Polyethylene glycol-stabilized nano zero-valent iron supported by biochar for highly efficient removal of Cr(VI).

In this study, polyethylene glycol (PEG)-stabilized nano zero-valent iron (nZVI) supported by biochar (BC) (PEG-nZVI@BC) was prepared to remedy Cr(VI) with high efficiency. The morphology, functional groups, and crystalline structure of PEG-nZVI@BC composites were characterized, revealing that when PEG was added, a large number of -OH functional groups were introduced, and nZVI was effectively dispersed on the BC surface with a smaller particle size. The results of Cr(VI) remediation experiments showed Cr(VI) removal rate by PEG-nZVI@BC (97.38%) was much greater than that by BC-loaded nZVI (nZVI@BC) (51.73%). The pseudo second-order and Sips isotherm models provide the best simulation for Cr(VI) removal experimental data, respectively. The main remediation mechanism of Cr(VI) was reduction and co-precipitation of Cr-containing metal deposits onto PEG-nZVI@BC. Ecotoxicity assessment revealed PEG-nZVI@BC (1.00 g/L) has little influence on rice germination and growth, but resisted the toxicity of Cr(VI) to rice. The modified Community Bureau of Reference (BCR) sequential extraction showed pyrolysis could increase the percentage of oxidizable and residual Cr and diminish the environmental risk of Cr release from post-removal composites.

Preparation and evaluation of tert-leucine derivative functionalized polymeric monoliths for micro-liquid chromatography.

In this study, a novel functional monomer N-[1-(α-naphthyl)ethylaminocarbonyl]-D-tert-leucine-[2-(methacryloyloxy)ethyl] amide (NA-D-tert-Leu-MA) was synthesized, and then employed to prepare polymeric monoliths (240 mm × 100 µm id) functionalized with tert-leucine derivative through a single step thermo-initiated co-polymerization approach or a multi-step post-modification approach. The multi-step approach involves the post-modification of a thiol-containing monolith with NA-D-tert-Leu-MA via "thiol-ene"click reaction. The physicochemical properties of the resulting monoliths were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry and micro-liquid chromatography. Good column stability, permeability, efficiency and reproducibility were obtained for the optimized monoliths. The poly (NA-D-tert-Leu-MA-co-ethylene dimethacrylate) monolith prepared through the single step co-polymerization approach exhibited satisfactory achiral separation performance for various analytes, including phenols, aniline derivatives and intact proteins, while its enantioseparation ability is rather poor. In contrast to that, the monolith prepared through the multi-step post-modification approach showed much higher enantioselectivity for 7-nitro-2,1,3-benzoxadiazole (NBD)-derivatized amino acids. Three NBD-derivatized amino acids (theanine, proline and norleucine) could be baseline enantioseparated.

Biomimetic affinity membrane roll column for rapid purification of C-reactive protein.

To in-depth explore the action mechanism of C-reactive protein (CRP) and precisely study its signaling pathways, it is essential to acquire high-purity CRP while preserving its intact structure and functionality. In this study, we propose and fabricate a high-density 2-methacryloyloxyethyl phosphorylcholine (MPC)-modified membrane roll column (MPC-MRC) using a surface-initiated atom transfer radical polymerization (SI-ATRP) approach, which can overcome these limitations (long incubation time and low adsorption capacity) of conventional enrichment materials. The MPC-MRC incorporates a high-density 2-hydroxyethyl methacrylate polymer brush to prevent non-specific protein adsorption and multiple MPC polymer brush layers for high-performance enrichment of CRP in the company of calcium ions. Furthermore, the MPC-MRC exhibits high permeability, hydrophilicity, and mechanical strength. Compared to previous technologies, this novel material demonstrates significantly higher CRP binding capacity (310.3 mg/g), shorter processing time (only 15 min), and lower cost (only 12 USD/column). Notably, the MPC-MRC enables fast and effective purification of CRP from both human and rat serum, exhibiting good selectivity, recovery (> 91.3 %), and purity (> 95.2 %). Thus, this proposed purification approach based on MPC-MRC holds great potential for target protein enrichment from complex samples, as well as facilitating in-depth studies of its biological functions.

Self-assembled single-atom nanozyme for enhanced photodynamic therapy treatment of tumor.

