Computational Design of Ni6@Pt1M31 Clusters for Multifunctional Electrocatalysts.

High-efficiency and low-cost multifunctional electrocatalysts for hydrogen evolution reaction (HERs), oxygen evolution reaction (OERs) and oxygen reduction reaction (ORRs) are important for the practical applications of regenerative fuel cells. The activity trends of core-shell Ni6@M32 and Ni6@Pt1M31 (M = Pt, Pd, Cu, Ag, Au) were investigated using the density functional theory (DFT). Rate constant calculations indicated that Ni6@Pt1Ag31 was an efficient HER catalyst. The Volmer-Tafel process was the kinetically favorable reaction pathway for Ni6@Pt1M31. The Volmer-Heyrovsky reaction mechanism was preferred for Ni6@M32. The Pt active site reduced the energy barrier and changed the reaction mechanism. The ORR and OER overpotentials of Ni6@Pt1Ag31 were calculated to be 0.12 and 0.33 V, indicating that Ni6@Pt1Ag31 could be a promising multifunctional electrocatalyst. Ni6@Pt1M31 core-shell clusters present abundant active sites with a moderate adsorption strength for *H, *O, *OH and *OOH. The present study shows that embedding a single Pt atom onto a Ni@M core-shell cluster is a rational strategy for designing an effective multifunctional electrocatalyst.

Vaginal enterocele after cystectomy: A case report.

BACKGROUND: After undergoing radical cystectomy combined with hysterectomy, female patients may suffer from pelvic organ prolapse due to the destruction of pelvic structures, which mainly manifests as the prolapse of tissues of the vulva to varying degrees and can be accompanied by symptoms, such as bleeding and inflammation. Once this complication is present, surgical intervention is needed to resolve it. Therefore, preventing and managing this complication is especially important. CASE SUMMARY: The postoperative occurrence of acute enterocele is rare, and a case of acute small bowel vaginosis 2 mo after radical cystectomy with hysterectomy is reported. When the patient was admitted, physical examination revealed that the small bowel was displaced approximately 20 cm because of vaginocele. A team of gynecological, general surgery, and urological surgeons was employed to return the small bowel and repair the lacerated vaginal wall during the emergency operation. Eventually, the patient recovered, and no recurrence was seen in the half year of follow-up. CONCLUSION: We review the surgical approach for such patients, analyze high-risk factors for the disease and suggest corresponding preventive measures.

Chromium doping: A new approach to regulate electronic structure of cobalt carbonate hydroxide for oxygen evolution improvement.

Highly efficient catalysts are required to solve the intrinsically sluggish kinetics of oxygen evolution reaction (OER). Herein, chromium doped cobalt carbonate hydroxide nanowire array on Ni foam (Cr-CoCH/NF) has been synthesized for the enhancement of OER activity and stability. Compared with pure CoCH/NF, Cr0.2-CoCH/NF, the optimal doping of Cr, shows a low overpotential of 203 mV at the current density of 10 mA cm-2 and a small Tafel slope of 84 mV dec-1 in 1.0 M NaOH. In addition, there is little deterioration in electrocatalytic performance after 1000-cycle cyclic voltammetry and the high activity can be maintained over 25 h. Density functional theory calculations reveal the Cr doping can regulate the electronic structure of nearby Co active center to achieve great enhancement of OER activity.

Theoretical design and preparation research of molecularly imprinted polymers for steviol glycosides.

In this paper, a novel molecularly imprinted polymer (MIP) for specific adsorption of steviol glycosides was designed, and the imprinting mechanism of self-assembly system between template and monomers was clearly explored. Firstly, steviol (STE) was chosen as dummy template, and the density functional theory (DFT) at B3LYP/6-31 + G (d, p) level was used to select monomers, imprinting molar ratios, solvents, and cross-linking agents. The selectivity to five steviol glycosides was also calculated. Importantly, reduced density gradient (RDG) theory combined with atom in molecules (AIM) and infrared spectrum (IR) was applied to investigate the bonding situation and the nature of noncovalent interaction in self-assembly system. The theoretical designed results showed that the template which interacts with acrylic acid (AA) has the minimum binding energy, and the complex with the molar ratio of 1 : 4 has the most stable structure. Toluene (TL) and ethylene glycol dimethacrylate (EGDMA) were chosen as the optimal solvent and cross-linking agent, respectively. Five hydrogen bonds formed in the self-assembly system are the key forces at the adsorption sites of MIPs through the RDG and AIM analyses. The MIPs were synthesized by theoretical predictions, and the results showed that the maximum adsorption capacity towards dulcoside A is 26.17 mg/g. This work provided a theoretical direction and experimental validation for deeper researches of the MIPs for steviol glycosides. In addition, the method of RDG theory coupled with AIM and IR also could be used to analyze other imprinting formation mechanisms systematically.

