Correction: Fluorido-bridged robust metal-organic frameworks for efficient C2H2/CO2 separation under moist conditions.

[This corrects the article DOI: 10.1039/D2SC06699H.].

Fluorido-bridged robust metal-organic frameworks for efficient C2H2/CO2 separation under moist conditions.

The modern technology for acetylene production is inevitably accompanied by the contamination of carbon dioxide and moisture impurities. Metal-organic frameworks (MOFs), with rational configurations of fluorine as the hydrogen-bonding acceptor (HBA), exhibit excellent affinities to capture acetylene from the gas mixtures. Currently, most research studies feature anionic fluorine groups as structural pillars (e.g., SiF6 2-, TiF6 2-, NbOF5 2-), whereas in situ insertion of fluorine into metal clusters is rather challenging. Herein, we report a unique fluorine-bridged Fe-MOF, i.e., DNL-9(Fe), which is assembled by mixed-valence FeIIFeIII clusters and renewable organic ligands. The fluorine species in the coordination-saturated structure offer superior C2H2-favored adsorption sites facilitated by hydrogen bonding, with a lower C2H2 adsorption enthalpy than other reported HBA-MOFs, demonstrated by static/dynamic adsorption tests and theoretical calculations. Importantly, DNL-9(Fe) shows exceptional hydrochemical stability under aqueous, acidic, and basic conditions, and its intriguing performance for C2H2/CO2 separation was even maintained at a high relative humidity of 90%.

"Explosive" synthesis of metal-formate frameworks for methane capture: an experimental and computational study.

In this work, we show a solvent-free "explosive" synthesis (SFES) method for the ultrafast and low-cost synthesis of metal-formate frameworks (MFFs). A combination of experiments and in-depth molecular modelling analysis - using grand canonical Monte Carlo (GCMC) simulations - of the adsorption performance of the synthesized nickel-formate framework (Ni-FA) revealed extremely high quality products with permanent porosity, prominent CH4/N2 selectivity (ca. 6.0), and good CH4 adsorption capacity (ca. 0.80 mmol g-1 or 33.97 cm3 cm-3) at 1 bar and 298 K. This performance is superior to those of many other state-of-the-art porous materials.

Template-based Synthesis of a Formate Metal-Organic Framework/Activated Carbon Fiber Composite for High-performance Methane Adsorptive Separation.

Simultaneous improvement in adsorption selectivity and capacity for single adsorbents is challenging but counting for much in adsorptive separations. To this end, a formate metal-organic framework and activated carbon fiber composite was synthesized in our work by a simple two-step process, involving homogeneous precipitation of a MOF precursor on an activated carbon fiber and subsequent template replication. The resultant core-shell composite, ACF@[Ni3 (HCOO)6 ], exhibited optimized adsorption performance both in selectivity and capacity for the separation of CH4 /N2 to most of state-of-the-art adsorbents.

Insulin down-regulates the expression of ubiquitin E3 ligases partially by inhibiting the activity and expression of AMP-activated protein kinase in L6 myotubes.

While insulin is an anabolic hormone, AMP-activated protein kinase (AMPK) is not only a key energy regulator, but it can also control substrate metabolism directly by inducing skeletal muscle protein degradation. The hypothesis of the present study was that insulin inhibits AMPK and thus down-regulates the expression of the ubiquitin E3 ligases, muscle atrophy F-box (MAFbx) and muscle RING finger 1 (MuRF1) in skeletal muscle cells. Differentiated L6 myotubes were treated with 5-aminoimidazole-4-carboxamide-1-ß-4-ribofuranoside (AICAR) and/or compound C to stimulate and/or block AMPK respectively. These treatments were also conducted in the presence or absence of insulin and the cells were analysed by western blot and quantitative real-time PCR. In addition, nucleotide levels were determined using HPLC. The activation of AMPK with AICAR enhanced the mRNA levels of MAFbx and MuRF1. Insulin reduced the phosphorylation and activity AMPK, which was accompanied by reduced MAFbx and MuRF1 mRNA levels. Using a protein kinase B (PKB/Akt) inhibitor, we found that insulin regulates AMPK through the activation of Akt. Furthermore, insulin down-regulated AMPK α2 mRNA. We conclude that insulin inhibits AMPK through Akt phosphorylation in L6 myotubes, which may serve as a possible signalling pathway for the down-regulation of protein degradation. In addition, decreased expression of AMPK α2 may partially participate in inhibiting the activity of AMPK.

