Rapid Insertion Research Articles

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion.

Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C-C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C-C bond cleavage, and C-H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C-C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven to be general: various transition metals including Pd, Cu, Rh, Ni, Co, and Ir are effective catalysts; the scope of the reaction has also been extended to substrates other than diazo compounds; and various cascade processes have also been devised based on the carbene migratory insertion. This review will summarize the achievements made in this field since 2001.

Characteristics and key to manipulation of fire needle

To explore the characteristics and key to manipulation and of traditional fire needle in China. Fire needle refers to a therapy with red-hot needle inserting into the skin. Special requirements are proposed in terms of selected acupoints, to burn needle body, fire needle manipulation, needle withdrawal disposal and other aspects. The therapy is characterized by “paying equal attention to needling and scorching, and laying emphasis on warming and unblocking”, “rapid needle insertion and withdrawal with coherent manipulations”, and “performing needling based on pattern differentiation”. In the process of applying red-hot needling with fire needles, normalized and unified manipulations, accurate point selection and safe stimulus should be emphasized, and the performer should be dedicated and scrupulous, and keep the manipulations coherent in order to achieve the “stable, accurate and rapid” effect. The popularization and application of red-hot needling with fire needles in TCM clinical practice can further enrich the acupuncture therapy, so that this ancient and traditional needling method can give play to its role renewedly.

Synthesis and electrochemical performance of three-dimensional ordered hierarchically porous Li4Ti5O12 for high performance lithium ion Batteries

In this work, a three-dimensional ordered hierarchically porous (3DOHP) Li4Ti5O12 that possesses inner-particle mesopores resulting from a soft template method and a three-dimensional ordered macroporous (3DOM) Li4Ti5O12 using polystyrene spheres as a hard template have been synthesized. Both 3DOM Li4Ti5O12 and 3DOHP Li4Ti5O12 have ordered macropores and interconnected skeletons with a regular periodicity revealed by SEM and TEM observations. The specific surface area of 3DOHP Li4Ti5O12 is up to 135m2g−1 which is much higher compared with that of 3DOM Li4Ti5O12 because of the existence of inner-particle mesopores. Attributed to the higher surface area and smaller crystal grain size, more excellent cycle performance and rate capability are obtained for 3DOHP Li4Ti5O12 compared to 3DOM Li4Ti5O12. In addition, the hierarchically porous structure of 3DOHP Li4Ti5O12 can meet rapid insertion and deinsertion of lithium ion even at extremely high rate. It is apparent that 3DOHP Li4Ti5O12 has a lower total resistance and faster Li+ diffusion coefficient compared to 3DOM Li4Ti5O12 according to electrochemical impendence spectroscopy analysis.

Effect of routine rapid insertion of Bakri balloon tamponade on reducing hemorrhage from placenta previa during and after cesarean section.

To evaluate the effectiveness of routine rapid insertion of a Bakri balloon during cesarean section for placenta previa based on a retrospective control study. Women with singleton pregnancies who underwent cesarean section for placenta previa at our institution between 2003 and 2016 were enrolled. Between 2015 and 2016, women who routinely underwent balloon tamponade during cesarean section were defined as the balloon group. Between 2003 and 2014, women who underwent no hemostatic procedures except balloon tamponade were defined as the non-balloon group. The clinical outcomes of the two groups were retrospectively analyzed. Of the 266 women with placenta previa, 50 were in the balloon group and 216 were in the non-balloon group. The bleeding amounts were significantly smaller in the balloon group than in the non-balloon group: intraoperative bleeding (991 vs. 1250g, p<0.01), postoperative bleeding (62 vs. 150g, p<0.01), and total bleeding (1066 vs. 1451g, p<0.01). Furthermore, the mean surgical duration was shorter in the balloon group than the non-balloon group (30 vs. 50min, p<0.01). In the balloon group, five patients suffered from increasing hemorrhage due to prolapse of the balloon from the uterus after the operation, but the hemorrhage was controlled by balloon re-insertion without additional hemostatic procedures. This study demonstrated that the routine rapid insertion of Bakri balloon tamponade during cesarean section significantly decreased intra- and postoperative hemorrhage and shortened the surgical duration in women with placenta previa.

