Search

Abstract Metallic circular tube with external uniform grooves has excellent behaviors on axial crashworthiness during axial compression because it can generate stable responses. In the present research, three novel energy absorbers are proposed based on uniform grooved tube (UGT), namely, depth gradient grooved tube (D-GGT), thickness gradient grooved tube (T-GGT) and coupling gradient grooved tube (C-GGT). A theoretical model considering both the depth and thickness gradients and an efficient numerical model based on axisymmetric assumption are put forward. Meanwhile, some quasi-static compression experiments are performed to validate the theoretical and numerical models. The results conclude that the deformation of gradient grooved tubes (GGTs) under axial buckling can be classified into two modes, namely, random asymptotic buckling (RAB) and sequential asymptotic buckling (SAB). Compared with UGT, the D-GGT has a slight improvement on the axial energy performance even though the sum of depth of thin-walled sections is constant; for T-GGT, a force-displacement curve with upward trend and an obvious improvement of energy absorption are observed; specially, the energy absorption characteristics of D-GGT and T-GGT will occur simultaneously when C-GGT is subjected to axial loading. Graphical abstract fx1 Highlights • A novel theory of gradient grooved tube (GGT) under axial compression is obtained. • An axisymmetric numerical modeling method for GGT is proposed. • The axial buckling modes of GGT are defined. • GGT has better axial crashworthiness compared with uniform grooved tube (UGT). [ABSTRACT FROM AUTHOR]

Two sections of marine carbonate strata, Podu and Lengshuixi, from the Yangtze platform, South China, are investigated in terms of major geological events and carbon-strontium isotope responses. The results show a large-scale regression and a Large Igneous Province (LIP) event occurred in succession in the short interval of the late Guadalupian, inducing a biodiversity crisis. The regression event, marked by an increase in the 87Sr/86Sr ratio, is observed in the Jinogondolella postserrata Zone. It contributed significantly to the reduction in species habitat, leading to notable losses within the shallow-water species assemblage. A subsequent LIP event occurred after the appearance of Jinogondolella altudaensis, releasing CO2 and numerous other deleterious gases that further amplified the crisis in shallow-water to deep-sea environments. The corresponding decline in Sr and C isotopes could have been a response to the basaltic eruption (relative increase from mantle-derived Sr) and release of 12C-enriched CO2. During the process of creation of the LIP, the decline in δ13Ccarb was mainly associated with 12C-enriched CO2 release from organic matter in sedimentary strata, and high-temperature isotope fractionation during the volcanic eruption stage (exceeding 1200 °C). This study could further provide valuable clues regarding the development process of the major geological events and the causes of the biodiversity crisis. [ABSTRACT FROM AUTHOR]

Microwater droplet splitting and merging in a parallel-plate electrowetting-on-dielectric (EWOD) device have been studied numerically. The transient governing equations for the microfluidic flow are solved by a finite volume scheme with a two-step projection method on a fixed computational domain. The inteiface between liquid and gas is tracked by a coupled level set (LS) and volume-of-fluid (CLSVOF) method. A continuum surface force (CSF) model is employed to model the surface tension at the inteiface. Contact angle hysteresis which is an essential component in EWOD modeling is implemented together with a simplified model for the viscous stresses exerted by the two plates at the solid-liquid interface. The results of the numerical model have been validated with published experimental data and the physics of droplet motion within the EWOD device has been examined. A parametric study has been performed in which the effects of channel height and several other parameters on the fluid motion have been studied. [ABSTRACT FROM AUTHOR]

An efficient and green process of catalytic hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ) to 2,3,5-trimethylhydroquinone (TMHQ) on Pd/C catalyst using the LBA (a commercial mixed solvent) as solvent is described. The important reaction parameters (e.g. temperature, catalyst loading, initial concentration of TMBQ, hydrogen pressure, and agitation speed) have been investigated to acquire the optimal process conditions. The hydrogenation molar yield of TMHQ by HPLC analysis is 99.4 %. The solvent could be recovered by steam distillation, while the isolated TMHQ overall molar yield reaches up to 96.7 %. The deactivation of Pd/C during the reuse of catalysts was ascribed to the depositions of TMHQ and TMBQ based on various characterizations and regeneration study of catalyst. The possible catalytic hydrogenation mechanism is also discussed. [ABSTRACT FROM AUTHOR]

