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In this work, a chiral core-shell microspheres composite, L-his-MIL-53-NH2@SiO2, was prepared through in situ growth and chiral post-modification strategies. The core-shell microspheres were applied as a novel chiral stationary phase for HPLC enantiomeric separation. Various racemates were separated on the L-his-MIL-53-NH2@SiO2 packed column using n-hexane/isopropanol as the mobile phase. The chiral column showed excellent separation efficiency for fourteen chiral compounds, including alcohols, alkanes, esters, phenols, ketones, and organic acids. The influence of injection mass and temperature on the separation performance of the chiral column were investigated. The relative standard deviations (n = 5) of the retention time and peak area by repeated separation of benzoin are 0.28% and 0.63%, respectively. The results show that the L-his-MIL-53-NH2@SiO2 packed column exhibited good reproducibility and stability. In addition, the chiral resolution ability of the L-his-MIL-53-NH2@SiO2 packed column was compared with that of a commercial chiral column (Chiralpak AD-H). The L-his-MIL-53-NH2@SiO2 packed column exhibits unique advantages in chiral separations that can be complementary to the commercial chiral column. It was demonstrated that the chiral core-shell microspheres composite L-his-MIL-53-NH2@SiO2 prepared based on in situ growth and chiral postmodification strategies has great potential for enantiomeric separation by HPLC. [ABSTRACT FROM AUTHOR]

Both Down syndrome (DS) individuals and animal models exhibit hypo‐cellularity in hippocampus and neocortex indicated by enhanced neuronal death and compromised neurogenesis. Ubiquitin‐specific peptidase 25 (USP25), a human chromosome 21 (HSA21) gene, encodes for a deubiquitinating enzyme overexpressed in DS patients. Dysregulation of USP25 has been associated with Alzheimer's phenotypes in DS, but its role in defective neurogenesis in DS has not been defined. In this study, we found that USP25 upregulation impaired cell cycle regulation during embryonic neurogenesis and cortical development. Overexpression of USP25 in hippocampus promoted the neural stem cells to glial cell fates and suppressed neuronal cell fate by altering the balance between cyclin D1 and cyclin D2, thus reducing neurogenesis in the hippocampus. USP25‐Tg mice showed increased anxiety/depression‐like behaviors and learning and memory deficits. These results suggested that USP25 overexpression resulted in defective neurogenesis and cognitive impairments, which could contribute to the pathogenesis of DS. USP25 may be a potential pharmaceutical target for DS. [ABSTRACT FROM AUTHOR]

To strengthen the understanding of the clinical features for CASPR2 neurological autoimmunity in children. A multicenter retrospective and prospective analysis of CASPR2 autoimmunity was conducted. Twenty-six patients were enrolled, including 25 with serum positivity and 3 with cerebrospinal fluid (CSF) positivity; 5 patients were co-positive with anti-NMDAR or anti-GABABR antibodies. Eleven patients (who manifested with refractory epilepsy, psychobehavioral abnormalities or germinoma) presented with low antibody titers, relatively normal MRI/EEG/CSF examinations, and poor response to immunotherapy and were thus considered false positive (42.3%). Fifteen patients were diagnosed with autoimmune encephalitis/ encephalopathy/ cerebellitis (including 1 whose condition was secondary to Japanese encephalitis). The most common symptoms included disorders of consciousness (10/15), fever (8/15), psychological symptoms/abnormal behaviors (8/15), sleep disorders (8/15), seizures (7/15), movement disorders (5/15), autonomic symptoms (5/15). Brain MRI revealed abnormalities in 10 patients (66.7%). Electroencephalography (EEG) recordings revealed a slow wave background in 13 patients (86.7%). Five patients showed elevated WBCs in CSF, and 4 patients showed elevated protein levels in the CSF. Thirteen patients received immunotherapy (rituximab was adopted in 2 cases) and recovered well. Two patients received symptomatic treatment, and the recovery was slow and accompanied by emotional abnormalities and developmental delay. Autoimmune encephalitis is the most common clinical phenotype; it can be secondary to Japanese encephalitis. Rituximab can be used in patients who respond poorly to conventional immunotherapy. The high false-positive rate of anti-CASPR2 in refractory epilepsy and the psychobehavioral abnormalities needs to be explored further. [ABSTRACT FROM AUTHOR]

This study was designed to assess the clinical efficiency and long-term outcomes of hepatic vein (HV) and accessory hepatic vein (AHV) recanalization in patients with HV-type Budd-Chiari syndrome (BCS). A total of 27 patients with HV-type BCS underwent AHV recanalization and 94 patients had HV recanalization at our center from January 2012 to December 2019. The treatment effectiveness and long-term outcomes were compared. Technical success was accomplished in all patients, without any procedure-related complications. The clinical success rates were 96.3% (26/27) and 95.7% (90/94) (p = 1.000). In the AHV and HV groups, re-obstruction was observed in 5 and 36 patients, respectively (p = 0.056). The median primary durations of AHV and HV patency were 64 and 49 months, respectively (p = 0.036), while the median secondary durations of AHV and HV patency were 70 and 64 months, respectively (p = 0.134). The median overall survival after AHV and HV recanalization was 73 and 78 months, respectively (p = 0.263). Our findings suggest that AHV could be employed as a replacement for HV, as a hepatic drainage vein, in HV-type BCS patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: To analyze early changes in white blood cells (WBCs), C-reactive protein (CRP) and procalcitonin (PCT) in children with multiple trauma, before secondary inflammation develops. METHODS: This single-center retrospective study collected data from patients with blunt traumatic injury admitted to the pediatric intensive care unit (PICU). According to the prognostic outcome of 28 d after admission to the PICU, patients were divided into survival group (n=141) and non-survival group (n=36). Characteristics between the two groups were compared. Receiver operation characteristic (ROC) curve analysis was conducted to evaluate the capacity of different biomarkers as predictors of mortality. RESULTS: The percentages of children with elevated WBC, CRP, and PCT levels were 81.36%, 31.07%, and 95.48%, respectively. Patients in the non-survival group presented a statistically significantly higher injury severity score (ISS) than those in the survival group: 37.17±16.11 vs. 22.23±11.24 (t=6.47, P<0.01). WBCs were also higher in non-survival group than in the survival group ([18.70±8.42]×109/L vs. [15.89±6.98] ×109/L, t=2.065, P=0.040). There was no significant difference between the survival and non-survival groups in PCT or CRP. The areas under the ROC curves of PCT, WBC and ISS for predicting 28-day mortality were 0.548 (P=0.376), 0.607 (P=0.047) and 0.799 (P<0.01), respectively. CONCLUSIONS: Secondary to multiple trauma, PCT levels increased in more patients, even if their WBC and CRP levels remained unchanged. However, early rising WBC and ISS were superior to PCT at predicting the mortality of multiple trauma patients in the PICU. [ABSTRACT FROM AUTHOR]

