Construction of n-type homogeneous to improve interfacial carrier transfer for enhanced photoelectrocatalytic hydrolysis

Photoelectrocatalyzed hydrogen production plays an important role in the path to carbon neutrality. The construction of heterojunctions provides an ideal example of an oxygen precipitation reaction. In this work, the performance of the n-n type heterojunction CeBTC@FeBTC/NIF in the photoelectronically coupled catalytic oxygen evolution reaction (OER) reaction is presented. The efficient transfer of carriers between components enhances the catalytic activity. Besides, the construction of heterojunctions optimizes the energy level structure and increases the absorption of light, and the microstructure forms holes with a blackbody effect that also enhances light absorption. Consequently, CeBTC@FeBTC/NIF has excellent photoelectric coupling catalytic properties and requires an overpotential of only 300 mV to drive a current density of 100 mA cm-2 under illumination. More importantly, the n-n heterojunction was found to be effective in enhancing charge and photogenerated electron migration by examining the carrier density of each component and carrier diffusion at the interface.

Self-reporting and Biodegradable Thermosetting Solid Polymer Electrolyte

To date, significant efforts have been dedicated to improve their ionic conductivity, thermal stability, and mechanical strength of solid polymer electrolytes (SPEs). However, direct monitoring of physical and chemical changes in SPEs is still lacking. Moreover, existing thermosetting SPEs are hardly degradable. Herein, by overcoming the limitation predicted by Flory theory, self-reporting and biodegradable thermosetting hyperbranched poly(β-amino ester)-based SPEs (HPAE-SPEs) are reported. HPAE is successfully synthesized through a well-controlled "A2+B4" Michael addition strategy and then crosslinked it in situ to produce HPAE-SPEs. The multiple tertiary aliphatic amines at the branching sites confer multicolour luminescence to HPAE-SPEs, enabling direct observation of its physical and chemical damage. After use, HPAE-SPEs can be rapidly hydrolysed into non-hazardous β-amino acids and polyols via self-catalysis. Optimized HPAE-SPE exhibits an ionic conductivity of 1.3×10-4  S/cm at 60 °C, a Na+ transference number (t N a + ${{t}_{Na}^{+}}$ ) of 0.67, a highly stable sodium plating-stripping behaviour and a low overpotential of ≈190 mV. This study establishes a new paradigm for developing SPEs by engineering multifunctional polymers. The self-reporting and biodegradable properties would greatly expand the scope of applications for SPEs.

Enzymatically Activatable Polymers for Disease Diagnosis and Treatment

The irregular expression or activity of enzymes in the human body leads to various pathological disorders and can therefore be used as an intrinsic trigger for more precise identification of disease foci and controlled release of diagnostics and therapeutics, leading to improved diagnostic accuracy, sensitivity, and therapeutic efficacy while reducing systemic toxicity. Advanced synthesis strategies enable the preparation of polymers with enzymatically activatable skeletons or side chains, while understanding enzymatically responsive mechanisms promotes rational incorporation of activatable units and predictions of the release profile of diagnostics and therapeutics, ultimately leading to promising applications in disease diagnosis and treatment with superior biocompatibility and efficiency. By overcoming the challenges, new opportunities will emerge to inspire researchers to develop more efficient, safer, and clinically reliable enzymatically activatable polymeric carriers as well as prodrugs.

Dual-Functional Eu-Metal-Organic Framework with Ratiometric Fluorescent Broad-Spectrum Sensing of Benzophenone-like Ultraviolet Filters and High Proton Conduction

The construction of attractive dual-functional lanthanide-based metal-organic frameworks (Ln-MOFs) with ratiometric fluorescent detection and proton conductivity is significant and challenging. Herein, a three-dimensional (3D) Eu-MOF, namely, [Eu4(HL)2(SBA)4(H2O)6]·9H2O, has been hydrothermally synthesized with a dual-ligand strategy, using (4-carboxypiperidyl)-N-methylenephosphonic acid (H3L = H2O3PCH2-NC5H9-COOH) and 4-sulfobenzoic acid monopotassium salt (KHSBA = KO3SC6H4COOH) as organic linkers. Eu-MOF showed ratiometric fluorescent broad-spectrum sensing of benzophenone-like ultraviolet filters (BP-like UVFs) with satisfactory sensitivity, selectivity, and low limits of detection in water/ethanol (1:1, v/v) solutions and real urine systems. A portable test paper was prepared for the convenience of actual detection. The potential sensing mechanisms were thoroughly analyzed by diversified experiments. The synergistic effect of the forbidden energy transfer from the ligand to Eu3+, the internal filtration effect (IFE), the formation of a complex, and weak interactions between the KHSBA ligand and BP-like UVFs is responsible for the ratiometric sensing effect. Meanwhile, Eu-MOF displayed relatively high proton conductivity of 2.60 × 10-4 S cm-1 at 368 K and 95% relative humidity (RH), making it a potential material for proton conduction. This work provides valuable guidance for the facile and effective design and construction of multifunctional Ln-MOFs with promising performance.

Dynamically Stabilized Electronic Regulation and Electrochemical Reconstruction in Co and S Atomic Pair Doped Fe3 O4 for Water Oxidation

The electronic regulation and surface reconstruction of earth-abundant electrocatalysts are essential to efficient oxygen evolution reaction (OER). Here, an inverse-spinel Co,S atomic pair codoped Fe3 O4 grown on iron foam (Co,S-Fe3 O4 /IF) is fabricated as a cost-effective electrocatalyst for OER. This strategy of Co and S atomic pair directional codoping features accelerates surface reconstruction and dynamically stabilizes electronic regulation. CoS atomic pairs doped in the Fe3 O4 crystal favor controllable surface reconstruction via sulfur leaching, forming oxygen vacancies and Co doping on the surface of reconstructed FeOOH (Co-FeOOH-Ov /IF). Before and after surface reconstruction via in situ electrochemical process, the Fe sites with octahedral field dynamically maintains an appropriate electronic structure for OER intermediates, thus exhibiting consistently excellent OER performance. The electrochemically tuned Fe-based electrodes exhibit a low overpotential of 349 mV at a current density of 1000 mA cm-2 , a slight Tafel slope of 43.3 mV dec-1 , and exceptional long-term electrolysis stability of 200 h in an alkaline medium. Density functional theory calculations illustrate the electronic regulation of Fe sites, changes in Gibbs free energies, and the breaking of the restrictive scaling relation between OER intermediates. This work provides a promising directional codoping strategy for developing precatalysts for large-scale water-splitting systems.