A smart potential-responsive ion exchange nanomaterial with superparamagnetism for cesium ion separation and recovery

Abstract A smart magnetic potential-responsive ion exchange nanomaterials (MPiX), γ-Fe 2 O 3 @nickel hexacyanoferrate (NiHCF), with three-dimensionally ordered macroporous (3DOM) structure for toxic ion separation and recovery is firstly reported. The smart nanomaterial (3DOM MPiX) is successfully synthesized by coating potential-responsive NiHCF on the surface of three-dimensionally ordered macroporous γ-Fe 2 O 3 with superparamagnetism. Such a 3DOM MPiX shows high ion exchange capacity, excellent selectivity and rapid ion insertion kinetics, which is attributed to the open and interconnected porous channels and the large specific surface area of 3DOM and good affinity of NiHCF toward Cs + . The Cs + adsorbed 3DOM MPiX can be regenerated by simply switching potential of magnetic electrode in a novel electromagnetic coupling regeneration system. Surprisingly, the capacity of the 3DOM MPiX toward Cs + is nearly invariable after 20 adsorption–regeneration cycles and a high regeneration efficiency over 98% is maintained in each cycle. Moreover, the sensitive regeneration mechanism is illuminated by electrochemical experiment as well as advanced quantum chemistry calculation. It is expected to provide a versatile strategy for developing some intelligently potential-responsive nanomaterials in the controlled ion insertion/release field and designing separation devices to promote practical applications in environmental protection and resource reuse.

Discovery of Rapid and Reversible Water Insertion in Rare Earth Sulfates: A New Process for Thermochemical Heat Storage.

Thermal energy storage based on chemical reactions is a prospective technology for the reduction of fossil-fuel consumption by storing and using waste heat. For widespread application, a critical challenge is to identify appropriate reversible reactions that occur below 250 °C, where abundant low-grade waste heat and solar energy might be available. Here, it is shown that lanthanum sulfate monohydrate La2 (SO4 )3 ⋅H2 O undergoes rapid and reversible dehydration/hydration reactions in the temperature range from 50 to 250 °C upon heating/cooling with remarkably small thermal hysteresis (<50 °C), and thus it emerges as a new candidate system for thermal energy storage. Thermogravimetry and X-ray diffraction analyses reveal that the reactions proceed through an unusual mechanism for sulfates: water is removed from, or inserted in La2 (SO4 )3 ⋅H2 O with progressive change in hydration number x without phase change. It is also revealed that only a specific structural modification of La2 (SO4 )3 exhibits this reversible dehydration/hydration behavior.

Vertical Aligned Graphene/Metal Sulfides/N-Doped Carbon Ternary Sandwich Hierarchical Structure for Sodium Storage

Nowadays, sodium ion batteries (SIBs), one of the realistic promising alternatives to the lithium ion batteries (LIBs), have drawn increasing attention because of the high availability, the low cost and the intercalation chemical similarity of sodium compared with lithium. However, many active materials in application of LIBs are invalid for SIBs as far as the different ionic radium (Na+ ,1.06 Å vs. Li+ ,0.76 Å). Thus, much effort has been taken to explore suitable host material to allow reversible and rapid sodium ion insertion or extraction, especially for advanced anode materials. Fortunately, the transition metal dichalcogenides (TMDs) with the formula MoX2 (S or Se) and graphene-like structure are widely studied as anode materials for SIBs due to the unique two-dimensional layered structure and high specific capacity. Nevertheless, the practical application of the graphene-like TMDs is impeded by its inherent limitations. First, layered TMDs nanosheets are so easy to restack with the van der Waals interaction, resulting into the decrease of accessible active sites for sodium ions. Second, compared with carbon-based materials, especially, graphene or carbon nanotubes, the TMDs have lower electrical conductivity, which is not favor electrode reactions. Third, the volume change and structural variation during discharge-charge process cause the pulverization and loose contact of the active materials, resulting rapid capacity fading. Fourth, the TMDs-based anodes face the dissolution issue of polysulfides or polyselenides, resulting in fast capacity fading and low Coulombic efficiency during the discharger-charge process. To combat the aforementioned problems, in this present work, we have made double modifications on the MoX2 by introducing the vertical aligned graphene (VG) as support backbone and nitrogen-doped carbon (N-C) coating as outer protective layer via a simple two-step process. The curved MoX2 nanoflakes are controlled deposited on the VG skeleton, which the cloth fabric server as current collector, via a facile hydrothermal method; subsequently, the N-C layer uniformly coats on the MoX2 nanoflakes by self-polymerizing dopamine followed by a post carbonization process. These samples are directly assembled into SIBs without any binders or conductive materials, and exhibit excellent electrochemical performance for SIBs. For example, our synthesized VG/MoSe2/N-C ternary composite exhibits superior storage sodium performance, with high capacity (540 mAh g-1), enhanced high rate capability and long-term cycling stability (298 mAh g-1 at 2.0 A g-1 after 1000 cycles). These designed ternary sandwich VG/MoX2/N-C ternary sandwichhierarchical structures, which provide a flexible vertical aligned graphene to accommodate volume changes, introduces large efficient active areas, good conductivity, and omnibearing paths for sodium ion and electrons, contributes to their superior performances and enables its application in energy storage.

