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Understanding the fundamental catalytic principles when the catalytic centre is confined in nanoscale space that is dimensionally comparable to the reactant molecule is crucial for designing high-performance catalysts. Theoretical studies with simplified model systems and ensemble experimental measurements have shown that chemical reactions in nanoconfined environments are largely different from those in bulk solution. Here, we design a well-defined platform with catalytic centres confined in the end of nanopores with controlled lengths to study the in situ dynamic behaviour of catalytic processes under nanoconfinement at the single-molecule and single-particle level. Variable single molecular mass transport behaviour reveals the heterogeneity of the confined environment in the nanopores. With the capability of decoupling mass transport factors from reaction kinetics in the well-defined platform, we quantitatively uncovered a confinement-induced enhancement in the activity of platinum nanoparticles inside the nanopores. The combination of the unique model catalyst and the single-molecule super-localization imaging technique paves the way to understanding nanoconfinement effects in catalysis. Nanoconfinement effects are crucial in any process that involves porous materials. Here, the authors present a nanoporous catalyst platform that enables these effects to be studied in situ at the single-molecule and single-particle level with turnover resolution.

The establishment of structure–property relationships in heterogeneous catalysis is of prime importance but remains a formidable challenge. Metal–organic frameworks (MOFs) featuring excellent chemical tunability are emerging as an auspicious platform for the atomic-level control of heterogeneous catalysis. Herein, we encapsulate palladium nanoparticles (Pd NPs) in a series of isoreticular mixed-linker MOFs, and the obtained MOF-Pd NPs catalysts were used to unveil the electronic and steric effects of linker substitution on the activity of these catalysts in the Suzuki–Miyaura cross-coupling reactions. Significantly, m-6,6′-Me2bpy-MOF-Pd exhibits a remarkable enhancement in the activity compared to non-functionalized m-bpy-MOF-Pd and m-4,4′-Me2bpy-MOF-Pd. This study unambiguously demonstrates that the stereoelectronic properties of linker units are crucial to the catalytic activity of nanoparticles encapsulated in MOFs. More interestingly, the trend of activity change is consistent with our previous work on catalytic sites generated in situ from Pd(II) coordinated in MOFs bearing the same functional groups, which suggests that both MOF-Pd NPs and MOF-Pd(II) catalysts generate similar active centers during Suzuki–Miyaura coupling reactions. This work paves a new avenue to the fabrication of advanced and tunable MOF-based catalysts through rational linker engineering. We encapsulate palladium nanoparticles in a series of isoreticular mixed-linker MOFs, and the obtained Pd-doped MOFs catalysts were used to unveil the electronic and steric effects of linker substitution on the activity of these catalysts in the context of Suzuki–Miyaura cross-coupling reactions. Impressively, m-6,6′-Me2bpy-MOF-Pd exhibits a remarkable enhancement in the activity compared to non-functionalized m-bpy-MOF-Pd and m-4,4′-Me2bpy-MOF-Pd, thus implementing atomic-level controls of heterogeneous catalysis.

The outbreak of cyanobacterial blooms has posed a huge threat to drinking water safety and the natural water environment. Among the harmful cyanobacterial bloom types, Microcystis aeruginosa is a force to be recognized with. The purpose of this work was to develop an efficient and eco-friendly technology to curb harmful cyanobacteria blooms and purify bodies of water from polluting algal organic matter. A novel and efficient electrochemical system with a graphite felt (GF) anode and Pt cathode was proposed to treat water containing M. aeruginosa, and its performance and mechanism were investigated. Without chemical consumption, the GF-Pt system with a pH widely ranging from three to nine can inactivate approximately 90% of algal cells in a short time. The ideal GF-Pt system for the removal of algal cells and Microcystin-LR operated under a pH of 7 at 75 mA, achieving removal efficiencies of 94 ± 2% and 50%, respectively. The removal mechanism was determined to be the continuous direct discharging of the anodes, with superior electro-adsorption being the key to anodization efficiency enhancement. After only flushing and drying the GF anodes before reuse, the GF-Pt system was able to maintain an algal cell removal efficiency of 83% after 10 cycles.

Clinically nonfunctioning pituitary adenomas (NFAs) range from those causing significant hypothalamic/pituitary dysfunction and visual field compromise due to their large size to those being completely asymptomatic. In the absence of hypersecretion, hypopituitarism or visual field defects, patients with NFAs may be followed by periodic surveillance using MRI to detect tumor enlargement. In some cases, endocrine tests are also needed during observation to discover new pituitary dysfunction. Enlargement of NFAs without treatment occurs in about 10% of microadenomas and 23% of macroadenomas. Growth of a pituitary incidentaloma, the development of visual field defects or the development of hypopituitarism are potential indications for surgery during follow up.