The role of epigenetic methylation/demethylation in the regulation of retinal photoreceptors

Photoreceptors are integral and crucial for the retina, as they convert light into electrical signals. Epigenetics plays a vital role in determining the precise expression of genetic information in space and time during the development and maturation of photoreceptors, cell differentiation, degeneration, death, and various pathological processes. Epigenetic regulation has three main manifestations: histone modification, DNA methylation, and RNA-based mechanisms, where methylation is involved in two regulatory mechanisms-histone methylation and DNA methylation. DNA methylation is the most studied form of epigenetic modification, while histone methylation is a relatively stable regulatory mechanism. Evidence suggests that normal methylation regulation is essential for the growth and development of photoreceptors and the maintenance of their functions, while abnormal methylation can lead to many pathological forms of photoreceptors. However, the role of methylation/demethylation in regulating retinal photoreceptors remains unclear. Therefore, this study aims to review the role of methylation/demethylation in regulating photoreceptors in various physiological and pathological situations and discuss the underlying mechanisms involved. Given the critical role of epigenetic regulation in gene expression and cellular differentiation, investigating the specific molecular mechanisms underlying these processes in photoreceptors may provide valuable insights into the pathogenesis of retinal diseases. Moreover, understanding these mechanisms could lead to the development of novel therapies that target the epigenetic machinery, thereby promoting the maintenance of retinal function throughout an individual's lifespan.

Phosphocholine-Functionalized Zwitterionic Highly Branched Poly(β-amino ester)s for Cytoplasmic Protein Delivery

Proteins have tremendous potential for vaccine development and disease treatment, but multiple extracellular and intracellular biological barriers must be overcome before they can exert specific biological functions in the target tissue. The use of polymers as carriers would greatly improve their bioavailability and therapeutic efficiency. Nevertheless, effective protein packaging and cell membrane penetration without causing cytotoxicity is particularly challenging, due largely to the simultaneous distribution of positive and negative charges on protein surface. Here, phosphocholine-functionalized zwitterionic poly(β-amino ester)s, HPAE-D-(±), are developed for cytoplasmic protein delivery. The zwitterionic phosphocholine is capable of binding to both proteins and the cell membrane to facilitate protein packaging and nanoparticle cellular uptake. Compared to amine-functionalized HPAE-E-(+) and carboxylic acid-functionalized HPAE-C-(-), HPAE-D-(±) exhibits much higher cytoplasmic protein delivery efficiency and lower cytotoxicity. In addition, HPAE-D-(±) are readily degraded in aqueous solution. This strategy may be extended to other zwitterions and polymers, thus having profound implications for the development of safe and efficient protein delivery systems.

(Controlled) Free radical (co)polymerization of multivinyl monomers: strategies, topological structures and biomedical applications

Free radical (co)polymerization (FRP/FRcP) of multivinyl monomers (MVMs) has emerged as a powerful strategy for the synthesis of chemically and topologically complex polymers due to its unique reaction kinetics, which enables the preparation of polymers with multiple functional groups and novel macromolecular structures. However, conventional FRP/FRcP of MVMs inevitably leads to insoluble crosslinked materials. Therefore, the development of advanced strategies for the controlled polymerization of MVMs is essential for the preparation of chemically and topologically complex polymers. In this review, we introduce the gelation mechanism of conventional FRP of MVMs and present the strategies of controlled polymerization of MVMs for the preparation of chemically and topologically complex polymers. We also discuss polymers with unique topologies synthesized by controlled polymerization of MVMs, such as crosslinked networks, (hyper)branched, star, cyclic, and single-chain cyclized/knotted structures. Finally, biomedical applications of various advanced polymeric materials prepared by controlled polymerization of MVMs are highlighted and the challenges is this field are discussed.

Two Stable Cd-MOFs as Dual-Functional Materials with Luminescent Sensing of Antibiotics and Proton Conduction

Construction and investigation of dual-functional metal-organic frameworks (MOFs) with luminescent sensing and proton conduction provide widespread applications in clean energy and environmental monitoring fields. By selecting a phosphonic acid ligand 4-pyridyl-CH₂N(CH₂PO₃H₂)₂ (H₄L) and coligand 2,2'-biimidazole (H₂biim), two cadmium-based MOFs [Cd_1.5(HL)(H₂biim)_0.5] (1) and (H₄biim)_0.5·[Cd₂(L)(H₂biim)Cl] (2) with different structures and properties have been hydrothermally synthesized by controlling reaction temperature. Based on the excellent thermal and chemical stabilities, and good luminescent stabilities in water solution, 1 and 2 can serve as luminescent sensors of chloramphenicol (CAP) with different quenching constant (K_SV) values and detection limits (LODs) in water, simulated environmental system, and real fish water system. Meanwhile, different sensing effects and possible sensing mechanisms are analyzed in detail. Moreover, 1 and 2 can also serve as good proton-conducting materials. The proton conductivities can reach up to 1.41 × 10^-4 S cm^-1 for 1 and 1.02 × 10^-3 S cm^-1 for 2 at 368 K and 95% relative humidity (RH). Among them, 2 shows better luminescent sensing and proton conduction performance than 1, which indicates that different crystal structures have a great impact on the properties of MOFs. Through the discussion of the relationship between structures and properties in detail, the possible reasons for the differences in properties are obtained, which can provide theoretical guidance for the rational design of this kind of dual-functional MOFs in the future.

Systematic review of Yougui pills combined with levothyroxine sodium in the treatment of hypothyroidism

BACKGROUND

Yougui pills have long been used to treat hypothyroidism, usually in combination with levothyroxine sodium in clinical treatment, while their clinical efficacy and safety are still controversial when compared to levothyroxine treatment alone.

AIM

To explore the clinical efficacy and safety of Yougui pills combined with levothyroxine sodium in the treatment of hypothyroidism.

METHODS

This meta-analysis was performed in accordance with the PRISMA guidelines. Randomized controlled trials on Yougui pills in the treatment of hypothyroidism published from 2008 to May 2021 were searched in a total of 8 databases (4 databases in Chinese and 4 databases in English). The quality of the included studies was evaluated according to the Cochrane risk assessment tool. Weighted mean difference (WMD) was used for continuous variables, and relative risk (RR) was used for binary variables. Data were extracted, and the meta-analysis was conducted with the statistical software of Stata15.0 and RevMan5.0.

RESULTS

A total of 140 articles were retrieved, and 9 of them were finally included, with a total sample size of 936 cases. The main meta-analysis results are as follows: (1) The group of Yougui pills combined with levothyroxine sodium had a significantly higher overall response rate than the group of levothyroxine sodium (RR = 1.20, 95%CI 1.12, 1.28, P < 0.00001); (2) Yougui pills combined with levothyroxine sodium achieved significantly better efficacy than levothyroxine sodium alone in alleviating adverse symptoms [standard mean difference (SMD) = -1.10, 95%CI: -1.37, -0.84, P < 0.00001]; (3) The level of thyrotropin stimulating hormone in the group of Yougui pills combined with levothyroxine sodium was significantly lower than in the control group of levothyroxine sodium (WMD = -1.38, 95%CI: -2.10, -0.67, P = 0.00001); (4) The level of free triiodothyronine in the group of Yougui pills combined with levothyroxine sodium was higher than that in the control group of levothyroxine sodium (WMD = 0.41, 95%CI: 0.03, 0.79, P = 0.03); (5) The level of free thyroxine in the group of Yougui pills combined with levothyroxine sodium was significantly higher than that in the control group of levothyroxine sodium (SMD = 0.83, 95%CI: 0.44, 1.22, P ≤ 0.0001); and (6) The adverse reactions in the group of Yougui pills combined with levothyroxine sodium were significantly less than those in the control group of levothyroxine sodium (RR = 0.33, 95%CI: 0.20, -0.53, P < 0.00001).

