Chemotherapeutic agents fail in clinical chemotherapy in the absence of targeting and acquired resistance. We, therefore, synthesized Fe3O4@ZIF-8@Sor@TA nanocomposite drugs based on the drug delivery properties of nanomaterials. ZIF-8 is a nanomaterial with a porous structure that can load anticancer drugs. The nanodrug used the paramagnetic property of Fe3O4 to deliver sorafenib (Sor) precisely to the tumor site, then used the pH responsiveness of ZIF-8 to slowly release Sor in the tumor microenvironment, and finally used tannic acid (TA) to inhibit P-glycoprotein to suppress the Sor resistance. The results of material characterization presented that the prepared material was structurally stable and was able to achieve a cumulative drug release of 38.2% at pH 5.0 for 72 h. The good biocompatibility of the composite was demonstrated by in vitro and in vivo experiments, which could improve antitumor activity and reduce Sor resistance through magnetic targeting TA. In conclusion, the Fe3O4@ZIF-8@Sor@TA material prepared in this study demonstrated high antitumor activity in hepatocellular carcinoma treatment, promising to reduce drug resistance and providing a novel research approach for cancer treatment.

Mechanically and thermally stable hydrophobic aerogels were prepared by simple boric acid condensation, freeze-drying, and chemical vapor deposition for the treatment of oily wastewater.

ObjectiveThis study aimed to determine the associations between the first-attempt success and arterial depth in ultrasound-guided radial artery catheterization (RAC) with dynamic needle tip positioning (DNTP) technique. This study also aimed to further explore the cut-off depth correlated to improved first-attempt success catheterization in less time.MethodsThe cases undertaken by RAC within the DNTP technique between March 2019 and July 2020 were extracted from our institutional cohort database. Relevant variables were collected, including patients' demographics and catheterized information. Univariable and multivariable logistic regression analyses were performed to determine the association. The receiver operating characteristic (ROC) curve and the Youden index were used to explore the cut-off values of the arterial depth. Categorized cases according to the cut-off values, the Kaplan-Meier analysis, and the log-rank test were used to determine the difference of first-attempt success with limited catheterized time between groups.ResultsIn this study, 119 patients were enrolled and 98 achieved first-attempt success. The first-attempt success catheterization was observed to be correlated to arterial depth (p < 0.01, odds ratio 6.47). An optimal cut-off depth of 2.25 mm was found using the Youden index (0.53) by ROC curve (area under curve 0.77). Arterial depth of more than 2.25 mm was correlated to improved first-attempt success catheterization in less time (log-rank p < 0.01).ConclusionTo achieve first-attempt success catheterization using the DNTP technique, an arterial depth of more than 2.25 mm was associated with less catheterized time.

ConspectusGroup 14 Zintl anions [Ex]q- (E = Si-Pb, x = 4, 5, 9, 10) are synthetically accessible, and their diverse chemical reactivity makes them valuable synthons in the construction of larger nanoclusters with remarkable structures, intriguing patterns of chemical bonding, and tunable physical and chemical properties. A plethora of novel cluster anions have now been isolated from the reactions of polyanionic [Ex]q- precursors with low-valent d-/f-block metal complexes, main-group organometallics, or organics in polar aprotic solvents. The range of products includes intermetalloid clusters with transition metal atom(s) embedded in main-group element cages, organometallic Zintl anions in which [Ex]q- acts as a ligand, intermetallic Zintl anions where [Ex]q- is bridged by ligand-free transition metal atom(s), organo-Zintl anions where [Ex]q- is functionalized with organic-group(s), and oligomers formed through oxidative coupling reactions. The synthesis and characterization of these unconventional complexes, where important contributions to stability come from ionic, covalent, and metal-metal bonds as well as weaker aurophilic and van der Waals interactions, extend the boundaries of coordination chemistry and solid-state chemistry. Substantial progress has been made in this field over the past two decades, but there are still many mysteries to unravel related to the cluster growth mechanism and the controllable synthesis of targeted clusters, along with the remarkable and diverse patterns of chemical bonding that present a substantial challenge to theory. In this Account, we hope to shed some light on the relationship between structure, electronic properties, and cluster growth by highlighting selected examples from our recent work on homoatomic deltahedral [Ex]q- anions, including (1) germanium-based Zintl clusters, such as the supertetrahedral intermetallic clusters [M6Ge16]4- (M = Zn, Cd) and the sandwich cluster {(Ge9)2[η6-Ge(PdPPh3)3]}4- with a heterometallic Ge@Pd3 interlayer; (2) tin-based intermetalloid clusters [Mx@Sny]q- and the application of [Co@Sn9]4- in bottom-up synthesis; and (3) lead clusters with precious metal cores, including the largest Zintl anion [Au12Pb44]8-. In addition to their intrinsic appeal from a structural and electronic perspective, these new cluster anions also show promise as precursors for the development of new materials with applications in heterogeneous catalysis, where we have recently reported the selective reduction of CO2.