• Swollen-induced in-situ encapsulation of catalysts in cross-linked polysiloxane elastomers polymer. • Silicone rubber-based microchannel reactor was employed for asymmetric transforms. • Cross-linked polysiloxane elastomers was proved to be easily recycled by filtration or pick-up,reused by several times and exhibits excellent enantioselectivities 94–96% ees The immobilization of molecular catalysts to fabricate heterogeneous catalysts for catalytic asymmetric transformations is extremely important and has attracted great attentions. Herein we developed a simple and new strategy for the heterogenization of homogeneous molecular complexes into the cross-linked polymer. It is demonstrated for the first time that the cross-linked polysiloxane elastomers can be applied for the swollen-induced in-situ encapsulation of homogeneous catalysts with or without chiral ligands. The swollen-induced in-situ encapsulation of silver catalyst system in the cross-linked polysiloxane elastomers led to the formation of silicone rubber-based hierarchically porous that could be used in asymmetric [3+2] cycloaddition, asymmetric tandem conjugate addition−elimination reaction and oxidation of hydrosilanes to silanols. The swollen-induced in-situ encapsulation of chiral silver complex in the cross-linked polysiloxane elastomers was proved to be easily recycled by filtration or pick-up and reused by several times. The simplest heterogeneous catalysis by the strategy of swollen-induced in-situ encapsulation can be extended to the encapsulation of chiral metal catalysts into different polymeric materials for the heterogenization of homogeneous catalysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Here new evidence of the isotope geochronology and the geochemistry from the Yuanmou-Miyi complexes reveal the Precambrian tectono-magmatism geodynamic process in the study area. The Yangtze Block basement with 1.81- ~1.77 Ga and negative εHf(t) values of −7.8 to −0.7 corresponded to the assembly of the Columbia-supercontinent. However, the rifting magmatic event of ~ 1.70 Ga, which caused the continental crust extension-thinning in the study area, may exert influence on the subduction-magmatism in the Grenvillian period. The Yuanmou-Miyi complexes of 1.19- ~1.00 Ga are characterized by (La/Sm)N＞1, depletion in HFSEs, negative anomalies of Nb-Ta, and enrichment of LILEs, which show a genetic link with the subduction-magmatism. The temporal tendency that the magmatism from Yuanmou to Miyi gradually became younger, may be responsible for the subducting direction. The subduction caused the reactivation of the Anninghe-Lvzhijiag fault zone, and created the rupture windows of the subduction slab, leading to upwelling of the deep magma. These granitoids were derived from the partial melting of the mantle wedge, while the small-scale gabbro dikes intruded into the granitoids were likely spillover products from the asthenosphere mantle melts through the rupture windows. [ABSTRACT FROM AUTHOR]

In the present research, the axial crushing behaviors of foam-filled holed tube are investigated by performing quasi-static compression tests. The possible deformation modes are obtained. The experimental results show that the energy absorption performance of empty holed tube can be greatly enhanced by filling aluminum foam. Furthermore, a novel theoretical model for concertina mode of foam-filled holed tube is proposed based on super folding element method, and validated by present and previous experimental results. The interaction between the tube wall and foam filler, normalized mean crushing force and specific energy absorption are obtained theoretically and discussed in detail. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses geological and geochemical evolution of forming of kalium-rich brine in Sichuan Basin in China. Topics discussed include effects of numerous distinct tectonic events on salt brine reservoir in Sichuan Basin, varied ion concentration of sea water due to sea water evaporation, occurrence of small amount of evaporites, and occurrence of celestite precipitate.

