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Raman and surface-enhanced Raman scattering (SERS) spectroscopy are highly specific and sensitive optical modalities that have been extensively investigated in diverse applications. Noise reduction is demanding in the preprocessing procedure, especially for weak Raman/SERS spectra. Existing denoising methods require manual optimization of parameters, which is time-consuming and laborious and cannot always achieve satisfactory performance. Deep learning has been increasingly applied in Raman/SERS spectral denoising but usually requires massive training data, where the true labels may not exist. Aiming at these challenges, this work presents a generic Raman spectrum denoising algorithm with self-supervised learning for accurate, rapid, and robust noise reduction. A specialized network based on U-Net is established, which first extracts high-level features and then restores key peak profiles of the spectra. A subsampling strategy is proposed to refine the raw Raman spectrum and avoid the underlying biased interference. The effectiveness of the proposed approach has been validated by a broad range of spectral data, exhibiting its strong generalization ability. In the context of photosafe detection of deep-seated tumors, our method achieved signal-to-noise ratio enhancement by over 400%, which resulted in a significant increase in the limit of detection thickness from 10 to 18 cm. Our approach demonstrates superior denoising performance compared to the state-of-the-art denoising methods. The occlusion method further showed that the proposed algorithm automatically focuses on characterized peaks, enhancing the interpretability of our approach explicitly in Raman and SERS spectroscopy.

This article presents an enhanced physical SPICE model for insulated gate bipolar transistor (IGBT) modules, grounded in a two-dimensional charge distribution. The model accurately delineates the lateral charge distribution under both static conduction and transient conditions, providing a precise representation of the PNP and PIN components of the IGBT. The improved model more effectively describes current distribution and clarifies parasitic effects, such as latch-up phenomenon. Furthermore, a negative carrier lifetime near the gate is introduced in accordance with the carrier movement direction, resulting in a catenary charge distribution in the PIN segment of the IGBT. This aligns closely with the technology computer-aided design (TCAD) results. Notably, the carrier concentration in the N-base region significantly escalates under high-level injection conditions. The model incorporates an N+N- junction and a P+N- junction within the channel to portray the carrier concentration variation during the transient state, also factoring in the effect of temperature on the IGBT characteristics. Implemented in PSPICE, the model's findings are compared with TCAD outcomes and experimental data. These comparisons illustrate that the proposed model precisely delivers the charge distribution, as well as dynamic/static characteristics and unbalanced current in parallel devices of the IGBT.

The interleaved dc/dc boost converter (IBC) has been widely used to interface the solar photovoltaic panels and fuel cells to dc microgrids. With the penetration of self-regulated power electronic loads, which tend to consume constant power, the stability of dc microgrids is severely challenged. To guarantee the large signal stability of IBC fed dc microgrids with constant power loads, this article proposes a novel data-driven linear quadratic regulator. It provides model-free online control optimization with very low computational burden. To verify the effectiveness of the proposed method, experiments are carried out using the low cost Texas Instrument C2000 series digital signal processor.

This article presents a reinforcement learning (RL) controller based on the twin delayed deep deterministic (TD3) policy gradient algorithm for single-inductor multiple-input multiple-output (SI-MIMO) dc–dc converters. The controller aims to address the power allocation challenges arising from parallel input sources and mitigate cross-regulation among multiple output channels. The objective is to enable the converter to exhibit outstanding performance in both steady-state and dynamic regulation during operation. The proposed RL controller is trained using the TD3 algorithm. It directly generates duty cycle control signals based on the observed states from the controlled converter. After applying input-side power allocation modulation and output-side time-multiplexing modulation, the controller generates the switching signals for each switch, completing the closed-loop control of the SI-MIMO converter. To validate the effectiveness of the proposed controller, stability analysis of the RL controller is conducted, and an experimental platform is established. Experimental results demonstrate that the proposed controller exhibits superior control performance. It effectively addresses the challenges associated with input-side power allocation and output voltage cross-regulation in SI-MIMO dc–dc converters.

Despite the recent advances in the selective functionalization of C–C bonds in specific substrates, cleavage and functionalization of C–C bonds in acyclic substrates, such as ethane derivatives, remains challenging. In contrast to the well-developed functionalization of one carbon fragment after C–C bond cleavage, herein, we report a novel electro-reductive carboxylation of C (sp3)–C(sp3) bond in multi-aryl ethanes with carbon dioxide (CO2) by utilizing both carbon fragments. Thus, this reaction exhibits an atom-, step-economic approach for the synthesis of carboxylic acids, fulfilling principal aspirations of organic synthesis. Moreover, this method features mild reaction conditions, broad substrate scope, and good functional group tolerance. Symmetric and asymmetric substrates bearing primary, secondary, or tertiary C(sp3)–C(sp3) bonds are all amenable to this strategy, enabling one or two structurally different carboxylic acids to be facilely constructed at the same time. Mechanistic investigations indicate that carbanions might be the key intermediates in this reaction, which could be captured by CO2efficiently.

Carbon dioxide (CO2) is recognized as a greenhouse gas and a common waste product. Simultaneously, it serves as an advantageous and commercially available C1 building block to generate valuable chemicals. Particularly, carboxylation with CO2is considered a significant method for the direct and sustainable production of important carboxylic acids. However, the utilization of CO2is challenging owing to its thermodynamic stability and kinetic inertness. Recently, organic electrosynthesis has emerged as a promising approach that utilizes electrons or holes as environmentally friendly redox reagents to produce reactive intermediates in a controlled and selective manner. This technique holds great potential for the CO2utilization.

