RESUMO
Separation of C2H6/C2H4 mixtures is of significant importance in the chemical industry but remains a challenge due to the physicochemical similarities of C2H6 and C2H4. Herein, a metal-organic framework (MOF), [Zn4(µ4-O)(PCTF)3]n (Zn-PCTF) (PCTF2-= 5-trifluoromethyl-1H-pyrazole-4-carboxylic), is provided for the removal of C2H6 from C2H6/C2H4 mixtures. Zn-PCTF displays a three-dimensional framework featuring one-dimensional pore channels with periodic bottleneck segments. The well-balanced C2H6 adsorption capacity (79.0 cm3 g-1 at 298 K) and C2H6/C2H4 selectivity (1.8) for Zn-PCTF under ambient conditions boost Zn-PCTF with highly promising potentials for efficient purification of C2H4 from C2H6/C2H4 mixtures, which is verified by the dynamic column breakthrough experiments. The well-matched caged pores and suitable pore chemistry (particularly the presence of abundant Lewis base sites (N, O, and F) on the pore surfaces) for C2H6 account for the high-performance C2H6/C2H4 separation of Zn-PCTF unveiled by computational simulations.
RESUMO
RNA silencing (or RNA interference, RNAi) is a conserved mechanism for regulating gene expression in eukaryotes, which plays vital roles in plant development and response to biotic and abiotic stresses. The discovery of trans-kingdom RNAi and interspecies RNAi provides a theoretical basis for exploiting RNAi-based crop protection strategies. Here, we summarize the canonical RNAi mechanisms in plants and review representative studies associated with plant-pathogen interactions. Meanwhile, we also elaborate upon the principles of host-induced gene silencing, spray-induced gene silencing and microbe-induced gene silencing, and discuss their applications in crop protection, thereby providing help to establish novel RNAi-based crop protection strategies.
Assuntos
Proteção de Cultivos , Plantas , Interferência de RNA , Plantas/genética , Eucariotos/genética , RNA Interferente Pequeno/genéticaRESUMO
Adsorption separation of the Xe/Kr mixture remains a tough issue since Xe and Kr have an inert nature and similar sizes. Here we present a chlorinated metal-organic framework (MOF) [JXNU-19(Cl)] and its nonchlorinated analogue (JXNU-19) for Xe/Kr separation. The two isostructural MOFs constructed from the heptanuclear cobalt-hydroxyl clusters bridged by organic ligands are three-dimensional structures. Detailed contrast of the Xe/Kr adsorption separation properties of the MOF shows that significantly enhanced Xe uptakes and Xe/Kr adsorption selectivity (17.1) are observed for JXNU-19 as compared to JXNU-19(Cl). The main binding sites for Xe in the MOF revealed by computational simulations are far away from the chlorine sites, suggesting that the introduction of the chlorine groups results in the unfavorable Xe adsorption for JXNU-19(Cl). The optimal pores, high surface area, and multiple strong Xe-framework interactions facilitate the effective Xe/Kr separation for JXNU-19.
