Biphase-to-monophase structure evolution of Na_(0.766+x)Li_(x)Ni_(0.33-x)Mn_(0.5)Fe_(0.1)Ti_(0.07)O_(2) toward ultradurable Na-ion batteries

Layered composite oxide materials with O3/P2 biphasic crystallographic structure typically demonstrate a combination of high capacities of the O3 phase and high operation voltages of the P2 phase.However,their practical applications are seriously obstructed by difficulties in thermodynamic phase regulation,complicated electrochemical phase transition,and unsatisfactory cycling life.Herein,we propose an efficient structural evolution strategy from biphase to monophase of Na_(0.766+x)Li_(x)Ni_(0.33-x)Mn_(0.5)Fe_(0.1)Ti_(0.07)O_(2) through Li+substitution.The role of Li+substitution not only simplifies the unfavorable phase transition by altering the local coordination of transition metal(TM)cations but also stabilizes the cathode–electrolyte interphase to prevent the degradation of TM cations during battery cycling.As a result,the thermodynamically robust O_(3)-Na_(0.826)Li_(0.06)Ni_(0.27)Mn_(0.5)Fe_(0.1)Ti_(0.07)O_(2) cathode delivers a high capacity of 139.4 mAh g^(-1) at 0.1 C and shows prolonged cycling life at high rates,with capacity retention of 81.6%at 5 C over 500 cycles.This work establishes a solid relationship between the thermodynamic structure evolution and electrochemistry of layered cathode materials,contributing to the development of long-life sodium-ion batteries.

Simultaneous regulation on coordination environment and interfacial chemistry via taurine for stabilized Zn metal anode

Aqueous Zn-ion batteries(AZIBs)are the potential options for the next-generation energy storage scenarios due to the cost effectiveness and intrinsic safety.Nevertheless,the industrial application of AZIBs is still impeded by a series of parasitic reactions and dendrites at zinc anodes.In this study,taurine(TAU)is used in electrolyte to simultaneously optimize the coordination condition of the ZnSO4electrolyte and interfacial chemistry at the anode.TAU can preferentially adsorb with the zinc metal and induce an in situ stable and protective interface on the anode,which would avoid the connection between H_(2)O and the zinc metal and promote the even deposition of Zn^(2+).The resulting Zn//Zn batteries achieve more than 3000 hours long cyclic lifespan under 1 mA cm^(-2)and an impressive cumulative capacity at 5 mA cm^(-2).Moreover,Zn//Cu batteries can realize a reversible plating/stripping process over 2,400cycles,with a desirable coulombic efficiency of 99.75%(1 mA cm^(-2)).Additionally,the additive endows Zn//NH_(4)V_(4)O_(10)batteries with more stable cyclic performance and ultrafast rate capability.These capabilities can promote the industrial application of AZIBs.

Factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients:A single-center retrospective study

BACKGROUND At present,many studies have reported the risk factors for postoperative intracranial reinfection,including age,sex,time to surgery,duration of postoperative catheterization,emergency procedures,type of disease and cerebrospinal fluid leakage,but the academic community has not reached a unified conclusion.AIM To find factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients.METHODS Ninety-four patients who underwent elective craniotomy from January 1,2015 to December 31,2022 in the Department of Neurosurgery,First Hospital of Jilin University,were included in this study.Of those,45 patients were enrolled in the infection group,and 49 were enrolled in the control group.The clinical data of the patients were collected and divided into three categories,including preoperative baseline conditions,intraoperative characteristics and postoperative infection prevention.The data were analyzed using SPSS 26.0 software.RESULTS There were 23 males and 22 females in the infection group with a mean age of 52.8±15.1 years and 17 males and 32 females in the control group with a mean age of 48.9±15.2 years.The univariate analysis showed that the infection group had higher systolic blood pressures and postoperative temperatures,fewer patients who underwent a supratentorial craniotomy,more patients with a history of hypertension and higher initial postoperative white blood cell counts than the control group,with statistically significant differences(P<0.05).The multifactorial logistic regression analysis showed that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative infection in neurosurgical patients.CONCLUSION The results obtained in this study indicated that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative neurological symptoms.