CONCLUSION

In the treatment of hypothyroidism, the combination of Yougui pills with levothyroxine sodium may be better than levothyroxine sodium treatment alone.

Boosting oxygen evolution by nickel nitrate hydroxide with abundant grain boundaries via segregated high-valence molybdenum

High-valence metal doping and abundant grain boundaries (GBs) have been proved to be effective strategies to promote the oxygen evolution reaction (OER). However, the reasonable design of the two to facilitate OER collaboratively is challenging. Herein, a convenient and novel one-step molten salt decomposition strategy is proposed to fabricate segregated-Mo doped nickle nitrate hydroxide with substantial GBs on MoNi foam (Mo-NNOH@MNF). When processed in molten salt, the Mo species on the conductive substrate migrates unevenly to the surface of Mo-NNOH@MNF, which not only induces the formation of abundant GBs to modulate electronic structure, but also improves the intrinsic activity as high-valence dopants, synergistically elevating OER activity. As verification, the optimized Mo-NNOH@MNF-10h exhibits low overpotential of 150 mV at 10 mA cm^-2, which can be attributed to the reduced valence charge transition energy of Ni by high-valence Mo dopant, coupled with the fine-tuning of d-band center bond and corresponding local electron density by induced GBs and Mo doping, as DFT calculations revealed. Moreover, the intrinsic robustness and strong adhesion ensure the long-term stability of 6 h at 500 mA cm^-2. This work provides a promising molten salt decomposition approach to synthesize advanced materials with unique structures.

Active Microstructure Transformation and Enhanced Stability of Iron Foam Derived from Industrial Water Oxidation

Tracking microstructure transformation under industrial conditions is significant and urgent for the development of oxygen evolution reaction (OER) catalysts. Herein, employing iron foam (IF) as an object, we closely monitor related morphologies and composition evolution under 300 mA cm^-2 at 40 °C (IF-40-t)/80 °C (IF-80-t) in 6 M KOH and find that the OER activity first increases and then decreases with the continuous generation of FeOOH. Moreover, the reasons for different tendencies of Tafel slope, double-layer capacitance, and impedance for IF-40-t/IF-80-t have been investigated thoroughly. In detail, the OER activity of IF-40-t is governed by electron and mass transport, while for IF-80-t, the dominating factor is electron transfer. Further, to improve the stability, guided by the above results, two versatile methods that do not sacrifice electron and mass transport have been proposed: surface coating and dynamic interface construction. The synchronous improvements of stability and activity are deeply revealed, which may provide inspiration for catalyst design for industrial applications.

Social support and depressive symptoms: exploring stigma and self-efficacy in a moderated mediation model

BACKGROUND

Although some psychological processes, such as stigma and self-efficacy, affect the complicated relationship between social support and depressive symptoms, few studies explored a similar psychological mechanism among individuals with substance use disorders (SUDs). Hence, this research investigates the mediating effects of stigma and the moderating effects of self-efficacy among the psychological mechanism that social support affects depressive symptoms.

METHODS

The study included 1040 Chinese participants with SUDs and completed a series of self-report questionnaires. R software was used to organize and clean up data sets and analyze mediation and moderation effects.

RESULTS

The result showed that stigma partially mediated depressive symptoms, while self-efficacy moderated this relationship. More specifically, less social support increased depression symptoms by bringing about higher stigma. Besides, subjects with higher self-efficacy are less susceptible to stigma and therefore have mild depressive symptoms. Furthermore, clinical and theoretical implications are discussed in our study.

CONCLUSIONS

Chinese SUDs patients' depressive symptoms were indirectly affected by perceived social support via stigma and less affected by stigma with improved self-efficacy. The theoretical and practical implications of these results are discussed.

O3-Type Na2/3Ni1/3Ti2/3O2 Layered Oxide as a Stable and High-Rate Anode Material for Sodium Storage

Sodium-ion batteries (SIBs) are currently the most promising candidates for large-scale energy storage devices owing to their low cost and abundant resources. Titanium-based layered oxides have attracted widespread attention as promising anode materials due to delivering a safe potential of about 0.7 V (vs Na⁺/Na) and a small volume contraction during cycles; P2-type Ti-based layered oxides are typically reported, due to the challenging synthesis of the O3-type counterpart resulting from the high percentage of unstable Ti³⁺. Herein, we report an anomalous O3-Na_2/3Ni_1/3Ti_2/3O₂ layered oxide as an ultrastable and high-rate anode material for SIBs. The anode material delivers a reversible capacity of 112 mA h g^-1 after 300 cycles at 0.1 C, a good capacity retention rate of 91% after 1400 cycles at 2 C, and, in particular, a capacity of 52 mA h g^-1 even at a high rate of 20 C (1780 mA g^-1). Furthermore, the in situ X-ray diffraction monitoring reveals no phase transitions and almost zero strain both underlie the good long-cycle stability. The measured high apparent Na⁺ diffusion coefficient (2.06 × 10^-10 cm² s^-1) and the low migration energy barrier (0.59 eV) from density functional theory calculations are responsible for the superior rate capability. Our results promise advanced high-performance O3-type Ti-based layered oxides as promising anode materials toward application for SIBs.

Crystal-amorphous NiO/MoO2 with high-density interface for hydrogen evolution

Distinctive interfacial catalysis play a vital role for achieving ultrahigh activity for hydrogen evolution reaction (HER) under alkaline media. In fact, the optimized regulation of electronic structure of heterostructures interface...

Triple captured iron by defect abundant NiO for efficient water oxidation

Fe-doped NiO host in well-defined nanorod assembly (Fe-NiMoO4@NiO-30) with large surface area is designed to achieve the triple capture of Fe via adjustable surface reconstruction and impregnation to optimize OER...

A sensitive fluorescence biosensor based on metal ion-mediated DNAzyme activity for amplified detection of acetylcholinesterase

In this paper, we developed an amplified fluorescence biosensor for acetylcholinesterase (AChE) activity detection by taking advantage of the mercury ion-mediated Mgzyme (Mg2+-dependent DNAzyme) activity.