Insights into the Reactive and Deactivation Mechanisms of Manganese Oxides for Ozone Elimination: The Roles of Surface Oxygen Species.

Manganese oxides with varied Mn valance states but identical morphologies were synthesized via a facile thermal treatment of γ-MnOOH. Also, their catalytic performance on ozone decomposition was investigated following the order of Mn3O4 < Mn2O3 < MnO2 < MnO2-H-200. In combination with X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), H2-temperature-programmed reduction (TPR), O2-temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS) characterization, it was deduced that the superior O3 decomposition capacity for MnO2-H-200 was strongly associated with abundant oxygen vacancies on its surface. Among Mn3O4, Mn2O3, and MnO2, the difference in O3 decomposition efficiency was dependent on the divergent nature of oxygen vacancy. Density functional theory (DFT) calculation revealed that Mn3O4 and MnO2 possessed lower formation energy of oxygen vacancy, while MnO2 had the minimum desorption energy of peroxide species (O2*). It was deduced that the promotion of the O3 decomposition capability was attributed to the easier O2* desorption. Insights into the deactivation mechanism for MnO2-H-200 further validated the assumptions. As the reaction proceeded, adsorbed oxygen species accumulated on the catalyst surface, and a portion of them were transformed to lattice oxygen. The consumption of oxygen vacancy led to the deactivation of the catalyst.

Clinical significance of phenotyping and karyotyping of detecting circulating tumor cells in renal cell carcinoma using subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH).

BACKGROUND AND OBJECTIVES: Circulating tumor cells (CTCs) as a noninvasive detection technology have become a research hotspot in the field of precision medicine. However, CTC detection faces great challenges with respect to specificity and sensitivity. METHODS: We divided 39 subjects into three groups: renal carcinoma, renal stones and healthy persons. Using subtraction enrichment (SE) combined with immunostaining-fluorescence in situ hybridization technology, we identified and characterized CTCs. CTCs were identified as DAPI +/CD45-/PanCK + (-). We explored whether the number of CTCs was related to clinicopathological factors and their clinical application. RESULTS: The CTC count in the renal carcinoma group (29/39) was 86.20% using a cut-off value of 1 CTC, which was significantly higher than that of other technologies in detecting CTCs, demonstrating that SE-iFISH technology can be used for CTC detection. The CTC count was much higher in the renal carcinoma group than that in the other control groups, with an area under the ROC curve of 0.931 (95% confidence interval 0.851 to 1.000, P < 0.01). In addition, the tetraploid count on chromosome 8 of T4 stage renal carcinoma was much higher than that of other stages (T1-T3), which may suggest that tetraploid count could be a marker of renal carcinoma prognosis and influence treatment decisions for better clinical management. CONCLUSIONS: Our study showed that SE-iFISH technology can be used to detect CTCs in renal carcinoma with high sensitivity and specificity. Therefore, the analysis of CTCs with SE-iFISH has clear potential to improve the management of patients with renal carcinoma.

Glutamine Deprivation Induces PD-L1 Expression via Activation of EGFR/ERK/c-Jun Signaling in Renal Cancer.