RESUMO
BACKGROUND: Perioperative hypothermia (PH) negatively affects the physical and mental health of patients to varying degrees. Currently, there is no effective multidisciplinary team (MDT) intervention for gynecological patients with PH. AIM: To apply the best evidence on the prevention and management of PH in gynecological patients, improve the quality of perioperative evidence-based care based on treatment by an MDT for gynecological patients and analyze the effect of MDT- and evidence-based practice (EBP) projects on the psychological status and cognitive function of gynecological patients with PH. METHODS: Under the guidance of knowledge translation and combined with the opinions of involved stakeholders and clinical experts, the best evidence for PH prevention and management in gynecological patients was selected and adjusted to suit the practice setting. Based on the evidence, the practice plan was developed, and the MDT intervention was carried out in the preoperative ward, the preoperative preparation room, the intraoperative operating room, the postanesthesia care unit, and the 24-hour postoperative gynecological ward through the EBP program. The incidence of hypothermia, the nurses' awareness, the implementation rate of examination indicators, and the thermal comfort level, psychological status and cognitive function of patients were compared before and after the implementation of the program. RESULTS: The incidence of PH in gynecological patients decreased from 43.33% to 13.33% after the implementation of the scheme. The implementation rate of examination indicators 6-10, 12, 14, 16-18, 21, and 22 reached 100%, and that of other indicators was above 90%, except for examination indicators 5 and 13, which was 66.67%; the indices were significantly improved compared with the baseline (before evidence application) (P < 0.05). The score of nurses' awareness of PH prevention and management in gynecological patients increased from 60.96 ± 9.70 to 88.08 ± 8.96, and the difference was statistically significant (P < 0.001). The total score of the perioperative thermal comfort level of patients undergoing gynecological surgery was 27.97 ± 2.04, which was significantly increased compared with the score of 21.27 ± 1.57 observed by researchers at baseline (P < 0.001). The perioperative Hamilton Depression Scale and Hamilton Anxiety Scale scores of patients undergoing gynecological surgery decreased from 15.03 ± 3.16 and 13.93 ± 2.64 to 4.30 ± 1.15 and 3.53 ± 0.78, respectively, with statistically significant differences (P < 0.001). The perioperative Montreal Cognitive Assessment Scale score of the gynecological surgery patients increased from 23.17 ± 1.68 to 26.93 ± 1.11, also with statistical significance (P < 0.001). CONCLUSION: MDT-based EBP for PH prevention and management in gynecological patients during the perioperative period can standardize nursing operations, improve nurses' awareness and behavioral compliance with gynecological hypothermia management, and reduce the occurrence of PH in gynecological patients while playing a positive role in reducing patients' negative emotions and enhancing their cognitive function.
RESUMO
Herein, a metal-organic framework (MOF), {[(Me2NH2)4][Cd(H2O)6][Cd18(TrZ)12(TPD)15(DMF)6]}n (denoted as JXNU-18, TrZ = triazolate), constructed from the unique cucurbituril-shaped Cd18(TrZ)12 secondary building units bridged by 2,5-thiophenedicarboxylic (TPD2-) ligands, is presented. The formation of the cucurbituril-shaped Cd18(TrZ)12 unit is unprecedented, demonstrating the geometric compatibility of the organic linkers and the coordination configurations of the cadmium atoms. Each Cd18(TrZ)12 unit is connected to eight neighboring Cd18(TrZ)12 units through 30 TPD2- linkers, affording the three-dimensional structure of JXNU-18. More interesting is that JXNU-18 displays an efficient C2H2/CO2 separation ability, as revealed by the gas adsorption experiments and dynamic gas breakthrough experiments, which afford insights into the potential applications of JXNU-18 in gas separation. The tubular pores composed of two Cd18(TrZ)12 units bridged by six 2,5-thiophenedicarboxylic linkers provide the suitable pore space for C2H2 trapping, as unveiled by computational simulations.
RESUMO
Astrocytes are intimately linked with brain blood vessels, an essential relationship for neuronal function. However, astroglial factors driving these physical and functional associations during postnatal brain development have yet to be identified. By characterizing structural and transcriptional changes in mouse cortical astrocytes during the first two postnatal weeks, we find that high-mobility group box 1 (Hmgb1), normally upregulated with injury and involved in adult cerebrovascular repair, is highly expressed in astrocytes at birth and then decreases rapidly. Astrocyte-selective ablation of Hmgb1 at birth affects astrocyte morphology and endfoot placement, alters distribution of endfoot proteins connexin43 and aquaporin-4, induces transcriptional changes in astrocytes related to cytoskeleton remodeling, and profoundly disrupts endothelial ultrastructure. While lack of astroglial Hmgb1 does not affect the blood-brain barrier or angiogenesis postnatally, it impairs neurovascular coupling and behavior in adult mice. These findings identify astroglial Hmgb1 as an important player in postnatal gliovascular maturation.