We update the Standard Model (SM) predictions for the branching ratios of the rare top-quark decays t → c g (g) , and evaluate the maximum rates that can be reached in the aligned as well as in the four conventional two-Higgs-doublet models (2HDMs) with Z 2 symmetries. Taking into account the relevant constraints on the model parameters resulting from a global fit obtained at the 95.5 % confidence level, we find that the branching ratios of t → c g and t → c g g decays can reach up to 3.36 × 10 - 9 and 2.95 × 10 - 9 respectively, being therefore of the same order, in the aligned 2HDM (A2HDM). This is obviously different from the SM case, where the predicted branching ratio of the three-body decay t → c g g is about two orders of magnitude larger than that of the two-body decay t → c g . On the other hand, compared with the SM predictions, no significant enhancements are observed in the four conventional 2HDMs with Z 2 symmetries for the branching ratios of these two decays. Nevertheless, the predicted branching ratios of t → c g and t → c g g decays in the A2HDM are still out of the expected sensitivities of the future high-luminosity Large Hadron Collider and the Future Circular Collider in hadron-hadron mode. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel chiral core–shell composite [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 was prepared by an in-situ growth method. • The [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 -packed exhibited excellent resolution ability towards various racemates. • Positional isomers were well separated on the [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 -packed column. Chiral metal–organic frameworks, an emerging type of chiral porous materials, possess many outstanding characteristics such as high surface area, tunable pore sizes, and good chemical stability. Herein, we prepared a chiral [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 core–shell composite on the SiO 2 -NH 2 microspheres by an in-situ growth method. The prepared [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 -packed column exhibited high-resolution separation of racemic compounds and positional isomers at a low column backpressure (9–12 bar). Twelve pairs of enantiomers including alcohols, amines, epoxides, ketones, and esters were well resolved with sharp peak shapes on the [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 chromatographic column. Compared the separation performance of [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 -packed column and two chromatographic columns (commercial Chiralpak AD-H column and as-prepared SiO 2 -NH 2 column), the [Zn 2 (D-Cam) 2 (4,4′-bpy)] n -packed column and the commercial Chiralpak AD-H column have a good complementarity in chiral separation, and it also offered better separation performance compared to the SiO 2 -NH 2 column for separating positional isomers. The effects of column temperature and analyte mass on the HPLC separation were investigated. Additionally, the [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 packed column has good repeatability and stability for HPLC separation of enantiomers and positional isomers. The relatvive standard deviations (RSDs) for repeated separations of 2,2,2-trifluoro-1-(9-anthryl)ethanol and o , m , p -bromoaniline were less than 0.8 % and 1.2 % for the retention time and peak area, respectively. After continuous use for one month, the RSDs for the retention time and peak area of them were in the range of 1.1–1.3 % and 1.5–1.8 % (inter-day and intra-day, n = 5), respectively. This work also indicates that the chiral MOFs@SiO 2 composites are promising for HPLC separation. [ABSTRACT FROM AUTHOR]

With updated experimental data and improved theoretical calculations, several significant deviations are being observed between the Standard Model predictions and the experimental measurements of the branching ratios of B ¯ s 0 → D s ∗ + L − decays, where L is a light meson from the set {π, ρ, K(∗)}. Especially for the two channels B ¯ 0 → D + K − and B ¯ s 0 → D s + π − , both of which are free of the weak annihilation contribution, the deviations observed can even reach 4–5σ. Here we exploit possible new-physics effects in these class-I non-leptonic B-meson decays within the framework of QCD factorization. Firstly, we perform a model-independent analysis of the effects from twenty linearly independent four-quark operators that can contribute, either directly or through operator mixing, to the quark-level b → c u ¯ d s transitions. It is found that, under the combined constraints from the current experimental data, the deviations observed could be well explained at the 1σ level by the new-physics four-quark operators with γμ(1 − γ5) ⨂ γμ(1 − γ5) structure, and also at the 2σ level by the operators with (1 + γ5) ⨂ (1 − γ5) and (1 + γ5) ⨂ (1 + γ5) structures. However, the new-physics four-quark operators with other Dirac structures fail to provide a consistent interpretation, even at the 2σ level. Then, as two specific examples of model-dependent considerations, we discuss the case where the new-physics four-quark operators are generated by either a colorless charged gauge boson or a colorless charged scalar, with their masses fixed both at the 1 TeV. Constraints on the effective coefficients describing the couplings of these mediators to the relevant quarks are obtained by fitting to the current experimental data. [ABSTRACT FROM AUTHOR]

Pore structure characteristics are significant factor in the evaluation of the physical characteristics of low-rank coal. In this study, three low-rank coal samples were collected from the Xishanyao Formation, Santanghu Basin, and low-temperature liquid-nitrogen adsorption (LP-N2A) measurements were taken under various pretreatment temperatures. Owing to the continuous loss of water and volatile matter in low-rank coal, the total pore volume assumes a three-step profile with knee temperatures of 150 °C and 240 °C. However, the ash in the coal can protect the coal skeleton. Pore collapse mainly occurs for mesopores with aperture smaller than 20 nm. Mesopores with apertures smaller than 5 nm exhibit a continuous decrease in pore volume, whereas the pore volume of mesopores with apertures ranging from 5 to 10 nm increases at lower pretreatment temperatures (<150 °C) followed by a faint decrease. As for mesopores with apertures larger than 10 nm, the pore volume increases significantly when the pretreatment temperature reaches 300 °C. The pore structure of low-rank coal features a significant heating effect, the pretreatment temperature should not exceed 150 °C when the LP-N2A is used to evaluate the pore structure of low-rank coal to effectively evaluate the reservoir characteristics of low-rank coal. [ABSTRACT FROM AUTHOR]

• A newly improved scheme called AUSM+M is devised. • It reconstructs pressure diffusion term and velocity diffusion term. • It attains stronger shock robustness and better low-speed accuracy. • A series of test cases show its potential application to all Mach number flows. With the increasing popularity of Computational Fluid Dynamics (CFD), the reliability of numerical scheme becomes prominent. The work presents a newly improved scheme more reliable in all Mach number regimes to circumvent some typical symptoms of the previous AUSM-family schemes observed in hypersonic and very low speeds. This scheme is facilitated by reconstructing pressure diffusion term in mass flux, velocity diffusion term in pressure flux and numerical sound speed. Then, a variety of benchmark test cases are selected to systematically assess the effects of these key ingredients and investigate the additional features in terms of robustness and accuracy. The proposed scheme attains stronger shock robustness against carbuncle instability, better low-speed accuracy and higher resolution of oblique shocks compared with many existing upwind schemes. Moreover, it can exactly resolve contact discontinuity, preserve positivity, damp numerical overshoots and avert the global cut-off strategy. Numerical results for a wide spectrum of Mach numbers indicate its potential and reliable application to all Mach number flows. [ABSTRACT FROM AUTHOR]