The programmed death-ligand 1/programmed death-1 (PD-L1/PD-1) pathway plays a pivotal role in the immune escape of tumors. Many tumor cells show "glutamine dependence." However, the relationship between glutamine metabolism and PD-L1 expression has not been reported. In this study, changes in PD-L1 expression in renal carcinoma cells were evaluated during glutamine deprivation and recovery. Although PD-L1 expression differed in two renal cancer cell lines, both cell lines upregulated PD-L1 during glutamine deprivation, and the upregulated PD-L1 was restored to normal after glutamine recovery. Mechanistically, glutamine deprivation resulted in activation of EGFR signaling via ERKs 1 and 2 (ERK1/2) and c-Jun. In addition, treatment of renal cancer cells with EGF also induced PD-L1 expression and ERK1/2 phosphorylation. Finally, inhibitors of EGFR, ERK, and c-Jun all inhibited phosphorylation of c-Jun and downregulated PD-L1 expression induced by glutamine deprivation. Taken together, the data suggest that glutamine regulates the expression of PD-L1 through the EGFR/ERK/c-Jun pathway in renal cancer. IMPLICATIONS: This study reveals glutamine deprivation induces PD-L1 expression via activation of EGFR/ERK/c-Jun signaling in renal cancer and provides novel markers for the treatment of renal cancer.

Eleven novel SLC12A1 variants and an exonic mutation cause exon skipping in Bartter syndrome type I.

INTRODUCTION: Bartter syndrome type I (BS1) has been rarely reported in large groups. On the other hand, the phenomenon of exon skipping, in which exonic mutations result in abnormal splicing, has been reported to be associated with various diseases. Specifically, mutations that result in the disruption of exonic splicing enhancers (ESEs) and/or the creation of exonic splicing silencers (ESSs) can promote exon skipping. However, the aberrant exon skipping caused by an exonic variant in such splicing regulatory elements (SREs) sequences has never been reported in the causal gene of SLC12A1 in BS1. METHODS: We analyze the variants in nine Chinese families with BS1, including eight with antenatal BS (aBS) and one presenting as classical BS (cBS), by next-generation sequencing. Then we used bioinformatics programs to analyze all these variants found in this study and identify candidate mutations that may induce exon skipping. Furthermore, the effects of identified variants were classified according to the 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines. RESULTS: Fifteen different variants of SLC12A1 gene were identified, including 11 novel ones. Two of the nine probands were homozygotes, the rest seven ones were compound heterozygotes. One candidate variant (c.1435C>G), not only significantly reduced ESEs scores but also markedly increased ESSs scores, were further investigated by mini-gene splicing assay, and found this single-nucleotide substitution causes abnormal splicing in vitro (exclusion of exon 11). Finally, among 15 variants, 9, 3, and 3 were classified as "pathogenic variants", "likely pathogenic variants", "variants with uncertain significance", respectively. CONCLUSION: These data would enrich the human gene mutation database (HGMD) and would provide valuable references to the genetic counseling and diagnosis of BS1 for Chinese population. Additionally, our results suggest that aberrant exon skipping is one previously unrecognized mechanism by which an exonic variant in SLC12A1 can lead to BS1.

Tuned Fabrication of the Aligned and Opened CNT Membrane with Exceptionally High Permeability and Selectivity for Bioalcohol Recovery.

Synthetic membranes usually suffer from a ubiquitous trade-off between permeability and selectivity. Carbon nanotube (CNT)-based hybrid materials have shown attractive properties in high-performance membrane preparation; however, the aggregation of random CNTs in polymer remains a great challenge. Herein, the aligned and open-ended CNT/(polydimethylsiloxane) PDMS membranes are controllably fabricated to form a hamburger-like structure that possesses nanochannels (∼10 nm) in the intermediate layer as well as angstrom cavities in the embedded PDMS. These aligned CNT membranes surpass the filling content limitation of the nonaligned CNT/PDMS membrane (37.4 wt % versus ∼10 wt %), leading to excellent mechanical properties and a multiplying performance increase of mass flux and selectivity for the separation of alcohols. The membranes break the permeability-selectivity trade-off with both parameters remarkably increasing (maximum 9 times) for bioalcohol separation. The established pervaporative-ultrafiltration mechanism indicates that the penetrant molecules preferentially pass through CNT internal nanochannels with increasing membrane permeability, thereby paving a way to nanoscale design of highly efficient channeled membranes for separation application.

Synthesis, Crystal Structure, UV-Vis Adsorption Properties, Photoelectric Behavior, and DFT Computational Study of All-Inorganic and Lead-Free Copper Halide Salt K2Cu2Cl6.