A novel model of burn-blast combined injury and its phasic changes of blood coagulation in rats.

Burn-blast combined injury has a complex pathological process that may cause adverse complications and difficulties in treatment. This study aims to establish a standard animal model of severe burn-blast combined injury in rats and also to investigate early phasic changes of blood coagulation. By using 54 Wistar rats, distance from explosion source (Hexogen) and size of burned body surface area were determined to induce severe burn-blast combined injury. Thereafter, 256 rats were randomly divided into four groups (n = 64): blast injury group, burn injury group, burn-blast combined injury group, and sham injury group. Gross anatomy and pathological changes in lungs were investigated at 3, 24, 72, and 168 h, respectively. Blood was also collected for analyzing coagulation parameters as prothrombin time, activated partial thromboplastin time, and plasma levels of fibrinogen, D-dimer, antithrombin III, and α2-antiplasmin from 0 to 168 h after injury. Severe burn-blast combined injury was induced by inflicting rats with a moderate blast injury when placing rats 75 cm away from explosion source and a full-thickness burn injury of 25% total body surface area. The rats with burn-blast combined injury had more severe lung injuries when compared with the other three groups. Pathological examination in the BBL group showed diffused alveolar hemorrhage, fluid filling, alveolar atelectasis, rupture and hyperplasia of partial alveolar septum, emphysema-like change, reduced capillary bed, and infiltration of extensive polymorphonuclear cells after injury. The blood of combined injured rats was in a hypercoagulable state within 24 h, shortly restored from 24 to 48 h, and rehypercoagulated from 48 to 72 h after injury. A secondary excessively fibrinolytic function was also found thereafter. The rat model of burn-blast combined injury was successfully established by simulating real explosion characteristics. Rats with burn-blast combined injuries suffered from more severe lung injuries and abnormal coagulation and fibrinolytic function than those induced by a burn injury or a blast injury component. Hence, a time-dependent treatment strategy on coagulation function should be emphasized in clinical therapy of burn-blast combined injury.

Optimization of human umbilical cord mesenchymal stem cell isolation and culture methods.

Human umbilical cord mesenchymal stem cells (hUCMSCs) are considered to be an ideal replacement for bone marrow MSCs. However, up to date, there is no convenient and efficient method for hUCMSC isolation and culture. The present study was carried out to explore the modified enzyme digestion for hUCMSC in vitro. Conventional enzyme digestion, modified enzyme digestion, and tissue explant were used on hUCMSCs to compare their efficiencies of isolation and culture, to observe primary cell growth and cell subculture. The results show that the cells cultured using the tissue explant method had a longer culture cycle (P < 0.01) and lower yield of primary cells per centimetre of umbilical cord (P < 0.01) compared with the two enzyme digestion methods. Subculture adherence and cell doubling took significantly less time with the tissue explant method (P < 0.05) than with the conventional enzyme digestion method; however, there was no significant difference between the tissue explant method and the modified enzyme digestion method (P > 0.05). Comparing two enzyme digestion methods, the modified method yielded more cells than did the conventional method (P < 0.01), and primary cell adherence took significantly less time with the modified method than with the conventional method (P < 0.05). Cell cycle analysis of the third-generation hUCMSCs cultured by modified enzyme digestion method indicated that most cells were quiescent. Immunofluorescence staining showed that these cells expressed MSC markers CD44 and CD90. And Von Kossa and oil red O staining detection showed that they could be differentiated into osteoblasts and adipocytes with induction medium in vitro. This study suggests that hUCMSC isolation and culture using 0.2 % collagenase II at 37 °C for digestion of 16-20 h is an effective and simple modified enzyme digestion method.

[Effect of different concentration of tamoxifen ointment on the expression of TGF-beta2 of hypertrophic scar at rabbit ears].