Ni-based oxides are promising catalysts for CO2methanation. However, Ni-based catalysts also have some unresolved issues and drawbacks in practical applications. The activity and selectivity of Ni-based catalysts in CO2methanation at low temperatures still need to be improved. Here, Ni/ZrO2nanofibers with high surface areas (up to 101.2 m2/g) were prepared by electrospinning methods. The Ni/ZrO2-ES (also named as 66Ni/ZrO2) catalyst showed excellent catalytic performance in CO2methanation (the CO2conversion = 81% and CH4selectivity = 99% at 350 °C) and excellent stability for 100 h, which was better than most reported Ni/ZrO2catalysts. However, the comparison sample Ni/ZrO2-CP prepared by the coprecipitation method had poor catalytic performance (the CO2conversion = 54% and CH4selectivity = 90% at 350 °C). Within 100 h, the CO2conversion decreased to 30% and the CH4selectivity decreased to 52%. Both EPR and O1SXPS confirmed that Ni/ZrO2nanofibers can form more reactive oxygen species vacancies, and CO2-TPD confirmed that nanofibers had more CO2adsorption sites compared with the control sample Ni/ZrO2-CP. In situ DRIFTS analysis showed that bidentate carbonate and monodentate carbonate were key intermediates in CO2methanation. The catalytic performance of Ni/ZrO2nanofiber catalysts would be attributed to higher dispersion of Ni species on the surface of nanofibers, high specific surface area (101.2 m2/g), more oxygen vacancies, more CO2adsorption sites, and the synergistic effect between Ni nanoparticles and ZrO2nanofibers. This work may inspire the rational design of Ni/ZrO2nanofiber catalysts with rich oxygen vacancies for low-temperature CO2methanation.

To investigate the characteristics of three-dimensional distribution of subchondral fracture lines on the surface of the osteonecrosis femoral head, and to discuss the underlying mechanisms that contribute to its collapse.

• Ce-CdS/N-rGO composites were constructed through coupling Cerium-doped CdS and ultrathin N-rGO. • Interfacial modification of ultrathin N-rGO helped to improve the adsorption capacity and interfacial carriers transfer efficiency. • Adsorption-driven photocatalytic degradation processes were proposed based on in-situ FTIR and MS analysis. • Radical trapping and ESR experiments indicated that TC was gradually decomposed under the synergistic effect of •O 2 −, 1O 2 , h+, and •OH. The charge carrier separation efficiency and the adsorption capacity of the photocatalyst usually affect the degradation rate of antibiotics. Herein, Cerium-doped leaf-like CdS (Ce-CdS) modified with ultrathin N-doped rGO (N-rGO) composites were successfully constructed (Ce-CdS/N-rGO) to investigate the removal efficiency of tetracycline (TC). X-ray photoelectron spectroscopy (XPS) and photoelectrochemical results revealed that Ce ions doped in CdS acting as the electron capture sites facilitated the interfacial charge transfer. Theoretical calculation (DFT) results indicated that the interfacial effect between Ce-CdS and ultrathin N-rGO promoted the transfer of photogenerated electrons under the synergistic effect between the doping and interface modification strategy. The optimized Ce5-CdS/N-rGO20 composites had the maximum TC removal capability (94.5%) and maintained a stable cycling performance. In addition, the adsorption-driven photocatalytic degradation pathway of TC was studied through mass spectrometry (MS) and in-situ Fourier transform infrared spectroscopy (in-situ FTIR). This study will provide an effective strategy for the construction of efficient photocatalytic composites for wastewater treatment. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the long-term outcomes in patients with degenerative mitral regurgitation (MR) undergoing mitral valve repair (MVr) versus mitral valve replacement (MVR) without concomitant surgeries.

The discovery of high-entropy oxides (HEOs) in 2015 has provided a family of potential solid catalysts, due to their tunable components, abundant defects or lattice distorts, excellent thermal stability (ΔG↓ = ΔH– TΔS↑), and so on. When facing the heterogeneous catalysis by HEOs, the micrometer bulky morphology and low surface areas (e.g., <10 m2g–1) by traditional synthesis methods obstructed their way. In this work, an electrospinning method to fabricate HEO nanofibers with diameters of 50–100 nm was demonstrated. The key point lay in the formation of one-dimensional filamentous precursors, during which the uniform dispersion of five metal species with disordered configuration would help to crystallize into single-phase HEOs at lower temperatures: inverse spinel (Cr0.2Mn0.2Co0.2Ni0.2Fe0.2)3O4(400 °C), perovskite La(Mn0.2Cu0.2Co0.2Ni0.2Fe0.2)O3(500 °C), spinel Ni0.2Mg0.2Cu0.2Mn0.2Co0.2)Al2O4(550 °C), and cubic Ni0.2Mg0.2Cu0.2Zn0.2Co0.2O (750 °C). As a proof-of-concept, (Ni3MoCoZn)Al12O24nanofiber exhibited good activity (CH4Conv. > 96%, CO2Conv. > 99%, H2/CO ≈ 0.98), long-time stability (>100 h) for the dry reforming of methane (DRM) at 700 °C without coke deposition, better than control samples (Ni3MoCoZn)Al12O24-Coprecipitation-700 (CH4Conv. < 3%, CO2Conv. < 7%). The reaction mechanism of DRM was studied by in situ infrared spectroscopy, CO2-TPD, and CO2/CH4-TPSR. This electrospinning method provides a synthetic route for HEO nanofibers for target applications.

In this investigation, we explored the molecular dynamics guiding the progression of castration-resistant prostate cancer (CRPC) influenced by Helicobacter pylori(H. pylori)-mediated M2 polarization of macrophages through the IL-17RA/CTSK/EMT axis. An 830-patient clinical trial categorized subjects into hormone-sensitive prostate cancer (HSPC) and CRPC groups. H. pyloriinfection, evaluated by ELISA, exhibited a higher incidence in CRPC patients, impacting overall survival (OS) and progression-free survival. In-depth in vitro and in vivo experiments, including 16S rDNA sequencing, immunohistochemical tests, and transcriptome analysis, unveiled that H. pyloripromotes CRPC growth and metastasis by upregulating IL-17RA and CTSK, leading to enhanced EMT. Notably, M2 macrophages emerged as pivotal immune cells influencing CRPC progression. This study uncovers a novel pathway wherein H. pylorienrichment exacerbates CRPC by inducing macrophage M2 polarization, IL-17RA/CTSK expression, and EMT activation, shedding light on a previously unrecognized mechanism contributing to the growth and metastasis of CRPC.