Assuntos
Astrócitos , Barreira Hematoencefálica , Proteína HMGB1 , Animais , Camundongos , Aquaporina 4 , Encéfalo , Morfogênese , Proteína HMGB1/metabolismoRESUMO
A pair of metal-organic frameworks (MOFs) of JXNU-15 (formulated as [Co6(µ3-OH)6(BTB)2(BPY)3]n, BTB3- = benzene-1,3,5-tribenzoate and BPY = 4,4'-bipyridine) and its fluorinated JXNU-15(F) ([Co6(µ3-OH)6(SFBTB)2(BPY)3]n) based on the fluorous 1,3,5-tri(3,5-bifluoro-4-carboxyphenyl)benzene (SFBTB3-) ligands were presented. The detailed comparisons of the acetylene/carbon dioxide (C2H2/CO2) separation abilities between the isostructural JXNU-15(F) and JXNU-15 were presented. In comparison with the parent JXNU-15, the higher C2H2 uptake, larger adsorption selectivity of the C2H2/CO2 (50/50) mixture, and enhanced C2H2/CO2 separation performance endow JXNU-15(F) with highly efficient C2H2/CO2 separation performance, which is demonstrated by singe-component gas adsorptions and dynamic gas mixture breakthrough experiments. The fluorine substituents exert the crucial effects on the enhanced C2H2/CO2 separation ability of JXNU-15(F) and play the dominant role in the C2H2-framework interactions, as uncovered by computational simulations. This work illustrates a powerful fluorine substitution strategy for boosting C2H2/CO2 separation ability for MOFs.
RESUMO
BACKGROUND: ATP-binding cassette (ABC) transporters comprise a superfamily of genes encoding membrane proteins with nucleotide-binding domains (NBD). These transporters, including drug efflux across the blood-brain barrier (BBB), carry a variety of substrates through plasma membranes against substrate gradients, fueled by hydrolyzing ATP. The expression patterns/enrichment of ABC transporter genes in brain microvessels compared to peripheral vessels and tissues are largely uncharacterized. METHODS: In this study, the expression patterns of ABC transporter genes in brain microvessels, peripheral tissues (lung, liver and spleen) and lung vessels were investigated using RNA-seq and WesTM analyses in three species: human, mouse and rat. RESULTS: The study demonstrated that ABC drug efflux transporter genes (including ABCB1, ABCG2, ABCC4 and ABCC5) were highly expressed in isolated brain microvessels in all three species studied; the expression of ABCB1, ABCG2, ABCC1, ABCC4 and ABCC5 was generally higher in rodent brain microvessels compared to those of humans. In contrast, ABCC2 and ABCC3 expression was low in brain microvessels, but high in rodent liver and lung vessels. Overall, most ABC transporters (with the exception of drug efflux transporters) were enriched in peripheral tissues compared to brain microvessels in humans, while in rodent species, additional ABC transporters were found to be enriched in brain microvessels. CONCLUSIONS: This study furthers the understanding of species similarities and differences in the expression patterns of ABC transporter genes; this is important for translational studies in drug development. In particular, CNS drug delivery and toxicity may vary among species depending on their unique profiles of ABC transporter expression in brain microvessels and BBB.
RESUMO
The stellate ganglion (SG), as a type of sympathetic ganglion, consists of the sixth and seventh cervical vertebrae and the first thoracic sympathetic ganglia. SG block (SGB) is a minimally invasive injection that aims to inject low-concentration local anesthetics to induce a broad sympathetic blocking effect near the SG. There have been no changes and progress in the clinical application of SGB since the 1830s due to several potential risks, including hematoma from blood vessel injury, hoarseness from recurrent laryngeal nerve injury, and cardiopulmonary arrest. The feasibility and safety of SGB have greatly improved since the appearance of ultrasound-guided SGB. In recent years, SGB has been widely applied in the field of non-anesthesiology sedation, with significant therapeutic effects on pain, immunological diseases, somnipathy, psychological disorders, arrhythmias, and endocrine diseases. The present study reviews the present application of SGB in clinical practice.
RESUMO
Fluorinated dicopper(II) metal-organic framework JXNU-16F with 1,3,5-tri(3,5-bifluoro-4-carboxyphenyl)benzene ligands and nonfluorinated JXNU-16 exhibit high propyne uptakes of 443 and 496 cm3 g-1 under ambient conditions, respectively. Their remarkable propyne uptakes result from suitable pore spaces and strong propyneâ¯propyne interactions amongst the adsorbed propyne molecules, as revealed by computational simulations.