A metal catalyst supported on an inert substrate could consist of both metal nanoparticles and singly dispersed metal atoms. Whether these singly dispersed metal atoms are active and how different their catalytic mechanism could be in contrast to a supported metal catalyst are fundamentally important for understanding catalysis on a supported metal or oxide. By taking reduction of NO with CO on singly dispersed Rh atoms anchored on an inert support SiO2 as a probe system (Rh1/SiO2), here we demonstrated how singly dispersed metal atoms on an inert support could perform a complex multi-step catalytic cycle through a mechanism distinctly different from that for a supported metal nanoparticle with continuously packed metal sites. These singly dispersed Rh1 atoms anchored on SiO2 are active in reducing nitric oxide with carbon monoxide through two reaction pathways that are different from those of Rh nanoparticles. In situ IR studies show that a CO molecule and a NO molecule coadsorb on a singly dispersed Rh ...

Bridging the structure-properties relationship of bimetallic catalysts is essential for the rational design of heterogeneous catalysts. Different from random alloys, intermetallic compounds (IMCs) present atomically-ordered structures, which is advantageous for catalytic mechanism studies. We used Pt-based intermetallic nanoparticles (iNPs), individually encapsulated in mesoporous silica shells, as catalysts for the hydrogenation of nitroarenes to functionalized anilines. With the capping-free nature and ordered atomic structure, PtSn iNPs show >99% selectivity to hydrogenate the nitro group of 3-nitrostyrene albeit with a lower activity, in contrast to Pt3Sn iNPs and Pt NPs. The geometric structure of PtSn iNPs in eliminating Pt threefold sites hampers the adsorption/dissociation of molecular H2 and leads to a non-Horiuti-Polanyi hydrogenation pathway, while Pt3Sn and Pt surfaces are saturated by atomic H. Calculations using density functional theory (DFT) suggest a preferential adsorption of the nitro group on the intermetallic PtSn surface contributing to its high selectivity.

Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal-organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2 ) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2 , Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2 . Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2 ). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.

We demonstrate that dynamic nuclear polarization (DNP)-enhanced 1H-X heteronuclear correlation (HETCOR) measurements of hydrogen-rich surface species are better accomplished by using proton-free solvents. This approach notably prevents HETCOR spectra from being obfuscated by the solvent-derived signals otherwise present in DNP measurements. Additionally, in the hydrogen-rich materials studied here, which included functionalized mesoporous silica nanoparticles and metal organic frameworks, the use of proton-free solvents afforded higher sensitivity gains than the commonly used solvents containing protons. We also explored the possibility of using a solvent-free sample formulation and the feasibility of indirect detection in DNP-enhanced HETCOR experiments.

Circulation patterns associated with cold events over East Asia during the winter months of 1948–2014 are classified into four regimes by applying a k-means clustering method based on the area-weighted pattern correlation. The earliest precursor signals for two regimes are anticyclonic anomalies, which evolve into Ural and central Siberian blocking-like circulation patterns. The earliest precursor signals for the other two regimes are cyclonic anomalies, both of which evolve to amplify the East Asian trough (EAT). Both the blocking-like circulation patterns and amplified EAT favor the initialization of cold events. On average, the blocking-related regimes tend to last longer. The lead time of the earliest precursor signal for the central Siberian blocking-related regime is only 4 days, while those for the other regimes range from 16 to 18 days. The North Atlantic Oscillation plays essential roles both in triggering the precursor for the Ural blocking-related regime and in amplifying the precursors for all regimes. All regimes preferentially occur during the positive phase of the Eurasian teleconnection pattern and the negative phase of the El Nino–Southern Oscillation. For three regimes, surface cooling is primarily due to reduced downward infrared radiation and enhanced cold advection. For the remaining regime, which is associated with the southernmost cooling center, sensible and latent heat release and horizontal cold advection dominate the East Asian cooling.

To examine the combined effects of the different spatial patterns of the Arctic Oscillation (AO) related sea level pressure (SLP) anomalies and the El Nino/Southern Oscillation (ENSO) related sea surface temperature (SST) anomalies on the wintertime surface temperature anomalies over East Asia, a nonlinear method based on self-organizing maps is employed. Investigation of identified regimes reveals that the AO can affect East Asian temperature anomalies when there are significant SLP anomalies over the Arctic Ocean and northern parts of Eurasian continent. Analogously, ENSO is found to affect East Asian temperature anomalies when significant SST anomalies are present over the tropical central Pacific. The regimes with the warmest and coldest temperature anomalies over East Asia are both associated with the negative phase of the AO. The ENSO-activated, Pacific-East Asian teleconnection pattern could affect the higher latitude continental regions when the impact of the AO is âĂŸswitched offâĂŹ. When the spatial patterns of the AO and ENSO have significant, but opposite, impacts on the coastal winds, no obvious temperature anomalies can be observed over South China. Further, the circulation state with nearly the same AO and Nino3 indices may drive rather different responses in surface temperature over East Asia. The well-known continuous weakening (recovery) of the East Asian winter monsoon that occurred around 1988 (2009) can be attributed to the transitions of the spatial patterns of the SLP anomalies over the Arctic Ocean and Eurasian continent, through their modulation on the occurrences of the Ural and central Siberian blocking events.