Parallel pipeline detection is a difficult problem in underground pipeline detection. Gravity and magnetic surveys have the advantages of convenient monitoring, high sensitivity, and high accuracy. Therefore, we used gravity and magnetic surveys to detect parallel pipelines. In this paper, the effect of parallel pipeline parameters on the characteristics of gravity and magnetic surveys is studied in order to find out the quantitative relationships between them and to provide the theoretical basis for inversion interpretation. When calculating the magnetic anomaly of a pipeline, we considered the demagnetization effect of the pipeline and determined its demagnetization coefficient to be 0.12 by numerical calculation. Parallel pipeline parameters include geometric parameters (such as outer diameter ratio, pipe axis spacing, buried depth, and azimuth, etc.) and physical parameters (density and magnetic susceptibility). The characteristics of gravity and magnetic surveys include not only the amplitude of abnormal peaks, the number of abnormal peaks, and abnormal peak spacing of gravity and magnetic anomaly curves, but also the detection error of gravity and magnetic surveys in parallel pipelines. We defined the relative error of the pipe axis spacing of parallel pipelines as the detection error. We established a forward model for parallel pipeline detection and analyzed the effect of model parameters on the characteristics of gravity and magnetic surveys. Results show that gravity and magnetic surveys cannot detect pipelines parallel to the measurement line and the magnetic survey can only detect pipelines with ferromagnetism. The amplitude of abnormal peaks is affected by all parallel pipeline parameters, while the number of abnormal peaks, abnormal peak spacing, and detection error are only affected by the outer diameter ratio, pipe axis spacing and buried depth. If the upper limit of the detection error is determined to be 10%, gravity and magnetic surveys of parallel pipelines have minimum discernible pipe axis spacing. Through further research, it is found that when the outer diameter ratio is 1, the minimum discernible pipe axis spacing is minimal. The minimum discernible pipe axis spacing increases linearly with the increase of buried depth. When all parallel pipeline parameters are identical, the minimum discernible pipe axis spacing of the gravity survey is greater than that of the magnetic survey. The research results show that the magnetic survey is more suitable for detecting parallel underground pipelines than the gravity survey, and the experiment of magnetic anomaly measurement of parallel pipelines also shows that it is feasible to detect parallel underground pipelines by the magnetic survey. • A parallel pipeline is detected by gravity and magnetic surveys. • We considered the demagnetization effect of a pipeline. • The effect of parallel pipeline parameters on the characteristics of gravity and magnetic surveys is analyzed. [ABSTRACT FROM AUTHOR]

Purpose of review: To review the current status and ideal time interval of the combination therapy of transarterial chemoembolization (TACE) and local ablation for patients with HCCs. Recent findings: In recent years, local ablation has been proposed as an alternative curative treatment in the management of HCC. Additionally, many treatment options are available including TACE molecular targeted agents and immune checkpoint inhibitors. Similar overall survival rates and prognoses have been obtained with radiofrequency ablation (RFA) microwave ablation (MWA) and cryoablation for patients with HCCs up to 3 cm in diameter. Yet, MWA has shown superiority in treating large HCCs while cryoablation has several advantages compared with RFA or MWA. Furthermore, the treatment strategy of TACE combined with local ablation is widely accepted by many physicians in order to further increase the survival rate and improve the prognosis of patients with HCCs. However, the time interval between the two sessions of combination therapy remains uncertain in the current guidelines. Summary: Combination therapy of TACE and local ablation has advantages on survival and prognosis in patients with HCC compared with monotherapy. Good patient selection for the right modality needs to be carried out to guarantee the most efficacious treatment for HCC patients. Further studies are needed to find the ideal time interval between TACE and local ablation for HCC patients. [ABSTRACT FROM AUTHOR]

The species composition and resource status of wild edible and medicinal fungi in Ningxia Province were meticulously analyzed and systematically organized using available published data on higher fungi. This comprehensive investigation delved into the effectiveness of the dominant edible and medicinal mushrooms. The findings unequivocally demonstrated the abundant presence of wild edible and medicinal mushroom resources in Ningxia Province, encompassing a total of 204 species, spanning edible fungi, medicinal fungi, and edible and medicinal mushrooms. These belong to 10 genera, 8 families, and 3 orders, originating from 2 phyla. Among the 204 species, a substantial 176 are categorized as edible mushrooms, constituting an impressive 86.27% of the total species, while 28 species are recognized as medicinal fungi, contributing 13.73% of the overall species. Additionally, 36 species encompass the unique category of edible and medicinal fungi, accounting for 17.65% of the total species. Notably, 90 species are identified within Agaricus, Cortinarius, Tricholoma, Lactarius, Clitocybe, Coprinus, Gestrum, Suillus, Russula, Ramaria, Melanoluca, and Agrocybe, collectively representing 43.9% of the total species. The species within these dominant genera play a pivotal role in the realm of edible and medicinal mushrooms in Ningxia Province. Furthermore, an in-depth analysis of the functional components of these dominant genera unveiled the considerable potential for the utilization of wild edible and medicinal fungi distributed in Ningxia Province. These findings not only offer fundamental insights but also establish a robust foundation for the establishment of a comprehensive resource database of edible and medicinal fungi in Ningxia Province. Moreover, they serve as a crucial resource for researchers in their exploration of locally distinctive edible and medicinal mushrooms. [ABSTRACT FROM AUTHOR]

In August 2017, severe powdery mildew was observed on Potentilla indica in Minhe, Qinghai province, China. The identification of fungal species was performed by morphological study using an optical microscope and scanning electron microscope (SEM), supplemented by sequence analysis of the internal transcribed spacer (ITS) region of rDNA. Based on a combination of morphology, ITS sequence, and host, the powdery mildew on Potentilla indica was identified as Erysiphe thuemenii, a species belonging to the E. aquilegiae complex. This is the first report of E. thuemenii causing powdery mildew on a new host species, P. indica, in China and also worldwide. [ABSTRACT FROM AUTHOR]

The reaction mechanisms of dirhodium-catalyzed [3 + 2] and [3 + 3] cycloaddition between enol diazoacetate and isoquinolinium methylide have been studied in detail using density functional theory and a solution-phase translational entropy model. The reaction starts with the formation of a metallic carbene intermediate first, from which two competing reaction channels of [3 + 2] and [3 + 3] cycloaddition take place. For CAT1-catalyzed reactions, the calculated activation free energy barriers for [3 + 3] and [3 + 2] cycloaddition reactions are 14.3 and 16.0 kcal mol-1, respectively, which is in good agreement with the ratio of products. Both the steric and electronic effects have been considered for CAT2- and CAT3-catalyzed reactions, with which the ratio of products has also been rationalized. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed dehydrogenative homocoupling of two arenes provides a powerful and straightforward method for the synthesis of biaryls. In contrast to the Heck reaction for efficient cross-coupling of arene with alkene, dehydrogenative homocoupling of two arenes is not readily accessible through traditional PdII/0/II catalytic cycles, which limits its application to the construction of desired C-C bonds. Herein, we performed DFT studies to explore the detailed mechanisms of the PdII-catalyzed homocoupling of benzophenones in the presence of the strong oxidant K2S2O8. Calculation results demonstrated that the favorable reaction pathway is a PdII/IV/IIcatalytic cycle, including four sequential processes: C-H activation at the PdII center, oxidation of PdII to PdIV, C-H activation at the PdIV center, and reductive elimination. It was found that C-H activation at the PdIV center is the rate-determining process, with a free energy barrier of 26.0 kcal mol-1. The oxidant K2S2O8 plays an important role in converting PdII to PdIV and facilitating the second C-H activation step. In contrast, the alternative PdII/0/II pathway has been characterized as an inaccessible reaction channel from our calculations, because the second C-H activation is hindered by a free energy barrier of 38.9 kcal mol-1. In addition, the electronic effect of the spectator ligand on C-H activation has been investigated in terms of molecular orbital theory, which disclosed the origin of the critical role of PdIV intermediates in promoting the biaryl synthesis. [ABSTRACT FROM AUTHOR]