In this study, all-inorganic copper halide salt K2Cu2Cl6 single-crystal and thin films were prepared. The single-crystal diffraction data belonged to the monoclinic K2Cu2Cl6 (space group = P 2(1)/C, unit cell parameters of a = 4.0340 Å, b = 13.7987 Å, c = 8.7445 Å, α = 90.000, ß = 97.123, and γ = 90.000). As far as we know, this is the first study of the copper halide salt K2Cu2Cl6 for optoelectronic applications. The band gap of K2Cu2Cl6 is calculated to be approximately 1.85 eV. A low-cost photodetector based on the K2Cu2Cl6 thin film was efficient under different monochromatic light from 330 to 390 nm with different chopping frequencies (1.33-30 Hz). Density functional theory (DFT) computational results indicate that the valence bands (VBs) and conduction bands (CBs) are shifted up in energy using the orbital-dependent correction to the DFT energy. Partial density of states reveals that the VBs and narrow CBs are derived from the hybrid orbitals of Cu2+ 3d and Cl- p, respectively.

DFT studies on the palladium-catalyzed dearomatization reaction between naphthalene allyl chloride and allyltributylstannane.

The Pd-catalyzed dearomatization of naphthalene allyl chloride with allyltributylstannane has been investigated using density functional theory (DFT) calculations at the B3LYP level. The calculations indicate that the (ŋ(1)-allyl)(ŋ(3)-allyl)Pd(PH3) complex is responsible for the formation of ortho-dearomatized product. Moreover it is easy to produce the ortho-dearomatized product when reductive elimination starts from (ŋ(3)-allylnaphthalene)(ŋ(1)-allyl)Pd complex 7, while it is easy to form the para-dearomatized product when reductive elimination starts from (ŋ(3)-allylnaphthalene)(ŋ(1)-allyl)Pd complex 9. The Stille coupling products can't be produced due to high reaction energy barrier. Graphical Abstract Two mechanisms of dearomatization are investigated by DFT, and (ŋ(1)-allyl)(ŋ(3)-allyl)Pd(PH3) complexes are the main intermediates for ortho-dearomatized product.

Framework stability and Brønsted acidity of isomorphously substituted interlayer-expanded zeolite COE-4: a density functional theory study.

COE-4 zeolites possess a unique two-dimensional ten-ring pore structure with the Si(OH)2 hydroxyl groups attached to the linker position between the ferrierite-type layers, which has been demonstrated through the interlayer-expansion approach in our previous work (H. Gies et al. Chem. Mater. 2012, 24, 1536). Herein, density functional theory is used to study the framework stability and Brønsted acidity of the zeolite T-COE-4, in which the tetravalent Si is isomorphously substituted by a trivalent Fe, B, Ga, or Al heteroatom at the linker position. The influences of substitution energy and equilibrium geometry parameters on the stability of T-COE-4 are investigated in detail. The relative acid strength of the linker position is revealed by the proton affinity, charge analysis, and NH3 adsorption. It is found that the range of the ⟨T-O-Si⟩ angles is widened to maintain the stability of isomorphously substituted T-COE-4 zeolites. The smaller the ⟨O1-T-O2⟩ bond angle is, the more difficult is to form the regular tetrahedral unit. Thus, the substitution energies at the linker positions increase in the following sequence: Al-COE-4 < Ga-COE-4 < Fe-COE-4 < B-COE-4. The adsorption of NH3 as a probe molecule indicates that the acidity can affect the hydrogen-bonding interaction between (N-H⋅⋅⋅O2) and (N⋅⋅⋅H-O2). The relative Brønsted-acid strength of the interlayer-expanded T-COE-4 zeolite decreases in the order of Al-COE-4 > Ga-COE-4 > Fe-COE-4 > B-COE-4. These findings may be helpful for the structural design and functional modification of interlayer-expanded zeolites.

TDDFT study on intramolecular hydrogen bond of photoexcited methyl salicylate.