OBJECTIVE: To observe the effect of different concentration of Tamoxifen ointment on the fibroblasts and transforming growth factor (TGF-beta2) of hypertrophic scar at rabbit ears, so as to explore the possibility of treatment of hypertrophic scar with Tamoxifen. METHODS: The hypertrophic scar model was established in 96 New Zealand rabbits' ears. The wounds were divided into four groups (A, B, C and D), with 144 wounds in each group. Different concentration of tamoxifen ointment (0.5%, 1%, 2%) was topically administered in groups A, B and C respectively, and blank ointment in group D. On postoperative day 30, 60 and 90, the scar samples were harvested. The scar thickness, scar histological change and the content of TGF-beta2 were detected. RESULTS: (1) On the 30th day after operation, the difference of scar tissue thickness among groups A, D and B, C reached statistical significance (group A, D < group B < group C). However, there was a contrary tendency in fibroblasts density and TGF-beta2 content of the scar tissue simultaneously. (2) On 60th, 90th day after injury, there was statistical difference in scar thickness, fibroblasts density and the content of TGF-beta2 in scar of four groups (P < 0.05). The content of TGF-beta2 in group A, B, C, D was (43.97 +/- 3.63) microg/L, (41.92 +/- 3.91) microg/L, (36.69 +/- 4.15) microg/L, (54.90 +/- 4.71) microg/L, respectively, on 60th day; and (45.69 +/- 2.63) microg/L, (40.43 +/- 3.87) microg/L, (38.76 +/- 3.24) microg/L, (52.59 +/- 4.92) microg/L, respectively, on 90th day. The fibroblasts density of scar in groups A, B, C, D was (4392.07 +/- 327.84) point/mm2, (4208.57 +/- 329.76) point/mm2 (4 033.44 +/- 427.91) point/mm2, (4863.03 +/- 387.98) point/mm2, respectively, on 60th day; and (4418.41 +/- 432.52) point/mm2, (4077.65 +/- 386.70) point/mm2, (3844.53 +/- 354.29) point/mm2, (4838.64 +/- 390.52) point/mm2, respectively, on 90th day. The content of TGF-beta2 and fibroblasts density of scar were lined up as group D > group A > group B > group C (P < 0.05). CONCLUSIONS: Topical Tamoxifen can reduce the content of TGF-beta2 and fibroblast, decrease fibroblasts density and the formation of hypertrophic scar at rabbit ears. It offers a new way for the treatment of the hypertrophic scar.

[Effects on collagen I and III after transplantation of porcine acellular dermal matrix with hyaluronic acid].

OBJECTIVE: To investigate the changes of collagens I and III after the addition of hyaluronic acid in the transplantation of porcine acellular dermal matrix. METHODS: Full-thickness skin defects were created on the dorsa of Japanese white rabbits. And the rabbits were divided randomly into 3 groups: Group A (hyaluronic acid, porcine acellular dermal matrix plus thin skin autografts), Group B (porcine acellular dermal matrix plus thin skin autografts) and Group C (skin autografts). Skin biopsies were performed at Day 50 post-grafting to detect the contents of collagens I and III by histological examinations, immunohistochemistry method and Western blot. RESULTS: The areas of skin graft were (13.3 ± 1.2), (9.5 ± 0.9) and (10.0 ± 1.4) cm(2) in Groups A, B and C respectively. Group A was larger than Groups B and C(all P < 0. 01). There was no statistical difference between Groups B and C (P > 0.05). The expressions of collagen I were 1894 ± 164, 515 ± 38 and 395 ± 43 in Groups A, B and C respectively. Group A was higher than Groups B and C (P < 0.01). And the expressions of collagen III were 5411 ± 435, 874 ± 70 and 2078 ± 175 in Groups A, B and C respectively. Group C was higher than Group B and yet lower than Group A (all P < 0.01). The ratios of collagen I and collagen III in Group A (0.39) and Group B (0.59) were higher than that of Group C (0.19) (all P < 0.01). CONCLUSION: The addition of hyaluronic acid may boost the expression of collagens I and III and decrease the ratio of collagen I/collagen III. Thus it facilitates wound healing and basilar membrane remodeling and alleviates the contraction of skin transplant.

[Growth and migration of umbilical cord mesenchymal stem cells on polycarbonate membrane with different pore sizes].