Objective: Exploring the correlation between bone turnover marks (BTMs) with lumbar BMD in middle-aged populations. Methods: The cross-sectional analysis fetched data came from NHANES. The level of serum bone alkaline phosphatase (sBAP) and urinary N-telopeptide (uNTx) were regarded as representative of bone turnover. Lumbar BMD was the outcome of the study. Multivariable linear regression models were utilized to detect the correlation of sBAP and uNTx with Lumbar BMD. Results: The level of sBAP and uNTx was negatively correlated with lumbar BMD in every multivariable linear regression. For sBAP, this inverse correlation was stable in both men and women (P < 0.01). uNTx indicated a negative association after all relevant covariables were adjusted (P < 0.01). The men group remained the negative correlation in gender subgroup analysis (P < 0.01). Conclusion: This study indicated that the increased level of sBAP and uNTx associated with lumbar BMD decreased among middle-aged adults. This correlation could prompt researchers to explore further the relationship between bone turnover rate and BMD, which may provide information for the early detection of BMD loss and provide a new strategy for clinical practice. [ABSTRACT FROM AUTHOR]

This paper presents a composite color-characterization model for Liquid Crystal Displays (LCDs), considering channel dependence and poor chromaticity constancy of primaries. The proposed model consists of two parts, that is, the Piecewise Linear assuming Variation in Chromaticity (PLVC) model and a partition compensation error model. PLVC model can accurately predict CIEXYZ for primaries and calculate the CIEXYZ of any digital input values ( d r, d g, d b) based on the channel independence assumption. In addition, the prediction error of PLVC model is compensated in RGB subspace using the partition compensation error model. The color difference Δ [ABSTRACT FROM AUTHOR]

With a burial depth of 1000 m as the demarcation, the coal reservoir in South Yanchuan Block, China is divided into deep reservoir and shallow reservoir regions. A combination of coalbed methane well production data, well logging interpretation, coalbed methane numerical simulations and reservoir properties were used to research various production characteristics at different depths. The results indicate that coal thickness and gas content are not key factors that influence methane production. The shallow reservoir is located in a tension zone, while the deep reservoir is located in both a transformation zone and a compression zone. Although the reservoir and closure pressures increase with the burial depth, the pressures fluctuate in the deep reservoir, especially in the transformation zone. This fluctuation influences the opened degree of the fractures in the reservoir. The effective stress is lower in the deep reservoir than in the shallow reservoir, leading to higher permeability in the deep reservoir. This difference in effective stress is the key factor that influences the methane production. The combination of coal thickness and gas content also significantly influenced the methane production. Influenced by the reservoir and closure pressures, the Type III coal in the shallow reservoir is more developed, while the deep reservoir contained more developed Type I and Type II coal. The permeability increases exponentially with increasing thickness of Type I and Type II coal, which determines the high reservoir permeability in the deep reservoir. The development of Type III coal leads to the poor reservoir hydraulic fracturing effect. However, a reservoir with thick Type I and Type II coal can have a positive effect. [ABSTRACT FROM AUTHOR]

A comprehensive DFT investigation has been performed for a series of the Pd(OAc)2-catalyzed C-H activations, updating and extending the understanding of directing group effect. In the beginning, the directed and undirected C-H activation mechanisms, based on 10 model reactions, have been discussed comparatively, which disclosed that directing group can exert a thermodynamic driving force, not necessarily a kinetic promotion, on the C-H activation process. Formation of the open palladation species via the undirected pathway is thermodynamically unspontaneous (ΔG = 4-9 kcal/mol), in sharp contrast to that of the cyclopalladation species via the directed pathway (ΔG < 0). Further calculations revealed that the free-energy barriers of proton-transfer are in fact not so high on the undirected pathway (17-24 kcal/mol), while mediation of some O-center groups in the directed pathway would increase the free-energy barriers of proton-transfer. For pyridine N-oxide systems, the undirected mechanism was estimated to be more plausible than the 4-member-directed one both thermodynamically and kinetically. In addition, the uncommon 7-membered cyclopalladation has been tentatively explored using two current examples, predicting that electron-rich directing groups can help to stabilize the 7-membered palladacycles formed. [ABSTRACT FROM AUTHOR]

Carbon nanodots (C-dots) are recently well examined due to the emissions with color-tuning and nonblinking properties, while more studies are still needed for the appropriate understanding and application of distinct emissions. In this work, we found the emission of chemiluminescence (CL) by introducing low-temperature plasma (LTP) into C-dots solutions without any reagent added, whose intensity was affected by the presence of different metal ions. Based on both experimental data and theoretical calculations, we found with the ozonation by ozone from LTP, excited oxidized-C-dots would be generated with the addition of ozone onto the conjugated double bonds of C-dots, and these excited species could directly initiate strong CL combining with the deactivation of excited species to the ground state. Significantly, the cross-reactive CL signals were obtained from different kinds of C-dots with the presence of different metal ions. Therefore, a new sensor array (electronic tongue) composed of five different C-dots was designed for fast discrimination of metal ions, which achieved the accurate discrimination of 13 kinds of metal ions in pure water and real samples. It exhibited good reproducibility and sensitivity, which can be used for the quantitative analysis of metal ions such as showing a linear range from 4 × 10-7 to 6 × 10-5 mol·L-1 (R² > 0.99) for Fe3+ with a detection limit of 2.5 × 10-7 mol·L-1. This work not only provides a novel finding of CL from C-dots revealing explicit relationship between structures and CL properties, but also realizes the fast discrimination of metal ions, showing potentials in environmental monitoring and quality identifications. [ABSTRACT FROM AUTHOR]

Metal-organic cages (MOCs), as a promising class of crystalline porous materials with well-defined cavities, have attracted wide attention due to their multifarious potential applications in gas storage, host-guest chemistry, molecular recognition, separation, catalysis, sensing, and drug delivery and so on. Herein, we report that a chiral MOC [Fe 4 L 6 ](ClO 4) 8 coated capillary column was fabricated for high-resolution gas chromatographic separation of various analytes, including n-alkanes, n-alcohols, positional isomers, aromatic hydrocarbon mixture, especially for racemic compounds. A series of racemic compounds such as alcohols, epoxides, aldehydes, ketones, ethers, esters, alkenes, sulfoxides and amino acid derivatives could be well separated on the [Fe 4 L 6 ](ClO 4) 8 coated capillary column with high enantioselectivity and good reproducibility. Comparing the chiral resolution ability of the MOC [Fe 4 L 6 ](ClO 4) 8 coated column with the commercial β-DEX 120 column and the porous organic cage (POC) CC10 coated column, the chiral MOC column can be complementary to the two different types of columns. The results show that the chiral MOC [Fe 4 L 6 ](ClO 4) 8 exhibited excellent separation performance toward a wide range of organic compounds, which will be very attractive as a new chiral separation media and has potential application prospects in separation science. [Display omitted] • A novel capillary column was fabricated using MOC as stationary phase for GC separations. • The column exhibited high enantioselectivity and excellent resolution ability for various racemates. • Positional isomers were also efficiently separated on the capillary column. [ABSTRACT FROM AUTHOR]