[Nb(η6-C6H3Me3)2] reacts with ethylenediamine (en) solutions of K4Ge9 in the presence of 18-crown-6 to give [(η6-C6H3Me3)NbHGe6]2- (1) and [(η6-C6H3Me3)NbGe6Nb(η6-C6H3Me3)]2- (2) as their corresponding [K(18-crown-6)]+ salts. The crystalline solids are dark brown, air-sensitive, and sparingly soluble or insoluble in most solvents. The [K(18-crown-6)]+ salts of cluster ions 1 and 2 have been characterized by energy-dispersive X-ray (EDX) analysis, NMR studies, single-crystal X-ray diffraction, and electrospray ionization time-of-flight (ESI-TOF) mass spectrometry studies. Cluster ions 1 and 2 have markedly different [Ge6] moieties: an electron-deficient carborane-like subunit in 1 and a two-center, two-electron cyclohexane-like subunit in 2.

Taking sponge-like porous nickel foam (NF) with a pore size of about 100 mu m as the carrier, superhydrophobic carbon nanoparticles (CNPs) as the filler, and hydrophobic polydimethylsiloxane (PDMS) as the binder, a single layer superhydrophobic nickel foam composite (NF/CNP-PDMS) is prepared by the simple immersion method. Then the single-layer is laminated into a multi-layer composite with high porosity and micro-nano rough structure for water-in-oil emulsion separation. In addition, in the pressing process, the factors affecting the flux and efficiency of emulsion separation are explored by controlling the areal density and thickness of the threedimensional multilayer material. As a consequence, the surface of the micro-nano structure has a static water contact angle (WCA) of about 150 degrees. When the areal density is 875 g/m(2), the thickness is 2 mm, and the efficiency of emulsion separation is as high as 98%. Moreover, the NF/CNP-PDMS has excellent chemical stability, mechanical durability and abrasion resistance, which can be reused for emulsion separation. This work is one of the few experimental schemes using foamed metal for emulsion separation. And the number of pressed layers of nickel foam can be changed to meet different needs of emulsion separation. This work will be beneficial to the research of stable underoil superhydrophobic materials and efficient emulsion separation device.

Cluster anions [Cp*RuPb11]3- (1) and [Cu@Cp*RuPb11]2- (2) represent the first vertex-substituted zintl icosahedra and 1 is the first non-centered zintl icosahedron isolated in the condensed phase. Complexes 1 and 2 are both 12-vertex, 26-electron closo-clusters with C5v point symmetry and are static on the 207Pb NMR time scale in solution.

The icosahedral [M@Pb-12](3-) (M=Co(1), Rh(2), Ir(3)) cluster ions were prepared from K4Pb9 and Co(dppe)Cl-2 (dppe=1,2-bis(diphenylphosphino)ethane)/[Rh(PPh3)(3)Cl]/[Ir(cod)Cl](2) (cod=1,5-cyclooctadiene), respectively, in the presence of 18-crown-6/ 2,2,2-cryptand in ethylenediamine/toluene solvent mixtures. The [K(2,2,2-cryptand)](+) salt of 1 and the [K(18-crown-6)](+) salt of 3 were characterized via X-ray crystallography; the ions 1 and 3 are isostructural and isoelectronic to the [Rh@Pb-12](3-) (2) ion as well as to the group 10 clusters [M '@Pb-12](2-) (M '=Ni, Pd, Pt). The ions are all 26-electron clusters with near perfect icosahedral I-h point symmetry. Clusters 1-3 show record downfield Pb-207 NMR chemical shifts due to sigma-aromaticity of the cluster framework. Calculated and observed Pb-207 NMR chemical shifts and Pb-207-M-x J-couplings (M-x=Co-59, Rh-103, Ir-193) are in excellent agreement and DFT analysis shows that the variations of Pb-207 NMR chemical shifts for the [M@Pb-12](2, 3-) ions (M=Co, Rh, Ir, Ni, Pd, Pt) are mainly governed by the perpendicularly oriented sigma(11) component of the chemical shift anisotropy tensor. The laser desorption ionization time-of-flight (LDI-TOF) mass spectra contain the molecular ions as well as several new gas phase clusters derived from the parents. The DFT-minimized structures of these ions are described.