A unique 1,3-dipolar [3+2] cycloaddition of alkyl 4-oxo-4-arylbut-2-enoates bearing two different electron-withdrawing groups was completed by using the silver/(R)-DTBM-Segphos catalyst system, which gives the corresponding fully substituted pyrrolidines with four stereogenic centers in good yields and with excellent enantioselectivities (up to 98% ee). [ABSTRACT FROM AUTHOR]

We report herein the use of covalent organic frameworks (COFs) to facilitate the energy transfer from sensitizer to the active sites for efficient photocatalysis. The results indicate that the photocatalytic efficiency can be apparently enhanced by using the layered COFs. The visible-light-induced hydrogen evolution rate (10.4 mmol g−1 h−1) for Pd0/TpPa-1 sensitized by Eosin Y was 10 times higher than that of Pd/C. The enhanced photocatalytic H 2 -production activity could be originated from the improvement of the photogenerated electron transfer in conjugated COFs. The important role of COFs in facilitating the transfer of photogenerated electrons was verified by the transient photocurrent response and the luminescence analysis. This research highlights the use of COFs to investigate the energy transfer process. • COFs were used to improve the energy transfer from sensitizer to active sites. • Enhanced photocatalytic efficiency can be achieved by using COFs. • The role of COFs in facilitating the energy transfer was proposed. [ABSTRACT FROM AUTHOR]

Understanding the processes and products of carbonate diagenesis is crucial to the exploration and optimum development of palaeokarst hydrocarbon reservoirs in Permian carbonate rocks. Several well-documented outcrops and well drills in the Permian marine carbonate strata around the Sichuan Basin, South China, encompassing well-developed paleokarst landforms in the Middle-Upper Maokou Formation have been investigated. The sections and cores recording paleokarst reservoirs exhibit very similar carbonate diagenetic products and processes from various diagenetic environments by much most cementation and formation of secondary porosity in carbonates. The major diagenetic environments experience the zones of seawater, surface or near-surface atmospheric water, and subsurface mixed water between marine and meteoric. Characteristic diagenetic textures produced in each environment are described and different generations of calcite cements related to the process are responsible for their formation by sedimentary petrology and stable isotope geochemistry. Paleokarst under the constrained condition of surface and near-surface atmospheric water is the most favorable for oil-gas accumulation and presents some karst-related pores-caves-fissures with less or no fillings. Dissolution and corrosion of carbonate by atmospheric freshwater can alter the accumulation spaces and develop better fractures-caves system. These characteristic could exhibit some substantial data for better predicting porosity trends in Permian carbonate rocks and also provide important geological information for further exploring oil-gas resource in marine carbonate strata. [ABSTRACT FROM AUTHOR]

The remains of trilobites and other species were unexpectedly discovered in a volcanic ash layer beneath the Permian–Triassic Boundary (PTB). Based on a biostratigraphic investigation of the Zhongliangshan section in Chongqing, South China, the quantity of the species gradually decreased with subsequent volcanism. This finding provides an opportunity to further understand the disappearance of trilobites and the evolution of the mass extinction event. The temporal coincidence between the volcanic eruption event and the loss of trilobites and other species supports the idea of a cause-and-effect relationship. The species remains in the ash bed appeared before the disappearance ofClarkinayiniand the climax of the negative carbon isotope excursion, which implies that the onset of the mass extinction occurred at the end-Permian. The explosive volcanic events caused massive releases of CO2, toxic gases and volcanic ash and resulted in loss of habitat for certain species in the Tethys domain. This phenomenon may have led to the abrupt death of trilobites and the catastrophic collapse of biodiversity. [ABSTRACT FROM AUTHOR]

Well-documented outcrops around the Emeishan Large Igneous Province (ELIP) in South China, eastern Tethys, encompassing the end-Guadalupian mass extinction have been investigated. Correlatable sections recording the event exhibit very similar lithological characters, positive-then-negative C isotope excursions and massive biotic demise. Detailed analyses of the fossil record and carbon isotopic variations were carried out on the Guadalupian–Wuchiapingian Boundary sections over the inner, middle, outer zones of the ELIP and its margin. Due to a pronounced decrease in marine habitat area and the environmental and ecological change over this part of the Tethys, the biota crisis records show the loss of numerous tropical invertebrate taxa, and exhibit fewer genera and smaller testing sizes and low productivity. The biota crisis was a sustainable and gradual reduction in diversity over the Capitanian. The associated carbon isotopic data reveal unusually high δ13C(carb) values before the late Capitanian, representing higher primary productivity (or buried rate) and more13C-enriched CO2released by hydrothermal carbonate breakdown from the upper crust into the sediments at that time. Subsequently, an accelerated negative excursion across the boundary and the gradual excursion with low carbon isotope amplitude favours an increased influx of light12C sourced by the volcanism around the eastern Tethys. The very similar time–space relation between the biota crisis and the Emeishan volcanism confirms that volcanic eruptions may have triggered the biota crisis event in South China. Intensive volcanism could result in detrimental environmental and ecological stresses, habitat loss, organic material splitting, or the emission of light carbon and thermal fluid (or aerosol), implying that the losses of the shallow-marine invertebrates either occurred geologically instantaneously or in a series of closely spaced crises coinciding with the initial phase of ELIP formation. These findings in South China may reveal the causal relation between mass extinctions and LIPs in a global context. [ABSTRACT FROM AUTHOR]