Ultrahigh activity of molybdenum/vanadium-doped Ni-Co phosphides nanoneedles based on ion-exchange for hydrogen evolution at large current density

Heteroatom doping is a promising strategy to optimize the electronic structure of transition metal phosphides so enhancing the hydrogen evolution reaction (HER). However, complex and harsh experimental design is often required to achieve homogeneous doping of corresponding elements while achieving the best regulating effect. Herein, a facile ion-exchange (IE) strategy is applied to dope Mo/V species evenly into Ni-Co phosphides under mild conditions while maintaining the nanoneedle morphology. The electrochemical characterization verifies Mo dopants have a better electronic regulation effect on NiCoP crystal than V dopants, corresponding to the better hydrogen evolution performance of Mo-NiCoP/NF. Notably, due to the highly dispersed nanoneedle morphology, the synergistic effect of Ni-Co phosphides, and the optimized electronic structure, Mo-NiCoP/NF demonstrates a higher activity than that of the noble metal Pt/C at the high current density (>99 mA cm^-2). The present work is supposed to open new sights for the development of high-performance catalysts by ion-exchange strategy.

Dual-Functional Metal-Organic Framework for Luminescent Detection of Carcinoid Biomarkers and High Proton Conduction

It remains a challenge to exploit dual-functional metal-organic frameworks (MOFs) for applications, including luminescence detection and proton conduction. With the deliberate selection of the bifunctional organic ligand 5-sulfoisophthalic acid monosodium salt (NaH₂bts), and the phosphonic acid ligand N,N'-piperazine (bismethylenephosphonic acid; H₄L), a robust three-dimensional (3D) noninterpenetrating dual-functional MOF, [Tb(H₂L)(H₂bts)(H₂O)]·H₂O (1), has been synthesized hydrothermally. On the basis of the excellent thermal and chemical as well as superior luminescence stabilities in water and solutions with different pHs, 1 can serve as the simple, rapid, and highly selective and sensitive luminescence detection of the carcinoid biomarkers 5-hydroxytryptamine (HT) and its metabolite 5-hydroxyindole-3-acetic acid (HIAA) with detection limits of nanomolar magnitude in water and in simulated blood plasma and urine systems. Due to the change in the signals that could be readily differentiated by the naked eye under a UV lamp, a portable test paper has been developed. The probable quenching mechanisms are discussed in detail. In addition, a great number of hydrogen-bonding networks are formed among the uncoordinated carboxylic oxygen atoms, sulfonate oxygen atoms, protonated nitrogen atoms, and water molecules, which provide potential proton-hopping sites for proton conduction, leading to a maximum proton conductivity of 2.3 × 10^-4 S cm^-1 at 368 K and 95% relative humidity. The above results suggest that rationally designed dual-functional MOFs can open an avenue for the development of occupational diagnostic tools and alternative energy technology.

Oriented and robust anchoring of Fe via anodic interfacial coordination assembly on ultrathin Co hydroxides for efficient water oxidation

The oriented distribution and strong bonding of Fe active sites in multiple metal hydroxides are crucial to modulate activity and stability for efficient oxygen evolution reaction (OER). However, the dispersion and inevitable dissolution of Fe species still need to be addressed through deliberate design. Here, trace amounts of Fe chelated with tannic acid (TA) are precisely anchored to ultrathin Co hydroxides (TF@Co(OH)₂-t) through a new anodic interfacial coordination assembly strategy: firstly, the ZIF-67@Co(OH)₂ precursor with ultrathin Co(OH)₂ nanosheets vertically grown on the shell, provides abundant active sites and sufficient anchoring regions for subsequent TA-Fe coating; secondly, the TA-Fe ligand network quickly and robustly coats the surface of the Co(OH)₂via positive potential-driven chronopotentiometry, yielding TF@Co(OH)₂-t with good dispersion and controllable Fe species. The TA-Fe network efficiently activates Co species and prevents the dissolution of Fe ions. Physical characterization and DFT simulations reveal that the optimized OER activity with 317 mV at 10 mA cm^-2 for TF@Co(OH)₂-500 can be attributed to the accelerated electron transfer, increased active sites, and the moderate fall in d-band center levels due to Fe integration. Moreover, prolonged stability is realized benefiting from the robust TA-Fe coating protecting the actives sites.

Promoting Oxygen Evolution by Deep Reconstruction via Dynamic Migration of Fluorine Anions

Promoting the reconstruction of electrocatalysts during the oxygen evolution reaction (OER) is generally regarded as a promising strategy for enhanced activity. F anions with strong electronegativity are predicted to enhance this transformation. Herein, a fluorine-anion doping route is proposed to convert the well-latticed NiMoO₄@MNF to amorphous F-NiMoO₄@MNF by a facile and versatile molten salt strategy. The well-defined nanorod arrays guarantee abundant exposed active sites, rapid mass transfer, and fast gas bubble release. Moreover, the emerged loose amorphous structure is conducive to the dynamic migration of F species and effective penetration of the electrolyte; therefore, the resulting exchange between F and hydroxide anions induces the formation of an active oxy(hydroxide) layer, thus finally optimizing the electronic structure and absorption/desorption energy on the surface of F-NiMoO₄@MNF. The boosted OER performance of reconstructed F-NiMoO₄@MNF is reliably confirmed by a low overpotential of 188 mV at 50 mA cm^-2, a small Tafel slope of 33.8 mV dec^-1, and favorable long-term stability. In addition, accelerated hydrogen evolution is observed, which is ascribed to the finely tuned electron distribution. This work would provide a new reconstruction route assisted by F-anion doping to the development of high-performance catalysts.

Effects of PIM3 in prognosis of colon cancer

PURPOSE

PIM kinase is called proto-oncogene, but there are less research on PIM family in colon cancer. This study was designed to explore the prognosis of PIM3 in colon cancer.

METHODS

In this study, we downloaded RNA-seq and clinical information of colon cancer from the Gene Expression Omnibus (GEO) database. Kaplan-Meier method was used for analyzing the impact of PIM3 on the survival of patients with colon cancer. Single-factor and multi-factor cox regression analysis were used for verifying the prognostic value of PIM3. Spearman correlation analysis was used for screening PIM3 related genes. Functional enrichment analysis was used for analyzing the biological functions and pathways in which PIM3 related genes may be involved. STRING online tools were used for building a co-expression network. Cytoscape was used for co-expression network visualization.

RESULTS

Compared with the low expression group, the patients in the PIM3 high expression group lived longer time. Single-factor and multi-factor cox regression analysis indicated that PIM3 was an independent prognostic factor for colon cancer. Sixty-two PIM3 related genes were screened, and GO and KEGG enrichment analyses suggested that PIM3 related genes might be involved in the MAPK and WNT pathways. The co-expression network showed a strong correlation between PIM3 and MLKL, MYL5, PPP3R1 and other genes.

CONCLUSIONS

PIM3 is an independent prognostic factor of colon cancer and may be a target for the diagnosis and treatment of colon cancer.