The equilibrium geometries, IR-spectra and transition mechanism of intramolecular hydrogen-bonded methyl salicylate in excited state were studied using DFT and TDDFT with 6-31++G (d, p) basis set. The length of hydrogen bond OH⋯OC is decreased from 1.73 Å in the ground state to 1.41 and 1.69 Å in the excited S1 and S3 states. The increase of bond length for HO and CO group also indicates that in excited state the hydrogen bond OH⋯OC is strengthened. IR spectra show HO and CO stretching bands are strongly redshifted by 1387 and 67 cm(-1) in the excited S1 and S3 states comparing to the ground state. The excitation energy and the absorption spectrum show the S3 state is the main excited state of the low-lying excited states. By analyzing the frontier molecular orbitals, the transition from the ground state to the excited S1 and S3 states was predicted to be the π→π∗ mode.

The dynamic motion of a M (M = Ca, Yb) atom inside the C74 (D3h) cage: a relativistic DFT study.

The interaction between M (M = Ca, Yb) atom and C74 (D 3h) has been investigated by all electron relativistic density function theory. With the aid of the representative patch of C74 (D 3h), we studied the interaction between C74 (D 3h) and M (M = Ca, Yb) atom and obtained the interaction potential. Optimized structures show that there are three equivalent stable isomers and there is one transition state between every two stable isomers. According to the minimum energy pathway, the possible movement trajectory of M (M = Ca, Yb) atom in the C74 (D 3h) cage is explored. The calculated energy barrier for Yb atoms moving from the stable isomer to the transition state is 10.4 kcal mol(-1) and the energy barrier for Ca atoms is 6.1 kcal mol(-1). The calculated NMR spectra of M@C74 (M = Ca, Yb) are in good agreement with the experimental data. There are nine lines in the spectra: one 1/6 intensity signal, four half intensity signals and four full intensity signals.

Thin porous alumina sheets as supports for stabilizing gold nanoparticles.

Thin porous alumina sheets have been synthesized using a lysine-assisted hydrothermal approach resulting in an extraordinary catalyst support that can stabilize Au nanoparticles at annealing temperatures up to 900 °C. Remarkably, the unique architecture of such an alumina with thin sheets (average thickness ~15 nm and length 680 nm) and rough surface is beneficial to prevent gold nanoparticles from sintering. HRTEM observations clearly showed that the epitaxial growth between Au nanoparticles and alumina support was due to strong interfacial interactions, further explaining the high sinter-stability of the obtained Au/Al2O3 catalyst. Consequently, despite calcination at 700 °C, the catalyst maintains its gold nanoparticles of size predominantly 2 ± 0.8 nm. Surprisingly, catalyst annealed at 900 °C retained the highly dispersed small gold nanoparticles. It was also observed that a few gold particles (6-25 nm) were encapsulated by an alumina layer (thickness less than 1 nm) to minimize the surface energy, revealing a surface restructuring of the gold/support interface. As a typical and size-dependent reaction, CO oxidation is used to evaluate the performance of Au/Al2O3 catalysts. The results obtained demonstrated Au/Al2O3 catalyst calcined at 700 °C exhibited excellent activity with a complete CO conversion at ∼30 °C (T100% = 30 °C), and even after calcination at 900 °C, the catalyst still achieved its T50% at 158 °C. In sharp contrast, Au catalyst prepared using conventional alumina support shows almost no activity under the same preparation and catalytic test conditions.

Dynamic motion of La atom inside the C74 (D3h) cage: a relativistic DFT study.

The interaction between lanthanum atom (La) and C74 (D 3h) was investigated by all-electron relativistic density function theory (DFT). With the aid of the representative patch of C74 (D 3h), we studied the interaction between C74 (D 3h) and La and obtained the interaction potential. Optimized structures show that there are three equivalent stable isomers, with La located about 1.7 Å off center. There is one transition state between every two stable isomers. According to the minimum energy pathway, the possible movement trajectory of La atoms in the C74 (D 3h) cage was explored. The calculated energy barrier for La atoms moving from the stable isomer to the transition state is 18.4 kcal mol(-1). In addition, the dynamic NMR spectra of La@C74 according to the trajectory was calculated.

C(3i)-symmetric octanuclear cadmium cages: double-anion-templated synthesis, formation mechanism, and properties.