Isofunctional reactions involving the cleavage of carbon-carbon double bonds (C=C) hold an important position in organic synthesis, as they allow for the restructuring of alkene carbon chains and enable the exchange of functional groups without introducing exogenous groups. Currently, these reactions are primarily divided into C=C/C=C metathesis and C=C/C=O metathesis, with most relying on the use of transition metal catalysts. We report herein a C=C/CH2metathesis reaction that obviates the need for transition metals and directing groups, and is characterized by economic and straightforward operation. This reaction not only facilitates the replacement of nitriles with ketones, but also enables the replacement of ketones with nitriles, demonstrating great universality.

Structurally defective UiO-66 has garnered significant interest due to its remarkable performance in the domains of adsorption and catalysis. In this research, the successful synthesis of Mn-doped defective UiO-66 (Mn1D40UiO-66) was confirmed by XRD and FTIR characterization. More than 95% of As(iii) (C0= 1.1 mg L−1) was removed in 1 h (Ccatalyst= 0.2 g L−1, CPMS= 0.1 mM). Compared with the original UiO-66, when coupled with peroxymonosulfate (PMS), Mn1D40UiO-66 accelerated the generation of reactive oxygen species (ROS), resulting in an increase in As(iii) removal efficiency by about 50%. XPS spectra and EXAFS spectra indicated that As(iii) adsorbed in the Mn1D40UiO-66/PMS system was fully oxidized to As(v) and the adsorption was attributed to As–O–Zr coordination. Several types of ROS (·OH, SO4−, and O2−) generated by PMS activation acted collectively on As(iii) oxidation, so a single ROS scavenger did not have a marked inhibitory effect on As(iii) removal. In addition, the system maintained efficiency over a broad pH range (3–11), and retained an arsenic removal rate higher than 89.8% even in the presence of high concentrations of several anions (SO42−/Cl−/NO3−, 10 mM). Meanwhile, 99.3% of the As(iii) could be removed by Mn1D40UiO-66 at extremely high humic acid concentrations (100 mg L−1). Due to the excellent stability of the material, only trace amounts of metal leaching were detected (Mn ion ≤ 3 μg L−1) during the whole experiment. The whole oxidation and adsorption process demonstrated excellent anti-interference ability and stability. This study shows the great potential of transition metal doped defective metal–organic frameworks in the field of adsorption and catalysis and provides a novel idea for the high-efficiency management of As(iii) pollution in water environments.

Quantitative detection of various molecules at very low concentrations in complex mixtures has been the main objective in many fields of science and engineering, from the detection of cancer-causing mutagens and early disease markers to environmental pollutants and bioterror agents1–5. Moreover, technologies that can detect these analytes without external labels or modifications are extremely valuable and often preferred6. In this regard, surface-enhanced Raman spectroscopy can detect molecular species in complex mixtures on the basis only of their intrinsic and unique vibrational signatures7. However, the development of surface-enhanced Raman spectroscopy for this purpose has been challenging so far because of uncontrollable signal heterogeneity and poor reproducibility at low analyte concentrations8. Here, as a proof of concept, we show that, using digital (nano)colloid-enhanced Raman spectroscopy, reproducible quantification of a broad range of target molecules at very low concentrations can be routinely achieved with single-molecule counting, limited only by the Poisson noise of the measurement process. As metallic colloidal nanoparticles that enhance these vibrational signatures, including hydroxylamine–reduced-silver colloids, can be fabricated at large scale under routine conditions, we anticipate that digital (nano)colloid-enhanced Raman spectroscopy will become the technology of choice for the reliable and ultrasensitive detection of various analytes, including those of great importance for human health.

Due to its advantages, such as simple structure, high power density, and strong scalability, single-input multiple-output (SIMO) dc–dc converters exhibit vast application prospects. However, a significant challenge arises in the control design of SIMO converters. This challenge stems from the shared usage of the inductor in the main circuit by all loads, inevitably leading to mutual interference and cross-regulation among the output voltages. Consequently, research on control methods for SIMO dc–dc converters has been a widely discussed topic. In this article, we propose a deep deterministic policy gradient algorithm based reinforcement learning (RL) controller. The proposed control method is applicable to multivariable and nonlinear control systems, offering excellent regulation performance and robustness. It effectively addresses the issues of mutual interference and cross-regulation among the outputs of SIMO dc–dc converters. This approach also enhances the steady-state performance and dynamic regulation capabilities of the converter when operating in continuous conduction mode. Simulations and experiments are conducted to validate the effectiveness of the proposed RL multivariable controller. The results demonstrate that SIMO converters, when controlled by the RL multivariable controller, exhibit improved steady-state and dynamic response performance. This approach effectively mitigates the cross-regulation issues among the outputs of SIMO converters.

Catalytic cleavage of C=C double bonds in alkenes is highly important to convert feedstocks into high-value compounds. However, these approaches are mainly limited to oxidative cleavage of alkenes with excess oxidants and redox-neutral alkene metathesis. In contrast, reductive C=C double bond cleavage and functionalization have not been reported. Herein, we report a novel visible-light photoredox-catalyzed carboxylation of styrenes with CO2viareductive C=C double bond cleavage. The use of dicyclohexylmethylamine as scission reagent is the key to the success. Different from previous homologation reactions with CO2, this protocol enabled exchange of the carbon of styrenes with CO2, affording important aryl acetic acids viaC=C double bond cleavage. Moreover, preliminary mechanistic investigation and DFT calculations shed light on the reaction mechanism, disclosing aminomethyl-carboxylation intermediate, benzylic radicals and carbanions as key intermediates in the reaction.