Fe(Co)OOH Dynamically Stable Interface Based on Self-Sacrificial Reconstruction for Long-Term Electrochemical Water Oxidation

FeOOH on the real catalytic interface for the oxygen evolution reaction (OER) is chemically unstable to dissolve in alkaline media. Herein, based on the perspective of the dynamically stable interface, we purposely design the well-dispersed nanorod arrays of CoMoO₄ as a host on activated iron foam (IF) to realize the optimal redeposition of FeOOH, constructing a self-sacrificial template rich in the FeOOH surface. Notably, at long-time oxidation potential, the precatalyst FeOOH-CoMoO₄ can realize MoO₄^2- dissolution and redeposition of Co oxyhydroxides on FeOOH host simultaneously, constructing a dynamically stable Fe(Co)OOH interface. The introduction of CoOOH improves conductivity and provides synergistic effect with FeOOH to lower the energy barrier for OER and maintain long-time stability, eventually exhibiting a low overpotential of 298 mV to reach the current density of 100 mA cm^-2 and high stability over 60 h. This work demonstrates the feasibility of manipulating metal dissolution-redeposition process for a dynamically stable interface.

P3/O3 Integrated Layered Oxide as High-Power and Long-Life Cathode toward Na-Ion Batteries

Low-cost and stable sodium-layered oxides (such as P2- and O3-phases) are suggested as highly promising cathode materials for Na-ion batteries (NIBs). Biphasic hybridization, mainly involving P2/O3 and P2/P3 biphases, is typically used to boost their electrochemical performances. Herein, a P3/O3 intergrown layered oxide (Na_2/3 Ni_1/3 Mn_1/3 Ti_1/3 O₂ ) as high-rate and long-life cathode for NIBs via tuning the amounts of Ti substitution in Na_2/3 Ni_1/3 Mn_{2/3- x} Ti_x O₂ (x = 0, 1/6, 1/3, 2/3) is demonstrated. The X-ray diffraction (XRD) Rietveld refinement and aberration-corrected scanning transmission electron microscopy show the co-existence of P3 and O3 phases, and density functional theory calculation corroborates the appearance of the anomalous O3 phase at the Ti substitution amount of 1/3. The P3/O3 biphasic cathode delivers an unexpected rate capability (≈88.7% of the initial capacity at a high rate of 5 C) and cycling stability (≈68.7% capacity retention after 2000 cycles at 1 C), superior to those of the sing phases P3-Na_2/3 Ni_1/3 Mn_2/3 O₂ , P3-Na_2/3 Ni_1/3 Mn_1/2 Ti_1/6 O₂ , and O3-Na_2/3 Ni_1/3 Ti_2/3 O₂ . The highly reversible structural evolution of the P3/O3 integrated cathode observed by ex situ XRD, ex situ X-ray absorption spectra, and the rapid Na⁺ diffusion kinetics, underpin the enhancement. These results show the important role of P3/O3 biphasic hybridization in designing and engineering layered oxide cathodes for NIBs.

[Epidemiological characteristics of COVID-19 in Wuchang district of Wuhan]

Objective: To analyzes epidemiological characteristics of COVID-19 and provide evidence for adjustment for COVID-19 prevention and control strategies. Methods: The data of COVID-19 cases in Wuchang district reported as of 19 March, 2020 were obtained from National Notifiable Disease Report System of Chinese Disease Prevention and Control Information System. The software's of Excel 2010, SPSSS 22.0, Arc GIS10.2 and Joinpoint regression program 4.8.0.0 were used for statistical analysis. Results: A total of 7547 COVID-19 cases had been reported as of 19 March, 2020 in Wuchang district, including 5 448 confirmed cases (72.19%), 2009 clinical diagnosed cases (26.62%) and 90 asymptomatic cases case (1.19%). The age of the cases was (56.65±16.25) years and age ranged from 2 days to 105 years among confirmed cases, 2634 were males (48.35%) and 2814 were females (51.65%), 2 492 were retirees (45.74%). A total of 545 health workers were infected with SARS-CoV-2 (7.22% of all cases) including 365 confirmed cases and 5 cases have died. A total of 430 cases of death were reported with case fatality rate of 7.89% (430/5 448), case fatality rate of males (10.9%, 266/2 634) was higher than that of females (5.82%, 164/2 814). The first phase of epidemic peak was from January 24 to January 26, the second phase of epidemic peak was from February 1 to February 5 and there was no one of new confirmed case in one day for the first time on March 18. The first four Streets with the highest incidence rates of confirmed cases were Huanghelou Street (1 043.77/100 000), Ziyang Street (627.97/100 000), Yangyuan Street (503.67/100 000) and Shuiguohu Street (486.02/100 000). Compared with females, aged ≤50 years and mild cases of clinical classification respectively, males (RR=0.690, 95%CI: 0.322-1.478), aged >50 years (RR=11.745, 95%CI: 6.878-20.058), severe cases (RR=2.317, 95%CI: 1.789-3.000) and critical cases of clinical classification (RR=10.794, 95%CI: 7.997-14.569), and gender time-dependent covariate (RR=1.392, 95%CI: 1.053-1.840) were major influencing factors of prognosis of COVID-19 confirmed cases. Conclusions: The gender, ages and occupation of distribution were wide among COVID-19 cases in Wuchang district. Males, aged >50 years, severe cases and critical cases of clinical classification were influencing factors of prognosis of COVID-19 confirmed cases. The standardized management of discharged cases, asymptomatic infected cases and close contact persons were main measures to reduce incidence rates of COVID-19 cases.

The safety and efficacy of endoscopic submucosal dissection for treating early oesophageal carcinoma: a meta-analysis

INTRODUCTION

Oesophageal carcinoma is the sixth most lethal cancer in the world. At present, the choice of specific surgical methods is controversial. This study compares the safety and efficacy of endoscopic submucosal dissection and endoscopic mucosal resection in treating early oesophageal carcinoma.

METHODS

We carried out a search of online databases including the Web of Science, PubMed, Embase and the Cochrane Library with no language restrictions. The inclusion criteria were patients with early oesophageal carcinoma who accepted the treatment of endoscopic submucosal dissection compared with endoscopic mucosal resection.

FINDINGS

A total of 1,462 patients with 1,650 lesions from nine studies were included in the meta-analysis. When compared with the endoscopic mucosal resection group, the en bloc resection (endoscopic submucosal dissection 67.94% vs endoscopic mucosal resection 52.78%; odds ratio 19.79, p = 0.000) and complete resection (endoscopic submucosal dissection 75.57% vs endoscopic mucosal resection 59.47%; odds ratio 16.10, p = 0.000) rates were significantly higher in the endoscopic submucosal dissection group, while the local recurrence rate was significantly lower in the endoscopic submucosal dissection group (endoscopic submucosal dissection 0.08% vs endoscopic mucosal resection 2.66%; odds ratio 0.08, p = 0.000). The incidence of complications and procedural time were also tested.