A novel full-field initialization strategy based on the dimension-reduced projection four-dimensional variational data assimilation (DRP-4DVar) is proposed to alleviate the well-known initial shock occurring in the early years of decadal predictions. It generates consistent initial conditions, which best fit the monthly mean oceanic analysis data along the coupled model trajectory in 1 month windows. Three indices to measure the initial shock intensity are also proposed. Results indicate that this method does reduce the initial shock in decadal predictions by Flexible Global Ocean-Atmosphere-Land System model, Grid-point version 2 (FGOALS-g2) compared with the three-dimensional variational data assimilation-based nudging full-field initialization for the same model and is comparable to or even better than the different initialization strategies for other fifth phase of the Coupled Model Intercomparison Project (CMIP5) models. Better hindcasts of global mean surface air temperature anomalies can be obtained than in other FGOALS-g2 experiments. Due to the good model response to external forcing and the reduction of initial shock, higher decadal prediction skill is achieved than in other CMIP5 models.

Compositing graphene oxide (GrO) as a robust support into MIL-53(Cr) can provide a feasible strategy to stabilize its flexible structure from CO2-triggered shrinkage, resulting in an enhanced CO2 uptake together with a higher CO2/CH4 adsorptive selectivity of the GrO@MIL-53(Cr) composites for biomethane upgrade. In this work, a series of novel GrO@MIL-53(Cr) composites were prepared from GrO and MIL-53(Cr). Their adsorptive performance for CO2/CH4 separation was experimentally investigated. IAST was applied to predict their adsorptive selectivity for CO2/CH4 separation. Results show that a small amount of GrO doping (1%) could significantly improve surface area and pore volume of the resulting 1GrO@MIL-53(Cr), while a remarkably enhanced CO2 uptake was observed with sufficient GrO doping (10%) for 10GrO@MIL-53(Cr) at 5 bar and room temperature, which is 62% higher than that of its parental MIL-53(Cr). XRD indicates a quenched “breathing effect” could be responsible for the remarkably enhanced CO2 uptake. With this quenched breathing effect, 10GrO@MIL-53(Cr) shows a 16 times higher CO2/CH4 selectivity at 5 bar for the equimolar CO2/CH4 mixture. SEM and TEM show well-defined compositing structures, while IR, Raman and TG suggest GrO@MIL-53(Cr) composites manage to preserve most of the crystallographic and chemical characteristics of their parent MIL-53(Cr).

It has been previously demonstrated that 1,25(OH)2D3 prevents the progression of epithelial to mesenchymal transition (EMT). However, it remains unclear whether 1,25(OH)2D3 has a role in peritoneal EMT stimulated by high glucose (HG) peritoneal dialysis fluid (PDF). The present study was performed to investigate the role of 1,25(OH)2D3 in the progression of EMT in the peritoneal mesothelium. A total of 35 male Kunming mice were randomly assigned into seven groups. In the control group, no diasylate or saline was infused. In the saline group, the mice were intraperitoneally injected with saline every day for 4 weeks. In the vitamin D group, the mice were subjected to intraperitoneal injections of 1 or 5 µg/kg of 1,25(OH)2D3 once weekly (every Monday) for 4 weeks. The peritoneal dialysis (PD) group were intraperitoneally injected with a conventional 4.25% PDF daily for 4 weeks. The vitamin D+PD group were intraperitoneally injected with 4.25% PDF daily and co‑treated with 1 µg/kg or 5 µg/kg 1,25(OH)2D3 once weekly, for 4 weeks. The peritoneal morphology and thickness were assessed by hematoxylin and eosin and Masson's trichrome staining. The peritoneal protein level of EMT markers (α‑smooth muscle actin, fibronectin and E‑cadherin), vitamin D receptor (VDR), B cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated X protein, transforming growth factor (TGF)‑β and Smad3 were evaluated by western blot analysis or immunohistochemical staining. Furthermore, apoptosis was assessed using a Caspase‑3 activity assay. The results demonstrated that after 4 weeks of intraperitoneal injections in mice, HG‑PDF decreased the expression of VDR, promoted EMT and apoptosis, and increased the thickness of the peritoneal membrane. However, 1,25(OH)2D3 treatment attenuated HG‑induced EMT and apoptosis, and decreased peritoneal thickness, which may partially occur through inhibition of transforming growth factor TGF‑β/Smad pathways via 1,25(OH)2D3 binding to VDR. The present study demonstrated that 1,25(OH)2D3 attenuated HG‑induced EMT and apoptosis in the peritoneal mesothelium through TGF‑β/Smad pathways. 1,25(OH)2D3 treatment in conjunction with HG dialysate may provide an improved solution to the peritoneal injury in the process of PD.