RESUMO
Here, a hexanuclear Co6(µ3-OH)6 cluster-based metal-organic framework (MOF), [Co6(µ3-OH)6(BTB)2(bpy)3]n (JXNU-15) (bpy = 4,4'-bipyridine), with the 1,3,5-tri(4-carboxyphenyl)benzene (BTB3-) ligand was synthesized for the challenging propadiene/propylene separation. The combination of a large pore volume and a suitable pore environment boosts the significantly high propadiene (C3H4) uptake (311 cm3 g-1 at 298 K and 100 kPa) for JXNU-15. An amine-functionalized MOF of JXNU-15(NH2) was further obtained with the 1,3,5-tri(4-carboxyphenyl)benzene analogue of 3,3â³-diamino-5'-(3-amino-4-carboxyphenyl)-[1,1':3',1â³-terphenyl]-4,4â³-dicarboxylic ligand. The comparative studies of propadiene/propylene(C3H4/C3H6) separation performance between isostructural JXNU-15 and JXNU-15(NH2) are provided. JXNU-15(NH2) exhibits an impressive C3H4 capacity at low pressures with 69.1 cm3 g-1 at 10 kPa, which is twice that of JXNU-15 under the same conditions. Moreover, the separation selectivity of JXNU-15(NH2) is 1.3-fold higher as compared to JXNU-15. JXNU-15(NH2) with enhanced C3H4/C3H6 separation performance was elegantly illustrated by gas separation experiments and theoretical simulations. This work presents an amine-functionalized strategy for the enhancement of the C3H4/C3H6 separation performance of MOF.
RESUMO
Xe/Kr separation is industrially important but remains a daunting issue in chemical separations. Herein, a fluorinated metal-organic framework (MOF), [Ni2(µ2-O)(TFBPDC)(tpt)2]n (named JXNU-13-F), built from 3,3',5,5'-tetrakis(fluoro)biphenyl-4,4'-dicarboxylic (TFBPDC2-) and 2,4,6-tri(4-pyridinyl)-1,3,5-triazine (tpt) ligands is provided. JXNU-13-F displays a three-dimensional (3D) framework constructed from distorted octahedral cages and an impressive Xe capacity of 144 cm3 g-1 at 273 K and 1 bar, ranking among top MOFs. The high Xe uptake and moderate Xe/Kr adsorption selectivity endow JXNU-13-F with efficient Xe/Kr separation demonstrated by experimental column breakthrough tests. The comparative studies of gas adsorption between isostructural JXNU-13-F and JXNU-13 (the nonfluorinated analogue ([Ni2(µ2-O)(BPDC))(tpt)2]n with biphenyl-4,4'-dicarboxylic (BPDC2-)) revealed that the F groups serve as the innocent groups during the Xe and Kr adsorption in JXNU-13-F. Thus, a combination of highly hydrophobic and π-electron-rich pore surfaces made of aromatic rings with strong interactions with the Xe atom possessing large polarizability and appropriate pore sizes that match well Xe having a large atom diameter has resulted in high Xe uptake and effective Xe/Kr separation characteristics of JXNU-13-F.
RESUMO
Two rare-earth (RE) metal-organic frameworks (MOFs) formulated as {(Me2NH2)2[RE9(µ3-OH)8(µ2-OH)3(DCPB)6(H2O)3]}n (RE = Y3+ and Tb3+; termed JXNU-10) built from a triangular 3,5-di(4'-carboxylphenyl)benzoic acid (DCPB3-) ligand are presented. JXNU-10 features the rarely observed 18-connected nonanuclear [RE9(µ3-OH)8(µ2-OH)3] clusters, one-dimensional-nanosized tubular channels, and trigonal-bipyramidal cavities. The presence of the high-nuclear RE-oxo clusters and the robust coordination bonds between the highly charged RE ions and the hard base of the carboxylate/hydroxyl oxygen atoms yielded the water-resistant JXNU-10 materials. JXNU-10 exhibits highly selective sorption of C2H2 over CO2 and highly efficient separation of a C2H2 and CO2 mixture. The carboxylate oxygen atoms and the rich π systems of the organic ligands on the pore walls are the desirable binding sites for a C2H2 molecule with acidic hydrogen atoms and an alkyne group, facilitating the excellent efficiency of JXNU-10 for C2H2/CO2 separation demonstrated by breakthrough experiments.