A Membrane‐Intercalating Conjugated Oligoelectrolyte with High‐Efficiency Photodynamic Antimicrobial Activity

AbstractA membrane‐intercalating conjugated oligoelectrolyte (COE), PTTP, was designed and synthesized with the goal of providing red‐shifted absorption spectra relative to previously synthesized COE analogs. Specifically, electron‐rich and electron‐poor subunits were introduced in the conjugated backbone to modulate the band gap. PTTP exhibits maxima of absorption at 507 nm and of emission at 725 nm. PTTP can also efficiently function to generate singlet oxygen in situ (ΦΔ≈20 %) and has appropriate topology and dimensions to interact with lipid membranes. The resulting rapid membrane insertion and sensitizing ability provide PTTP with a highly efficient antibacterial capability under a low light dose (0.6 J cm−2) toward Gram‐negative bacteria E. coli, making it a remarkably efficient optically mediated antimicrobial agent.

A Membrane-Intercalating Conjugated Oligoelectrolyte with High-Efficiency Photodynamic Antimicrobial Activity.

A membrane-intercalating conjugated oligoelectrolyte (COE), PTTP, was designed and synthesized with the goal of providing red-shifted absorption spectra relative to previously synthesized COE analogs. Specifically, electron-rich and electron-poor subunits were introduced in the conjugated backbone to modulate the band gap. PTTP exhibits maxima of absorption at 507 nm and of emission at 725 nm. PTTP can also efficiently function to generate singlet oxygen in situ (ΦΔ ≈20 %) and has appropriate topology and dimensions to interact with lipid membranes. The resulting rapid membrane insertion and sensitizing ability provide PTTP with a highly efficient antibacterial capability under a low light dose (0.6 J cm-2 ) toward Gram-negative bacteria E. coli, making it a remarkably efficient optically mediated antimicrobial agent.

Grafting Charged Species to Membrane-Embedded Scaffolds Dramatically Increases the Rate of Bilayer Flipping.

The cell membrane is a barrier to the passive diffusion of charged molecules due to the chemical properties of the lipid bilayer. Surprisingly, recent experiments have identified processes in which synthetic and biological charged species directly transfer across lipid bilayers on biologically relevant time scales. In particular, amphiphilic nanoparticles have been shown to insert into lipid bilayers, requiring the transport of charged species across the bilayer. The molecular factors facilitating this rapid insertion process remain unknown. In this work, we use atomistic molecular dynamics simulations to calculate the free energy barrier associated with “flipping” charged species across a lipid bilayer for species that are grafted to a membrane-embedded scaffold, such as a membrane-embedded nanoparticle. We find that the free energy barrier for flipping a grafted ligand can be over 7 kcal/mol lower than the barrier for translocating an isolated, equivalent ion, yielding a 5 order of magnitude decrease in the corresponding flipping time scale. Similar results are found for flipping charged species grafted to either nanoparticle or protein scaffolds. These results reveal new mechanistic insight into the flipping of charged macromolecular components that might play an important, yet overlooked, role in signaling and charge transport in biological settings. Furthermore, our results suggest guidelines for the design of synthetic materials capable of rapidly flipping charged moieties across the cell membrane.

Microwave-assisted binder-free synthesis of 3D Ni-Co-Mn oxide nanoflakes@Ni foam electrode for supercapacitor applications

The outstanding performance of nickel foam (NF) as a current collector owing to its better dimensional stability, high electrical conductivity, and less contact resistance has made it a promising candidate for binder-free electrode for supercapacitors. In addition to the current collector, highly stable structures are also favored to facilitate rapid ion insertion and prevent structural collapse of the electrode materials. In this work, a binder-free and controlled structure of Ni-Co-Mn oxide on NF was constructed effectively using microwave irradiation. The structure obtained from the optimal conditions (concentration and holding time) involved hierarchical interconnected nanoflakes with void spaces, forming a stable and conductive network of nanoflakes on the NF. The synergistic effects of three metal (Ni-Co-Mn) oxides resulted in a high specific capacitance of 2536Fg−1 at 5mAcm−2 (6.49Ag−1) in a mixed KOH/K3Fe(CN)6 electrolyte. The as-prepared symmetric device also obtained a high capacitance of 298Fg−1, a high energy density of 41.4Whkg−1, and a high power density of 5.4kWkg−1. The highly architectured Ni-Co-Mn oxide nanoflakes improved the pseudocapacitive performance significantly, making it a promising electrode material for high-performance binder-free supercapacitors.