OBJECTIVE: To observe the growth and migration of human umbilical cord mesenchymal stem cells (hUCMSCs) on polycarbonate membrane with different pore sizes and explore the criteria of selecting optimal Transwell insert for indirect co-culture to induce the differentiation of hUCMSCs. METHODS: hUCMSCs were isolated in vitro and then expanded in culture medium. After the treatment of mitomycin C, the cells were seeded on porous membranes of 6-well-dish Transwell inserts with different pore sizes of 0.4, 3.0 and 8.0 µm respectively. After culturing for 7 days, the cells were observed and counted on the bottom of each porous membrane. Then the calculation of migration ratio was performed. The growth and migration of hUCMSCs on porous membranes were also examined under scanning electron microscope (SEM). RESULTS: The migration ratios of hUCMSCs on membranes of 0.4, 3.0 and 8.0 µm pore sizes were 0, 1.8% and 8.0% respectively. The migration ratio of cells on 0.4 µm pore size membrane was statistically different from that of the other two pore size groups (P < 0.01). Under SEM, a small portion of cells were growing on the bottoms of membranes and moving through the pores. But there was no cell movement through 0.4 µm pore size membrane. CONCLUSIONS: hUCMSCs can migrate through the polycarbonate membranes of 3.0 µm and 8.0 µm pore sizes but not through the 0.4 µm one. Thus both sides of polycarbonate membrane of 0.4 µm pore size may be used for close indirect co-culture to induce the differentiation of hUCMSCs.

[Early changes in serum neutrophil elastase in rats with burn, blast injury or combined burn-blast injury and its significance].

OBJECTIVE: To explore the early changes in serum neutrophil elastase (NE) in rats with burn, blast injury or combined burn-blast injury and its significance. METHODS: A total of 176 male Sprague Dawley rats were randomly divided into four groups: control (C), burn (BU), blast injury (BL) and burn-blast combined injury (BB). Rats in C group were not injured. Animals in BU group were subjected to 25% TBSA full-thickness burn on back with 94 degrees C water for 12 seconds; Animals in BL group were inflicted with moderate blast injury with 5 g 8701 compressed dynamite stick as the explosion source 75 cm away while left chest facing the explosive source; Rats in BB group were burned immediately after the blast injury similarly as in BL group. During the first 24 h post-injury, animals in BU and BB groups received intraperitoneal injection of sodium lactate Ringer's solution at a dose of 50 ml x kg(-1) x 12 h(-1). Protein concentration in bronchoalveolar lavage fluid (BALF), water content of lung tissue and NE content in serum were determined at 0 h (C group), 3 h, 6 h, 12 h, 1 d, 2 d, 3 d, 7 d post-injury. RESULTS: Protein concentration in BALF, water content of lung tissue and NE content in serum in SD rats of the injured groups were significantly higher than those in C group (P < 0.01 or P < 0.05), peaked within 2 d post-injury, especially at 2 d post-injury (NE content in serum: BU group, 319. 85 +/- 19.50 ng/ml; BL group, 467.43 +/- 31.64 ng/ml; BB group, 626.00 +/- 26.38 ng/ml vs. C group, 78.53 +/- 25.10 ng/ml). Overall, protein concentration in BALF, water content of lung tissue and NE content in serum in BB group were significantly higher than BU and BL groups (P < 0.01 or P < 0.05). Correlation analysis showed that within 3 d postinjury, a significant positive correlation was found between the protein concentration in BALF, water content of lung tissue and NE content in serum (r = 0.7910, 0.8078, P < 0.05) in BU group. NE content in serum and protein concentration in BALF were significantly positively correlated in BB group (r = 0.8672, P < 0.05). CONCLUSION: NE may play an important role in early lung injury of burn or blast injury, especially in combined burn-blast injury.

Treatment strategies for mass burn casualties.