RESUMO
A novel metal-organic framework (MOF) of [Co8(OH)4(TCA)4(H2O)4]n (abbreviation: JXNU-9) based on the unique octanuclear Co8(µ3-OH)4 clusters linked by 4,4',4â³-nitrilotribenzoate (TCA3-) ligands featuring small caged structures and one-dimensional channels was prepared and characterized. JXNU-9 shows a high C2H6 uptake capacity of 3.60 mmol g-1 (4.46 mmol cm-3) at 298 K and 1 atm with a small isosteric heat of adsorption (23.6 kJ mol-1) and a moderate C2H6/C2H4 adsorption selectivity of 1.7, resulting in excellent C2H6/C2H4 separation performance. The pore walls decorated by plenty of aromatic rings provide π-electron-cloud-surrounding environments to accommodate the large polarizable C2H6 molecules. The calculations demonstrate that the rich π-systems in JXNU-9 facilitate an adsorption affinity for large C2H6 molecules through multiple C-H···π interactions. Additionally, the open metal sites located in the concave pores with a close Co···Co separation (4.21 Å) in octanuclear Co8(µ3-OH)4 clusters make the open metal sites inaccessible for the C2H4 molecule with a kinetic diameter of 4.163 Å. Thus, the annihilation of open metal sites in this structure is achieved, which further facilitates the C2H6-selective C2H6/C2H4 separation.
RESUMO
The phenomenon and potential mechanisms of trans-kingdom RNA silencing (or RNA interference, RNAi) are among the most exciting topics in science today. Based on trans-kingdom RNAi, host-induced gene silencing (HIGS) has been widely applied to create crops with resistance to various pests and pathogens, overcoming the limitations of resistant cultivars. However, a lack of transformation technology in many crops limits the application of HIGS. Here, we describe the various fates of trans-kingdom RNAs in recipient organisms. Based on the assumption that small RNAs can be transferred between the host and its microbiome or among microbiome members, we propose a possible alternative strategy for plant protection against pathogens without the need for crop genetic modification.
Assuntos
Microbiota , Células Vegetais/metabolismo , Interferência de RNA , RNA Bacteriano/genética , RNA Fúngico/análise , RNA de Plantas/genéticaRESUMO
Two thorium-organic frameworks of [Th6O4(OH)4(TFBPDC)6(H2O)6]n (Th-TFBPDC) and [Th6O4(OH)4(TFBPDC)4(HCOO)4(H2O)6]n (Th-TFBPDC-i) constructed from the 3,3',5,5'-tetrakis(fluoro)biphenyl-4,4'-dicarboxylate (TFBPDC2-) ligand were obtained in a reaction. At an early stage of the reaction, the formation of the three-dimensional (3D) framework of Th-TFBPDC was discovered. At a later stage of the reaction, the complete product of Th-TFBPDC-i was obtained. The structural evolution from a noninterpenetrated network of Th-TFBPDC to a 2-fold interpenetrated network of Th-TFBPDC-i is a dissolution-recrystallization process and rationalized as the four equatorial TFBPDC2- ligands in an octahedral [Th6O4(OH)4(TFBPDC)12] unit were displaced by four formate ligands to form a [Th6O4(OH)4(TFBPDC)8(HCOO)4] unit via a ligand substitution reaction. The large pore volume as well as the strong interactions between the host framework and guest propyne (C3H4) molecules demonstrated by computational results endow the highly water-stable Th-TFBPDC with the best-performing C3H4 storage under ambient conditions. This work presents a rare example of structural evolution from a 3D noninterpenetrated network to a 2-fold 3D interpenetrated network and a highly promising metal-organic framework (MOF) for C3H4 storage with a C3H4 uptake of 8.16 mmol g-1 at 298 K.