聚合物气体辅助挤出成型研究进展

挤出成型是聚合物加工领域出现得较早且应用最广泛的技术之一,聚合物传统挤出成型过程中存在的挤出胀大、扭曲变形等问题严重阻碍了该技术的进一步发展及推广应用。聚合物气辅挤出是本世纪初发展起来的一种新型成型工艺,通过在口模内壁与熔体表面间形成稳定的气垫膜层,使熔体以完全滑移非粘着方式挤出成型,改善了口模内熔体的流场分布,从而有效减小甚至消除了传统挤出过程中存在的影响制品质量的固有问题。该技术因具有节能、环保、改善制品质量等优良特性,自问世以来即受到聚合物加工领域诸多学者的广泛关注,相关研究成果对丰富和发展聚合物成型理论及其加工技术的进一步推广应用均具有重要的科学意义和工程价值。文中综述了聚合物气辅挤出成型问世以来国内外研究进展,主要介绍了该技术的成型机理和成型装置,气体辅助单层挤出、双层共挤、微管挤出及气垫膜层等方面的研究方法与研究成果,并在综述现有的研究基础上展望了气辅挤出成型的研究趋势。

中国、英国、美国、日本规范关于直墙波谷力计算方法的对比

文章介绍了英国标准BS6349、美国陆军工程兵团《海岸工程手册》、日本《港口设施技术标准》中直墙所受波谷力的计算原理、应用范围和参数选取,并借助工程实例与中国《港口与航道水文规范》中计算方法进行了对比。对于立波波谷力的计算,各国较常用的均为森弗罗公式,但在公式使用过程中应注意特征波高的选取。当d/L在0.139~0.2范围内时,应用中国规范的波谷力计算值介于美国与日本规范、英国规范之间,英国规范水平波谷力计算值偏大17%左右。当d/L在0.05~0.139时,中国规范浅水立波法计算值与美国及日本规范接近,均远低于英国规范值。由于英国规范采用了特征波Hmax与Ts计算,在波浪浅水变形较显著的工况下,计算可能偏离实际较大。美国规范及日本规范计算值则较中国规范偏低,偏低幅度根据相对水深及波陡等参数的不同而在5%~10%波动。

中国规范和欧洲规范关于地基整体稳定性计算比较分析

文章针对中国港口工程规范《水运工程地基设计规范(JTS147-2017)》、欧洲规范(BSEN1997-1-2004Eurocode7)和英国规范(BS6031-2009)对于地基整体稳定计算规定的不同,分析其计算理论、计算方法及参数选取等方面的异同。通过不同的软件,结合实例给出计算结果及稳定性判断上的差异,为海外项目提供参考和依据。

C-reactive protein aggravates myocardial ischemia/reperfusion injury through activation of extracellular-signal-regulated kinase 1/2

Background Ischemia/reperfusion injury （IRI） is an inflammatory response that occurs when tissue is reperfused following a prolonged period of ischemia. Several studies have indicated that C-reactive protein （CRP） might play an important role in inducing IRI. However, the effects of CRP on myocardial IRI and the underlying mechanisms have not been fully elucidated. This study aimed to investigate the association between CRP and myocardial IRI and the underlying mechanisms. Methods We simulated ischemia/reperfusion using oxygen-glucose deprivation/ reoxygenation （OGD/R） in neonatal Sprague-Dawley rat cardiomyocytes; reperfusion injury was induced by three hours of hypoxia with glucose and serum deprivation followed by one hour of reperfusion. Cell viability was tested with MTS assays, and cardiomyocyte damage was evaluated by lactate dehydrogenase （LDH） leakage. Mitochondrial membrane potential was measured using tetramethylrhodamine ethyl ester （TMRE） and mitochondrial permeability transition pore （mPTP） opening was measured using calcein/AM; both TMRE and caocein/AM were visualized with laser scanning confocal microscopy. In addition, we studied the signaling pathways underlying CRP-mediated ischemia/reperfusion injury via Western blot analysis. Results Compared with the simple OGD/R group, after intervention with 10 pg/mL CRP, cell viability decreased markedly （82.36 % ± 6.18% vs. 64.84% ± 4.06%, P = 0.0007）, and the LDH leakage significantly increased （145.3 U/L ± 16.06 U/L vs. 208.2 U/L ± 19.23 U/L, P = 0.0122）. CRP also activated mPTP opening and reduced mitochondrial membrane potential during myocardial ischemia/reperfusion. Pretreatment with 1 pM atorvastatin （Ator） before CRP intervention protected cardiomyocytes from IRI. Mitochondrial KATP channel opener diazoxide and mPTP inhibitor cyclosporin A also offset the effects of CRP in this process. The level of phosphorylated extracellular-signal-regulated kinase （ERK） 1/2 was significantly higher after pre-treatment with CRP compared with the OGD/R group （170.4% ± 3.00% v.v. 93.53% ± 1.94%, P 〈 0.0001）. Western blot analysis revealed that Akt expression was markedly activated （184.2% ± 6.96% vs. 122.7% ± 5.30%, P = 0.0003） and ERK 1/2 phosphorylation significantly reduced after co-treatment with Ator and CRP compared with the level after CRP pretreatment alone. Conclusions Our results suggested that CRP directly aggravates myocardial IRI in myocardial cells and that this effect is primarily mediated by inhibiting mitochondrial ATP- sensitive potassium （mitoKATp） channels and promoting mPTP opening. Ator counteracts these effects and can reduce CRP-induced IRI. One of the mechanisms of CRP-induced IRI may be related to the sustained activation of the ERK signaling pathway.