The co-occurrence of wintertime temperature anomalies over eastern Asia and eastern North America is examined. The winter days during 1948–2014 are assigned to nine regimes by applying the Self-Organizing Map clustering method to the area-averaged land surface temperature anomalies over these two regions. About half of the winter days are associated with concurrent temperature anomalies. The occurrence of the concurrent/non-concurrent regimes is closely related to the large-scale circulation conditions. The Eurasian teleconnection pattern and the Pacific-North American teleconnection pattern are two dominant large-scale circulation modes associated with the co-occurrence of the temperature anomalies, through their impacts on the intensities of the corresponding troughs. The precursor analysis reveals that the lead time of the early signals for the concurrent cold anomalies is about four days longer than that for the concurrent warm anomalies. In addition, the average lead time of the precursor signals for the wintertime temperature anomalies over eastern Asia is longer than that is over eastern North America.

International audience; In this research, magnetite and ethylenediamine-N,N'-disuccinic acid (EDDS) are used in a heterogeneous photo-Fenton system in order to find a new way to remove organic contaminants from water. Influence of different parameters including magnetite dosage, EDDS concentration, H2O2 concentration, and pH value were evaluated. The effect of different radical species including HO(·) and HO2(·)/O2(·-) was investigated by addition of different scavengers into the system. The addition of EDDS improved the heterogeneous photo-Fenton degradation of bisphenol A (BPA) through the formation of photochemically efficient Fe-EDDS complex. This effect is dependent on the H2O2 and EDDS concentrations and pH value. The high performance observed at pH 6.2 could be explained by the ability of O2(·-) to generate Fe(II) from Fe(III) species reduction. GC-MS analysis suggested that the cleavage of the two benzene rings is the first degradation step followed by oxidation leading to the formation of the benzene derivatives. Then, the benzene ring was opened due to the attack of HO(·) radicals producing short-chain organic compounds of low molecular weight like glycerol and ethylene glycol. These findings regarding the capability of EDDS/magnetite system to promote heterogeneous photo-Fenton oxidation have important practical implications for water treatment technologies.

Nine potential vorticity (PV) regimes over East Asia are identified by applying a Self-Organizing Map and Hierarchical Ascendant Classification regime analysis to the daily PV reanalysis fields on the 300K isentropic surface for December-March 1948–2014. According to the surface temperature anomalies over East Asia, these nine regimes are further classified into three classes, i.e., cold class (three regimes), warm class (four regimes), and neutral class (two regimes). The PV-based East Asian winter monsoon index (EAWMI) is used to study the relationship between PV distributions and the temperature anomalies. The magnitude of cold (warm) anomalies over the land areas of East Asia increases (decreases) quasi-linearly with the EAWMI. Regression analysis reveals that cold temperature anomalies preferentially occur when the EAWMI exceeds a threshold at ∼0.2PVU (where 1PVU≡10−6 m2 Kkg−1 s−1). PV inversion uncovers the mechanisms behind the relationships between the PV regimes and surface temperature anomalies, and reveals that cold (warm) PV regimes are associated with significant warming (cooling) in the upper troposphere and lower stratosphere. On average, cold regimes have longer durations than warm regimes. Interclass transition probabilities are much higher for paths from warm/neutral regimes to cold regimes than for paths from cold regimes to warm/neutral regimes. Besides, intraclass transitions are rare within the warm or neutral regimes. The PV regime analysis provides insight into the causes of severe cold spells over East Asia, with blocking circulation patterns identified as the primary factor in initiating and maintaining these cold spells.

Wind forcing is one of the most important sources for the oceanic energy cycle and is especially critical to the heat budget of surface mixed layer. The sensitivity of heat budget in the equatorial Atlantic cold tongue (EACT) region (5°S–5°N, 25°W–5°E) to wind forcing and the related mechanism are explored in this study. Based on the experiments forced by different wind forcing from both reanalysis and idealized datasets, it is revealed that the contribution ratio for each of the dominant physical processes in the heat budget is insensitive (the variations within 1% of the mean) to the variations in the local winds (the largest variation is about 20% of the mean) over the EACT region. Therefore, a ‘self-adjustment’ mechanism exists in the mixed-layer heat budget: as local zonal winds over the EACT region strengthen (weaken), both the cooling effects of turbulent mixing and the combined warming effects of surface net heat flux and zonal advection simultaneously increase (decrease) by nearly the same percentage and thus their contribution ratios are kept constant. Finally, owing to the impact of meridional winds on each term of heat budget can be neglected, the above mechanism is also tenable under the situation when the localmore » meridional winds change.« less

NiFe-layered double hydroxide (LDH) is thought of as a promising bifunctional water-splitting catalyst, owing to its excellent performances for alkaline oxygen evolution reactions (OERs). However, it shows extremely poor activity toward hydrogen evolution reactions (HERs) due to the weak hydrogen adsorption. We demonstrated that the integration of Rh species and NiFe-LDH can dramatically improve its HER kinetics without sacrificing the OER performance. The Rh species were initially integrated into NiFe-LDH as oxidized dopants and metallic clusters (< 1 nm). In 1 M KOH electrolyte, an overpotential of 58 mV is needed to catalyze 10 mA cm-2 HER current density. Furthermore, this catalyst only requires 1.46 V to drive an electrolyzer at 10 mA cm-2. A strong interaction between metallic Rh clusters and NiFe hydroxide during the HER process is revealed. The theoretical calculation shows the Rh ions replace Fe ions as the major active sites that are responsible for OERs.