This letter presents a high-gain, low-coupling, omnidirectional, and dual-polarized dielectric resonator antenna (DRA). The high-order TE021+δ and TM02δ modes of the cylindrical DRA are used in the design. The TE021+δ mode is excited by four radial slots with in-phase and equal-magnitude inputs, which produces a horizontal-polarized omnidirectional radiation pattern. A central probe is used to excite the TM02δ mode, which generates a vertical-polarized omnidirectional radiation pattern. The relatively narrow impedance bandwidths of the two high-order modes present a challenge for the design. To solve this problem, the “×” shape and central air layers are introduced at the vertical planes of the E-fields of the TE021+δ and TM02δ modes, respectively, which are found to enhance the impedance bandwidths of the corresponding DRA modes effectively and almost independently. The proposed DRA has an overlapping bandwidth of 7.7%, with a low coupling of −34 dB achieved. Most importantly, it offers a high peak gain of 6.0 dBi.

Graphical Abstract:

This article proposes a novel deep deterministic policy gradient (DDPG) assisted integral reinforcement learning (IRL)-based control algorithm for the three-phase dc/ac inverter feeding a resistive–inductive (RL) load. The proposed controller autonomously updates its control gains online without the need to know the system model. Excellent steady-state and dynamic system responses are achieved by the proposed control algorithm with reasonably low computational complexity. Moreover, the important initial stabilizing control problem is solved through offline training that uses the DDPG technique. Details of the DDPG-based training procedures are presented. Experimental results are presented to verify the efficacy of the proposed IRL-based control method.

Formic acid (FA) can serve as a hydrogen carrier and is easy to store and transport. However, the decomposition of FA requires the use of a catalyst to accelerate the reaction rate and improve the hydrogen yield, which is of great significance for promoting the development of hydrogen energy technology and achieving sustainable development goals. Herein, chitosan-derived nitrogen-doped biochar-supporting palladium nanoparticles were synthesized and used as catalysts for formic acid dehydrogenation, showing excellent catalytic performance. The initial TOF of the Pd 9.2/C–N catalyst reached 615 mol H2mol Pd–1h–1and the activation energy was 39.15 kJ mol–1. The good catalytic performance of the catalyst was attributed to the well-distributed ultrafine palladium nanoparticles with a size of 2.2–2.6 nm and proper metal-carrier interaction, which enhanced the capability of the palladium nanoparticles in the cleavage of the C–H bond of FA. Parameters, such as palladium loading and reaction time, were investigated along with an improved and comprehensive kinetic study, which provides new insights into the field of FA dehydrogenation.

Locating distinct objects within a thick scattering medium remains a long-standing challenge in the fields of materials science, health, and engineering. Transmission Raman spectroscopy (TRS) with the use of surface-enhanced Raman scattering (SERS) nanoparticles has proven to be an effective approach to detect deep-seated lesions inside thick biological tissues. However, it has not yet been proven to spatially locate deep lesions in three dimensions using optical modalities. Herein, we present the concept of tomographic TRS and report its successful use for accurately locating SERS nanoparticles in elongated rod-like thick tissues. Our work starts with theoretical simulations of Raman photon propagation in tissues. We discovered a linear relationship between the Raman spectral peak ratio and propagation distance of Raman photons in tissues, allowing us to predict the location of lesions tagged by SERS NPs. Based on this, we propose a two-step tomographic TRS strategy, which includes axial scanning and ring scanning. We demonstrate the robustness of our approach using ex vivothick tissue (4.5 cm in thickness) and locate an embedded SERS phantom lesion, with a ring scanning step of 10–30°. We successfully locate multiple SERS phantom lesions in the ex vivoporcine muscle stack with high accuracy (absolute error of <2 mm). Our method is rapid, efficient, and of low cost compared to current tomographic medical imaging techniques. This work advances Raman techniques for three-dimensional positioning and offers new insights toward practical diagnosis applications.

Skin is the first line of the body to resist pathogen invasion. A potentially fatal infection may result from problems with wound healing. Small molecule drugs like astragaloside IV (AS‐IV) show pro‐healing activities, but the mechanisms are not fully understood. Using real‐time quantitative PCR and a western blot assay, the amount of gene expression was evaluated. The proliferation and migration of keratinocytes were determined by MTS and wound healing assay, respectively. The binding of lncRNA H19 to RBP protein ILF3 and the binding of ILF3 protein to CDK4 mRNA were confirmed by RNA immunoprecipitation. Treatment with AS‐IV enhanced the expression of lncRNA H19, ILF3, and CDK4 and improved the proliferation and migration of keratinocytes HaCaT. Additionally, apoptosis of keratinocytes was attenuated by AS‐IV. Further studies showed that both lncRNA H19 and ILF3 were important for AS‐IV‐mediated keratinocyte growth and migration. In addition, lncRNA H19 recruited ILF3 to increase CDK4 mRNA level and enhanced cell proliferation. We discovered a lncRNA H19/ILF3/CDK4 axis that is activated by AS‐IV to promote keratinocyte migration and proliferation. These results elucidate the mechanism of action of AS‐IV and justify its application in further application in wound healing treatment.