In this study, a novel hydroxyapatite (HA)/polyurethane (PU) composite porous 3D scaffold was developed byin situpolymerization. Aliphatic hexamethylene diisocyanate (HDI) as a nontoxic and safe agent was adopted to produce the rigid segment in PU polymerization. HA powder was compounded in a PU polymer matrix during the polymeric process. The macrostructure and morphology as well as mechanical strength of the scaffolds were characterized by FTIR, XRD and SEM. The results show that the HDI can react mildly with hydroxyl (-OH) groups of polytetramethylene ether glycol and a mild foaming action caused by the release of CO(2)gas occurred simultaneously in the reactive process, thus producing a uniform porous structure of HA/PU scaffold. The HA/PU composite scaffold with a high HA content of about 30 wt% has a porosity of more than 60% and a pore size from 100 to 800 mu m. After immersed in simulated body fluid, the scaffolds were investigated by weight loss experiments and FTIR. The results show that polymerized component of HA/PU scaffolds degraded graduallyin vitro, while HA component presented a classic trend of dissolution then deposition procedure. Three hydrolysis processes may happen in the PU degradation. The HA/PU scaffolds should be a promising material for bone tissue regeneration in clinic.

We report the formation mechanism and compositions of a solid-electrolyte interphase (SEI) on a microporous carbon/sulfur (MC/S) cathode in Li-S batteries using a carbonate-based electrolyte (1 M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate, v:v = 1:1). Through characterizations using 1D and 2D solution-phase nuclear magnetic resonance spectroscopy, coupled with model chemical reactions and DFT calculations, we have identified two critical roles of Li+ in steering the SEI formation. First, the preferential solvation of Li+ by EC in the mixed carbonate electrolyte renders EC as the dominant participant in the SEI formation, and second, Li+ coordination to the EC carbonyl alters activation barriers and changes the reaction pathways relative to Na+. The main organic components in the SEI are identified as lithium ethylene monocarbonate and lithium methyl carbonate, which are virtually identical to those formed on Li and graphite anodes of lithium-ion batteries but via a different pathway.

提出一种新型高温磁反馈电路,包括高温反馈脉冲发生电路、高温磁反馈变压器、变压器复位电路、整流滤波电路、取样比较电路.所提磁反馈电路解决了高温环境(185 ℃)下无合适隔离反馈形式的问题,突破了常规半导体器件175℃结温的限制,具有适用温度范围广、静态电流小、系统响应性能好等特点,可广泛应用于各类高温开关电源.

针对水热法制备的氮掺杂TiO2/还原氧化石墨烯纳米颗粒(NTG)分离回收性及稳定性差的问题,采用电化学法制备了氮掺杂TiO2纳米管/还原氧化石墨烯复合膜(ENTG),并通过场发射扫描电镜(FESEM)等表征其特性.结果 表明,ENTG中纳米管阵列的管径约为167 nm、管长约为6 μm,TiO2晶型为锐钛矿相,氮以间隙掺杂形式进入TiO2晶格.不同光催化剂(TiO2纳米管TNT、氮掺杂TiO2纳米管N/TNT、NTG、ENTG)对腐殖酸(HA)的去除效果表明,当HA浓度较低时,4种光催化剂去除HA的过程均符合准一级动力学模型;无论在紫外光区还是可见光区,ENTG的光催化性能均优于其他3种催化剂,且在可见光区去除HA的效果更好.另外,光催化重复试验结果表明,ENTG分离回收方便且催化稳定性较好,在饮用水处理领域具有较大的应用潜能.

Reactions of K12Si17 with the low-valent transition-metal complex Mo(CO)(3)(C7H8) in ethylenediamine/toluene solutions in the presence of 2,2,2-cryptand yield the {Si(NHCH2CH2NH)(3)[Mo(CO)(3)](2)}(2-) dianion, which contains an octahedral Si(NHCH2CH2NH)(3)(2-) subunit. The SiN6 core comprises a rare example of a doubly deprotonated ethylenediame ligand in a coordination complex and is also the first structurally characterized example of a homoleptic Si(N boolean AND N)(3) trischelate. Its structure and spectroscopic properties are described.

The [Sb6(RuCp*)2]2- (1) anion represents the first example of a Zintl cluster with a boat-like cyclo-Sb6 subunit and the first ruthenium polyantimonide complex. The anion is dynamic in solution and fragments in the gas phase. Structural parameters and DFT calculations suggest the possibility of Sb[double bond, length as m-dash]Sb double bond character.