Hexagonal boron nitride nanosheets (h-BNNS), the isoelectric analog to graphene, have received much attention over the past decade due to their high thermal oxidative resistance, high bandgap, catalytic activity and low cost. The molecular functional groups that terminate boron and nitrogen zigzag and/or armchair edges directly affect their chemical, physical and electronic properties. However, an understanding of the exact molecular edge termination present in h-BNNS is lacking. Here, high-resolution magic-angle spinning (MAS) solid-state NMR (SSNMR) spectroscopy and plane-wave density-functional theory (DFT) calculations are used to determine the exact molecular edge termination in exfoliated h-BNNS. 1H→11B cross-polarization MAS (CPMAS) SSNMR spectra of h-BNNS revealed multiple hydroxyl/oxygen coordinate boron edge sites that were not detectable in direct excitation experiments. A dynamic nuclear polarization (DNP)-enhanced 1H→15N CPMAS spectrum of h-BNNS displayed four distinct 15N resonances while a 2D 1H{14N} dipolar-HMQC spectrum revealed three distinct 14N environments. Plane-wave DFT calculations were used to construct model edge structures and predict the corresponding 11B, 14N and 15N SSNMR spectra. Comparison of the experimental and predicted SSNMR spectra confirms that zigzag and armchair edges with both amine and boron hydroxide/oxide termination are present. The detailed characterization of h-BNNS molecular edge termination will provide usefulness for many material science applications and the techniques outlined here should be applicable to comprehensively understand the molecular edge terminations in other 2D materials.

Pituitary adenomas are common. The impact of pituitary tumors on fertility are mainly caused by oversecretion and/or undersecretion of pituitary hormones or compression of pituitary stalk and normal pituitary tissue by the tumor. Diagnosing and managing pituitary tumors during pregnancy involve many challenges, including the effect of hormone excess or deficiency on pregnancy outcome, changes in the pituitary or pituitary-related hormones, changes in tumor size, and the impact of various treatments of pituitary tumors on maternal and fetal outcomes. This article discusses the diagnosis and treatment of patients with prolactinomas, acromegaly, Cushing disease, and other pituitary tumors during pregnancy.

The design of efficient catalysts capable of delivering high currents at low overpotentials for hydrogen evolution reactions (HERs) is urgently needed to use catalysts in practical applications. Herein, we report platinum (Pt) alloyed with titanium (Ti) from the surface of Ti

The outstanding catalytic activity and chemical selectivity of intermetallic compounds make them excellent candidates for heterogeneous catalysis. However, the kinetics of their formation at the nanoscale is poorly understood or characterized, and precise control of their size, shape and composition during synthesis remains challenging. Here, using well-defined Pt nanoparticles (5 nm and 14 nm) encapsulated in mesoporous silica, we study the transformation kinetics from monometallic Pt to intermetallic PtSn at different temperatures by a series of time-evolution X-ray diffraction studies. Observations indicate an initial transformation stage mediated by Pt surface-controlled intermixing kinetics, followed by a second stage with distinct transformation kinetics corresponding to a Ginstling–Brounstein (G–B) type bulk diffusion mode. Moreover, the activation barrier for both surface intermixing and diffusion stages is obtained through the development of appropriate kinetic models for the analysis of experimental data. Our density-functional-theory (DFT) calculations provide further insights into the atomistic-level processes and associated energetics underlying surface-controlled intermixing.

Prolactin (PRL) levels are elevated in chronic kidney disease (CKD) due to reduced clearance and increased secretion. Hyperprolactinemia manifests as galactorrhea and hypogonadism. Treatment of hyperprolactinemia should focus on improving bothersome galactorrhea or hypogonadism by using dopamine agonists and replacement of sex hormone(s). Changes in the hypothalamic-pituitary-adrenal (HPA) axis in CKD are characterized by increases in adrenocorticotropic hormone (ACTH) and sometimes cortisol levels, largely preserved circadian rhythms of ACTH and cortisol, and a normal response of cortisol to ACTH, metyrapone, and insulin-induced hypoglycemia. However, the HPA axis is less inhibited by 1 mg of dexamethasone but retains normal suppression by higher-dose dexamethasone. Diagnosis of adrenal insufficiency in CKD patients, as in normal subjects, is usually made by finding a subnormal cortisol response to ACTH. The mainstay of treatment of adrenal insufficiency is to replace glucocorticoid hormone. Cushing’s disease in CKD is difficult to diagnose and relies on the dexamethasone suppression test and the midnight salivary cortisol test since 24-h urine-free cortisol test is not useful. Treatment of Cushing’s disease involves surgery, complemented by radiation and/or medical therapy if necessary. In CKD, arginine vasopressin (AVP) levels are elevated due to decreased clearance, and there is also impairment of AVP signaling in renal tubules. Diabetes insipidus can be masked in advanced kidney disease until kidney transplantation. Diagnosis of syndrome of inappropriate antidiuretic hormone is similar in mild or moderate kidney disease as in normal subjects but is challenging in those with advanced kidney disease owing to the impairment in urine dilution.