Hypoxia of solid tumor compromises the therapeutic outcome of photodynamic therapy (PDT) that relies on localized O2 molecules to produce highly cytotoxic singlet oxygen (1O2) species. Herein, we present a safe and versatile self-assembled PDT nanoagent, i.e., OxgeMCC-r single-atom enzyme (SAE), consisting of single-atom ruthenium as the active catalytic site anchored in a metal-organic framework Mn3[Co(CN)6]2 with encapsulated chlorin e6 (Ce6), which serves as a catalase-like nanozyme for oxygen generation. Coordination-driven self-assembly of organic linkers and metal ions in the presence of a biocompatible polymer generates a nanoscale network that adaptively encapsulates Ce6. The resulted OxgeMCC-r SAE possesses well-defined morphology, uniform size distribution and high loading capacity. When conducting the in situ O2 generation through the reaction between endogenous H2O2 and single-atom Ru species of OxgeMCC-r SAE, the hypoxia in tumor microenvironment is relieved. Our study demonstrates a promising self-assembled nanozyme with highly efficient single-atom catalytic sites for cancer treatment.

A Mesoporous Nanoenzyme Derived from Metal-Organic Frameworks with Endogenous Oxygen Generation to Alleviate Tumor Hypoxia for Significantly Enhanced Photodynamic Therapy.

Tumor hypoxia compromises the therapeutic efficiency of photodynamic therapy (PDT) as the local oxygen concentration plays an important role in the generation of cytotoxic singlet oxygen (1 O2 ). Herein, a versatile mesoporous nanoenzyme (NE) derived from metal-organic frameworks (MOFs) is presented for in situ generation of endogenous O2 to enhance the PDT efficacy under bioimaging guidance. The mesoporous NE is constructed by first coating a manganese-based MOFs with mesoporous silica, followed by a facile annealing process under the ambient atmosphere. After removing the mesoporous silica shell and post-modifying with polydopamine and poly(ethylene glycol) for improving the biocompatibility, the obtained mesoporous NE is loaded with chlorin e6 (Ce6), a commonly used photosensitizer in PDT, with a high loading capacity. Upon the O2 generation through the catalytic reaction between the catalytic amount NE and the endogenous H2 O2 , the hypoxic tumor microenvironment is relieved. Thus, Ce6-loaded NE serves as a H2 O2 -activated oxygen supplier to increase the local O2 concentration for significantly enhanced antitumor PDT efficacy in vitro and in vivo. In addition, the NE also shows T2 -weighted magnetic resonance imaging ability for its in vivo tracking. This work presents an interesting biomedical use of MOF-derived mesoporous NE as a multifunctional theranostic agent in cancer therapy.

Intradermal Growing Hair: Two Case Reports.

Hair growing inside the skin and burrowing in the uppermost dermis, previously termed as "ingrowing hair," is a rarely reported cutaneous disorder. Up to July 31, 2018, only five cases have been reported, all were male. The authors report two Chinese Han men, 26-year-old and 31-year-old respectively, presenting with progressive extending black lines inside the skin on the right mandibular angle and the neck respectively. The black lines were finally demonstrated as growing beard hairs. The 26-year-old man was cured after the hair was pulled out, whereas the 31-year-old patient had re-occurrence after the initial hair was extracted and was cured finally by destroying the individual beard follicle. The authors would prefer the term of "intradermal growing hair" to "ingrowing hair" when describing the condition of hair growing inside the skin and extending in the uppermost dermis. Pulling out the growing hair, and sometimes destroying the beard follicle, may be of choice for its treatment.

Co-electrospraying of tumour cell mimicking hollow polymeric microspheres for diffusion magnetic resonance imaging.

Diffusion magnetic resonance imaging (dMRI) is considered as a useful tool to study solid tumours. However, the interpretation of dMRI signal and validation of quantitative measurements of is challenging. One way to address these challenges is by using a standard reference material that can mimic tumour cell microstructure. There is a growing interest in using hollow polymeric microspheres, mainly prepared by multiple steps, as mimics of cells in healthy and diseased tissue. The present work reports on tumour cell-mimicking materials composed of hollow microspheres for application as a standard material in dMRI. These microspheres were prepared via one-step co-electrospraying process. The shell material was poly(d,l-lactic-co-glycolic acid) (PLGA) polymers with different molecule weights and/or ratios of glycolic acid-to-lactic, while the core was polyethylene glycol (PEG) or ethylene glycol. The resultant co-electrosprayed products were characterised by optical microscopy, scanning electron microscopy (SEM) and synchrotron X-ray micro-CT. These products were found to have variable structures and morphologies, e.g. from spherical particles with/without surface hole, through beaded fibres to smooth fibres, which mainly depend on PLGA composition and core materials. Only the shell material of PLGA polymer with ester terminated, Mw 50,000-75,000 g mol-1, and lactide:glycolide 85:15 formed hollow microspheres via the co-electrospraying process using the core material of 8 wt% PEG/chloroform as the core. A water-filled test object (or phantom) was designed and constructed from samples of the material generated from co-electrosprayed PLGA microspheres and tested on a 7 T MRI scanner. The preliminary MRI results provide evidence that hollow PLGA microspheres can restrict/hinder water diffusion as cells do in tumour tissue, implying that the phantom may be suitable for use as a quantitative validation and calibration tool for dMRI.