Three-dimensional porous carbon-coated graphene composite as high-stable and long-life anode for sodium-ion batteries

Sodium-ion batteries (SIBs) have been investigated as promising alternatives to lithium-ion batteries (LIBs) because of the rich sodium natural resource. Exploring suitable electrode materials is still a great challenge for the practical applications of SIBs. Herein, we demonstrate a novel three-dimensional porous carbon-coated graphene (3D PG@C) anode for SIBs using silica as the porous template combined with a subsequent polyaniline (PANI)-converted carbon coating. The synthesis process mainly consists of deposition of SiO2 nanoparticles on graphene surface, in situ polymerization of aniline monomers and carbonization of PANI and etching of SiO2. The resultant 3D PG@C composite possesses high electrical conductivity, rapid ion insertion, sufficient active sites, short ionic diffusion distance and stable structural integrity for efficient Na-storage. As an anode material for SIBs, the 3D PG@C composite delivers excellent Na-storage performance, in terms of high initial discharge capacity (824mAhg−1 at 50mAg−1), large reversible capacity and long cyclability (323mAhg−1 after 1000 cycles at 1000mAg−1) and remarkable rate capability (207mAhg−1 at 10000mAg−1). The design strategy reported in this work would provide a promising approach toward high-stable and long-life carbonaceous anode materials for SIBs.

Sponge-Like Li4Ti5O12 Constructed on Graphene for High Li Electroactivities.

A sponge-like Li(4)Ti(5)O(12)/graphene composite was prepared via sequential hydrothermal process and solid-state heat treatment process for the application to high-power lithium ion batteries. The as-prepared electrode showed outstanding Li electroactivities with a rapid and reversible Li insertion/ extraction of up to 10 C-rate (1.75 A/g). It delivered a discharge capacity of 174 mAh/g at 0.5 C, near the theoretical capacity of Li(4)Ti(5)O(12), with good rate capability and cyclic stability. First-principles calculations revealed the intimate interaction of the Li(4)Ti(5)O(12) and graphene, which implies that graphene functions as an ‘electron tunnel.’ Electrochemical impedance spectroscopy also proved that the graphene-hybridization and the unique structure of the Li(4)Ti(5)O(12) material significantly reduce the resistive behavior of electrodes. The 3D structured Li(4)Ti(5)O(12)/graphene hybrid reported herein could be a promising candidate for a safe, low-cost, high-power anode for lithium ion batteries, and our seeding-growth-sintering method for decorating graphene with active material will offer an effective upgrade on highly insulating Li(4)Ti(5)O(12) materials.

Comparison of multiple diagnostic techniques to study soot formation and morphology in a diffusion flame

Different non-intrusive optical and intrusive non optical diagnostic methods are used to measure flame and soot properties in a laminar coflow diffusion flame in order to compare and analyze the sensitivity of each technique to soot particles with different age and morphology. Flame temperature is measured using rapid thermocouple insertion (RTI) method and also by measuring soot spectral emissions (SSE). Soot volume fraction (fv) is measured quantitatively with laser extinction (LE), time resolved laser induced incandescent (TiRe-LII) and SSE methods and qualitatively from the transmission electron microscope (TEM) images of the thermophoretically sampled soot particles. Particle internal/aggregate nanostructure, and primary particle diameter are also analyzed based on TEM images from the sampled particles and TiRe-LII. It is shown that the optical methods are only sensitive to mature soot particles with solid appearance and cannot detect either temperature or fv in regions where liquid like nascent soot particles are dominant. fv measured by LE and TiRe-LII agree well while the values measured by SSE are lower. This discrepancy is attributed to the high sensitivity of fv measured by SSE to the measured temperature values. Temperature profiles measured by SSE are considerably higher than the values measured by RTI. It is shown that not considering the change of the surface emissivity of the thermocouple junction due to particle deposition for estimating radiation loss in regions where nascent or mature soot particles are dominant contributes to this discrepancy. Primary particle sizes measured based on TEM images and TiRe-LII agree reasonably well. Soot aggregate fractal dimension is shown to decrease as the soot particles age and become more mature.

Proton Wire Dynamics in the Green Fluorescent Protein.