This paper describes the creation of mesoporous inorganic films based on the plasma processing of ligand-capped nanocrystals. We use nanorods of HfO2 as a model system and report an extensive chara...

Quantitative GC-MS analysis was performed on 138 oils from the cratonic regions of the Tarim Basin, northwestern China. Crossplots of (1) biomarker concentrations versus maturity ratios, (2) diamondoid concentrations versus sterane concentrations, (3) ratios of (Pr + Ph)/(n-C17+n-C18), and (4) Σn-C15–35/Σn-C9–14, were constructed and compared with oil densities, GOR and gas dryness. The results clearly show oil mixing resulting from a very complex charging history. At least four oil/gas charging episodes can be identified. One episode is represented by oils which have relatively high biomarker concentrations with maturity ratios suggesting an early to middle oil window source. There is second charge resulting in intermediate to low biomarker concentrations in many of the oils indicating a charge generated in the mid-to late-oil window. The third charge can be seen in oils in which biomarkers are absent indicating that they were sourced at late oil to wet gas levels of thermal maturity. Finally, the fourth charge is indicated by the high diamondoid concentrations in virtually every oil in this study. This charge was generated from very deeply buried source rocks at dry gas levels of thermal maturity where extensive oil to gas cracking has taken place. The fact that the oils show varying concentrations of biomarkers from low to high and yet similar low-maturity biomarker ratios suggests oil mixing to various extents, in which the biomarkers are predominantly derived from the least mature source, but they are differentially diluted by higher-maturity liquids poor in biomarkers. Furthermore, the deep charge represented by the high diamondoids concentrations is present in virtually every sample. Our results suggest that the oils in this study are all mixtures containing varying percentages of components derived from these four charges.

BACKGROUND: Skip metastasis is a common lymph node metastatic pattern in non-small cell lung cancer (NSCLC). The relationship between skip metastasis and specific clinicopathologic factors and the prognostic value of skip metastasis are controversial. METHODS: A systematic search and analysis of skip metastasis in NSCLC was conducted in the databases of PubMed, EMBASE, and Web of Science up to Dec 2019. Summarized hazard ratio (HR), mean difference (MD), and odds ratio (OR) with associated 95% confidence intervals (CI) were evaluated to investigating the relationship between skip metastasis and overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) and clinicopathological features in NSCLC. RESULTS: 29 studies with a total of 1,806 skip and 4,670 non-skip N2 patients were included. The upper lobe tumor showed a higher rate of skip metastasis compared with lower lobe one (RR =1.16, 95% CI: 1.00–1.34, P=0.044, I(2)=39.8%). The presence of skip metastasis correlated with superior overall survival (HR =0.74, 95% CI: 0.66–0.83, P

The present work reports the nanocrystalline Beta zeolites synthesis from the high concentration hydrogels and their behavior in the propionic acid esterification with cyclohexanol and in the ketonic decarboxylation of propionic acid. The solids were characterized by X-ray diffraction, N2-adsorption, transmission and scanning electron microscopy, diffuse reflectance infrared spectroscopy. Three types of acid sites has been evidenced in Beta zeolites: external silanol groups (Si–OH) (with weakly acidity), Si–OH–Al groups (with strong Bronsted acidity) and silanol nests associated with the defect sites (with Lewis acidity). In the propionic acid esterification with cyclohexanol, the highest cyclohexyl propionate yield was obtained over the sample with the highest specific surface area, the highest mesopore volume and the highest Bronsted acidity. In the propionic acid ketonic decarboxylation, the catalyst with the lowest ratio Bronsted acid sites/Lewis acid sites showed the highest activity and selectivity towards 3-pentanone compared to the other two which are more selective towards propanol.

This paper describes a study of the treatment of 2,4-dichlorophenol (2,4-DCP) with an ethylenediamine-N,N&rsquo, disuccinic-acid (EDDS)-modified photo-Fenton system in ultrapure water and different natural waters. The results showed that the EDDS-modified photo-Fenton system is adequate for 2,4-DCP degradation. Compared with a medium containing a single organic pollutant, the removal of pollutants in a more complex medium consisting of two organic compounds is slower by around 25 to 50% as a function of the organic pollutant. Moreover, 2,4-DCP can be further effectively degraded in the presence of organic materials and various inorganic ions. However, the photodegradation of 2,4-DCP in different natural waters, including natural lake water, effluent from domestic sewage treatment plants, and secondary effluent from pulp and paper mill wastewaters, is inhibited. Chemical compounds present in natural waters have different influences on the degradation of 2,4-DCP by adopting the EDDS-modified photo-Fenton system. In any case, the results obtained in this work show that the EDDS-modified photo-Fenton system can effectively degrade pollutants in a natural water body, which makes it a promising technology for treating pollutants in natural water bodies.