Recently, a series of high-magnitude earthquakes, including the 2008 Wenchuan earthquake (M 8.0), have occurred in the Longmenshan tectonic region of southwestern China. Many researchers are currently examining the geological aspects of the activity, but little attention has been given to the huge travertine deposits along large fault zones. Carbon isotopes were measured in 106 samples, and the results indicate that the travertine originated from 13 C-enriched CO 2 sourced from deep reservoirs and can be characterized by notable positive δ 13 C values. CO 2 is thought to have originated from isotopic equilibrium fractionation under thermal metamorphism temperature conditions (within 350–850 °C). The re-equilibrium fractionation between the deep CO 2 and the dissolved carbonate composition during travertine formation is due to the declining temperature of thermo-genetic CO 2 , which in turn leads to higher δ 13 C carb values. Based on oil drilling data and geochemical thermometry modeling, the depth of the 13 C-enriched CO 2 source is inferred to be below 4643 m, which coincides with the measured focal depth of the Wenchuan earthquake and subsequent aftershocks. The variation of tectonic activity intensity and the quantity of CO 2 from deep formations are mainly responsible for the δ 13 C fluctuations observed in the travertine. The δ 13 C values in travertine deposits have increased dramatically, which implies the rapid upwelling of the CO 2 -bearing fluid, the enhancement of thermal metamorphism and the continuous increase of the internal pressure in deep reservoirs. These findings may contribute to a better understanding of the deep seismic activity and high-frequency aftershocks in the Longmenshan region. [ABSTRACT FROM AUTHOR]

Knowledge of energy expenditure informs conservation managers for long term plans for endangered species health and habitat suitability. We measured field metabolic rate (FMR) of free-roaming giant pandas in large enclosures in a nature reserve using the doubly labeled water method. Giant pandas in zoo like enclosures had a similar FMR (14,182 kJ/day) to giant pandas in larger field enclosures (13,280 kJ/day). In winter, giant pandas raised their metabolic rates when living at − 2.4 °C (36,108 kJ/day) indicating that they were below their thermal neutral zone. The lower critical temperature for thermoregulation was about 8.0 °C and the upper critical temperature was about 28 °C. Giant panda FMRs were somewhat lower than active metabolic rates of sloth bears, lower than FMRs of grizzly bears and polar bears and 69 and 81% of predicted values based on a regression of FMR versus body mass of mammals. That is probably due to their lower levels of activity since other bears actively forage for food over a larger home range and pandas often sit in a patch of bamboo and eat bamboo for hours at a time. The low metabolic rates of giant pandas in summer, their inability to acquire fat stores to hibernate in winter, and their ability to raise their metabolic rate to thermoregulate in winter are energetic adaptations related to eating a diet composed almost exclusively of bamboo. Differences in FMR of giant pandas between our study and previous studies (one similar and one lower) appear to be due to differences in activity of the giant pandas in those studies. [ABSTRACT FROM AUTHOR]

