Fabrication of novel MXene (Ti3C2)/polyacrylamide nanocomposite hydrogels with enhanced mechanical and drug release properties.

A highly stretchable nanocomposite (NC) hydrogel was fabricated via in situ free radical polymerization of acrylamide. In particular, an exfoliated two-dimensional MXene (Ti3C2) nanosheet was utilized as a crosslinker instead of traditional organic crosslinkers. The exfoliated Ti3C2 nanosheets were confirmed by atomic force microscopy (AFM) and dynamic light scattering (DLS) measurements. Compared with traditional organic crosslinked N,N-methylene bisacrylamide (BIS)/polyacrylamide (PAM) hydrogels (fracture strength of 32.0 kPa and elongation of 109.6%), the synthesized Ti3C2/PAM NC hydrogels exhibited greatly improved mechanical properties with fracture strengths of 66.5 to 102.7 kPa, compressive strengths of 400.6 to 819.4 kPa and elongations at break of 2158.6% to 3047.5% as the Ti3C2 content increases from 0.0145% to 0.0436%. The enhanced mechanical performances can be attributed to the honeycomb-like fine structure with uniform pores as well as more flexible polymer chains in NC hydrogel networks. When loaded with drugs, Ti3C2/PAM NC hydrogels exhibited good sustained-release performance, higher drug loading amounts (97.5-127.7 mg g-1) and higher percentage releases (62.1-81.4%), greatly superior to those of the BIS/PAM hydrogel (46.4 mg g-1, 45.0%). Our work reveals the application of MXene materials in the fabrication of NC hydrogels with enhanced mechanical and drug release behaviors.

Synthesis of diastereometrically pure cubane-like photodimers from 2,4-pentanediyl-bis-2-naphthoates.

Irradiation of (2R,4R)-(-)- and (2S,4S)-(+)-2,4-pentanediyl-bis-2-naphthoates (1R and 1S, respectively) in organic solutions exclusively results in cubane-like anti(HH) photodimers in 100% yield. Asymmetric induction with 100% diastereometric excess (de) has been achieved and the absolute configuration of the yielded diastereomers has been established. Moreover, irradiation of (2R,4S)-2,4-pentanediyl-bis-2-naphthoate (1M) gives cubane-like syn(HH) photodimers in 100% yield.

[Treatment of upper respiratory infection by fangfeng tongsheng granule: a randomized controlled study].

OBJECTIVE: To evaluate the clinical effectiveness and safety of Fangfeng Tongsheng Granule (FTG) in the treatment of upper respiratory infection (superficial cold and interior heat syndrome, exterior and interior excess syndrome). METHODS: A randomized, double-blinded, multi-centered, placebo-parallel-controlled clinical trial was adopted. Totally 324 patients were enrolled and assigned to two groups, 216 patients in the treatment group and 108 patients in the control group. Those in the treatment group took FTG at the daily dose of 3 g, twice per day, the therapeutic course being 3 days. Those with axillary temperature more than 37 degrees C took one more time before medication. Those in the control group took simulated agent granules the same dose and dosage as the treatment group. The effect of Chinese medical syndrome (ECMS), the rate of temperature-dropping-to-normal (RT), the time of temperature-dropping-to-normal (TT), the curative effect of single symptom (CESS) and adverse reactions were observed. RESULTS: Totally 203 completed the trial in the treatment group and 101 in the control group. In the treatment group, the cured-effective rate was 55.67% (113/ 101), the total effective rate was 93.10% (189/101), the ECMS score decreased by 9.24 +/- 4.46, while they were 5.94% (6/101), 36.63% (37/101), and 3.27 +/- 3.29, respectively in the control group (P < 0.01). The RT was 87.50% (98/112) in the treatment group and 58.49% (31/53) in the control group (P < 0.01). The TT in the treatment group was superior to that of the control group (P < 0.01). As for CESS, all of the three primary symptoms and nine secondary symptoms were improved more obviously in the treatment group than in the control group. The integral decreased obviously, showing statistical difference (P < 0.01). The decrease was more obvious in the treatment group than in the control group (P < 0.01). There was no adverse event related to FTG. CONCLUSION: FTG was effective and safe in treating upper respiratory infection (superficial cold and interior heat syndrome, exterior and interior excess syndrome).

Enhancement of diastereoselectivity in photodimerization of alkyl 2-naphthoates with chiral auxiliaries via inclusion within γ-cyclodextrin cavities.

Irradiations of alkyl 2-naphthoates are known to result in four isomeric "cubane-like" photodimers: anti(HH)-2, syn(HH)-2, anti(HT)-2, and syn(HT)-2 where the anti(HH)-2, anti(HT)-2, and syn(HT)-2 consist of pairs of diastereomers. Here, chiral auxiliary and chiral microreactor strategies have been combined to achieve high diastereoselectivity in photodimerizations of an enantiomeric pair of 2-naphthoates with (R)- and (S)-1-methoxycarbonylethyl esters as chiral auxiliaries (1R and 1S). Thus, irradiations of their γ-cyclodextrin (γ-CD) complexes have been conducted. Fluorescence, IR, and NMR spectra of both enantiomers of 1 demonstrate that their γ-CD complexes are mainly 2:2 with the molecules of 1 in head-to-head orientations. Irradiation of the complexes in the solid state mainly resulted in anti(HH)-2. The absolute configuration of each diastereomer of anti(HH)-2 has been established for the first time here. The diastereomeric excesses (de's) of anti(HH)-2 from 1R and 1S were 94% and 86%, respectively. These de's are much higher than those found from irradiations in solution (55% for 1R and 1S), where the opposite diastereomeric form is in excess! Calculations of the energies of various conformations of the head-to-head 2:2 inclusion complexes were performed using the PM3 approach. The predicted major diastereomers based on the calculation are consistent with those found experimentally.

Photocatalytic organic transformation by layered double hydroxides: highly efficient and selective oxidation of primary aromatic amines to their imines under ambient aerobic conditions.

We report the first application of layered double hydroxide as a photocatalyst in the transformation of primary aromatic amines to their corresponding imines with high efficiency and selectivity by using oxygen in an air atmosphere as a terminal oxidant under light irradiation.