Numerical simulation on proppant migration and placement within the rough and complex fractures

Hydraulic fracturing is a key technology for the development of unconventional hydrocarbon resources.The proppant placement morphology determines the fracture conductivity,thus affecting the reservoir stimulation effect.In this paper,the proppant migration and placement within complex fractures was studied by considering the fracture wall roughness through computational fluid mechanics-discrete element method(CFD-DEM)in numerical simulation,which is a key approach to study the proppant migration and placement.The results show that the proppant placement non-uniformity,proppant migration capacity,and proppant volume filled in the far-end and the secondary branched fracture are enhanced within the rough fracture compared with those within smooth fractures.The proppant migration capacity is increased within the fracture at low inclination angles(<60°)and low approach angles(<90°),and the proppant placement area is larger in the inclined fracture than that in the vertical fracture.The rise of injection rate and fracturing fluid viscosity causes more proppants migrate to far-end or secondary fractures,resulting in a non-proppant area within the near-wellbore fracture.An increase by 1.3 times in the injection rate and 3 times in the fracturing fluid viscosity leads to a decrease by 26.6%and 27%,respectively,in the proppant placement area within the near-wellbore fracture.The staged injection with small size proppants followed by large size proppants increases the proppant placement area in the primary fracture by 13%-26%,and that with large size proppants followed by small size proppants increases the proppant placement area by 19%-25%,which is due to that the latter method facilitates filling of the secondary branched fracture.The injection location mainly affects the proppant filling degree within the near-wellbore fractures.Compared with the upper injection,the middle and lower injection is not beneficial to filling of proppants within the near-wellbore fracture.

Agreement of corneal curvature and central corneal thickness obtained from a swept-source OCT and Pentacam in ectopia lentis patients

AIM:To assess the inter-device consistency of corneal curvature and central corneal thickness between Pentacam and a swept-source Fourier-domain anterior segment optical coherence tomography(AS-OCT)in ectopia lentis patients.METHODS:Totally 72 eyes of ectopia lentis patients were recruited.Central corneal thickness(CCT),corneal curvature values and corneal astigmatism were obtained from both the Pentacam and AS-OCT(CASIA2).Repeatability was evaluated for both devices.The coef ficient of repeatability(COR)and the relative COR was calculated.Bland-Altman plots were conducted to evaluate the interdevice agreement of measurement.Orthogonal linear regression was used to examine any proportional bias.RESULTS:The mean difference of CCT,steep anterior corneal cur vature(anterior K_S),flat anterior corneal curvature(anterior K_f),anterior corneal astigmatism(ACA),steep posterior corneal cur vature(posterior K_S),flat posterior corneal cur vature(posterior K_f),posterior corneal astigmatism(PCA),steep true net power(TNP K_S),flat true net power(TNP K_f)and total corneal astigmatism(TCA)between Pentacam and CASIA2 were 7.03±9.70μm,-0.19±0.41 D,-0.27±0.35 D,0.04±0.47 D,-0.17±0.23 D,-0.11±0.11 D,-0.02±1.02 D-0.41±0.43 D,-0.52±0.46 D,and-0.15±0.96 D,respectively.For measurement of TNP K_f with the Pentacam and CASIA2,a mean difference of 0.52 D and COR of 0.90 with P=0.02 was detected.There was no significant difference in CCT(P=0.393),anterior K_f(P=0.107),anteriorKs(P=0.414),ACA(P=0.131),posterior K_f(P=0.286),posterior Ks(P=0.418),PCA(P=0.105),TNP Ks(P=0.054),and TCA(P=0.977)between Pentacam and CASIA2.CONCLUSION:Our study reveals good agreement of CCT,corneal curvature and corneal astigmatism measured by CASIA2 and Pentacam in ectopia lentis patients.However,there was significant difference for CCT and corneal curvature values obtained by the two devices.