Inside proteins, protons move on proton wires (PWs). Starting from the highest resolution X-ray structure available, we conduct a 306 ns molecular dynamics simulation of the (A-state) wild-type (wt) green fluorescent protein (GFP) to study how its PWs change with time. We find that the PW from the chromophore via Ser205 to Glu222, observed in all X-ray structures, undergoes rapid water molecule insertion between Ser205 and Glu222. Sometimes, an alternate Ser205-bypassing PW exists. Side chain rotations of Thr203 and Ser205 play an important role in shaping the PW network in the chromophore region. Thr203, with its bulkier side chain, exhibits slower transitions between its three rotameric states. Ser205 experiences more frequent rotations, slowing down when the Thr203 methyl group is close by. The combined states of both residues affect the PW probabilities. A random walk search for PWs from the chromophore reveals several exit points to the bulk, one being a direct water wire (WW) from the chromophore to the bulk. A longer WW connects the "bottom" of the GFP barrel with a "water pool" (WP1) situated below Glu222. These two WWs were not observed in X-ray structures of wt-GFP, but their analogues have been reported in related fluorescent proteins. Surprisingly, the high-resolution X-ray structure utilized herein shows that Glu222 is protonated at low temperatures. At higher temperatures, we suggest ion pairing between anionic Glu222 and a proton hosted in WP1. Upon photoexcitation, these two recombine, while a second proton dissociates from the chromophore and either exits the protein using the short WW or migrates along the GFP-barrel axis on the long WW. This mechanism reconciles the conflicting experimental and theoretical data on proton motion within GFP.

Coordinated process of polarized growth in filamentous fungi.

Filamentous fungi are extremely polarized organisms, exhibiting continuous growth at their hyphal tips. The hyphal form is related to their pathogenicity in animals and plants, and their high secretion ability for biotechnology. Polarized growth requires a sequential supply of proteins and lipids to the hyphal tip. This transport is managed by vesicle trafficking via the actin and microtubule cytoskeleton. Therefore, the arrangement of the cytoskeleton is a crucial step to establish and maintain the cell polarity. This review summarizes recent findings unraveling the mechanism of polarized growth with special emphasis on the role of actin and microtubule cytoskeleton and polarity marker proteins. Rapid insertions of membranes via highly active exocytosis at hyphal tips could quickly dilute the accumulated polarity marker proteins. Recent findings by a super-resolution microscopy indicate that filamentous fungal cells maintain their polarity at the tips by repeating transient assembly and disassembly of polarity sites.

A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State

AbstractA tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air‐ and moisture‐stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal–organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with PdIICl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with CoII ions and structural resolution by single crystal X‐ray diffraction. The Pd−Cl groups inside the pores are accessible to post‐synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd−CH3 activated material undergoes rapid insertion of CO2 gas to give Pd−OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd−N3 modified version resists CO insertion under the same conditions.

A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State

A tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air- and moisture-stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal-organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with Pd(II) Cl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with Co(II) ions and structural resolution by single crystal X-ray diffraction. The Pd-Cl groups inside the pores are accessible to post-synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd-CH3 activated material undergoes rapid insertion of CO2 gas to give Pd-OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd-N3 modified version resists CO insertion under the same conditions.

Objective reasons and the strategies on pain during the needle insertion and the key points in teaching program

Retrieving literature and summarizing the experience in lecturing acupuncture and clinical practice, the authors analyzed the objective reasons of pain during the needle insertion. Three factors are considered, including needles, skin tissue of inserting site and technique of insertion. The teaching program was discussed on how to alleviate or avoid pain during the concrete manipulation. It is viewed that no matter in teaching program of acupuncture or clinical operation, for alleviating pain during needle insertion, the key points must be on the rapid insertion through skin surface and the coordination of the puncture hand and pressing hand.

Mapping polaronic states and lithiation gradients in individual V2O5 nanowires.

The rapid insertion and extraction of Li ions from a cathode material is imperative for the functioning of a Li-ion battery. In many cathode materials such as LiCoO2, lithiation proceeds through solid-solution formation, whereas in other materials such as LiFePO4 lithiation/delithiation is accompanied by a phase transition between Li-rich and Li-poor phases. We demonstrate using scanning transmission X-ray microscopy (STXM) that in individual nanowires of layered V2O5, lithiation gradients observed on Li-ion intercalation arise from electron localization and local structural polarization. Electrons localized on the V2O5 framework couple to local structural distortions, giving rise to small polarons that serves as a bottleneck for further Li-ion insertion. The stabilization of this polaron impedes equilibration of charge density across the nanowire and gives rise to distinctive domains. The enhancement in charge/discharge rates for this material on nanostructuring can be attributed to circumventing challenges with charge transport from polaron formation.