This paper mainly analyzed the isotopic effect of precipitation in the Yarlung Zangbo River. On the whole, the isotopic compositions of most water samples fall on the upper right of the global meteoric water line. According to δD and δO data of the samples, the precipitation equation is figured out as δD=8 δO+10, showing that they are derived from precipitation but have experienced intensive evaporation. With obvious region-continental effect (a continuous depletion in heavy isotopes in water bodies occurs with increasing distance from the coast), the water presents a reducing trend of δD and δO westwards and southwards. Altitudinal effect is evident here, occurring in both trunk stream and main branches of the Yarlung Zangbo River. The distribution of water isotopic compositions is concerned with the movement of precipitation clouds from the Bay of Bengal and the Nujiang River and is affected by the topographic and climatic conditions of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The in situ zircon U‐Pb‐Lu‐Hf isotope records from end‐Permian volcanic interlayers in southwest China, integrated with previous studies, restructure the evolutionary history of the Yangtze Craton from Precambrian to Late Paleozoic. This includes early continental crust formation before ∼3.0 Ga and massive juvenile crustal growth at 2.6–2.4 Ga; large‐scale crustal reworking at ∼2.1–1.7 Ga; Neoproterozoic crust addition at ∼1.1 to 0.7 Ga; collision and subduction along the craton margin between ∼700–541 Ma; Early Ordovician to Late Silurian magmatism; and large tectono‐thermal events in the Middle Carboniferous to end‐Permian. Some zircons with TMD2 ages from 4.40 to 4.01 Ga and lower initial 176Hf/177Hf values of 0.280592 to 0.280726 may imply the existence of Hadean crust relics beneath the Yangtze Craton and their provenances could be associated with Hadean crustal remelting. This study further clarifies that the Precambrian‐age zircons between the end‐Permian volcanic interlayers, the complexes in the western margin of the Yangtze Craton, and the sedimentary Kangdian Basin, may share an affinity based on similar U‐Pb age spectra and Hf isotope features. It also shows that the Neoproterozoic tectono‐thermal event may be associated with large‐scale tectono‐rifting activity, which is different from the Grenville‐age continental collision between Yangtze and Cathaysia blocks in South China. The above findings support the inference of a widespread Archean basement extending to the western Yangtze Craton and a provenance in the Kangdian Basin that is derived from the weathering and erosion of Paleoproterozoic continental crust. [ABSTRACT FROM AUTHOR]

Growth of covalent organic frameworks (COFs) as single crystals is extremely challenging. Inaccessibility of open‐structured single‐crystal COFs prevents the exploration of structure‐oriented applications. Herein we report for the first time a non‐interpenetrated single‐crystal COF, LZU‐306, which possesses the open structure constructed exclusively via covalent assembly. With a high void volume of 80 %, LZU‐306 was applied to investigate the intrinsic dynamics of reticulated tetraphenylethylene (TPE) as the individual aggregation‐induced‐emission moiety. Solid‐state 2H NMR investigation has determined that the rotation of benzene rings in TPE, being the freest among the reported cases, is as fast as 1.0×104 Hz at 203 K to 1.5×107 Hz at 293 K. This research not only explores a new paradigm for single‐crystal growth of open frameworks, but also provides a unique matrix‐isolation platform to reticulate functional moieties into a well‐defined and isolated state. [ABSTRACT FROM AUTHOR]

Growth of covalent organic frameworks (COFs) as single crystals is extremely challenging. Inaccessibility of open‐structured single‐crystal COFs prevents the exploration of structure‐oriented applications. Herein we report for the first time a non‐interpenetrated single‐crystal COF, LZU‐306, which possesses the open structure constructed exclusively via covalent assembly. With a high void volume of 80 %, LZU‐306 was applied to investigate the intrinsic dynamics of reticulated tetraphenylethylene (TPE) as the individual aggregation‐induced‐emission moiety. Solid‐state 2H NMR investigation has determined that the rotation of benzene rings in TPE, being the freest among the reported cases, is as fast as 1.0×104 Hz at 203 K to 1.5×107 Hz at 293 K. This research not only explores a new paradigm for single‐crystal growth of open frameworks, but also provides a unique matrix‐isolation platform to reticulate functional moieties into a well‐defined and isolated state. [ABSTRACT FROM AUTHOR]

A novel and unusual palladium‐catalyzed [4+2] annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si−C(sp2) bond activation in synergy with ring expansion/insertion of cyclopropenes to form new C(sp2)−C(sp3) and Si−C(sp3) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo[4.1.0]heptanes, were formed in good yields with excellent diastereoselectivity under mild conditions. An asymmetric version of the reaction with a chiral phosphoramidite ligand furnished a variety of chiral bicyclic silaheterocycle derivatives with good enantioselectivity (up to 95.5:4.5 er). Owing to the mild reaction conditions, the good stereoselectivity profile, and the ready availability of the functionalized precursors, this process constitutes a useful and straightforward strategy for the synthesis of densely functionalized silacycles. [ABSTRACT FROM AUTHOR]