Baicalin protects neonatal rat brains against hypoxicischemic injury by upregulating glutamate transporter 1 via the phosphoinositide 3-kinase/protein kinase B signaling pathway

Baicalin is a flavonoid compound extracted from Scutellaria baicalensis root.Recent evidence indicates that baicalin is neuroprotective in models of ischemic stroke.Here,we investigate the neuroprotective effect of baicalin in a neonatal rat model of hypoxic-ischemic encephalopathy.Seven-day-old pups underwent left common carotid artery ligation followed by hypoxia（8% oxygen at 37°C） for 2 hours,before being injected with baicalin（120 mg/kg intraperitoneally） and examined 24 hours later.Baicalin effectively reduced cerebral infarct volume and neuronal loss,inhibited apoptosis,and upregulated the expression of p-Akt and glutamate transporter 1.Intracerebroventricular injection of the phosphoinositide 3-kinase/protein kinase B（PI3 K/Akt） inhibitor LY294002 30 minutes before injury blocked the effect of baicalin on p-Akt and glutamate transporter 1,and weakened the associated neuroprotective effect.Our findings provide the first evidence,to our knowledge that baicalin can protect neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the PI3 K/Akt signaling pathway.

Double balloon enteroscopy in the old: Experience from China

AIM: To evaluate the safety, efficacy and management of double balloon enteroscopy (DBE) carried out in those aged individuals with suspicious small intestine diseases. METHODS: DBE is a wonderful invention of the past decade and is widely used as an examination tool for the gastrointestinal tract. From January 2003 to July 2011, data from patients who were ≥ 65 years old and underwent DBE examination in the Nanfang Hospital were included in a retrospective analysis.RESULTS: Fifty-nine individuals were found and subsequently analyzed. The mean age was 69.63 ± 3.89 years (range 65-84), 34 were males. Indications for DBE were melena/hematochezia (36 cases), abdominal pain (15 cases), diarrhea (3 cases), stool change (1 case), weight loss (1 case), vomiting (2 cases), and debilitation (1 case). The average duration of symptoms was 33.34 ± 64.24 mo. Twenty-seven patients suffered from age-related diseases. Severe complications were not found during and after DBE. Comparison between systolic and diastolic blood pressure before and after DBE was statistically significant (mean ± SD, P < 0.01, P < 0.05, respectively). Small bowel pathologies were found by DBE in 35 patients, definite diagnoses were made in 31 cases, and detection rate and diagnostic yield for DBE were 68.6% and 60.8%, respectively. CONCLUSION: DBE is a safe and effective method for gastrointestinal examination in the aged population. Aging alone is not a risk factor for elderly patients with suspicious gastrointestinal diseases and thorough preparation prior to the DBE procedure should be made for individuals with multiple diseases especially cardiopulmonary disorders.

Dielectric nanocomposites with superb high-temperature capacitive performance based on high intrinsic dielectric constant polymer

Advancements in power electronics necessitate dielectric polymer films capable of operating at high temperatures and possessing high energy density.Although significant strides have been achieved by integrating inorganic fillers into high-temperature polymer matrices,the inherently low dielectric constants of these matrices have tempered the magnitude of success.In this work,we report an innovative nanocomposite based on sulfonylated polyimide(SPI),distinguished by the incorporation of sulfonyl groups within the SPI backbone and the inclusion of wide bandgap hafnium dioxide(HfO_(2))nanofillers.The nanocomposite has demonstrated notable enhancements in thermal stability,dielectric properties,and capacitive performance at elevated temperatures.Detailed simulations at both molecular and mesoscopic levels have elucidated the mechanisms behind these improvements,which could be attributed to confined segmental motion,an optimized electronic band structure,and a diminished incidence of dielectric breakdown ascribed to the presence of sulfonyl groups.Remarkably,the SPI-HfO_(2)nanocomposite demonstrates a high charge-discharge efficiency of 95.7%at an elevated temperature of 150℃and an applied electric field of 200 MV/m.Furthermore,it achieves a maximum discharged energy density of 2.71 J/cm^(3),signalling its substantial potential for energy storage applications under extreme conditions.