Cyphostemma, with ca. 200 species, is the second‐largest genus after Cissusin the grape family Vitaceae. Cyphostemmaexhibits a high degree of morphological variation both between and within species that confounds species delimitation. Additional questions remain due to limited taxon sampling, original reference specimens damaged or lost and incomplete descriptions of taxa. Previous molecular studies, with limited taxon sampling, suggested three major clades corresponding to their distribution in continental Africa, Madagascar and Asia. However, deep relationships and biogeographic history within Cyphostemmaremain unresolved. We conducted phylogenetic analysis and morphological character reconstruction of Cyphostemmausing 91 newly assembled plastomes, with a focus on resolving complex taxonomic issues in Madagascar. Our results strongly support the Malagasy Cyphostemmaas non‐monophyletic for the first time. Biogeographic reconstructions reveal two independent dispersals from continental Africa to Madagascar. The first dispersal is dated to the Oligocene and has led to the diversification of species with pinnate leaves in Madagascar. The second dispersal is estimated to have occurred during the late Miocene and has given rise to the only species with digitate leaves in Madagascar. Ancestral state reconstructions reveal that several morphological innovations may have promoted adaptation of Cyphostemmato a diverse range of habitats in Madagascar. In particular, a group of species from southern Madagascar have evolved both succulent stems and leaves to cope with extreme aridification in this region. Finally, relationships within three species complexes from the “Sambirano domain”, the southern spiny forest‐thicket and the northern limestone areas of Madagascar are clarified and four new taxa are proposed based on molecular and morphological evidence.

Photocatalytic carboxylation with CO2is a powerful strategy for the synthesis of functionalized carboxylic acids and their derivatives under mild conditions. However, the dicarboxylation of alkenes with CO2is still underdeveloped and confined to the formation of only two C–C bonds. Herein, we report the 1,3-dicarboxylation of unactivated alkenes with CO2via1,2-aryl migration, which involves the cleavage of one C–C bond and the formation of three C–C bonds. This visible-light photocatalytic protocol is also distinguished by good functional group tolerance, broad substrate scope, and facile derivations of products to heterocyclic scaffolds. Mechanistic studies indicate that the in situgenerated formate could act as the radical precursor of CO2˙−, and the following radical addition, 1,2-aryl migration, single electron reduction, and nucleophilic attack at the second CO2would afford the dicarboxylic acids.

Friction and wear tests were performed on five Cu-based materials and three polyether ether ketone (PEEK)-based composites sliding against 17-4PH and 42CrMo4 coated with tungsten carbide-reinforced Ni-based coating. Two types of pin-on-disk specimens were used to represent the slipper/eccentric drive and piston/sleeve gap seal tribo-pairs in water hydraulic radial piston pumps. The experimental results showed that the QSn8-0.3 slipper material exhibited the highest steady-state friction coefficients for sliding against both 17-4PH (0.156) and coated-42CrMo4 (0.894). Glass fiber-reinforced PEEK exhibited the highest steady-state friction coefficients for sliding against the two specimens (0.540 and 0.420). The ZCuPb15Sn8/17-4PH showed the highest wear rate for the representative slipper/eccentric drive tribo-pair (26.86  ×  10−6mm/Nm); glass fiber-reinforced PEEK/17-4PH showed the highest wear rate for the representative piston/sleeve gap seal tribo-pair (46.91  ×  10−6mm/Nm). The wear mechanisms of the two types of tribo-pairs were characterized through scanning electron microscopy, profilometry, and energy-dispersive spectroscopy analyses. Furthermore, the effects of hardness, pvvalues, coating, and reinforcement on the tribological behavior of the two types of tribo-pairs were analyzed.

Difunctionalizing carboxylation of alkynes with CO2is a sustainable and important strategy to generate valuable acrylate derivatives from both readily available starting materials. Such protocols, however, always suffer from the use of excess metallic reagents and transition metal residue. Herein, we report the first thio-carboxylation of alkynes with thiophenols and CO2, which is a visible-light-driven and transition metal-free process. In contrast to previous carboxylations of alkynes viatwo-electron activation of CO2, mechanistic and computational investigations suggest that the single-electron activation of CO2is involved in the thio-carboxylation, rendering unique β-carboxylation. The following cyclizing acylation affords important thiochromones efficiently. Moreover, the one-pot method features mild reaction conditions (room temperature, 1 atmosphere of CO2), high chemo- and regio-selectivity, easy scalability and facile derivatization of products to bioactive compounds.

Phosphogypsum is an industrial waste generated in the production of fertilizers causing environmental problems. Calcined phosphogypsum (CPG) is obtained by low-temperature calcination and dehydration of phosphogypsum. CPG is mainly used to produce building materials. However, mechanical strength properties and water resistance of CPG materials is extremely poor, which leads to its relatively low utilization rate in construction industry. To address this issue, various amount of Ordinary Portland cement (OPC), fly ash (FA), rice husk (RH) and modified admixtures (AD) were mixed with the CPG to obtain CPG-based composite cementitious materials, which enhanced the water resistance and mechanical strength of the corresponding hardened materials. The influence of different contents of cement on the setting time, hydration heat, hydration products, mechanical properties, water absorption, heavy metal leaching and deterioration coefficient of the composite cementitious material is investigated. The results showed that the optimal mixing ratio of CPG: OPC: FA: RH was 57: 20: 10: 13 considering the water resistance and mechanical strength properties of CPG-based composite cementitious materials. On these conditions, the compressive strength, the flexural strength, water absorption and deterioration coefficient of the specimens at 28 days are 6.1 MPa, 4.6 MPa, 29.4% and 0.66 respectively, which were in line with the national standard of phosphorus building gypsum wallboard. It was demonstrated that two skeleton types are present in the samples prepared using CPG-based composite cementitious materials, which had a synergistic support effect on the structure. The first skeleton was formed by gypsum dihydrate crystals (CaSO4·2H2O) and provided strength to the specimens at an early stage, while the second skeleton was formed by ettringite (AFt) and C–S–H gels, which provided strength at a later stage. The skeletons make the hardened materials denser and more waterproof. Moreover, the composite materials exhibited a positive solidification effect on heavy metals present in CPG.