RESUMO
Francisella tularensis subspecies tularensis (Ftt) is extremely virulent for humans when inhaled as a small particle aerosol (<5 µm). Inhalation of ≥20 viable bacteria is sufficient to initiate infection with a mortality rate ≥30%. Consequently, in the past, Ftt became a primary candidate for biological weapons development. To counter this threat, the USA developed a live vaccine strain (LVS), that showed efficacy in humans against inhalation of virulent Ftt. However, the breakthrough dose was fairly low, and protection waned with time. These weaknesses triggered extensive research for better vaccine candidates. Previously, we showed that deleting the clpB gene from virulent Ftt strain, SCHU S4, resulted in a mutant that was significantly less virulent than LVS for mice, yet better protected them from aerosol challenge with wild-type SCHU S4. To date, comprehensive searches for correlates of protection for SCHU S4 ΔclpB among molecules that are critical signatures of cell-mediated immunity, have yielded little reward. In this study we used transcriptomics analysis to expand the potential range of molecular correlates of protection induced by vaccination with SCHU S4 ΔclpB beyond the usual candidates. The results provide proof-of-concept that unusual host responses to vaccination can potentially serve as novel efficacy biomarkers for new tularemia vaccines.
RESUMO
Objective To investigate the current status of nutritional knowledge and skills of fast-food takeout practitioners in Chengdu City,so as to provide evidence for nutritional literacy education among takeout practitioners.Methods A questionnaire survey was conducted among 832 employees of fast-food takeout restaurants in Chengdu from April to September in 2019 through a multi-stage random sampling strategy.Results The awareness rate of nutritional knowledge of fast-food takeout practitioners in Chengdu was 77.28%,and the correct rates of answers to daily oil intake for adults,daily drinking water for adults and daily salt intake for adults in the Dietary Guidelines for Chinese Residents were respectively 17.43%,22.60% and 25.36%.In addition,the proportion of practitioners with the ability to estimate the recommended intake of food for a meal,the ability to estimate condiments intake and the ability to interpret nutrition labels were 8.77%,8.77% and 15.02%,respectively.The awareness rate of nutritional knowledge was the lowest(71.47%)in the practitioners aged≤25 and the highest(84.53%)in those aged 26-39,and the difference was statistically significant(χ
Assuntos
Adulto , Humanos , Comportamento Alimentar , Estado Nutricional , Restaurantes , Inquéritos e QuestionáriosRESUMO
The separation of C2H2 and CO2 is of industrial significance but is highly challenging due to their close similarities in physical-chemical properties. Metal-organic frameworks (MOFs) with tailored pore structures and tunable pore surfaces for the separation of C2H2/CO2 mixture are described in this perspective article. In terms of adsorption selectivity, MOF is classified into C2H2-selective MOF and CO2-selective MOF, which are discussed separately. Herein, we intend to present a short summary of the important advancements in C2H2/CO2 separation with MOFs. The relationship between the separation performance and structural features of MOFs, together with the separation mechanisms, has been discussed in detail. The challenges, research trends and opportunities in C2H2/CO2 separation with MOFs are highlighted.
RESUMO
The diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylic acid (H4-DPSDSDC) ligand and its coordination polymers, [K2Zn(C14H6S3O12)(H2O)4]n (1) and {[Cu3(µ3-OH)2(C14H6S3O12)(H2O)3(DMF)]·3(H2O)}n (2) (C14H6S3O12 = diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylate), were synthesized. The Zn(H2O)4 units in 1 are connected by DPSDSDC4- ligands to generate a one-dimensional (1D) chain, which is bridged by K-O bonds associated with bridging water molecules and sulfonate groups to yield a two-dimensional (2D) layer. In 2, the 1D hydroxyl-bridging Cu(II) chains are connected by DPSDSDC4- ligands to give a 2D layer. The 2D layers in 1 and 2 are further connected by interlayered hydrogen bonds to give three-dimensional (3D) frameworks. Compounds 1 and 2 have good conductivities of 1.57 × 10-4 and 5.32 × 10-5 S cm-1, respectively. Continuous well-defined hydrogen bonding networks associated with water molecules, sulfonate groups, and carboxylate groups were observed in compounds 1 and 2. Such hydrogen bonding networks provide hydrophilic domains and effective transfer pathways for protons. Here, we present elegant examples of a precise determination of the pathways for proton transport.