With the reduction of the working-age population and the increase of the population dependency ratio as the main indicators of the diminishing demographic dividend, China's potential growth rate is decreasing. Our results suggest that the demographic dividend contributed to nearly one fourth of the economic growth in China in the past three decades, while total factor productive growth explains another third and capital accumulation explaining the remaining growth (nearly half). China's potential growth rate will continue to slow-it was nearly 10 per cent during 1980-2010 but 6.65 per cent on average during 2016-2020-because of the diminishing demographic dividend, but reform measures are conductive to clearing the institutional barriers to the supply of factors and productivity, buffering the potential growth rate. The aggregate reform dividend could reach to 1-2 per cent on average during 2016-2050. [ABSTRACT FROM AUTHOR]

Plants containing podophyllotoxin and its analogues have been used as folk medicines for centuries. The characteristic chemical structures and strong biological activities of this class of compounds attracted attention worldwide. Currently, more than ninety natural podophyllotoxins were isolated, and structure modifications of these molecules were performed to afford a variety of derivatives, which offered optimized anti-tumor activity. This review summarized up to date reports on natural occurring podophyllotoxins and their sources, structural modification and biological activities. Special attention was paid to both structural modification and optimized antitumor activity. It was noteworthy that etoposide, a derivative of podophyllotoxin, could prevent cytokine storm caused by the recent SARS-CoV-2 viral infection. [ABSTRACT FROM AUTHOR]

A rationally designed small-molecule fluorogenic probe for nitric oxide (NO) detection based on a new switching mechanism has been developed. Attaching a NO-responsive dihydropyridine pendant group to a fluorophore led to a probe that displays a very high sensitivity to NO concentrations down to the low nM range and a very high specificity to NO while being insensitive to other oxidative oxygen/nitrogen species that often interfere with the sensing of NO. [ABSTRACT FROM AUTHOR]

Percutaneous vertebroplasty (PVP) is popular for the treatment of intractable pain due to vertebral collapse from various lesions, intervertebral disk leakage of cement is a frequent complication. The aim of this study was to determine whether bone cement causes disc degeneration, and to evaluate the degree of intervertebral disc degeneration (IDD) according to the time period following cement injection, and the type and volume of cement injected. Sixteen dogs were randomly divided into two groups that were sacrificed at 12 or 24 weeks following cement injection. Five intervertebral discs in each dog were studied, including one control untreated disc and four discs randomly injected with polymethylmethacrylate (PMMA) or calcium phosphate cement (CPC) in two quantities. Radiographic and magnetic resonance imaging (MRI) studies were performed prior to animal sacrifice. T2-weighted mid-sagittal images of the discs were qualitatively analyzed for evidence of degeneration by calculating the MRI index, and all harvested discs were studied histopathologically. IDD was not evident in control discs. Univariate analysis revealed significant differences in the MRI index and the histological grade of disc degeneration in terms of the time period following cement injection, as well as the type and volume of cement injected. Result indicate that direct contact with PMMA and CPC can lead to IDD. However, IDD induced by PMMA was more severe than that induced by CPC. The extent of IDD was found to correlate with the time period post-cement injection and the volume of cement injected into the disc. PMMA and CPC may lead to intervertebral disc degeneration. Intervertebral disc degeneration induced by PMMA is more serious than that of CPC. The degree of intervertebral disc degeneration is correlative to the time after operation and the doses of bone cement. [ABSTRACT FROM AUTHOR]

A novel heterostructure of BiS nanoparticles (NPs) and TiO nanotube arrays (NAs) was fabricated by a conventional hydrothermal method. The morphological features and the X-ray diffractogram of the obtained BiS/TiO NAs were characterized by field-emission scanning electron microscopy, transmission electron microscopy, and powder X-ray diffraction. The photoelectrochemical property of BiS/TiO NAs was also evaluated. The results demonstrated that photoelectrochemical solar cells based on BiS/TiO NAs had a short-circuit current of 4.54 mA/cm and photoelectric conversion efficiency of 1.86 %. Surface photovoltage spectroscopy and field-induced surface photovoltage spectroscopy data indicated the existence of a strong interfacial electronic field between the two components BiS NPs and TiO NAs, which can enhance the separation of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

Cytochrome P450c17 ( CYP17, 17α-hydroxylase/17,20-lyase) is a critical enzyme in the production of androgens and estrogens in vertebrates. A 2102 bp full-length cDNA of P450c17-II ( CYP17A2) has been isolated from the ovary of half-smooth tongue sole, C ynoglossus semilaevis which encodes 524 amino acids. The putative P450c17- II enzyme shares higher sequence identity with those of teleosts than with P450c17- I of vertebrate. The similarity between the two types of tongue sole P450c17 was 48%.Semi-quantitative RT- PCR analysis of spatial expression showed the enzyme was specifically expressed in the ovary and the head kidney. However, temporal expression shows that P450c17- II can be found in the brain. Furthermore, temporal expression pattern of P450c17- II in ovary and brain revealed developmental stage-dependency, and ovary P450c17- II expressed remarkably throughout the whole reproductive cycle. Otherwise, the expression pattern of P450c17- II in head kidney indicated negative ovary development-dependence. In addition, combined with our data on P450c17- I, T and E2 levels, the results further endorse the critical role of P450c17- II during shift in steroidogenesis, suggesting that P450c17- I and - II may act together to this physiological process. Based on the present study, we indicate an important role for P450c17- II during ovarian development. [ABSTRACT FROM AUTHOR]

The biosorption of Au(III) and Cu(II) ions in both single and binary systems byMagnetospirillum gryphiswaldense(MSR-1) was investigated. For comparison with the selective reinforced competitive biosorption process in a binary system, the experimental research first explored the biosorption of Au(III) and Cu(II) in a single system under various conditions. The biomass exhibited the highest single Au(III) and Cu(II) ion adsorption yields at room temperature (25°C), pH values of 2.5 and 5.0, respectively, and a biomass concentration of 10 g · L−1(3.83 g · L−1, dry basis). The experimental data from the single component system for the two metallic ions fitted well to a Langmuir isotherm and a pseudo second-order kinetic models. In the Au(III)-Cu(II) binary system, the coexistence of Cu(II) cations promoted the adsorption of Au(III) within a certain range of ratios. A new sigmoidal Cu(II) biosorption isotherm was determined specifically to reveal the Cu(II) adsorption behavior in this case. [ABSTRACT FROM AUTHOR]

A series of density functional theory (DFT) experiments, employing the B3LYP+IDSCRF/BS1 and B3LYP+IDSCRF/DZVP methods, have been carried out for the Pd(OAc)2-catalyzed enamide-siloxane C-H activation/C-C coupling reactions. The results reveal that there are four processes, namely C-H activation, transmetalation (TM), reductive elimination (RE), and separation of product (SP) and recycling of catalyst (RC), each of which is consist of different steps. In order to fully understand the origin of regiospecific C-H activation/C-C coupling on the alicyclic ring experimentally observed, the conformational preference, kinetic aspects, and relative stabilities of the competitive products have been explored. In addition, the roles of additive silver salt AgF and solvent dioxane have also been addressed, providing valuable details upon which to rationally optimize experimental conditions. [ABSTRACT FROM AUTHOR]