Icariin, a flavonoid glycoside isolated from Epimedium brevicornum , exerts a variety of biological activities. However, its effects on depression-induced glucocorticoid resistance in asthma and the underlying mechanisms have not been elucidated. In this study, a murine model of asthma with depression was established by exposure to ovalbumin combined with chronic unpredictable mild stress, and icariin was given orally during ovalbumin challenge and chronic unpredictable mild stress exposure. Depression-like behaviors were assessed by the open field test, forced swim test, and tail suspension test. The characteristic features of allergic asthma, including airway hyperreactivity, histopathology, inflammatory cytokine levels in bronchoalveolar lavage fluid, and immunoglobulin E and corticosterone levels in serum, were examined. Following splenocyte isolation in vitro , the inhibitory effects of corticosterone on the proliferation and cytokine secretion of splenocytes, glucocorticoid receptor DNA-binding activity, and expression of p-glucocorticoid receptor s226, glucocorticoid receptor α , and p-p38 mitogen-activated protein kinase in splenocytes were determined. We found that icariin had limited effects on depression-like behaviors, however, it markedly suppressed airway hyperresponsiveness, inflammatory infiltration in lung tissues, levels of interleukin-4, interleukin-5, and interleukin-6 in bronchoalveolar lavage fluid, and immunoglobulin E in serum. Furthermore, icariin improved the inhibitory effects of corticosterone on lipopolysaccharide-stimulated splenocytes, increased the glucocorticoid receptor expression and glucocorticoid receptor DNA-binding activity, and inhibited the phosphorylation of glucocorticoid receptors S226 and p38 mitogen-activated protein kinase. Taken together, icariin improved glucocorticoid resistance in a murine model of asthma with depression associated with enhancement of glucocorticoid receptor function and glucocorticoid receptor expression, and its effects on the glucocorticoid receptor function were related to decreased phosphorylation of glucocorticoid receptors S226 and p38 mitogen-activated protein kinase. [ABSTRACT FROM AUTHOR]

Vacancy engineering is an important means to improve the catalytic performance of photocatalysts. Both VMnand VOcan promote photocatalytic and thermocatalytic reactions of MnO2catalysts. From the point of view of reducing energy consumption, photocatalysis has incomparable advantages over thermocatalysis. Meanwhile, in-depth investigation of the relative contribution of VMnand VOon the photocatalytic reaction was not concluded yet. In this paper, VMn-1 and VMn-2 (with different levels of manganese vacancies (VMn)) and VMn,O(with both VMnand oxygen vacancies (VO)) were synthesized to investigate the relative contributions of VMnand VOin the photocatalytic process by MnO2. The catalysts were characterized by EDS, ICP, and XPS to explore their structures and the concentrations of VMnand VO. The contributions to phenol degradation were calculated to be 487 321.43 (mg L−1) phenol per mol VMnand 125 917.16 (mg L−1) phenol per mol VOfor 2 h irradiation under 400 mW cm−2visible light. Density-functional theory (DFT) calculations were performed to explain the different contributions of VMnand VO. The higher contribution of VMnis attributed to its induced formation of a continuous band gap on the (001) crystal surface, which is favourable for visible light absorption and carrier transport. This study provides theoretical guidance and research direction for the design of efficient photocatalysts using vacancy engineering.

Incorporating the intrinsic catalytic activity of discrete molecular catalysts into covalent frameworks often enables improved electrocatalytic performance. Metallocorroles that represent a burgeoning class of attractive metal-complexes, from the porphyrinoid family, are significantly promising molecular catalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). However, their low catalytic current density and poor stability are undesirable for practical applications. Heterogenizing metal corroles can potentially address these issues, and the resulting integrated catalysts greatly improve the electrocatalytic performance by efficiently avoiding the agglomeration of metallocorroles, but this process is challenging. Herein, a class of spatial, well-defined metal-corrole-based covalent organic polymers (COPs) were prepared and their electrocatalytic ORR, OER, and HER activities in 0.1 M KOH solution were studied. Compared with metallocorroles, M-COPs (M = H, Co, Fe, and Cu) showed obviously enhanced catalytic activity and stability. The Co-COP as a trifunctional electrocatalyst outperformed other M-COPs with a high half-wave potential of 0.80 V for ORR and a low overpotential for OER (560 mV) and HER (208 mV) at 10 mA cm−2. The Co-COP catalyst was utilized to assemble a rechargeable Zn–air battery that exhibited high specific capacity (734 mA h g−1) and power density (83.5 mW cm−2). This work is unparalleled in the development and exploration of metal-corrole-based COPs as multipurpose electrocatalysts.

The carboxylation of readily available organo halides with CO2represents a practical strategy to afford valuable carboxylic acids. However, efficient carboxylation of inexpensive unactivated alkyl chlorides is still underdeveloped. Herein, we report the electro-reductive carboxylation of CCl bonds in unactivated chlorides and polyvinyl chloride with CO2. A variety of alkyl carboxylic acids are obtained in moderate to good yields under mild conditions with high chemoselectivity. Importantly, the utility of this electro-reductive carboxylation is demonstrated with great potential in polyvinyl chloride (PVC) upgrading, which could convert discarded PVC from hydrophobic to hydrophilic functional products. Mechanistic experiments support the successive single electron reduction of unactivated chlorides to generate alkyl anion species and following nucleophilic attack on CO2to give desired products.

The Prospective Randomized On-X Mechanical Prosthesis Versus St Jude Medical Mechanical Prosthesis Evaluation (PROSE) trial purpose was to investigate whether a current-generation mechanical prosthesis (On-X; On-X Life Technologies/Artivion Inc) reduced the incidence of thromboembolic-related complications compared with a previous-generation mechanical prosthesis (St Jude Medical Mechanical Prosthesis; Abbott/St Jude Medical). This second report documents the valve-related complications by individual prostheses and by Western and Developing populations.

When a short-circuit fault occurs in the power grid, induction motors in the distribution network will contribute to the short-circuit current. Accurate short-circuit current calculation of the motors requires detailed modeling of distribution network. This method is not suitable for large-scale power grid. In this paper, an equivalent modeling method of induction motor contribution to short-circuit current is proposed, which is suitable for large-scale grid calculation and without changing the basic algorithm of short-circuit current or the basic data structure of electromechanical transient. An example of Central China Power Grid is shown, and the accuracy of the proposed method is verified by actual fault inversion.