A collection pipeline is designed to connect the divertor with the cooling and the baking systems in HL-2M. The ConFlat flange 25 used as the connecter in the pipeline is one of the feasible schemes. According to the requirements of the leak rate, the helium leak detector is used to research on the vacuum sealing performance of the flanges with the heating rate of 35 °C/h, 50 °C/h, 65 °C/h, 80 °C/h and 95 °C/h. The results show whatever the heating rate is, the leak rate increases as the temperature rises. When the temperature rises from 250 °C to 350 °C, the leak rate increases very rapidly. Moreover, the faster the temperature rises, the greater the fluctuation of the leak rate is. And the influence of helium pressure in the pipeline on the leak rate is very small. When the initial torque applied on the bolts is10 N m, the maximum leak rate is 7 × 10−10 Pa m3/s in the first heating process but is greater than 1.0 × 10−6 Pa m3/s in the second heating process which exceeds the acceptable leak rate of 1.0 × 10−9 Pa m3/s. So if we don't pre-tighten the bolts again in the heating cycles, the initial torque must be larger than 10 N m.

A novel dynamically based index that reflects the strength of the regional potential vorticity (PV) intrusion on the 300 K isentropic surface is proposed as a reliable measure of East Asian winter monsoon (EAWM) intensity. The index captures essential aspects of the EAWM, including its climatic influences on East Asia, its continuous weakening trend since the 1980s, and its close relationships with the Siberian high, Arctic Oscillation, and El Nino. The use of a potential vorticity framework enables the definition of a new metric called continuous PV intrusion duration (CPVID), which can be used to monitor and explain wintertime weather extremes like the extreme snowfall event that occurred in south China during January 2008. The CPVID of March is comparable to that of December, indicating that data from this month should be included in estimates of the strength of the EAWM.

A series of mixed-linker bipyridyl metal–organic framework (MOF)-supported palladium(II) catalysts were used to elucidate the electronic and steric effects of linker substitution on the activity of these catalysts in the context of Suzuki–Miyaura cross-coupling reactions. m-6,6′-Me2bpy-MOF-PdCl2 exhibited 110- and 496-fold enhancements in activity compared to nonfunctionalized m-bpy-MOF-PdCl2 and m-4,4′-Me2bpy-MOF-PdCl2, respectively. This result clearly demonstrates that the stereoelectronic properties of metal-binding linker units are critical to the activity of single-site organometallic catalysts in MOFs and highlights the importance of linker engineering in the design and development of efficient MOF catalysts.

NaAu2, in powder form, is known to be an active catalyst for CO oxidation. The goal of the present study is to elucidate the interaction of one reactant, molecular oxygen, with a single-crystal surface of this material, NaAu2(111). Exposing the clean surface to gas-phase molecular oxygen produces three types of oxygen on the surface. One type is bound in spurious carbonate that forms during exposure. The second is adsorbed atomic oxygen that interacts both with Na and Au. The third type is atomic oxygen that interacts mainly or only with Na. We propose that the last species is an oxide of Na distributed throughout the surface and near-surface region. Its formation is accompanied by surface segregation of Na.

An interfacial etching approach was developed for the synthesis of monodisperse and ultrasmall thiolated palladium nanoclusters (Pd NCs) using Zr-UiO-66-NH2 metal–organic frameworks (MOFs) as sacrificial templates. The Pd NCs were originally synthesized inside the cavities of the MOFs (Pd@UiO-66-NH2). The Pd NCs released from the MOFs have a strikingly small size with narrow distribution (1.1±0.1 nm), amounting to a cluster size of ca. 40 Pd atoms. The 1H NMR spectrum indicates that thiol is the only capping agent for these Pd NCs. We derived the composition of the thiolated Pd NCs using thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Moreover, the Pd NCs size can be tuned by using MOF templates with different cavity sizes. The thiolated Pd NCs are catalytically active in a model Suzuki–Miyaura coupling reaction.

Ultrawideline dynamic nuclear polarization (DNP)-enhanced (195)Pt solid-state NMR (SSNMR) spectroscopy and theoretical calculations are used to determine the coordination of atomic Pt species supported within the pores of metal-organic frameworks (MOFs). The (195)Pt SSNMR spectra, with breadths reaching 10 000 ppm, were obtained by combining DNP with broadbanded cross-polarization and CPMG acquisition. Although the DNP enhancements in static samples are lower than those typically observed under magic-angle spinning conditions, the presented measurements would be very challenging using the conventional SSNMR methods. The DNP-enhanced ultrawideline NMR spectra served to separate signals from cis- and trans-coordinated atomic Pt(2+) species supported on the UiO-66-NH2 MOF. Additionally, the data revealed a dominance of kinetic effects in the formation of Pt(2+) complexes and the thermodynamic effects in their reduction to nanoparticles. A single cis-coordinated Pt(2+) complex was confirmed in MOF-253.