A novel and unusual palladium‐catalyzed [4+2] annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si−C(sp2) bond activation in synergy with ring expansion/insertion of cyclopropenes to form new C(sp2)−C(sp3) and Si−C(sp3) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo[4.1.0]heptanes, were formed in good yields with excellent diastereoselectivity under mild conditions. An asymmetric version of the reaction with a chiral phosphoramidite ligand furnished a variety of chiral bicyclic silaheterocycle derivatives with good enantioselectivity (up to 95.5:4.5 er). Owing to the mild reaction conditions, the good stereoselectivity profile, and the ready availability of the functionalized precursors, this process constitutes a useful and straightforward strategy for the synthesis of densely functionalized silacycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Location effect of triptycene on carbazole-based dyes for DSSCs were investigated. • Compared to terminal-derived JY76 , lateral-derived JY77 gains 20% PCE enhancement. • The highest PCE of 8.01% has been achieved for JY77 & JY75 co-sensitized cells. Due to the unique three-dimensional spatial structure and special electronic properties, triptycene has been applied in dye-sensitized solar cells. Herein, two dyes JY76 / JY77 featuring triptycene at the different substitution position of carbazole donor have been synthesized, and location effect of triptycene on the photovoltaic performance of devices has been investigated. Lateral derived triptycene endows JY77 much more enhanced capability of impeding the interface charge recombination than JY76 which triptycene was decorated at terminal. Finally, JY77 -sensitized solar cells exhibit around 20% higher power conversion efficiency (PCE) than that of JY76. The photovoltaic properties are further tuned by co-sensitization strategy, and better PCEs are obtained. Under AM 1.5G irradiation, cells fabricated by the synergic adsorption of JY77 and JY75 , achieve the highest PCE of 8.01%. [ABSTRACT FROM AUTHOR]

The isotopic composition and parameters for deuterium excess of brines, which were sampled in the Sichuan Basin, show obvious regularities of distribution. The brine isotopic composition shows distinct two systems of marine and terrestrial deposits, with the Middle Triassic strata as the boundary. Brine hydrogen isotopic composition of marine deposits is lower while oxygen isotopic composition is higher than that of the SMOW, respectively, indicating that the brines were derived from seawater with different evaporating degrees at different times. From the Sinian strata, up to the Cambrian, Permian Maokou Formation and the Triassic Jialingjiang Formation, the δD values of brines tend to become relatively positive with the strata becoming younger. Brines of terrestrial deposits are considered to have been derived from precipitation and their isotopic composition is close to the globe meteoric water line (GMWL). Brines of transitional deposits between marine and terrestrial ones (the Upper Triassic Xujiahe Formation) have δD and δO values falling between the two end members of marine deposit brines and precipitation, indicating that the brines are a mixture of precipitation and vaporing seawater. Water samples from the brine-bearing strata of different ages show various deuterium excesses ( d) with an evident decreasing trend as the age of strata gets older and older. Brine-bearing strata of the Triassic Leikoupo-Jialingjiang Formation, the Permian Maokou Formation, the Cambrian and Sinian strata are all carbonate rocks which have experienced intensive water/rock reaction and the deuterium excess essentially changes with time. All brine-bearing-strata surrounding the basin or faults, as well as those brine wells exploited for resources, have been obviously influenced by the precipitation supply. Therefore, the deuterium excesses of their brines have increased to different extents, depending on the amount of involvement of meteoric water. The variation and distribution of d values of the brines from different Triassic strata are related to the embedded depth of the strata. The deuterium excesses of brines become lower with increasing burial depth of the strata. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To evaluate the feasibility and therapeutic efficacy of 1.5T conventional MR-guided percutaneous interstitial implantation of I-125 radioactive seeds in patients with hepatocellular carcinoma (HCC). Materials and methods: The institutional ethics committee approved this study. After imformed consent was obtained, twenty-three patients suffering from a total of 65 HCC lesions were treated with I-125 seed permanent interstitial implantation under the guidance of a 1.5T conventional magnetic resonance imaging (MRI) system. The FSE T2WI, T1 FSPGR, FIESTA 2D, 3D Dyn T1WI sequences were used to guide an 18G MR-compatible needle inserted into the lesions to introduce the I-125 seeds. The response evaluation criteria in solid tumors (RECIST) were used to evaluate the curative effect. Results: The needle and I-125 seed were seen clearly on MRI images. The final dose delivered to total decay was 173.46±32.44Gy (range, 110–270Gy) as calculated by postoperative TPS. The complete response (CR) was seen in 22 lesions (33.8%), partial response (PR) in 24 lesions (36.9%), stable disease (SD) in 9 lesions (13.8%), and progressive disease (PD) in 10 lesions (15.4%). The post-operative alpha-fetoprotein (AFP) was decreased (t =3.117, P =0.005<0.05). Two patients were observed a small area of subcapsular bleeding that did not lead to any symptoms or clinical sequelae. Conclusion: MR-guided I-125 implantation for HCC is technically feasible and effective. [Copyright &y& Elsevier]