In order to research the problem of gas in severe-outburst and low-permeability single coal seam, by applying the fracture mechanics and elastic theory, a technology about space mesh hydraulic fracturing by drilling through strata for outburst prevention in severe-outburst and low-permeability single coal seam was presented. A model was established to deduce the value of initiation pressure, and a new device exporting flowrates and pressure was produced. The industrial experiments were implemented with SF6 tracer investigating the fracture network. The results show that the technology can largely increase the permeability of the seam, improve the comprehensive gas drainage rate by 1.69-1.83 times, expand the coal seam 0. 581%, and reduce the electromagnetic radiation prediction index 35%-45%. Compared with the small areas, this method can eliminate the outburst by increasing permeability with hydraulic fracturing in large areas. [ABSTRACT FROM AUTHOR]

Through a series of relevant experiments of coal samples in main coal seams of study area, analyzed the variation of the pore characteristics and porosity characterization parameters, discussed the geological factors which control pore characteristics. The results show that the pore can be divided into four big types in main coal seams of Bide-Santang basin. Porosity is range from 4.06% to 10. 12%. Micropore and minipore takes the dominant position, and provides more than 80% of the total pore volume. The mercury withdrawal efficiency is high. Pore forms are mainly open, contains a number of semi-closed pore. Pore surface area is 18-21 m²/g, micropore occupies the highest proportion. Pore tortuosity has significant impact on threshold pressure. Median pore diameter of volume are mostly around 10 nm, the average of median pore diameter of area is 4. 58 nm. Porosity and pore volume show "U" shape tendency with the increase of coal rank, with Ro,max = 2. 0% as the cut-off point. The content of vitrinite is more than 70% in general control the amount of micropore and minipore. While the increase of minerals' content has negative impact on the development of pore system. [ABSTRACT FROM AUTHOR]

Abstract: The biosynthesis of nanoparticles is considered to be a novel, effective and eco-friendly procedure. In this paper, Magnetospirillum gryphiswaldense MSR-1 was successfully used to reduce gold ions to a zero-valent metal in a water environment, and more importantly, to accumulate them into spherical nanoparticles on the cell surface through biosorption. Transmission electron microscopy (TEM) was used to examine nanoparticle characteristics. The size range of the nano-gold made by MSR-1 was from 10 to 40nm. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses of the gold nanoparticles confirmed the formation of metallic gold. The pH value of the biosynthesis solution and the initial metal concentration were examined; both of these important parameters were isolated and screened to determine their role in controlling particle size. The results demonstrated that lower pH values and initial concentrations of Au(III) were individually responsible for reductions in nano-gold particle size. [Copyright &y& Elsevier]

Biosynthesis of the metallocenter in the active site of the [NiFe] hydrogenase enzyme requires the accessory protein HypB, which is a metal-binding GTPase. In this study, the interplay between the individual activities of Escherichia coli HypB was examined. The full-length protein undergoes nucleotide-responsive dimerization that is disrupted upon mutation of L242 and L246 to alanine. This mutant HypB is monomeric under all of the conditions investigated but the inability of L242A/L246A HypB to dimerize does not abolish its GTPase activity and the monomeric protein has metal-binding behavior similar to that of wild-type HypB. Furthermore, expression of L242A/L246A HypB in vivo results in hydrogenase activity that is approximately half of the activity produced by the wild-type control, suggesting that dimerization of HypB does not have a critical role in the hydrogenase maturation pathway. In contrast, the GTPase activity of HypB is modulated by metal loading of the protein. These results provide insight into the role of HypB in hydrogenase biosynthesis. [ABSTRACT FROM AUTHOR]

Three pH/temperature-dependent 2D MOFs containing 1D nanotubular meso-helical chains were firstly synthesized from multidentate 2,4ˈ-H2bpdc. Crystal structure analysis shows that 2and 3are monochiral and the resultant crystals were not racemic as evidenced by the observation of strong signals in vibrational circular dichroism (VCD) and circular dichroism (CD) spectra. [ABSTRACT FROM AUTHOR]

Under different temperatures, the reaction mixture of the multidentate organic ligand usy-L4and Zn(NO3)2+ NaN3crystallized to give three conformational isomers, namely Zn(usy-L4)(η1-N3)2(α-1, β-2and γ-3) (usy-L4= N,N-dimethyl-2-(pyridin-2-ylmethylimino)ethanamine). Single-crystal X-ray diffraction analyses reveal that the conformational isomerism of three compounds 1–3stems from the different orientations of two azide groups with η1-terminal nitrogen atom coordinating to central zinc ion in reference to the basal chelating plane of ligand usy-L4, and further resulting in different supramolecular networks with two-dimensional 44rhombic-grid for α-1, a three-dimensional 36·418·53·6 compressed-NbO framework for β-2, and a three-dimensional “dense” 424·64topology for γ-3. Meanwhile, three isomers may be also irreversibly converted from 1to 2, to 3through SC-to-SC transformation driven by temperature. [ABSTRACT FROM AUTHOR]

Through different synthetic strategies, four dinuclear cadmium(ii) complexes containing N2O/N2O2donor tridentate/tetradentate asymmetrical Schiff base ligands have been synthesized and characterized. The two complexes [Cd(L1)(μ2-Cl)(CH3OH)]2(1) and [Cd(L2)Cl]2·CH3OH (2) are constructed, respectively, from self-assembly of a Cd2+ion with two asymmetrical Schiff base ligands, namely 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL1) and 2-((2-(dimethylamino)ethylimino)methyl)-6-methoxyphenol (HL2). However, viasingle-crystal to single-crystal structural transformations driven by temperature, the other two corresponding compounds [Cd(L1)Cl]2(1a) (1→ 1a) and [Cd(L2)Cl]2(2a) (2→ 2a), with N2O2Cl and N2O3Cl donors, respectively, can be obtained. Obviously, the synthetic strategies presented in the text provide very effective methods for constructing the dinuclear CdIIcompounds with N2O/N2O2donor tridentate/tetradentate asymmetrical Schiff base ligands. Meanwhile, the strong fluorescence emission of 1and 2makes them potentially useful photoactive materials. [ABSTRACT FROM AUTHOR]

Self-assembly of the symmetrical tetradentate N2O2donor Schiff base ligand, that is, bis(salicylidene)trimethylenediamine (sy-H2L3), with different zinc salts has led to six anion-dependent complexes, namely, [Zn3(sy-L3)2(μ2-Cl)Cl(C2H5OH)]·C2H5OH (1), Zn[Zn(sy-L3)(μ2-NO2)(C2H5OH)]2·2H2O (2), Zn[Zn(sy-L3)(μ2-CH3COO)]2(3), Zn(DMF)2[Zn(sy-L3)(H2O)(SCN)]2(4), Zn[Zn(sy-L3)(μ2-HCOO)(DMF)]2·H2O (5) and Zn[Zn(sy-L3)(μ2-HCOO)]2(6), respectively. Six compounds were characterized by elemental analyses, IR spectra, mass spectrometry and thermogravimetric analyses, of which five structures 1,2,4,5, and 6were further determined by single-crystal X-ray diffraction analyses, and compound 3was previously reported in the literature. It was observed that μ2-bridges in these trinuclear complexes were formed through the phenolic oxygens of the ligand or the anions in the medium. In the presence of nitrite (for 2), acetate (for 3), thiocyanate (for 4), or formate (for 5−6), μ2-bridges formed between a pair of adjacent zinc atoms resulting in linear trinuclear complexes with one symmetrical center. However, μ2-bridges involving chloride and the phenolic oxygens of ligand sy-H2L3led to the formation of a V-shaped trinuclear complex 1. It is noteworthy that in the assembling process of complexes 4−6, when the appropriate amount of DMF was added to the reaction mixture, thiocyanate anion coordinated to the terminal Zn2+ion in a η1-N coordination manner and gave compound 4with a coordination of water molecules and DMF molecules to the terminal and the middle zinc ions in a range from room temperature to 70 °C. Above ∼70 °C, C−N bond cleavage of part of the solvent DMF molecules induced the formation of compound 5with coordination of formate and DMF to Zn2+. Upon increasing the temperature higher than 110 °C, because of the decomposition of a large number of DMF molecules, the same reaction produced trinuclear complex 6, in which only formate coordinated to a pair of the adjacent zinc atoms in a μ2-bridging coordination fashion. In addition, photoluminescent properties and biological activities of ligand sy-H2L3and six corresponding compounds were also studied. [ABSTRACT FROM AUTHOR]