K5Sb4 and K3Sb7 Zintl ion precursors react with Pd(PPh3)4 in ethylenediamine/toluene/PBu4+ solutions to give crystals of Sb@Pd12@Sb20n-/PBu4+ salts, where n = 3, 4. The clusters are structurally identical in the two charge states, with nearly perfect Ih point symmetry, and can be viewed as an Sb@Pd12 icosahedron centered inside of an Sb20 dodecahedron. The metric parameters suggest very weak Sb-Sb and Pd-Pd interactions with strong radial Sb-Pd bonds between the Sb20 and Pd12 shells. All-electron DFT analysis shows the 3- ion to be diamagnetic with Ih symmetry and a 1.33 eV HOMO-LUMO gap, whereas the 4- ion undergoes a Jahn-Teller distortion to an S = 1/2 D3d structure with a small 0.1 eV gap. The distortion is predicted to be small and is not discernible by crystallography. Laser desorption-ionization time-of-flight mass spectrometry (LDI-TOF MS) studies of the crystalline samples show intense parent Sb@Pd12@Sb20- ions (negative ion mode) and Sb@Pd12@Sb20+ (positive ion mode) along with series of Sb@Pd12-y@Sb20-x-/+ ions. Ni(cyclooctadiene)2 reacts with K3Sb7 in en/tol/Bu4PBr solvent mixtures to give black precipitates of Sb@Ni12@Sb20n- salts that give similar Sb@Ni12@Sb20-/+ parent ions and Sb@Ni12-y@Sb20-x-/+ degradation series in the respective LDI-TOF MS studies. The solid-state and gas-phase studies of the icosahedral Sb@M12@Sb20n-/n+ ions show that the clusters can exist in the -4, -3, -1, +1 (M = Pd) and +1, -1 (M = Ni) oxidation states. These multiple-charge-state clusters are reminiscent of redox-active fullerenes (e.g., C60n, where n = +1, 0, -1, -2, -3, -4, -5, -6).

The norbornadiene-like bimetallic dimer [(ZnSb6)2]4- anion (1) was prepared by direct extraction from a ternary alloy with nominal composition "K6ZnSb5" in ethylenediamine/toluene/2,2,2-crypt solutions. The structure represents a new type for coupled norbornadiene subunits, however, distortions around the Zn2+ ions degrade the overall symmetry. The Zn2+ ions achieve a 16e- configuration and reside in near perfect ZnSb3 triangular coordination environments. DFT calculations reveal a 2.35 eV HOMO-LUMO gap and suggest covalent bonding between the Zn and Sb atoms.

The structures and mechanisms for hydrogen abstraction from isopropylbenzene for four high-valence complexes, cis-beta-[Fe-IV(O) (BQCN)](2+) (Fe-2b and Fe-2b-2) and cis-beta-[Ru-IV(O)(BQCN)](2+) (Ru-2b and Ru-2b-2) (BQCN = N,N'-dimethyl-N,N'-bis(8-quinolyl)cyclohexanediamine), were investigated using density functional theory. Of the two iron complexes, Fe-2b-2 has more exposed FeO units than Fe-2b, with iron being further out of the equatorial plane because of the steric interaction of the same ligand topologies with the iron-oxo group trans to a quinolyl or amine nitrogen. The contribution of BQCN to Fe-2b is higher than the contribution to Fe-2b-2 as shown by the density-of-states spectra. The iron isomers can abstract hydrogen from isopropylbenzene via two-state reactivity patterns, whereas the ruthenium isomers react with isopropylbenzene via a single-state mechanism. In the gas phase, the relative reactivity exhibits the trend Fe-2b > Fe-2b-2, whereas with the addition of the ZPE correction and the SMD model, the relative reactivity follows Fe-2b-2 > Fe-2b. For the ruthenium complexes, the relative reactivity follows the trend Ru-2b-2 > Ru-2b in both the gas phase and solvent. Thus, the same ligand topologies with the metal-oxo group trans to a different nitrogen affect the reactivities of the iron and ruthenium complexes.

Objective:The aim of this study was to isolate and characterize manganese (Ⅱ)-oxidizing bacteria from surrounding area of manganese mine.Methods:Mn (Ⅱ)-oxidizing strains were isolated based on the ability to produce brown Mn oxides on agar plates. The presence of Mn oxides was confirmed by using the leucoberbelin blue (LBB) assay. The isolate was identified by morphological and physiological characterization and sequence analyses of 16S rRNA gene, gyrB gene and gyrA gene. The phylogenetic relationship between the isolated strain and reported Mn (Ⅱ) oxidizers was also analyzed. LBB assay was used to indicate the kinetics of Mn (Ⅱ) oxides formation. The Mn oxides morphology and chemical contents were determined by scanning electron microscope with energy dispersive spectrometer and X-ray diffraction.Results:An isolate, named strain CP133, with high manganese oxidizing activity was obtained and identified as Bacillus cereus. There were some phylogenetic differences between strain CP133 and other Mn (Ⅱ)-oxidizing Bacillus species isolated from deep sea and soils. Strain CP133 produced amorphous manganese oxides that adhered to spore surface after the stationary phase of the cell culture. About 0.3 mmol/L manganese oxides was obtained after 12 days.Conclusion:A Mn (Ⅱ)-oxidizing Bacillus cereus was successfully isolated. Our results suggest the diversity of Mn (Ⅱ)-oxidizing Bacillus species, and help understanding biogeochemical cycles in manganese mine and surrounding soils.