). Moreover, the brush-evoked pain behavior scores were significantly lower in the 20 Hz group than those in the sham-rTMS and 1 Hz group (P<0.05), suggesting that the spontaneous pain and brush-evoked pain in the 20 Hz group were significantly alleviated. Western blot analysis revealed that the expression of nNOS in ipsilateral L4-6 DRGs was significantly decreased in the 20 Hz group as compared with the sham-rTMS group and the 1 Hz group (P<0.01) after rTMS treatment. Double immunofluorescence suggested that the expression of GFAP and the co-localization with BrdU in astrocytes were less in the sham-operated group than those in the sham-rTMS group and the 1 Hz group in L4-6 spinal dorsal horn ipsilateral to the neuropathic pain. After rTMS treatment, the expression of GFAP and the co-localization with BrdU decreased in the 20 Hz group as compared with the sham-rTMS group and the 1 Hz group (P<0.05). In addition, the alleviation degree of spontaneous pain and brush-evoked pain in the 20 Hz group was negatively correlated with the expression of nNOS in ipsilateral DRGs and the number of GFAP/BrdU co-labelled astrocytes in L4-6 spinal dorsal horn ipsilateral to the neuropathic pain (P<0.05). It was suggested that high-frequency rTMS may relieve neuropathic pain through down-regulating the overexpression of nNOS in ipsilateral DRGs and inhibiting the activity and proliferation of astrocytes in L4-6 spinal dorsal horn ipsilateral to the neuropathic pain.

Effects of Fasudil on Patients with Pulmonary Hypertension Associated with Left Ventricular Heart Failure with Preserved Ejection Fraction: A Prospective Intervention Study.

Background: Pulmonary hypertension due to left ventricular heart failure with preserved ejection fraction (PH-HFpEF) is an increasingly medical problem. The aim of the study was to evaluate the clinical efficacy of fasudil on PH-HFpEF elderly patients and to figure out the subtype of PH-HFpEF which may be the therapeutic object of fasudil. Method: 58 PH-HFpEF elderly patients were enrolled. Patients were diagnosed with passive pulmonary hypertension (PPH) or reactive pulmonary hypertension (RPH) by right heart catheterization and all receiving Rho kinase inhibitor fasudil for 2 weeks. The endpoint includes changes in SpO2, NT-pro BNP, cardiac functional classification, and echocardiography measurements after 2 weeks treatment. Results: The course of disease in the RPH group was longer than the PPH group (p < 0.05). Cardiac output was found to be worse in the RPH group than the PPH group (p < 0.01). Besides, the RPH group demonstrated a greater transpulmonary pressure gradient (TPG) and pulmonary vascular resistance (PVR) than the PPH group (p < 0.01 for both) as well as pulmonary arterial systolic pressure (PASP) and mean pulmonary arterial pressure (mPAP) (p < 0.01 for both), which fits the feature of RPH. After treatment of fasudil, in RPH group, PASP significantly decreased (p < 0.01) with decreased E/E' and increased E/A (p < 0.05 for both), indicating that pulmonary haemodynamics and cardiac diastolic function were ameliorated, but the measurements in the PPH group had no significant changes. NT-pro BNP and 6 MWD of both groups were improved (p < 0.05). The total effective rate of the RPH group was 74.29%, which was higher than 47.83% of the PPH group (p < 0.05). Conclusion: The Rho kinase inhibitor fasudil can improve pulmonary and left ventricular haemodynamics in patients with PH-HFpEF. The total effective rate was higher in the RPH group. Fasudil may be a promising targeted drug for the RPH in PH-HFpEF patients. This trial is registered with ChiCTR-INR-16009511.

Multifunctional Au NPs-polydopamine-polyvinylidene fluoride membrane chips as probe for enrichment and rapid detection of organic contaminants.