Modulation engineering of in situ cathodic activation of FePx based on W-incorporation for the hydrogen evolution reaction

In situ electrochemical activation as a new pretreating method to adjust electrocatalytic performance attracts extensive attention. However, the activation mechanisms of electrocatalysts are still ambiguous. Herein, we propose a facile modulation strategy of in situ cathodic activation of FeP_x based on W-incorporation (W-FeP_x/IF) for the hydrogen evolution reaction (HER). The activated W-FeO_x with obvious surface reconstruction demonstrates the role of W-incorporation for driving the cathodic activation of FeP_x, which suggests the larger surface area and more active sites. In fact, W incorporation can not only accelerate the cathodic activation process but also act as the adsorption sites for H_ad to form the synergistic effect with FeO_x for water dissociation. The obtained W-FeO_x/IF exhibits greatly enhanced HER activity featuring decreased overpotential from 237.7 to 154.0 mV at 100 mA cm^-2, which may be ascribed to W-FeO_x with double catalytic active sites after cathodic activation. Additionally, the modulation effects of cathodic activation can be exactly achieved by changing electrochemical parameters such as CV cycles. W-FeO_x/IF also shows excellent long-term stability for at least 100 h at 100 mA cm^-2. This modulation engineering based on metal doping is expected to provide inspiration for the understanding of the cathodic activation process for efficient electrocatalysts.

Air-Stable and High-Voltage Layered P3-Type Cathode for Sodium-Ion Full Battery

The development of highly efficient and stable cathodes for sodium-ion batteries (SIBs) is strategically critical to achieving large-scale electrical energy storage. Creating air-stable and high-voltage layered cathodes for sodium-ion full batteries still remains a challenge. Herein, we describe a rational design and preparation of a stable P3-Na_2/3Ni_1/4Mg_1/12Mn_2/3O₂ cathode. The cathode displays a satisfactory working voltage of 3.6 V and excellent cyclic stability over 100 cycles at a 1 C rate without obvious capacity fading. The results of ex situ X-ray diffraction (XRD) demonstrate that the P3-type structure is well retained even when charged to 4.4 V. Furthermore, the structural characterization by XRD Rietveld refinement, scanning electron microscopy, and electrochemical testing certifies that the cathode maintains its structure commendably even when soaked in water for 12 h. In particular, the P3- Na_2/3Ni_1/4Mg_1/12Mn_2/3O₂∥hard carbon full battery exhibits a desired competitively high voltage of 3.45 V and an attractive energy density of up to 412.2 W h kg^-1 based on the cathode. The comprehensive results achieved by the specially designed strategy provide guidance toward the exploration of stable cathodes in the application of SIBs as modern energy-storage devices.

[Influence of apatinib and VEGFR2-906T>C polymorphism on clinical outcomes of advanced non-small cell lung cancer patients]

Objective: To investigate the clinical outcomes of advanced non-small cell lung cancer (NSCLC) treated by apatinib regimens and the influence of VEGFR2-906T>C polymorphism. Methods: A total of 109 patients with advanced NSCLC who were treated by apatinib after three and more lines from March 2015 to December 2017 in the Department of Oncology of the First Affiliated Hospital of Zhengzhou University were included in this study. Overall response rates were evaluated after 2 cycles, then progression free survival (PFS) and overall survival (OS) were investigated, and safety data were recorded. Additionally, peripheral blood and the biopsy tissue specimens of some NSCLC patients were collected for the genotyping of genetic variation and VEGFR2 gene mRNA expression, respectively. The association between genotype and other characteristics and VEGFR2 gene mRNA expression were analyzed. The univariate analysis of genotypes and prognosis was carried out by Kaplan-Meier survival analysis, and multivariate analysis were adjusted by Cox regression analysis. Results: The treatment effect could be evaluated in all the 109 patients, among them, complete remission (CR) 0 case, partial remission (PR) 19 case, stable disease (SD) 58 case, progression disease (PD) 32 case. Overall response rate (ORR) was 17.43%, disease control rate (DCR) was 70.64%, median PFS was 4.35 months, median OS was 8.35 months. Of the polymorphisms analyzed, only -906T>C was of clinical significance. The prevalence of -906T>C in VEGFR2 among the study population were as follows: TT genotype 64 cases (58.72%), TC genotype 37 cases (33.94%), CC genotype 8 cases (7.34%), minor allele frequency of -906T>C was 0.24. The distribution of three genotypes was in accordance with Hardy-Weinberg Equilibrium (P=0.418). CC and TC genotype patients were merged in the comparison of clinical outcomes. The analysis of patients with different genotypes found that the ORR of CC/TC genotypes and TT genotypes were 13.33% and 20.31% (P=0.377), respectively. And the median PFS of patients with CC/TC genotype and TT genotype were 3.25 and 5.35 months, respectively, which was statistically significant (P=0.007). In terms of OS, the median OS of the two genotypes were 7.35 and 9.15 (P=0.014), respectively. Adjusted in multivariate Cox regression analysis of PFS, TC/CC genotypes were an independent factor for PFS (OR=1.83, P=0.015). The correlation between -906T>C and adverse reactions was not found in the safety analysis. Additionally, of the 69 biopsy tissue specimens, gene expression analysis was conducted. And the results show that the mRNA expression of VEGFR2 in cancer tissues of the patients with CC/TC genotypes were significantly higher than those of the TT genotype patients (P<0.001). Conclusions: Apatinib is safe and effective for patients with advanced non-small cell in multiline therapy. VEGFR2 -906T>C CC/TC genotype has a worse effect on apatinib multiline treatment in patients with advanced NSCLC.

Terbium Oxalatophosphonate as Efficient Multiresponsive Luminescent Sensors for Chromate Anions and Tryptophan Molecules

A stable 2D terbium oxalatophosphonate with green luminescence, namely, [Tb2(H3L)(C2O4)3(H2O)4]·2H2O (1), has been hydrothermally obtained by using (4-carboxypiperidyl)-N-methylenephosphonic acid (H3L) and oxalate ligand. The luminescent investigation indicates that the emission behavior of compound 1 shows high water and pH stabilities. It can be applied as a multiresponsive luminescent probe with high selectivity, high sensitivity, recycling capability, and fast sensing of CrO4 2-, Cr2O7 2- anions and tryptophan (Trp) molecules in aqueous solution through the luminescence quenching effect. Moreover, the sensing results can be distinguished by the naked eye under the irradiation of UV light of 254 nm. In addition, the probable mechanisms for the quenching behavior are also discussed, which can be mainly attributed to the competitive absorption of excitation energy between compound 1 and the analytes.