褐帘石稀土活化对离子吸附型稀土矿床成矿的指示

古城矿床为华南地区新发现的一个同时富含轻重稀土的离子吸附型稀土矿床,矿体位于粗粒黑云母花岗岩风化壳中.褐帘石是粗粒黑云母花岗岩中一种重要的副矿物(占比约为0.09%(vol)),U-Pb年龄分析结果显示其结晶年龄为102.8±4.3 Ma.化学成分分析结果显示原生褐帘石具有富轻稀土的特征,其轻稀土、重稀土和轻稀土/重稀土比值分别为179778~189429、2165~4595 ppm(1 ppm=10^(–6)m^(3)/m^(3))和41~84.这些原生褐帘石轻稀土含量约占全岩轻稀土总量的97%,为古城矿区轻稀土元素的主要来源.褐帘石结构与成分分析指示,稀土元素的存在会导致其晶体结构中稀土元素与氧原子构成的化学键键长增加而键强减弱.在被岩浆-热液流体交代时,这些化学键发生破裂,进而导致轻稀土元素会被淋滤出来并进入到热液流体中,并在随后主要进入了氟碳钙铈矿中.综上,褐帘石被交代后形成氟碳钙铈矿的过程中轻稀土元素发生了活化、迁移和富集,且在该过程中轻稀土元素之间发生了分馏.本研究表明,原生褐帘石被热液流体交代有利于轻稀土元素的富集成矿,但对重稀土矿化的贡献较小.

通过柔性微针阵列集成的叉指电极装置产生电刺激用于癌症免疫治疗

免疫疗法通过化学或生物制剂来激活免疫系统,改变了癌症治疗的传统方式.但大多数免疫类药物在肿瘤组织内的渗透性差,容易产生副作用而使疗效不尽人意.电刺激疗法是一种新颖的癌症疗法,其可以不利用化学、生物制剂产生抑癌效果,但存在操作复杂和难以制备微米级小型电刺激装置的问题.本文通过将光学3D微打印技术与化学镀工艺结合,成功制备了柔性微针阵列集成的叉指电极装置.其能够生成交变电场触发肿瘤细胞内线粒体的钙离子过载和细胞内活性氧的产生,导致损伤相关分子模式释放,从而激活免疫应答并引起肿瘤免疫原性细胞死亡.实验结果显示,本文的通电微针装置具有良好的生物安全性和全身抑瘤作用,抑制了原发肿瘤和远处肿瘤的生长以及黑色素瘤肺转移.因此,本文将电刺激与免疫疗法相结合,为无药物癌症治疗提供了新方向并为癌症治疗领域提供了创新思路.

Adaptive vector field based accurate homing control of aerial delivery systems

This paper investigates the homing control problem of a flexible aerial delivery system with external wind,at-mospheric turbulence,and aerodynamic uncertainties.An accurate homing control strategy is presented,consisting of a trajectory generation algorithm and a lateral tracking controller.A high-altitude trajectory generation is de-veloped with system characteristics explicitly considered to generate the desired trajectory for the aerial delivery control system design.It significantly compensates for the altitude deviation of the existing multiphase theory based trajectory generation methodologies.A novel adaptive vector field control law is then designed to accomplish the lateral tracking maneuvers.The key feature of the proposed method is that the complete lateral closed-loop control,including position and heading angle loops,is achieved in the presence of disturbances and dynamic uncertainties.The homing control with high landing accuracy is therefore achieved.Simulation and hardware-in-loop testing results are finally presented to validate the proposed method’s effectiveness compared to a conventional homing control scheme.

Thermodynamics for the non-conventional synthesizing of out-of-plane ordered double-transition metal“312”and“413”MAX phases(o-MAX):A high throughput linear programing first-principles calculation

The reaction thermodynamics for synthesizing the“312”and“413”o-MAX phases using the powder met-allurgy are investigated using a linear programing optimization algorithm based on the high-throughput first principles phonon calculations.The validity and reliability of the current methodology are verified by correctly predicting the impurities in four experimentally known o-MAX systems including Cr-Ti-Al-C,Cr-V-Al-C,Mo-Sc-Al-C and Mo-Ti-Al-C.The formability of each investigated o-MAX phase is evaluated by means of formation enthalpy and formation Gibbs free energy in a temperature range from 0 K to 1700 K.It is revealed that the thermodynamic stability of the“413”o-MAX structure is no better than that of the“312”phase.The formability of“413”o-MAX is also reduced at high sintering temperature,compared to that of“312”phase.The optimal synthetic routes are predicted for all thermodynamically stable“312”and“413”o-MAX phases.It is found that most o-MAX phases considered could be prepared as the single phase using the non-conventional synthetic routes from the aspect of reaction thermodynamics.Few of them including Cr_(2)TaAlC_(2),Nb_(2)HfAlC_(2),Nb_(2)TaAlC_(2),Nb_(2)Hf_(2)AlC_(3),Nb_(2)Ta_(2)AlC_(3),Mo_(2)V_(2)AlC_(3)and Mo_(2)Ta_(2)AlC_(3)are predicted to be either destabilized at high temperature or overwhelmed by the most competing side reaction.