High-throughput and rapid detection of hazardous compounds in complicated samples is essential for the solution of environmental problems. We have prepared a "pH-paper-like" chip which can rapidly "indicate" the occurrence of organic contaminants just through dipping the chip in water samples for short time followed by fast analysis with surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The chips are composed of polyvinylidene fluoride membrane (PVDFM), polydopamine (PDA) film and Au nanoparticles (Au NPs), which are layer-by-layer assembled according to the adhesion, self-polymerization and reduction property of dopamine. In the Au NPs loaded polydopamine-polyvinylidene fluoride membrane (Au NPs-PDA-PVDFM) chips, PVDFM combined with PDA film are responsible for the enrichment of organic analyte through hydrophobic interactions and π-π stacking; Au NPs serve as effective SALDI matrix for the rapid detection of target analyte. After dipping into water solution for minutes, the Au-PDA-PVDFM chips with enriched organic analytes can be detected directly with SALDI-TOF MS. The good solid-phase extraction performance of the PDA-PVDFM components, remarkable matrix effect of the loaded AuNPs, and sensitivity of the SALDI-TOF MS technique ensure excellent sensitivity and reproducibility for the quantification of trace levels of organic contaminants in environmental water samples.

SOX2-mediated inhibition of miR-223 contributes to STIM1 activation in phenylephrine-induced hypertrophic cardiomyocytes.

Stromal interaction molecule 1 (STIM1) is the key molecule responsible for store-operated Ca2+ entry (SOCE). Numerous studies have demonstrated that STIM1 levels appeared to be enhanced during cardiac hypertrophy. However, the mechanism underlining this process remains to be clarified. In this study, phenylephrine (PE) was employed to establish a model of hypertrophic neonatal rat cardiomyocytes (HNRCs) in vitro, and low expression of primary and mature miR-223 was detected in PE-induced HNRCs. Our results have revealed that downregulation of miR-223 by PE contributed to the increase of STIM1, which in turn induced cardiac hypertrophy. As expected, overexpression of miR-223 could prevent the increase in cell surface and reduce the mRNA levels of ANF and BNP in cardiomyocytes. To address the mechanism triggering downregulation of miR-223 under PE, we demonstrated that PE-induced inhibition of GSK-3ß activity led to the activation of ß-catenin, which initiates the transcription of SOX2. Increased expression of SOX2 occupied the promoter region of primary miR-223 and suppressed its transcription. Therefore, miR-223 appears to be a promising candidate for inhibiting cardiomyocyte hypertrophy, and miR-223/STIM1 axis might be one of interesting targets for the clinical treatment of hypertrophy.

Continuous generation of hydroxyl radicals for highly efficient elimination of chlorophenols and phenols catalyzed by heterogeneous Fenton-like catalysts yolk/shell Pd@Fe3O4@metal organic frameworks.

Core/shell Fe3O4-decorated Pd nanoparticles (NPs) hybrids (Pd@Fe3O4) are prepared through a "green", and one-pot chemical process. The Pd@Fe3O4 hybrids consisted of faceted quasi-spherical Pd nanoparticles (NPs) cores (∼20 nm) surrounded by close-packed Fe3O4 NPs (∼7 nm). To improve the stability and avoid aggregation of Pd@Fe3O4 hybrids in water, hollow Fe-metal organic frameworks (Fe-MOFs) were applied to enwrap Pd@Fe3O4 to obtain yolk/shell structured composites. Sub-10 nm Fe3O4 and Pd NPs close to each other were distributed evenly in the MOFs shell of Pd@Fe3O4@MOFs. The yolk/shell Pd@Fe3O4@MOFs can catalyze the oxidative degradation of chlorophenols and phenols by hydroxyl radicals (OH) decomposed from H2O2. With low molar ratio of H2O2/pollutants, the pollutants are degraded and mineralized efficiently and rapidly. The outstanding catalytic efficiency of Pd@Fe3O4@MOFs is contributed by the fast and continuous generation of OH radicals in Pd@Fe3O4@MOFs suspension which is detected with the electron spin resonance spin-trap technique and a continuous-flow chemiluminescence system. Lack of consumption of hydroperoxyl radicals/superoxide radicals (HO2/O2-) in the Pd@Fe3O4@MOFs-H2O2 system might suggest that the production of OH radicals results from the electron transferring from Pd to Fe3O4 component both in the inner Pd@Fe3O4 and MOF shell, which facilitates fast Fe(III)/Fe(II) redox cycle.