Measurement of density fluctuation propagation direction via the far-forward collective scattering diagnostic based on polarimeter-interferometer

Previously, the 17-channel three-wave polarimeter-interferometer system (POLARIS) on the J-TEXT tokamak has been implemented to measure far-forward collective scattering (FFCS) from electron density fluctuations. Recently, this system has been exploited to measure the propagation direction of density fluctuation. After considering the refraction of the laser probe beam passing through plasma, the ray tracing result shows that the detector of POLARIS may receive asymmetric far-forward scattering beams. Thus, the heterodyne detection of FFCS is available to identify the propagation direction of density fluctuation by resolving the asymmetric scattering spectrum. Experimentally, the transform of the heterodyne scattering spectrum from symmetry to asymmetry has been observed, while the refraction effect becomes strong demonstrating the capacity of measuring the propagation direction of fluctuation. Furthermore, by changing the plasma potential through the use of an applied positive electrode biasing, the reverse of frequency shift for the heterodyne scattering spectrum is identified, confirming the validity of direction discrimination of density fluctuation.

Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak

The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k_⊥max ≤ 2 cm^-1 and time response up to 350 kHz. Feasibility of the diagnostic has been tested, showing higher sensitivity to detect fluctuation than interferometric measurement. Capability of providing spatial-resolved information of fluctuation has also been demonstrated in preliminary experimental applications.

High resolution polarimeter-interferometer system for fast equilibrium dynamics and MHD instability studies on Joint-TEXT tokamak (invited)

A high-performance Faraday-effect polarimeter-interferometer system has been developed for the J-TEXT tokamak. This system has time response up to 1 μs, phase resolution < 0.1° and minimum spatial resolution ∼15 mm. High resolution permits investigation of fast equilibrium dynamics as well as magnetic and density perturbations associated with intrinsic Magneto-Hydro-Dynamic (MHD) instabilities and external coil-induced Resonant Magnetic Perturbations (RMP). The 3-wave technique, in which the line-integrated Faraday angle and electron density are measured simultaneously by three laser beams with specific polarizations and frequency offsets, is used. In order to achieve optimum resolution, three frequency-stabilized HCOOH lasers (694 GHz, >35 mW per cavity) and sensitive Planar Schottky Diode mixers are used, providing stable intermediate-frequency signals (0.5-3 MHz) with S/N > 50. The collinear R- and L-wave probe beams, which propagate through the plasma poloidal cross section (a = 0.25-0.27 m) vertically, are expanded using parabolic mirrors to cover the entire plasma column. Sources of systematic errors, e.g., stemming from mechanical vibration, beam non-collinearity, and beam polarization distortion are individually examined and minimized to ensure measurement accuracy. Simultaneous density and Faraday measurements have been successfully achieved for 14 chords. Based on measurements, temporal evolution of safety factor profile, current density profile, and electron density profile are resolved. Core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Effects of non-axisymmetric 3D RMP in ohmically heated plasmas are directly observed by polarimetry for the first time.

[A technique for generating natural color images based on local endmembers]

A method for generating natural color composite of satellite images based on local endmembers of ground features was proposed. First, the reference satellite image which has similar land cover types with the target satellite image is segmented into multiple local patches. Secondly, endmembers of ground features are extracted from each local patch, then we choose better end-members and gather them into a sample set. Thirdly, we use the sample set to build up the relationship between the spectral values of the blue band and the other bands. Finally, the spectrum relationship is used to generate natural color composite of the target image. The verification experiment on Landsat TM5 images shows that the proposed method is reliable and stable to generate the natural color composite of images. The other experiment on IRS-P6 images shows that our method is able to promote for other satellite images. In experiments, we also compared the existing "reference image-image" method and "spectral library-image" method qualitatively and quantificationally, indicating that our method is more precise to simulate spectrums of all kinds of ground features.

Effect of Si-Miao-Yong-An on the stability of atherosclerotic plaque in a diet-induced rabbit model

ETHNOPHARMACOLOGICAL RELEVANCE

Si-Miao-Yong-An (Trade name: Mai-Luo-Ning), a Chinese herbal formulation comprising Flos Lonicerae Japonicae, Radix Scrophulariae Ningpoensis, Radix Angelicae Sinensis and Radix Glycyrrhizae Uralensis, has been used in treating ischemic cardiovascular and cerebrovascular diseases for many years. Clinical and experimental studies have shown that Si-Miao-Yong-An can inhibit the inflammatory response and antagonize the blood clotting process.

AIM OF THE STUDY

To investigate the effect of Si-Miao-Yong-An on atherosclerotic plaque stability in rabbit model.

MATERIALS AND METHODS

Seventy male rabbits were divided into four groups. Rabbits in the normal group were fed with normal diet, while rabbits in model group and drug treatment groups were fed with high cholesterol diet, underwent BSA-induced immunologic injury and balloon-induced mechanical injury. After atherosclerotic rabbits were treated with simvastatin or Si-Miao-Yong-An for 16 weeks, blood and aorta in four groups were collected for analysis.

RESULTS

Si-Miao-Yong-An reduced the level of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) in blood after treatment for 16 weeks. Compared with model group, Si-Miao-Yong-An decreased the content of many inflammatory cytokines in blood and plaque. Morphological analysis of abdominal aorta showed that Si-Miao-Yong-An increased fibrous cap thickness and smooth muscle cells, reduced lipid core area and macrophages, and contributed to inhibit matrix degradation and inflammatory response.

CONCLUSION

In this study, we provided evidence for that Si-Miao-Yong-An could promote the stability of atherosclerotic plaque in the rabbit model, indicating that this medicine was a reasonable drug treating cardiovascular diseases in clinical.

[Modeling and simulation activities to design sampling scheme for population pharmacokinetic study on amlodipine]

Reasonable sampling scheme is the important basis for establishing reliable population pharmacokinetic model. It is an effective method for estimation of population pharmacokinetic parameters with sparse data to perform population pharmacokinetic analysis using the nonlinear mixed-effects models. We designed the sampling scheme for amlodipine based on D-optimal sampling strategy and Bayesian estimation method. First, optimized sample scenarios were designed using WinPOPT software according to the aim, dosage regimen and visit schedule of the clinical study protocol, and the amlodipine population model reported by Rohatagi et al. Second, we created a NONMEM-formatted dataset (n = 400) for each sample scenario via Monte Carlo simulation. Third, the estimation of amlodipine pharmacokinetic parameters (clearance (CL/F), volume (V/F) and Ka) was based on the simulation results. All modeling and simulation exercises were conducted with NONMEM version 7.2. Finally, the accuracy and precision of the estimated parameters were evaluated using the mean prediction error (MPE) and the mean absolute error (MAPE), respectively. Among the 6 schemes, schemes 6 and 3 have good accuracy and precision. MPE is 0.1% for scheme 6 and -0.6% for scheme 3, respectively. MAPE is 0.7% for both schemes. There is no significant difference in MPE and MAPE of volume among them. Therefore, we select scheme 3 as the final sample scenario because it has good accuracy and precision and less sample points. This research aims to provide scientific and effective sampling scheme for population pharmacokinetic (PK) study of amlodipine in patients with renal impairment and hypertension, provide a scientific method for an optimum design in clinical population PK/PD (pharmacodynamics) research.

