Silica sulfuric acid promoted one-pot synthesis of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives under solvent-free conditions

A simple and efficient synthesis of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives has been accomplished by the reaction of 2-aminobenzimidazole, aldehydes and β-dicarbonyl compounds under solvent-free conditions in the presence of silica sulfuric acid. KEY WORDS: Benzo[4,5]imidazo[1,2-a]pyrimidine, Silica sulfuric acid, 2-Aminobenzimidazole, Aromatic aldehydes, β-Dicarbonyl compounds, Solvent-free Bull. Chem. Soc. Ethiop. 2010, 24(3), 417-423

Silica sulfuric acid: a versatile and reusable heterogeneous catalyst for the synthesis of N-acyl carbamates and oxazolidinones under solvent-free conditions

Silica sulfuric acid catalyzes efficiently the reaction of carbamates and oxazolidinones with anhydrides under solvent-free conditions. All the reactions were done at room temperature and the N-acyl carbamates and oxazolidinones were obtained with high yields and purity via an easy work-up procedure. This method is attractive and is in a close agreement with green chemistry.KEY WORDS: N-Acyl carbamates, N-Acyl oxazolidinones, Silica sulfuric acid, Solvent-free Bull. Chem. Soc. Ethiop. 2011, 25(1), 151-155

Formation and Dissociation of Field-Linked Tetramers

We investigate the static and dynamic properties of tetratomic molecules formed by two microwave-shielded polar molecules across field-linked resonances. In particular, we focus on two-body physics and experimental techniques unexplored in the recent experiment [X.-Y. Chen {\it et al}., Nature {\bf626}, 283 (2024)]. We show that, compared to the lowest tetramer state, higher tetramer states typically have longer lifetimes, which may facilitate a further cooling of tetramer gases towards quantum degeneracy. To detect tetramers, we identify the distinctive time-of-flight images from ramp dissociation, which can be observed by lowering the ramp rate of the microwave. Remarkably, in the modulational dissociation of tetramers, we find that multi-photon processes induce dissociation even below the threshold modulation frequency when the modulation amplitude is sufficiently high. Given the universal form of the inter-molecular potential for microwave-shielded polar molecules, our results also apply to other molecular gases widely explored in recent experiments

A self-induced mechanism of large-scale helical structures in compressible turbulent flows

A novel self-sustaining mechanism is proposed for large-scale helical structures in compressible turbulent flows. The existence of two channels of subgrid-scale and viscosity terms for large-scale helicity evolution is confirmed for the first time, through selecting a physical definition of the large-scale helicity in compressible turbulence. Under the influence of the fluid element expansion, it is found that the helicity is generated at small scales via the second-channel viscosity, and the inverse cross-scale helicity transfers at inertial scales through the second-channel helicity flux. Together, they form a self-induced mechanism, which provides a physical insight into the long-period characteristic of large-scale helical structures in the evolution of compressible flow systems

储能友好型频率响应服务市场 : 英国视角

To counterbalance the reduction of system inertia with increasing renewable generation, the frequency response (FR) service markets in the UK have been reforming to enable procurement from diverse technologies including energy storage systems (ESSs). The Enhanced FR product was introduced in 2016 to allow ESSs to manage the state of energy (SOE) within two envelopes. A two-year weekly auction trial was launched in 2019 to test closer-to-real-time procurement and reduce the financial risk of ESSs by evaluating their performance and payments in each week separately instead of an entire month. In addition, an integrated suite of end-state services has been successively released since 2020 with the phase-out of existing FR services so as to increase the standardisation and transparency of FR markets. The end-end services consisting of Dynamic Containment (DC), Dynamic Moderation (DM) and Dynamic Regulation (DR) deal with different frequency deviation levels and have a limited requirement on full-response duration, which mitigates the barrier to entry for ESSs. The SOE rules are additionally specified to indicate the cases in which ESSs will not be penalised for the under-delivery of DC, DM or DR. Based on the latest technical requirements and procurement/payment mechanisms of DM, this paper simulates the techno-economic operation of a grid-scale lithium-ion battery ESS (BESS) that provides DM to the AC grid while following its operational baselines to restore the SOE. The SOE levels and FR errors of the BESS are calculated to determine its compliance with the SOE rules and under-delivery penalties. Then the DM payment is compared with BESS costs to estimate the net present value at the end of the energy throughput-based lifetime, indicating the profitability of the BESS under the latest energy storage-friendly FR markets. The BESS operating strategy designed here fully considers the specific market mechanisms of end-state FR services, allowing the closer-to-real-time SOE management and meeting the required FR delivery. The specific and novel strategy design and the resulting simulation offer BESS developers with an insight into potential operating scenarios especially at the early stage of end-state FR service markets