Facile Synthesis of Magnetic Covalent Organic Framework with Three-Dimensional Bouquet-Like Structure for Enhanced Extraction of Organic Targets.

A facile strategy for the fabrication of novel bouquet-shaped magnetic porous nanocomposite via grafting a covalent organic framework (COF, TpPa-1) onto the surface-modified Fe3O4 nanoparticles (Fe3O4 NPs) was reported. The magnetic TpPa-1 (a COF synthesized from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1)) contains clusters of core-shell magnetic nanoparticles and interconnected porous TpPa-1 nanofibers. Thus, it possesses larger specific surface area, higher porosity, and supermagnetism, making it an ideal sorbent for enrichment of trace analytes. Its performance was evaluated by the magnetic solid-phase extraction (MSPE) of trace polycyclic aromatic hydrocarbons (PAHs) from environmental samples prior to high-performance liquid chromatographic analysis. The results indicated that the magnetic TpPa-1 possessed superior enrichment capacity of such organic compounds.

Investigation of the interaction modes between nonpolar organic pollutants with ionizable functional groups and natural organic matter via AuNP-based colorimetric assays.

For the first time, natural organic matter (NOM) modified AuNPs have been used as sensors to "observe" the specific interactions (such as hydrogen-bonds and halogen-bonds) between functional groups of organic compounds and NOM using colorimetric assays.

One-pot synthesis of C18-functionalized core-shell magnetic mesoporous silica composite as efficient sorbent for organic dye.

In this work, a facile one-pot strategy was proposed for the synthesis of C18-functionalized core-shell magnetic mesoporous silica composite (Fe3O4/mSiO2-C18). The Fe3O4/mSiO2-C18 composite, with an average size of 80 nm and a functionalized mesoporous silica shell of about 30 nm in thickness, has excellent adsorption ability toward methylene blue dye (MB) due to the large surface area (303 m(2) g(-1)) and the abundant hydrophobic C18 groups. The adsorption equilibrium was achieved within 20 min and the adsorption behavior of MB on Fe3O4/mSiO2-C18 composite fitted the pseudo-second-order kinetic model well (k2=1.29×10(-2) g mg(-1) min(-1), q(e)=144.72 mg g(-1), h(o)=270.27 mg g(-1) min(-1) under 25 °C and an initial MB concentration of 10 mg L(-1)). Langmuir and Freundlich isothermal adsorption models can both be used to describe the adsorption process and the maximum Langmuir adsorption capacity of MB on Fe3O4/mSiO2-C18 at 25 °C and pH 7.5 is 363.64 mg g(-1). Thermodynamic parameters show that the adsorption reaction is exothermic and spontaneous (ΔH(0)=-63.49 kJ mol(-1), ΔG(0)=-7.80 kJ mol(-1)). Ionic strength and pH affected the adsorption slightly. In addition, the MB adsorbed sorbent can be readily separated from water solution by an external magnet because of the high magnetic saturation value (22.62 emu g(-1)). After being regenerated by treatment with acidic methanol, the sorbent could be reused for at least 5 cycles with a little decrease in adsorption capacity.

Spatial confinement of a Co3O4 catalyst in hollow metal-organic frameworks as a nanoreactor for improved degradation of organic pollutants.