ABSTRACT Sulfate attack is one of the major durability problems in concrete structures. Sulfate ions present in concrete can react with cement hydration products to form gypsum and ettringite, and [...]

ABSTRACT This paper describes an experimental study on the expansion and subsequent damage of concrete specimens immersed in pure water, sulfate solutions of different sulfate concentrations, and mixed solutions of [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jtcvs.2009.07.081 Byline: Daniel R. Wong, Jian Ye, Anson Cheung, John G. Webb, Ronald G. Carere, Samuel V. Lichtenstein Abbreviations: AVR, aortic valve replacement; LV, left ventricle (ventricular); TAVI, transapical aortic valve implantation; TEE, transesophageal echocardiography Abstract: Transapical aortic valve implantation is a recent therapeutic advance for aortic valvular disease. We sought to identify complications -- and the relevant technical and management considerations -- from our learning curve with this procedure. Author Affiliation: Divisions of Cardiac Surgery and Cardiology, St Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada Article History: Received 30 March 2009; Revised 2 July 2009; Accepted 23 July 2009 Article Note: (footnote) Disclosures: Anson Cheung and John Webb report fees and grant support from Edwards.

A general and highly efficient method for the electrochemical C(sp2)–H amination of aldehyde hydrazones with azoles has been developed. This reaction proceeds under exogenous metal-, catalyst-, and oxidant-free conditions to provide aminated hydrazone derivatives in good to excellent yields. This strategy applies to both aromatic and aliphatic aldehyde hydrazones and tolerates a broad range of functional groups.

Surface-enhanced Raman scattering (SERS) nanotags have garnered much attention for in vivoand intraoperative imaging due to their high sensitivity and intrinsic fingerprint spectrum. Recently, in vivobioimaging at the second biological near-infrared (NIR-II) window has demonstrated significant advances with better spatial resolution and deeper tissue penetration. The development of SERS nanotags at the NIR-II window are therefore highly desired. The resonant strategy, i.e., the use of resonant substrates and resonant molecules, can be helpful in fabricating bright SERS nanotags at the NIR-II window; however, this strategy has not been demonstrated with the lack of quantitative assessments. Here we report a quantitative study on the Raman enhancements of the resonant strategy in preparing NIR-II SERS nanotags. By comparing the resonant and nonresonant plasmonic nanorod substrates, the resonant substrates have been shown to provide an enhancement factor of up to 4 orders of magnitude. When using the resonant Raman reporter molecules, SERS intensities can be further increased by 25–546 times. This work demonstrates the potential of the resonant strategy in fabricating ultrasensitive NIR-II SERS nanotags and provides insights into the design of related plasmonic devices.

A versatile synthesis of α-amino bisphosphonates has been achieved through one-pot interrupted Ritter-type reaction under mild conditions. The reactive Ritter intermediate nitrilium is in situgenerated by treatment of nitrile with readily accessible Tf2O/HC(OR1)3, which is trapped by phosphite ester to deliver the desired product. This protocol is efficient, scalable, and well compatible with a broad scope of substrates. In addition, plentiful characteristic JP–Ccouplings including unusual five-bond long-range 5JP–Cand 3JP–Cacross quaternary carbon and hetero (N) atoms were observed in 13C NMR spectra.

Reductive organic transformations, which are important in both academia and industry to generate valuable chemicals, have been widely investigated. However, the reductive transformations of inert substrates still face many challenges, such as high cost and potential safety issues arising from strong reductants in excess, UVC light irradiation, or strong current density for electrolysis. In this context, visible-light photocatalysis has emerged as an ideal approach to provide highly reductive systems for the activation of inert substrates via single-electron reduction under mild conditions. In this review, we highlight some recent contributions to this field, classify them as single- or multiphoton excitation systems, elucidate the mechanisms with different super electron donors, and analyze their structural features on reducibility. Furthermore, the limitations and potential applications of this field will be discussed.

In October 2021, a number of batches of irbesartan and irbesartan hydrochlorothiazide finished products were recalled from the US market, due to the presence of an unacceptable level of the probably carcinogenic nitrosamine N-nitrosoirbesartan. Nevertheless, there is no revealing of the exact structure of this hypothetical N-nitrosoirbesartan. In the current study, we performed a set of 10 reactions of irbesartan with nitrous acid under various conditions and found no trace of this hypothetical N-nitrosoirbesartan by a sensitive and accurate liquid chromatography–mass spectrometry (LC–MS) method with a limit of detection (LOD) of 30 ppb. With the use of LC-photodiode-array (PDA)/UV-high-resolution MSnand one-dimensional (1D)/two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy, the reaction products formed are found to be the two isomeric oxime derivatives of irbesartan, with the Z-isomer as the predominant product. Furthermore, no trace of this hypothetical N-nitrosoirbesartan can be detected in representative commercial batches of irbesartan. Despite the fact that in silicoevaluation suggests that the two irbesartan oximes may be controlled as regular impurities, analysis of representative irbesartan commercial batches by the LC–MS method indicates that the oximes are not detected (LOD: 30 ppb).

Spectral interference from backgrounds is not negligible for surface-enhanced Raman scattering (SERS) tags and often influences the accuracy and reliability of SERS applications. We report the design and synthesis of orthogonal gap-enhanced Raman tags (O-GERTs) by embedding alkyne and deuterium-based reporters in the interior metallic nanogaps of core–shell nanoparticles and explore their signal orthogonality as optical probes against different backgrounds from common substrates and media (e.g., glass and polymer) to related targets (e.g., bacteria, cancer cells, and tissues). Proof-of-concept experiments show that the O-GERT signals in the fingerprint region (200–1800 cm−1) are likely interfered by various backgrounds, leading to difficulty of accurate quantification, while the silent-region (1800–2800 cm−1) signals are completely interference-free. Moreover, O-GERTs show much higher photo and biological stability compared to conventional SERS tags. This work not only demonstrates O-GERTs as universal optical tags for accurate and reliable detection onto various substrates and in complex media, but also opens new opportunities in a variety of frontier applications, such as three-dimensional data storage and security labeling.