BACKGROUND: Mass burn casualties are always a great challenge to a medical team because a large number of seriously injured patients were sent in within a short time. Usually a high mortality is impending. Experiences gained from successful treatment of the victims may be useful in guiding the care of mass casualties in an armed conflict. METHODS: Thirty-five burn victims in a single batch, being transferred nonstop by air and highway from a distant province, were admitted 48 hours post-injury. All patients were male with a mean age of (22.4 +/- 8.7) years. The burn extent ranged from 4% to 75% ((13.6 +/- 12.9)%) total body surface area. Among them, thirty-two patients were complicated by moderate and severe inhalation injury, and tracheostomy had been performed in 15 patients. Decompression incisions of burn eschar on extremities were done in 17 cases before transportation. All the thirty-five patients arrived at the destination smoothly via 4-hour airlift and road transportation. Among them, twenty-five patients were in critical condition. RESULTS: These thirty-five patients were evacuated 6 hours from the scene of the injury, and they were transferred to a local hospital for primary emergency care. The patients were in very poor condition when admitted to our hospital because of the severe injury with delayed and inadequate treatment. Examination of these patients at admission showed that one patient was suffering from sepsis and multiple organ dysfunction syndrome. Dysfunction of the heart, lung, liver, kidney, and coagulation were all found in the patients. Forty-eight operations were performed in the 23 patients during one month together with comprehensive treatment, and the function of various organs was ameliorated after appropriate treatment. All the 35 patients survived. CONCLUSIONS: A well-organized team consisting of several cooperative groups with specified duties is very important. As a whole, the treatment protocol should be individualized, basing on the extent of the injury and the care that the patient had received at the spot. During airlift, the stretchers should be arranged perpendicular to the longitudinal axis of the cabin. The treatment protocol in our hospital consisted mainly of prompt effective relief of all life-threatening complications, followed by early closure of burn wounds, appropriate use of anti-infection therapy, emphasis on nutritional support, correction of metabolic disorders, alleviation of immunosuppression, correction of coagulopathy, and effective support and protection of organ function.

[Influence of carbachol on intestinal dysfunction after traumatic or burn injury].

OBJECTIVE: To investigate the influence of enteral administration of carbachol on the intestinal dysfunction of both severely burn patients and rabbits with partial intestinal ischemia/reperfusion (I/R) injury. METHODS: Seventy-five white rabbits were inflicted with I/R injury and randomized into intestinal I/R (I, n=25), carbachol [C, n=25, with 3g/L carbachol (3 mg/kg) injection into duodenum 1 h after SMA occlusion] and sham operation (SO, n=25, with SMA isolation but no occlusion) groups, and 5 other as normal controls. The blood flow of intestinal mucosa was detected before and after SMA occlusion or admission of carbachol. Changes in diamine oxidase (DAO), D-lactate, xylopyranose absorption, blue dextran discharging time were measured at 2, 4, 6, 8, 24, 48, 72 h after SMA occlusion. In addition, eight severe burn patients with TBSA of 84 +/- 12% were enrolled in the study, and carbachol (15 microg/kg) was administered to patients when abdominal distension or bowel sound was lower than 2 times/min, then the number of abdominal distension and bowel sounds per minute were observed. RESULTS: The blood flow in intestinal mucosa of rabbits without SMA occlusion was (102 +/- 5) PU, reduced to (48 +/- 6) PU after SMA occlusion, and increased to (77 +/- 3) PU after injection of carbachol. The plasma DAO activity and D-lactic acid content in I group began to increase 4 hours after SMA occlusion, and they reached the peak 24 hours after SMA occlusion (4.63 +/- 0.27 U/ml, 7.9 +/- 2.4 mg/L) , after that they decreased gradually, but still higher than the normal value (0.89 +/- 0.14 U/ml, 2.0 +/- 1.1 mg/L, P < 0.05). In carbachol group, data showed the same trends as that in intestine I/R group with lower values, while no obvious changes were in sham operation group (P > 0.05). The content of D-lactic decreased dramatically 2 hours after D-lactic administration in both I and C groups, increased 6 hours after SMA occlusion, then decreased gradually, but it in C group was always higher than normal values, and little fluctuation was in sham operation group. There was no blue dextran discharge 2 hours after SMA occlusion. The discharging distance increased 6 hours later, but it was obviously shorter than the normal value 24 hrs after operation (P < 0.05) , then it returned to normal 48 to 72 hrs after operation. In the C group, blue dextran discharge was found immediately after its injection, with obvious increase in the discharging distance to peak value (43 +/- 6 cm) 6 hours after injury, and returning to normal (28 +/- 3 cm) gradually. In severe burned patients, the bowel sounds was (1.6 +/- 1.1) per minutes before carbachol administration, then increased dramatically to (6.9 +/- 1.7) per minutes 10 mins after administration, reached to a higher level 30 minutes after administration (8.3 +/- 2.4 ) times/min, and it maintained to (6.1 +/- 1.3) times/min 1 hour after administration. Abdominal distension was ameliorated 2 hours after carbachol administration, six patients were able to defecate. CONCLUSION: Enteral administration of Carbachol can increase the blood flow of intestine mucosa, help to improve the movement, absorption and barrier functions of intestine, and ameliorate intestinal dysfunction in patients with severe burns.