Metal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. A series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Zeta potential analysis, UV–Vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA–IR), and nitrogen physisorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. Lastly, these results could contribute to the preparation of metal/oxide hybrid NPs for the applicationsmore » that require uniform dispersion.« less

Control of heterogeneous catalytic sites through their surrounding chemical environment at an atomic level is crucial to catalyst design. We synthesize Pd nanoclusters (NCs) in an atomically tunable chemical environment using isoreticular metal–organic framework (MOF) supports (Pd@UiO-66-X, X = H, NH2, OMe). In an aerobic reaction between benzaldehyde and ethylene glycol, these catalysts show product distributions that are completely altered from the acetal to the ester when we change the functional groups on the MOF linkers from −NH2 to −H/–OMe. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies, along with density functional theory (DFT) calculations, show that the coordination of the −NH2 groups to the Pd NCs could weaken their oxidation capability to a greater extent in comparison to that of the −OMe group. Moreover, the limited number of −NH2 groups per cavity in the MOF change the electronic properties of the Pd NCs while still leaving open sites for catalysis.

Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO2) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO2-encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO2. Among the intermetallic NPs, PtSn@mSiO2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used in Pt@mSiO2 for similar activity and near 100% selectivity to furfuryl alcohol. A high-temperature oxidation–reduction treatment easily reverses any carbon deposition-induced catalyst deactivation. X-ray photoelectron spectroscopy shows the importance of surface composition to the activity, whereas density functional theor...

Photocatalytic decomposition of a typical emerging pollutant perfluorooctanoic acid (PFOA) in aqueous solution by using noble metallic nanoparticles modified TiO 2 (M–TiO 2 , M = Pt, Pd, Ag) were investigated. The M–TiO 2 photocatalysts were obtained by chemical reduction method and were characterized by field emission scanning electron microscope with energy dispersive spectrometer, transmission electron microscopy, X-ray diffractometer system and UV–vis diffuse reflectance spectroscopy. Compared with pure TiO 2 , M–TiO 2 exhibited higher activities for PFOA decomposition. The rate constants of pseudo-first-order kinetics for Pt, Pd, Ag modified TiO 2 were 0.7267, 0.4369 and 0.1257 h −1 , which were 12.5, 7.5 and 2.2 times higher than that for TiO 2 respectively. Shorter chain perfluorinated carboxylic acids were identified as main products. The great photo-activities of M–TiO 2 were attributed to the noble metal nanoparticles, acting as electron sinks to store the excess electrons in conduction band when the holes in valence band were utilized in PFOA decomposition. Noble metal with larger work function such as Pt and Pd were more effective to capture the electrons, thereby Pt–TiO 2 and Pd–TiO 2 showed higher photo-activities.

We report palladium(II)-functionalized MOF-253 (MOF-253-Pd(OAc)2) as a recyclable catalyst to form all-carbon quaternary centers via conjugate additions of arylboronic acids to β,β-disubstituted enones in aqueous media. We demonstrate MOF-253-Pd(OAc)2 can be reused 8 times to form ketone products in yields above 75% while maintaining its crystallinity. Additions of a range of stereoelectronically diverse arylboronic acids to a variety of β,β-disubstituted enones catalyzed by MOF-253-Pd(OAc)2 occur in modest-to-high yields (34–95%).

Titanium dioxide is one of the most potential photocatalysts in the area of industrial advanced oxidation. Because TiO2 only responses to ultraviolet, modified TiO2 was widely studied to expand its utilization under solar irradiation. Photocatalytic degradation efficiency depends on two critical factors: the bandgap width of photocatalyst and the concentration of surface Ti3+. Herein, hydrogenated TiO2, fluorine-doped TiO2 and hydrogenated fluorine-doped TiO2 were synthesized and characterized. The effects of various modifications on photocatalysis under solar irradiation were studied. It was revealed that hydrogenation improved the solar-irradiated degradation by simultaneously modified the bandgap of TiO2 to a visible-light-favored width and created more Ti3+ sites. The degradation by photocatalysis was not always enhanced by nonmetal doping. The F doping process would also reduce the amount of Ti3+ and further impede the formation of O2–.

HL-2M device is a new tokamak under construction. The baking temperature of the vacuum vessel and its in-vessel components is approximately 300 °C. The vacuum coupling radius seals (VCR) which are employed as the in-vessel sealing joints of the cooling circuits for HL-2M divertor are also as the vacuum boundary, their leak rate must be less than 10−9 Pa m3/s. To ensure the VCR sealing performance, the leak tightness tests on VCR are performed. This paper presents the effects of the gaskets material, the heating rate and the torque on the sealing performance of VCR. The results show that the 316L stainless steel as the gaskets materials of VCR gets the best performance for HL-2M divertor in operation. And the slower the heating rate is, the better the leak tightness is. The torque for VCR is at least 200 N m to satisfy its sealability during HL-2M divertor operation, especially baking.