To address the issue that B4C ceramics are difficult to be wetted by aluminum metals in the composites, TiB2was introduced via an in-situ reaction between TiH2and B4C to regulate their wettability and interfacial bonding. By pressure infiltration of the molten alloy into the freeze-cast porous ceramic skeleton, the 2024Al/B4C–TiB2composites with a laminate-reticular hierarchical structure were produced. Compared with 2024Al/B4C composite, adding initial TiH2improved the flexural strength and valid fracture toughness from (484±27) to (665±30) MPa and (19.3±1.5) to (32.7±1.8) MPa·m1/2, respectively. This exceptional damage resistance ability was derived from multiple extrinsic toughening mechanisms including uncracked-ligament bridging, crack branching, crack propagation and crack blunting, and more importantly, the fracture model transition from single to multiple crack propagation. This strategy opens a pathway for improving the wettability and interfacial bonding of Al/B4C composites, and thus produces nacre-inspired materials with optimized damage tolerance.

Byline: Jian Ye (a), Jiankang Sun (a), Edward F. Hoffenberg (a), Jie Shen (a), Luojia Yang (a), Randy Summers (a), Tomas A. Salerno (b), Roxanne Deslauriers (a) Abstract: Objective: The purpose of this study was to determine whether retrograde continuous normothermic blood cardioplegic perfusion provides better protection to ischemic areas of the left and right ventricles than does antegrade continuous normothermic blood cardioplegic perfusion. Localized phosphorus 31 magnetic resonance spectroscopy was used to monitor the changes in energy metabolism and intracellular pH in the ventricles of pig hearts. Methods: Ten isolated pig hearts received 20 minutes of antegrade continuous normothermic blood cardioplegic perfusion for collection of control (baseline) data, followed by 60 minutes of either antegrade continuous normothermic blood cardioplegic perfusion (n = 5) or retrograde continuous normothermic blood cardioplegic perfusion (n = 5) with occlusion of the left anterior descending and the right coronary arteries. The hearts were then subjected to antegrade continuous normothermic blood cardioplegic perfusion for 20 minutes. The perfusion pressures were maintained between 80 and 100 mm Hg and between 38 and 43 mm Hg during antegrade and retrograde continuous normothermic blood cardioplegic perfusions, respectively. Intracellular pH and creatine phosphate, inorganic phosphate, and adenosine triphosphate levels were measured continuously in each ventricle by means of localized phosphorus 31 magnetic resonance spectroscopy with 2 surface coils. Results: Both antegrade and retrograde continuous normothermic blood cardioplegic perfusion resulted in a significant increase in inorganic phosphate level and decreases in creatine phosphate level, adenosine triphosphate level, and intracellular pH. No significant differences in these changes were observed between the two groups. The creatine phosphate and adenosine triphosphate levels were significantly lower in the right ventricle than in the left ventricle during retrograde continuous normothermic blood cardioplegic perfusion. On reperfusion, the inorganic phosphate level, creatine phosphate level, and intracellular pH recovered completely; however, no recovery in the adenosine triphosphate level was seen in the ventricles of either group. Conclusions: Retrograde continuous normothermic blood cardioplegic perfusion does not provide better protection to ischemic areas of the ventricles than does antegrade continuous normothermic blood cardioplegic perfusion under our experimental conditions. (J Thorac Cardiovasc Surg 1999;117:994-1003) Author Affiliation: (a) Institute for Biodiagnostics, National Research Council, Winnipeg, Manitoba, Canada (b) Department of Cardiothoracic Surgery, State University of New York at Buffalo, Buffalo, NY. Article History: Received 20 April 1998; Revised 7 July 1998; Revised 8 December 1998; Accepted 11 January 1999 Article Note: (footnote) [star] Supported by the National Research Council of Canada., [star][star] Address for reprints: Roxanne Deslauriers, PhD, or Jian Ye, MD, Institute for Biodiagnostics, National Research Council of Canada, 435 Ellice Ave, Winnipeg, Manitoba R3B 1Y6, Canada., a 12/1/97052

BackgroundTo demonstrate the efficacy and safety of intravitreal injections of conbercept versus laser photocoagulation in the treatment of diabetic macular oedema (DME).MethodsA 12-month multicentre, randomised, double-masked, double-sham, parallel controlled, phase III trial (Sailing Study), followed by a 12-month open-label extension study. Patients with centre-involved DME were randomly assigned to receive either laser photocoagulation followed by pro re nata (PRN) sham intravitreal injections (laser/sham) or sham laser photocoagulation followed by PRN 0.5 mg conbercept intravitreal injections (sham/conbercept). Patients who entered the extension study received PRN conbercept treatment. The primary endpoint was the changes in best-corrected visual acuity (BCVA) from baseline.ResultsA total of 248 eyes were included in the full analysis set and 157 eyes continued in the extension study. Significant improvement in mean change in BCVA from baseline to month 12 was observed in the sham/conbercept group (8.2±9.5 letters), whereas no improvement was observed in the laser/sham group (0.3±12.0 letters). Patients in the laser/sham group showed a marked improvement in BCVA after the switch to conbercept in the extension study, and there was no difference in BCVA between the two groups at the end of the extension study.ConclusionThe use of a conbercept PRN intravitreal injection regimen improved the BCVA of patients with DME, and its efficacy was better than that of laser photocoagulations, and the same efficacy was observed when the eyes treated with laser alone were switched to conbercept.Trial registration numberNCT02194634.