Hydrophilic polymeric monoliths containing choline phosphate for separation science applications.

In this research, a hydrophilic polymeric monolith containing choline phosphate (CP) was fabricated through the thermally initiated free-radical polymerization of 2-{2-(methacryloyloxy) ethyldimethylammonium}ethyl n-butyl phosphate (MBP) with ethylene dimethacrylate (EDMA) using isopropanol and tetrahydrofuran as the porogenic system. Excellent mechanical strength, permeability, stability and reproducibility were obtained on the optimized poly(MBP-co-EDMA) monolith. Column efficiency as high as 107,500 plates/m was achieved for the analysis of thiourea at a flow velocity of 0.2 mm/s on the monolith. Both hydrophilic and electrostatic interactions were observed for the retention of charged analytes on the poly(MBP-co-EDMA) monolith. It is worth noting that the resulting monolith exhibits higher selectivity and efficiency than the classical 2-(methacryloyloxy)ethyl phosphorylcholine functionalized polymeric monolith for the chromatographic separation of polar analytes. Also, the novel monolithic column was successfully applied to enrich N-glycopeptides from tryptic digest of human IgG. In a word, the versatile MBP functionalized polymeric monolith not only opens up interesting possibilities for reverse zwitterionic CP derivative-based polymeric materials in separation science, but also represents a promising hydrophilic interaction chromatography stationary phase.

Chiral separation of acidic compounds using an O-9-(tert-butylcarbamoyl)quinidine functionalized monolith in micro-liquid chromatography.

An O-9-(tert-butylcarbamoyl) quinidine (t-BuCQD) functionalized polymeric monolithic capillary column was prepared by the in situ copolymerization method. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy and micro-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained for this monolithic column. The chiral recognition ability of the resulting monolith was also evaluated using 47 N-derivatized amino acids, eight N-derivatized dipeptides, and two herbicides. Under the selected conditions, the enantiomers of all chiral analytes were baseline separated with exceptionally high selectivity and resolution using micro-LC. It is worth noting that this chiral stationary phase (CSP) containing quinidine with a tert-butyl carbamate residue as chiral selector exhibits much higher enantioselectivity and diastereoselectivity than the previously developed O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine (MQD) based CSP for N-derivatized amino acids and dipeptides. These results indicate that this novel quinidine-based polymeric monolith can be used as an effective tool for the enantioseparation of chiral acidic compounds.

The effect of glottal angle on intraglottal pressure.

Intraglottal pressure distributions depend upon glottal shape, size, and diameter. This study reports the effects of varying glottal angle on intraglottal and transglottal pressures using a three-dimensional Plexiglas model with a glottis having nine symmetric glottal angles and a constant minimal glottal diameter of 0.06 cm. The empirical data were supported by computational results using FLUENT. The results suggested that (1) the greater the convergent glottal angle, the greater outward driving forces (higher intraglottal pressures) on the vocal folds; (2) flow resistance was greatest for the uniform glottis, and least for the 10 degrees divergent glottis; (3) the greatest negative pressure in the glottis and therefore the greatest pressure recovery for diverging glottal shapes occurred for an angle of 10 degrees; (4) the smaller the convergent angle, the greater the flow resistance; (5) FLUENT was highly accurate in predicting the empirical pressures of this model; (6) flow separation locations (given by FLUENT) for the divergent glottis moved upstream for larger flows and larger glottal angles. The results suggest that phonatory efficiency related to aerodynamics may be enhanced with vocal fold oscillations that include large convergent angles during glottal opening and small (5 degrees - 10 degrees) divergent angles during glottal closing.