Six cadmium(II) complexes containing the N2O2donor tetradentate asymmetrical Schiff base ligand 2-{[2-(dimethylamino)ethylimino]methyl}-6-methoxyphenol (HL5), namely, [(Cd3L52Cl4)2]·CH3OH·H2O (1), [Cd(L5)Cl]2·CH3OH (2), [Cd2(HL5)Cl4]n(3), {[Cd3(H2L5)2Cl8]·2H2O}n(4), [(H2L5)2]2·[CdCl4]2−·H2O (5), and [(H2L5)2]2·[CdCl4]2−(6), have been synthesized using cadmium(II) chloride and the asymmetrical Schiff base ligand HL5under different pH conditions at room temperature. The diverse structures show the marked sensitivity of the structural chemistry of the tetradentate asymmetrical Schiff base ligand HL5. Complex 1formed at pH = 10 exhibits a rare zero-dimensional structure of trinuclear cadmium(II). At pH = 8−9, a dinuclear cadmium(II) complex 2is formed. The reaction at pH = 5−7 leads to two one-dimensional structures of 3and 4. A further decrease of the pH to 3−5 results in a zero-dimensional structure 5. Owing to the departure of lattice water molecules in the crystal, complex 5at room temperature can gradually undergo single-crystal-to-single-crystal transformation to result in complex 6.The results further show that conversions of complex 1−5can also be achieved by adjusting the pH value of the reaction solution, 1→ 2pH=8→ 5pH=3and 3→ 4pH=5. Comparing these experimental results, it is clear that the pH plays a crucial role in the formation of the resulting structures, which simultaneously provides very effective strategies for constructing the CdIIcompounds with N2O2donor tetradentate asymmetrical Schiff base ligand. The strong fluorescent emissions of the six compounds (1−6) make them potentially useful photoactive materials. Furthermore, six Schiff base cadmium complexes (1−6), with 2,2-dipheny1-1-picrylhydrazy1 (DPPH) as a co-oxidant exhibited the stronger scavenging activity. [ABSTRACT FROM AUTHOR]

Self-assemblies of two unsymmetrical tridentate N2O/N2S donor Schiff base ligands, that is, 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL1) and methyl-2-pyridylmethylidenehy-drazinecarbodithioate (HL2), with different cadmium salts have led to 11 anion-controlled complexes, namely, [Cd(Ln)2] [n= 1 for 1and n= 2 for 2], [Cd(L1)(HL1)](ClO4) (3), [Cd(HL2)(L2)](ClO4)(H2O) (4), [Cd(L2)Cl2] (5), [Cd(L1)Cl]2(6), [Cd(L1)(NO3)]2(7), [Cd(L2)(NO3)(CH3OH)]2(8), [Cd(L2)(NO3)(H2O)]2(8a), [Cd2(L1)2(SCN)2]n(9), and [CdL2(SCN)2]n(10), respectively. Eleven compounds were characterized by elemental analyses, IR spectra, MS and thermogravimetric analyses, of which 10 structures 2, 3, 4, 5, 6, 7, 8, 8a, 9, and 10were further determined by single-crystal X-ray diffraction analyses. The compounds 2, 3, and 4are mononuclear, in which the neutral molecule unit CdII(L2)2(in 2) as well as cation units [CdII(HL1−2)(L1−2)](L1for 3and L2for 4) are respectively connected by hydrogen bonds C−H···S, O−H···O, and C−H···O and form three-dimensional (3D) ordered network structures. With the replacement of Cd(CH3COO)2/Cd(ClO4)2by CdCl2/Cd(NO3)2in the above reactions, because of the coordination interactions of nitrate and chloride anions in these cases, the obtained corresponding compounds 6−8present dinuclear structures with planar Cd2O2/Cd2S2quadrilateral cores and only compound 5mononuclear, in which the folding effect of sulfur and solvent effect, to a certain extent, affect the microstructure of these complexes, such as the arrangements of the ligand L1−2and nitrate/chloride ions. Furthermore, through intermolecular weak interactions, for example, C−H···O, O−H···N hydrogen bonding and π···πstacking, 3D supramolecular structures are assembled in these compounds. However, reactions of Cd(CH3COO)2/Cd(ClO4)2 KSCN with L (L = L1(9), L2(10)) yield two one-dimensional (1D) chain-like compounds, and similarly, via interchain hydrogen bonds C−H···S (for 9) and N−H···N (for 10), 2D layer-like supramolecular networks are constructed. In addition, the photoluminescent properties of two ligands as well as 11 compounds were also studied. [ABSTRACT FROM AUTHOR]

Several 0D, 1D, and 3D metal–organic hybrid frameworks of ZnIIhave been synthesized by using the asymmetric ligand 6-(1H-benzoimidazol-2-yl)pyridinecarboxylic acid (HL) with control of the temperature and solvent in a solvothermal synthesis technique. In DMF, the structure at room temperature confirms that the resulting compound Zn(L)2·2(H2O) (1) is the 0D mononuclear structure, above ∼80 °C, C–N bond cleavage of partial DMF molecules induces the formation of the 1D chain-like compound {[Zn(L)(HCOO)]·2(H2O)}n(2), but on warming up to 120 and 160 °C, due to the decomposition of a large number of DMF molecules, the same reaction, respectively, gives two 3D metal–organic coordination polymers with 3D channels reported previously {[Zn(HCOO)3]−·[H2N(CH3)2]+}n(3) and [Zn(HCOO)2]n(4), in which the 3D channels of 3contain guest [H2N(CH3)2]+motifs, while at high temperature the 3D channels of 4are an open stable system without any guest molecules. Replacing DMF in the above reaction by ethanol or acetonitrile, only 0D compound 1is obtained in the range from room temperature to 160 °C. However, the same reaction in DMSO provides a 1D wave-like compound {[Zn(L)(DMSO)]·(ClO4)·H2O}n(5), in which the solvent DMSO molecule coordinates to the central metal ZnIIion. Furthermore, in three new complexes 1, 2and 5, through ππ stacking and hydrogen bonding interactions, 3D supramolecular networks are assembled. It is worth noting that the existence of the twelve-membered cyclic water–perchlorate dimers [(ClO4)(H2O)]22−with chair-conformation in the solid state of 5not only increases the stability of the supramolecular structure, but also results in a stronger fluorescence signal compared with ligand HL, 1and 2. [ABSTRACT FROM AUTHOR]