Elucidation of the sodium kinetics in layered P-type oxide cathodes

Sodium-ion intercalation oxides generally possess high compositional diversity according to their different stacking sequences.The sodium diffusion pathway in layered P-type materials used in sodium-ion batteries is open,which can increase their rate capability by directly transmitting Na+between adjacent triangular prismatic channels,rather than passing through an intermediate tetrahedral site in O-type structure.However,how the structure chemistry of the P-type oxides determines their electrochemical properties has not been fully understood yet.Herein,by comparing the crystalline structures,electrochemical behaviors,ion/electron transport dynamics of a couple of P-type intercalation cathodes,P2-Na_(2/3)Ni1/3Mn_(2/3)O_(2)and P3-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)with the same compositions,we demonstrate experimentally and computationally that the P2 phase delivers better cycling stability and rate capability than the P3 counterpart due to the predominant contribution of the faster intrinsic Na diffusion kinetics in the P2 bulk.We also point out that it is the electronic conductivity that captures the key electrochemistry of layered P3-type materials and makes them possible to enhance the sodium storage performance.The results reveal that the correlation between stacking structure and functional properties in two typical layered P-type cathodes,providing new guidelines for preparing and designing alkali-metal layered oxide materials with improved battery performance.

Factor graph based navigation and positioning for control system design:A review

Navigation and positioning is an important and challenging problem in many control engineering applications.It provides feedback information to design controllers for systems.In this paper,a bibliographical review on factor graph based navigation and positioning is presented.More specifically,the sensor modeling,the factor graph optimization methods,and the topology factor based cooperative localization are reviewed.The navigation and positioning methods via factor graph are considered and classified.Focuses in the current research of factor graph based navigation and positioning are also discussed with emphasis on its practical application.The limitations of the existing methods,some solutions for future techniques,and recommendations are finally given.

Experimental study of high to intermediate temperature alteration in porphyry copper systems and geological implications

Porphyry copper systems, which provide most of the world's copper resource, are commonly associated with characteristic concentric zonation of alteration and mineralization. In-depth knowledge of the distribution and transport mechanism of elements in the alteration zones is essential for understanding the ore-forming processes. We employed flow-reaction apparatus to simulate the fluid-rock interactions during porphyry ore formation so as to investigate the mechanisms that govern the transport of elements and the development of zonation. The results indicate more heterogeneous distribution of elements in the experimental products at 450°C compared to those at lower temperatures, which implies a crucial role of temperature in controlling elements redistribution in hydrothermal systems. Heating advances potassic alteration and Ca leaching of wall rocks.To achieve the same degree of sodic alteration, it requires a higher concentration of Na+in the fluid toward higher temperature.Temperature also facilitates the incorporation of Ti, Sr and Pb into silicate minerals through cation substitution. We infer from experimental results that from the center of intermediate to mafic volcanic wall rocks toward periphery, the contents of K and Ti should decrease and the contents of Ca, Zn and Mn should increase, whereas the trend for Si and Na could be non-monotonic.This study provides experimental and theoretical insights into a variety of vital geological observations, including anhydrite formation and the widespread development of potassic rather than sodic alteration in porphyry copper deposits.

Phenoxazine-based supramolecular tetrahedron as biomimetic lectin for glucosamine recognition

The design and synthesis of a phenoxazine-based metal-organic tetrahedro n(Zn4L4) as biomimetic lectin for selectively recognition of glucosamine(GlcN) was reported.Different from the free phenoxazinebased ligand(L),Zn4L4 displayed the highest fluorescent intensity enhancement efficiency toward GlcN over other related natural mono-and disaccharides.Fluorescence titration demonstrated a 1:1 stoichiometric host-guest complex was formed with an association constant about 4.03 × 104 L/mol.1H NMR spectroscopic studies confirmed this selectivity resulted from the multiple hydrogen bonding interactions formed between GlcN and Zn4L4.The present results suggested that rational arrangement of recognition sites in the confined space of metal-organic cage is crucial for the selectivity toward target guests.