A series of C(3i)-symmetric bicapped trigonal antiprismatic Cd(8) cages [2X@Cd(8)L(6)(H(2)O)(6)]⋅n Y⋅solvents (X = Cl(-), Y = NO(3)(-), n = 2: MOCC-4; X = Br(-), Y = NO(3)(-), n = 2: MOCC-5; X = NO(3)(-), Y = NO(3)(-), n = 2: MOCC-6; X = NO(3)(-), Y = BF(4)(-), n = 2: MOCC-7; X = NO(3)(-), Y = ClO(4)(-), n = 2: MOCC-8; X = CO(3)(2-), n = 0: MOCC-9), doubly anion templated by different anions, were solvothermally synthesized by means of a flexible ligand. Interestingly, the CO(3)(2-) template for MOCC-9 was generated in situ by two-step decomposition of DMF solvent. For other MOCCs, spherical or trigonal monovalent anions could also play the role of template in their formation. The template abilities of these anions in the formation of the cages were experimentally studied and are discussed for the first time. Anion exchange of MOCC-8 was carried out and showed anion-size selectivity. All of the cage-like compounds emit strong luminescence at room temperature.

The maximum number of carbonyl groups around an Ru6C polyhedral cluster: hexanuclear ruthenium carbonyl carbides.

Octahedral, trigonal prismatic, and capped square pyramidal structures have been optimized for the Ru(6)C(CO)(n) clusters (15 ≤ n ≤ 20) using density functional theory. The experimentally known very stable Ru(6)C(CO)(17) is predicted to have an octahedral structure in accord with experiment as well as the Wade-Mingos rules. The stability of Ru(6)C(CO)(17) is indicated by its high carbonyl dissociation energy of ~37 kcal mol(-1) and the high energy of ~33 kcal mol(-1) required for disproportionation into Ru(6)C(CO)(18) + Ru(6)C(CO)(16). Theoretical calculations predict a doubly carbonyl bridged octahedral Ru(6)C(CO)(17) structure to be ~0.7 kcal mol(-1) more stable than the experimentally observed singly bridged structure. A trigonal prismatic Ru(6)C(CO)(19) cluster isoelectronic with the known Co(6)C(CO)(15)(2-) dianion does not appear to be viable as indicated by a low carbonyl dissociation energy of 8.8 kcal mol(-1) and a required energy of only 4.9 kcal mol(-1) for disproportionation into Ru(6)C(CO)(20) + Ru(6)C(CO)(18). The predicted instability of Ru(6)C(CO)(n) (n ≥ 18) derivatives suggests a maximum of 17 external carbonyl groups around a stable polyhedral Ru(6)C structure.

Structural evolution of medium-sized Pd(n) (n=15-25) clusters from density functional theory.

Four types of possible structural motifs of the medium-sized Pd(n) (n=15-25) clusters i.e., fcc like, decahedron based, icosahedron based, and prolate ellipsoid based, have been generated from an empirical genetic algorithm search and further investigated using spin-polarized density functional theory calculations. fcc-like structures based on Pd(19) octahedron dominate the growth pathway of Pd(n) clusters (n=15-23). For larger clusters such as Pd(24) and Pd(25), a prolate ellipsoid-based geometry and a structure consisting of three interpenetrating decahedra are energetically favorable, respectively. The size-dependent cluster properties as well as the correlation between electronic properties and cluster geometry are also discussed, suggesting a particular stability cluster at Pd(19) with a fcc-like octahedron structure.

Competition among fcc-like, double-layered flat, tubular cage, and close-packed structural motifs for medium-sized Au n (n = 21-28) clusters.

Using density functional theory calculations, we compared four kinds of possible structural motifs of the medium-sized Aun (n = 21-28) clusters, i.e., fcc-like, double-layered flat, tubular cage, and close-packed. Our results show strong competition between those structural motifs in the medium-sized gold clusters. Aun (n = 21-23) adopt fcc-like structure owing to the high stability of tetrahedral Au20. A structural transition from fcc-like to tubular occurs at Au24, and the tubular motif continues at Au27 and Au28. Meanwhile, a double-layered flat structure was found at Au25, and a pyramid-based structure at Au26. The relationship between electronic properties and cluster geometry was also discussed.