Twisting two-dimensional iron sulfide layers into coincident site superlattices via intercalation chemistry.

Layered van der Waals (vdW) materials are susceptible not only to various stacking polymorphs through translations but also twisted structures due to rotations between layers. Here, we study the influence of such layer-to-layer twisting through the intercalation of ethylenediamine (EDA) molecules into tetragonal iron sulfide (Mackinawite FeS). Selected area electron diffraction patterns of intercalated FeS display reflections corresponding to multiple square lattices with a fixed angle between them, contrary to a single square lattice seen in the unintercalated phase. The observed twist angles of 49.13° and 22.98° result from a superstructure formation well described by the coincident site lattice (CSL) theory. According to the CSL theory, these measured twist angles lead to the formation of larger coincident site supercells. We build these CSL models for FeS using crystallographic group-subgroup transformations and find simulated electron diffraction patterns from the model to agree with the experimentally measured data.

Long-range magnetic order in hydroxide-layer-doped (Li1-x-y Fe x Mn y OD)FeSe.

The (Li1-x Fe x OH)FeSe superconductor has been suspected of exhibiting long-range magnetic ordering due to Fe substitution in the LiOH layer. However, no direct observation such as magnetic reflection from neutron diffraction has been reported. Here, we use a chemical design strategy to manipulate the doping level of transition metals in the LiOH layer to tune the magnetic properties of the (Li1-x-y Fe x Mn y OD)FeSe system. We find Mn doping exclusively replaces Li in the hydroxide layer resulting in enhanced magnetization in the (Li0.876Fe0.062Mn0.062OD)FeSe superconductor without significantly altering the superconducting behavior as resolved by magnetic susceptibility and electrical/thermal transport measurements. As a result, long-range magnetic ordering was observed below 12 K with neutron diffraction measurements. This work has implications for the design of magnetic superconductors for the fundamental understanding of superconductivity and magnetism in the iron chalcogenide system as well as exploitation as functional materials for next-generation devices.

Microtubes and hollow microspheres formed by winding of nanoribbons from self-assembly of tetraphenylethylene amide macrocycles.

New amide macrocycles based on tetraphenylethylene (TPE) were synthesized. It was found that the TPE amide macrocycles could form microtubes in H2O-THF with 70-80% water by the rolling up of big nanoribbons but produced hollow microspheres in 90% or more water by the winding of thin nanoribbons. The microtubes emitted blue light while the hollow microspheres showed blue-green fluorescence.

Monomer emission and aggregate emission of TPE derivatives in the presence of γ-cyclodextrin.

It was found for the first time that neutral amphiphilc tetraphenylethylene (TPE) derivatives showed an enhanced monomer emission and a decreased aggregate emission when they were included in the cavity of γ-cyclodextrin. This result provided a new insight into the aggregation-induced emission (AIE) effect.

[The changes in the pulmonary surface tension and the tissue content of surfactant substance protein B during early post-injury stage in rabbits inflicted with smoke inhalation injury].

OBJECTIVE: To investigate the changes in the pulmonary surface tension and the tissue content of surfactant substance protein B (SP-B) in rabbits during early post-injury stage after smoke inhalation injury. METHODS: Thirty-two healthy rabbits inflicted with smoke inhalation injury were employed in the study as injury group, and they were sacrificed at 0.5, 2.0, 6.0, 12.0 post injury hours (PIH), with 8 rabbits at each time point. Another 8 rabbits were assigned to normal control group. The pulmonary tissue samples of the rabbits in each group were harvested for the collection of bronchial-alveolar lavage fluid (BALF). The changes in maximal tension (Tmax), minimal tension (Tmin) and hysteresis square (HS) of BALF were measured after the addition of 0.5, 1.0 and 3.0 ml of SP-B antibody into the BALF of the rabbits in each group. The changes in SP-B and SP-B mRNA contents in rabbit pulmonary tissue of each group were assessed with immunohistochemistry and in situ hybridization techniques, respectively. RESULTS: There was no obvious difference in Tmax in BALF of each group or at each time point before and after the action of different concentrations of SP-B antibody in BALF (P > 0.05). But the Tmin in injury group at 2, 6 and 12 PIH was much higher than that before the addition of the antibody (P < 0.05). And the change in HS was similar to that in Tmin. The SP-B content in alveolar type II epithelial cells (AT-II) was decreased significantly at 2, 6 and 12 PIH, whereas the expression in SP-B mRNA exhibited no change. CONCLUSION: There was no obvious change in SP-B synthesis by AT-II in the lung tissue of the rabbits inflicted with smoke inhalation injury during early post injury stage. The increase of SP-B secretion from AT-II cells might be beneficial to the early protection of pulmonary tissue of the rabbits with smoke inhalation injury.

[The significance of the change of the subfractions in existence of the pulmonary surfactant in rabbits with smoke inhalation injury during early postburn stage].

OBJECTIVE: To investigate the change of the subfractions in existence (big and small polymers) of pulmonary surfactant (PS) and their influence on the decrease in PS activity during early postburn stage. METHODS: Forty rabbits were employed in the study and were randomly divided into pre-burn, 0.5 postburn hour (PBH), 2 PBH, 6 PBH and 12 PBH groups with 8 in each group. The BALF (bronchial alveolar lavage fluid) was harvested from each rabbit. The BALF samples were centrifuged, and the supernatant (small polymer) and precipitation (big polymer) were harvested for the determination of the contents of the total phospholipids, lecithin, total protein, and albumin in both polymers. RESULTS: Compared with those in pre-burn group, the above chemical contents of PS in big polymer exhibited no change after burn (P > 0.05), but the contents of albumin and total protein increased obviously in small polymer (P < 0.01). In addition, all the contents in the small polymer increased with the elapse of time. The percentage of lecithin in total phospholipids in small polymers decreased along with the passage of time. The pre-burn contents of total phospholipids, lecithin, TP, albumin, and the percentage of lecithin in total phospholipid in small polymer were (2.23 +/- 0.40),(1.54 +/- 0.11), (16.67 +/- 1.34), (3.65 +/- 0.15) mg/ml and (77.2 +/- 3.7)%, respectively. The above indices in small polymer were (3.15 +/- 0.30), (1.77 +/- 0.08), (106.59 +/- 5.50), (11.21 +/- 0.92) mg/ml and (57.2 +/- 3.5)% respectively at 6PBH. CONCLUSION: The ratio of small to big polymers increased obviously, which might be an important factor in inducing the decrease in PS activity during early postburn stage leading finally to pulmonary injury.