Density functional theory, employing B3LYP/DZVP and B3LYP/6-31G*(LANL2DZ for Tc), has been used to investigate the interconversion mechanism between formal TcO3+ and TcO2 + core of 99mTc labeled amine-oxime (AO) complex, in which two water molecules have been used to simulate the possible interconversion process. The obtained results indicate that the length of amine-amine hydrocarbon backbone of AO ligand has a significant influence on the stabilities of formal TcO3+ and TcO2 + complex. The interconversion process between TcO–BnAO and TcO2–BnAO has been amply discussed, which releases the useful information for the further investigation of the structure and hypoxic mechanism of 99mTc-HL91. [ABSTRACT FROM AUTHOR]

Abstract: High conductance Ca2+ activated K+ channels (BKCa) in vascular smooth muscles play important roles in controlling the vascular tone by determining the level of membrane potential and Ca2+ influx through voltage gated Ca2+ channels. Agents that alter the activity of Ca2+ channels or BKCa thus affect the vascular tone in both physiological and pathological conditions. Danshen, the dried root of Salvia miltiorrhiza, is a commonly used traditional Chinese medicine and is widely used as an effective remedy for cardiovascular and cerebral vascular diseases partly by its vasodilatation. Sodium tanshinoneII-A sulfonate (DS-201) is a water-soluble derivative of Tanshinone IIA, the main active component of Danshen. The purpose of this study was to explore possible mechanisms of vasodilative effects of DS-201 using porcine coronary artery smooth muscle. DS-201 induced relaxation of the coronary smooth muscle which had been contracted with 30 mM KCl, and the relaxation was inhibited by 100 nM iberiotoxin (IbTX), a specific BKCa channel blocker. Using perforated whole-cell recordings and single channel recordings, effects of DS-201 on BKCa were examined. The results showed that DS-201 activated BKCa. Extracellular application of DS-201 at 40, 80 µM under the whole-cell configuration induced increases of the BKCa macroscopic currents by 43.6%, 42.1% respectively, and the spontaneous transient outward K+ currents (STOCs) by 48.7%, 47.4% respectively. In inside-out patches, bath application of 20–150 μM of DS-201 activated BKCa by 5.4–173.2 fold. These results indicate that the vasodilatation by DS-201 is related to activation of BKCa. [Copyright &y& Elsevier]

Four typical thermal [1,3] sigmatropic rearrangements of bicyclic and tricyclic vinylcyclobutanes and one fancied analogous reaction (R2 in Scheme 1) were examined using CASSCF, CASPT2 and CAS+1+2 methods to discern the reaction mechanisms. Computed results indicate that it is difficult to simply designate these reactions as traditional single-step concerted or stepwise mechanisms, but a situation locating between these two extremes seems to be reasonable. The extent the reaction exhibits as a single-step concerted or stepwise path is much dependent on the geometrical constraints of reactant. For example, the system with three-member ring will tend to behave like a single-step concerted process, where only one rotation movement around C–C bond could be found when the bridged C–C is broken. However, the species with four-member ring will be much closer to the stepwise mechanism involving diradical varieties, because there are two different rotation movements exist when the bridged C–C is broken. Our calculation will also rationalize that only suprafacial retention product could be yielded for the thermal [1,3] sigmatropic rearrangement of tricyclic vinylcyclobutane. [ABSTRACT FROM AUTHOR]

Abstract: All vaccines and other biological products contain contaminating residual DNA derived from the production cell substrate. Whether this residual cell-substrate DNA can induce tumors in vaccine recipients and thus represent a risk factor has been debated for over 50years without resolution. As a first step in resolving this issue, we have generated expression plasmids for the activated human H-ras oncogene and for the murine c-myc proto-oncogene. Their oncogenic activity was confirmed in vitro using the focus-formation transformation assay. Two strains of adult and newborn immune-competent mice were inoculated with different amounts of either plasmid alone or with a combination of the H-ras and c-myc plasmids. Tumors developed only in mice inoculated with both plasmids and only at the highest amount of DNA (12.5μg of each plasmid). The NIH Swiss mouse was more sensitive than the C57BL/6 mouse, and newborn animals were more sensitive than adults. Cell lines were established from the tumors. PCR and Southern hybridization analyses demonstrated that both inoculated oncogenes were present in all of the tumor-derived cell lines and that the cells in the tumors were clonal. Western analysis demonstrated that both oncoproteins were expressed in these cell lines. These results demonstrate that cellular oncogenes can induce tumors following subcutaneous inoculation. Such information provides a possible way of evaluating and estimating the theoretical oncogenic risk posed by residual cell-substrate DNA in vaccines. [Copyright &y& Elsevier]

The article focuses on setting up a necessary guidance model for the educational system in China. China has a low level of education and a low-quality workforce, with university students occupying a special position in the labor market. University student employment is not affected by the economy over the long term, including short-term fluctuations in the labor market, as they do not constitute a conventional section of the labor market; therefore, they have other specific requirements unlike that of the average employee. For several years, due to insufficient market requirements, there were not enough jobs to go around, resulting in pressure when looking for employment. Therefore, difficulties in university graduates finding jobs has probably had a long time to develop and appears to be a problem that will last for a predetermined period, and it is quite likely that contradictions will accumulate. Therefore, if there is a government policy of guaranteeing re-employment needs of those that have been laid off, there has to be acceleration in removing systemic blockages to the problem of rural labor mobility, and the employment needs of university students should be completely market driven.

A new press mechanism with combined input is proposed in this paper. An ordinary motor supplies main power while a servomotor adjusts motion. A single-freedom linkage driven by a servomotor is not applied in a mechanical press needing big power because of high cost, but the advent of the mechanism with combined input solves the problem.Studies on the inverse kinematic analysis and optimal synthesis of this mechanism open a way to the application of the mechanism with combined input in flexible manufacture and propose a the research direction of the mechanical press. [Copyright &y& Elsevier]

The mechanisms dictating the developmental expression of individual neuropeptides within the hypothalamus have not yet been elucidated. In this paper we have studied the cis-acting elements involved in the repression of neuropeptide Y (NPY) gene expression in a gonadotropin-releasing hormone (GnRH) neuronal cell model, GT1-7 cells. Using transient transfection of the human NPY 5′ regulatory region into the GT1-7 neurons, we have found a repressor region located between −867 and −1078. DNase I footprint analysis of this region revealed three specific protein binding elements. Further analysis of the region between −942 and −922 bp using electrophoretic mobility shift assays revealed that four different transcription factor-DNA complexes form with GT1-7 nuclear proteins, whereas only three complexes are detected using baby hamster kidney (BHK) cell nuclear extract. Mutation of the consensus binding sequence abolishes all complex formation on the −924/−922 oligonucleotide. Antibody supershift assays revealed that Oct-1 and Pbx-1 antibodies were able to eliminate the appearance of two specific complexes. Therefore we suggest that this region may be important for transcriptional repression of the NPY gene in a heterologous cell model, through complex, coordinate protein–protein interactions. [Copyright &y& Elsevier]