• Mid-Permian strata in South China are characterized by high positive δ13C carb values. • Decarbonation during tectono-thermal events is the mechanism for 13C enrichment. • Emplacement causing regression and doming was responsible for δ13C carb fluctuations. During the Permian, Emeishan mantle plume activity created a large igneous province and deeply impacted carbon isotope records in marine carbonate strata in South China. To evaluate the isotopic variations caused by this catastrophic event, 140 carbonate samples from four sections were collected and analyzed. The δ13C carb values in the upper section of the Qixia Formation gradually increased, stabilized at ~4.0‰ in the lower-middle sections of the Maokou Formation, and then abruptly decreased in the upper section of the Maokou Formation. This isotopic evolution trend is likely related to mantle plume geochemical processes occurring during these respective stages. Large amounts of upwelling heat from the emplacement of the mantle plume triggered large-scale decarbonation reactions in the continental crust resulting in CO 2 production enriched in 13C. Substantial amounts of 13C-enriched CO 2 directly affected the isotope compositions of marine carbonates during this time. Temporal and spatial fluctuations in carbon isotopes were also controlled by terrestrial materials as a result of regression and doming caused by plume emplacement. The abrupt decrease in δ13C carb in the upper section of the Maokou Formation reflects the onset of volcanism, resulting in the breakdown of organic materials. These findings emphasize the contribution of a carbon reservoir (with a thermal decarbonation origin) in the upper crust, particularly against the Permian tectono-thermal background. This mechanism, which is similar to biological isotope fractionation in the carbon cycle, should not be overlooked. [ABSTRACT FROM AUTHOR]

Frontispiz: Controllable Si-C Bond Activation Enables Stereocontrol in the Palladium-Catalyzed [4+2] Annulation of Cyclopropenes with Benzosilacyclobutanes Keywords: Gespannte Moleküle; Palladium; Ringaufweitung; Si-C-Bindungsaktivierung; Silacyclen Gespannte Moleküle, Palladium, Ringaufweitung, Si-C-Bindungsaktivierung, Silacyclen. [Extracted from the article]

Circular tube with external wide grooves has been defined as "Type B" grooved tube in the previous research. However, there have been few studies highlighting the effects of aluminum foam filling and material of "Type B" grooved tube. In the present, axial crushing behaviors of aluminum foam-filled 304 stainless steel "Type B" grooved tube are investigated. Quasi-static axial crushing tests are conducted to examined the deformation modes and energy absorption performance of foam-filled uniform/thickness gradient grooved tube with weak/strong thick-walled section. Experimental results show that the foam filling and thickness gradient configuration have a more obvious effect on energy absorption characteristics of grooved tube with weak thick-walled section. A novel analytical model is put forward by taking the strain hardening effect and effective crushing distance into consideration. Compared with the previous researches, the theoretical predictions in this study are in better agreement with the experimental results. Moreover, by comparing the experimental results of 304 stainless steel and 2A12 aluminum grooved tube, it can be concluded that the mean crushing force, crushing force efficiency and structural effectiveness of steel grooved tube are 205%, 56% and 27% on average higher than those of aluminum grooved tube. [ABSTRACT FROM AUTHOR]