We here first proposed a yolk-shell Co3O4@metal-organic frameworks (MOFs) nanoreactor via a facile method to accommodate sulfate radical-based advanced oxidation processes (SR-AOPs) into its interior cavity. The mesoporous and adsorptive MOFs shells allow the rapid diffusion of reactant molecules to the encapsulated Co3O4 active sites, and the confined high instantaneous concentration of reactants in the local void space is anticipated to facilitate the SR-AOPs. As a proof of concept, the nanoreactor was fully characterized and applied for catalytic degradation of 4-chlorophenol (4-CP) in the presence of peroxymonosulfate (PMS). The enhancement of SR-AOPs in the nanoreactor is demonstrated by the result that degradation efficiency of 4-CP reached almost 100% within 60 min by using the yolk-shell Co3O4@MOFs catalysts as compared to only 59.6% under the same conditions for bare Co3O4 NPs. Furthermore, the applicability of this nanoreactor used in SR-AOPs was systematically investigated in terms of effect of reaction parameters and identification of intermediates and primary radical as well as mineralization of the reaction and stability of the composite. The findings of this study elucidated a new opportunity for improved environmental remediation.

Assembly of a nanoreactor system with confined magnetite core and shell for enhanced Fenton-like catalysis.

Conventional solid catalysts for heterogeneous Fenton-like reactions in bulk solution usually suffer from aggregation and vulnerability, which greatly lower the catalytic efficiency and hamper their practical application. Herein, we demonstrate a promising yolk-shell nanostructure with both the core and the shell composed of magnetite (designated as yolk-like Fe3O4@Fe3O4/C) as a nanoreactor capable of accommodating the Fenton-like reaction into its void space. Benefiting from the mesoporous shell and perfect interior cavity of this composite, reactants can access and be abundantly confined within the microenvironment where Fe3O4 sites are dispersed on the entire cavity surfaces, thus leading to a higher catalytic efficiency compared with the conventional solid catalysts in bulk solution. The chosen model reaction of chlorophenols degradation in the presence of the as-prepared materials as well as hydrogen peroxide (H2O2) confirms this assumption. Under the optimal reaction conditions, more than 97 % 4-chlorophenol (4-CP) can be degraded in the Fe3O4@Fe3O4/C nanoreactor, whereas only 28 % can be achieved by using bare Fe3O4 particles within 60 min. Furthermore, owing to the existence of the outermost carbon layer and high-magnetization properties, the nanoreactor can be re-used for several runs. The synthesized nanoreactor displays superior catalytic activity toward the Fenton-like reaction compared with the bare solid catalysts, and thereby holds significant potential for practical application in environmental remediation.

Sensitive colorimetric visualization of perfluorinated compounds using poly(ethylene glycol) and perfluorinated thiols modified gold nanoparticles.

In this work, we have developed a novel sensing strategy employing mixed poly(ethylene glycol)-terminated (PEG-thiols) and perfluoroalkyl-terminated (F-thiols) alkanethiols modified gold nanoparticles (Au@PEG-F NPs) as a probe to detect perfluorinated compounds (PFCs) from water samples. PEG-thiols with high density and long carbon chains make the Au NPs probe well-dispersed in solution and stable even in high concentration of salt solution; F-thiols provide specific fluorous-fluorous interactions to PFCs, which results in adsorption of PFCs on Au@PEG-F NPs. The adsorbed PFCs cause the aggregation of Au@PEG-F NPs probes and thus induce the insolubility of probes and precipitation directly from reaction solution due to the superhydrophobicity of perfluorocarbon monolayers, leading to color and absorbance response of the assay to PFCs. The preparation of the Au@PEG-F NPs probe is very simple, and the colorimetric assay based on this mechanism for the detection of PFCs is selective and convenient. Combined with UV-vis spectrophotometry, the assay demonstrates good sensitivities to PFCs with wide linear range. In the designed concentration range, the response of the colorimetric assay to long-chain PFCs (perfluoroalkyl chain ≥7) is discerned even as the concentration of these PFCs is as low as 10 µg L(-1). This low-cost and sensitive assay shows great potential to measure total PFCs in water samples. To the best of our knowledge, this is the first application of the specific fluorous-fluorous interactions and Au NPs based probes for colorimetric recognition for PFCs.

A functional rattle-type microsphere with a magnetic-carbon double-layered shell for enhanced extraction of organic targets.

A novel rattle-type sorbent with a surface-modified interior cavity and a magnetic Fe3O4-C double-layered shell was synthesized and first applied for magnetic solid-phase extraction.