Ultracold field-linked tetratomic molecules

Ultracold polyatomic molecules offer intriguing new opportunities in cold chemistry, precision measurements, and quantum information processing, thanks to their rich internal structure. However, their increased complexity compared to diatomic molecules presents a formidable challenge to employ conventional cooling techniques. Here, we demonstrate a new approach to create ultracold polyatomic molecules by electroassociation in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance. Starting from ground state NaK molecules, we create around $1.1\times 10^3$ tetratomic (NaK)$_2$ molecules, with a phase space density of $0.040(3)$ at a temperature of $134(3)\,\text{nK}$, more than $3000$ times colder than previously realized tetratomic molecules. We observe a maximum tetramer lifetime of $8(2)\,\text{ms}$ in free space without a notable change in the presence of an optical dipole trap, indicating these tetramers are collisionally stable. The measured binding energy and lifetime agree well with parameter-free calculations, which outlines pathways to further increase the lifetime of the tetramers. Moreover, we directly image the dissociated tetramers through microwave-field modulation to probe the anisotropy of their wave function in momentum space. Our result demonstrates a universal tool for assembling ultracold polyatomic molecules from smaller polar molecules, which is a crucial step towards Bose--Einstein condensation (BEC) of polyatomic molecules and towards a new crossover from a dipolar Bardeen-Cooper-Schrieffer (BCS) superfluid to a BEC of tetramers. Additionally, the long-lived FL state provides an ideal starting point for deterministic optical transfer to deeply bound tetramer states

Synergistic Role between p53 and JWA: Prognostic and Predictive Biomarkers in Gastric Cancer

Expression of p53 appears to be correlated to prognosis in patients with malignancy, but its role in gastric carcinoma has remained controversial. Recently we reported that JWA, an ADP-ribosylation-like factor 6 interacting protein 5 (ARL6ip5), was both prognostic for overall survival and predictive for platinum-based treatment of gastric cancer. In this study, we aimed to investigate p53 expression as a prognostic and predictive marker in resectable gastric cancer, alone and in combination with JWA. Expression of p53 was examined in three large patient cohorts (total n = 1155) of gastric cancer. High expression of p53 was significantly correlated with unfavorable clinicopathologic parameters and decreased overall patient survival. Furthermore, patients with high p53 expression in tumors acquired remarkable survival benefit from adjuvant first-line platinum-based-chemotherapy. The synergy between p53 and JWA in predicting patient outcome was demonstrated, while no significantly elevated predictive value concerning chemotherapy was observed. Thus, p53 expression is a potent prognostic and predictive factor for resectable gastric cancer with adjuvant platinum-based chemotherapy. A combined effect of p53 with JWA as efficient prognostic indicators was found for the first time.© 2012 Liu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Short-term effect of low-dose roxadustat combined with erythropoiesis-stimulating agent treatment for erythropoietin-resistant anemia in patients undergoing maintenance hemodialysis

BackgroundErythropoietin resistance is present in some patients with chronic kidney disease, especially in those undergoing hemodialysis, and is often treated using roxadustat rather than iron supplements and erythropoiesis-stimulating agents (ESAs). However, some patients cannot afford full doses of roxadustat. This retrospective study investigated the efficacy of low-dose roxadustat combined with recombinant human erythropoietin (rhuEPO) therapy in 39 patients with erythropoietin-resistant renal anemia undergoing maintenance hemodialysis (3-4 sessions/week).MethodsThe ability of the combination of low-dose roxadustat and rhuEPO to increase the hemoglobin concentration over 12 weeks was assessed. Markers of iron metabolism were evaluated. Eligible adults received 50–60% of the recommended dose of roxadustat and higher doses of rhuEPO.ResultsThe mean hemoglobin level increased from 77.67 ± 11.18 g/dL to 92.0 ± 8.35 g/dL after treatment, and the hemoglobin response rate increased to 72%. The mean hematocrit level significantly increased from 24.26 ± 3.99% to 30.04 ± 3.69%. The soluble transferrin receptor level increased (27.29 ± 13.60 mg/L to 38.09 ± 12.78 mg/L), while the total iron binding capacity (49.22 ± 11.29 mg/L to 43.91 ± 12.88 mg/L) and ferritin level (171.05 ± 54.75 ng/mL to 140.83 ± 42.03 ng/mL) decreased.ConclusionTherefore, in patients with ESA-resistant anemia who are undergoing hemodialysis, the combination of low-dose roxadustat and rhuEPO effectively improves renal anemia and iron metabolism

Ultracold field-linked tetratomic molecules

Ultracold polyatomic molecules offer intriguing new opportunities in cold chemistry, precision measurements, and quantum information processing, thanks to their rich internal structure. However, their increased complexity compared to diatomic molecules presents a formidable challenge to employ conventional cooling techniques. Here, we demonstrate a new approach to create ultracold polyatomic molecules by electroassociation in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance. Starting from ground state NaK molecules, we create around $1.1\times 10^3$ tetratomic (NaK)$_2$ molecules, with a phase space density of $0.040(3)$ at a temperature of $134(3)\,\text{nK}$, more than $3000$ times colder than previously realized tetratomic molecules. We observe a maximum tetramer lifetime of $8(2)\,\text{ms}$ in free space without a notable change in the presence of an optical dipole trap, indicating these tetramers are collisionally stable. The measured binding energy and lifetime agree well with parameter-free calculations, which outlines pathways to further increase the lifetime of the tetramers. Moreover, we directly image the dissociated tetramers through microwave-field modulation to probe the anisotropy of their wave function in momentum space. Our result demonstrates a universal tool for assembling ultracold polyatomic molecules from smaller polar molecules, which is a crucial step towards Bose--Einstein condensation (BEC) of polyatomic molecules and towards a new crossover from a dipolar Bardeen-Cooper-Schrieffer (BCS) superfluid to a BEC of tetramers. Additionally, the long-lived FL state provides an ideal starting point for deterministic optical transfer to deeply bound tetramer states