Differences in the activities of resveratrol and ascorbic acid in protection of ethanol-induced oxidative DNA damage in human peripheral lymphocytes

Previous studies have shown that ethanol induces oxidative DNA damage in human peripheral lymphocytes. In the present study, protective effect of resveratrol and ascorbic acid on ethanol-induced oxidative DNA damage in human peripheral lymphocytes in vitro were comparatively investigated. Pretreatments with resveratrol at 5, 25, and 50μM, which were in the concentration range of in vitro research, significantly inhibited ethanol-induced oxidative DNA damage in 24h, whereas ascorbic acid showed such DNA protective activity only in 1h. Further study showed that both compounds could directly scavenge hydroxyl radical produced during ethanol metabolism. Resveratrol significantly inhibited ethanol metabolism by regulating alcohol dehydrogenase 1B (ADH1B) and acetaldehyde dehydrogenase 2 (ALDH2) mRNA expressions. Moreover, resveratrol also activated the base excision repair (BER) system in mRNA and protein levels in DNA auto-repair process. However, ascorbic acid showed no effect on ethanol metabolic pathway and BER system. Thus, the present study provided the first evidence that even though both resveratrol and ascorbic acid are anti-oxidants, they possessed differential mechanisms of action in protection against ethanol-induced oxidative DNA damage in human peripheral lymphocytes.

Microvessel density of hepatocellular carcinoma: its relationship with prognosis

PURPOSE

To elucidate the relationship between angiogenesis and prognosis after curative resection of hepatocellular carcinoma (HCC).

METHODS

An immunohistochemical study using anti-CD34 monoclonal antibody was carried out on surgical specimens from 78 HCC patients who had undergone curative resection; microvessel density (MVD) was counted and the overall survival and disease-free survival were analyzed retrospectively.

RESULTS

Blood vessels in the tumor were strongly stained by anti-CD34 antibody, but not those in the surrounding liver parenchyma. There were three types of tumor vessels: capillary-like (n = 59), sinusoid-like (n = 16) and mixed-type (n = 3). The median MVD count was 100 per field. The HCC were designated as hypovascular (n = 36) with an MVD count below 100, and hypervascular (n = 42) with an MVD count of 100 or more per field. The 5-year survival and disease-free survival rates were 49.7% and 42.8% respectively, and statistical analysis showed that the MVD level was not correlated with tumor size, capsule status, Edmondson's grade, alpha-fetoprotein level, associated cirrhosis, gamma-glutamyltransferase, and serum HBsAg status. The sinusoid-like tumor vessels appeared more frequently in the more differentiated tumors (P<0.05). No statistical difference in overall and disease-free survival between different MVD levels and microvessel types was found. Tumor size was the only predicting factor in the entire series. In patients with small HCC (< or =5 cm, n = 40), 5-year survival and disease-free survival rates were 58.9% and 52.7% respectively, higher than the values in large HCC (39.8% and 32.0% respectively, P<0.05). The MVD level was an independent predicting factor of disease-free survival, 5-year disease-free survival in the hypovascular group (74.6%) being better than that in the hypervascular group (34.7%, P<0.05).

CONCLUSIONS

The MVD level was not related to tumor size, capsule statuo, Edmondson's grade, alpha-fetoprotein level, associated cirrhosis, gamma-glutamyltransferase and serum HBsAg status. In the entire series, tumor size was the only factor influencing survival after curative resection. However, in patients with small HCC, the MVD level was an independent factor of disease-free survival. The pathological and clinical implications of different types of tumor vessels in HCC remain to be studied.

The rpoB mutants destabilizing initiation complexes at stringently controlled promoters behave like "stringent" RNA polymerases in Escherichia coli

In Escherichia coli, stringently controlled genes are highly transcribed during rapid growth, but "turned off" under nutrient limiting conditions, a process called the stringent response. To understand how transcriptional initiation at these promoters is coordinately regulated, we analyzed the interactions between RNA polymerase (RNAP) (both wild type and mutants) and four stringently controlled promoters. Our results show that the interactions between RNAP and stringently controlled promoters are intrinsically unstable and can alternate between relatively stable and metastable states. The mutant RNAPs appear to specifically further weaken interactions with these promoters in vitro and behave like "stringent" RNAPs in the absence of the stringent response in vivo, constituting a novel class of mutant RNAPs. Consistently, these mutant RNAPs also activate the expression of other genes that normally require the response. We propose that the stability of initiation complexes is coupled to the transcription of stringently controlled promoters, and this unique feature coordinates the expression of genes positively and negatively regulated by the stringent response.

Multiple regions on the Escherichia coli heat shock transcription factor sigma32 determine core RNA polymerase binding specificity

We have analyzed the core RNA polymerase (RNAP) binding activity of the purified products of nine defective alleles of the rpoH gene, which encodes sigma32 in Escherichia coli. All mutations studied here lie outside of the putative core RNAP binding regions 2.1 and 2.2. Based on the estimated K(s)s for the mutant sigma and core RNAP interaction determined by in vitro transcription and by glycerol gradient sedimentation, we have divided the mutants into three classes. The class III mutants showed greatly decreased affinity for core RNAP, whereas the class II mutants' effect on core RNAP interaction was only clearly seen in the presence of sigma70 competitor. The class I mutant behaved nearly identically to the wild type in core RNAP binding. Two point mutations in class III altered residues that were distant from one another. One was found in conserved region 4.2, and the other was in a region conserved only among heat shock sigma factors. These data suggest that there is more than one core RNAP binding region in sigma32 and that differences in contact sites probably exist among sigma factors.

RNA polymerase beta mutations have reduced sigma70 synthesis leading to a hyper-temperature-sensitive phenotype of a sigma70 mutant

This work describes a mutational analysis of the interaction between the beta and sigma subunits of Escherichia coli RNA polymerase. The rpoD800 mutant has a temperature-sensitive growth phenotype because the mutant sigma70 polypeptide is not stable at a high temperature. Some rpoB mutations, including rpoB114, enhanced the temperature sensitivity of the rpoD800 mutant. We determined the mechanism by which the rpoB114 rpoD800 double mutant becomes hyper-temperature sensitive for growth. We found that the levels of the mutant sigma70 in the rpoB114 rpoD800 mutant were dramatically reduced compared to that in the rpoD800 mutant after temperature shift-up. The rate of synthesis of the sigma70 polypeptide was reduced in the rpoB114 rpoD800 double mutant compared to the rpoD800 mutant, whereas the half-life of the mutant sigma70 polypeptide after temperature shift-up was the same in both strains. We conclude that because of the reduction of expression of rpoD800 by rpoB114, in concert with the intrinsic instability of the mutant sigma70 polypeptide, the amount of holoenzyme containing sigma70 becomes limiting upon temperature shift-up. This results in the hyper-temperature sensitivity of the rpoB114 rpoD800 double mutant. Furthermore, the effect of rpoB114 on the expression of sigma70 is independent of the rpoD800 allele and is at the transcriptional level. In vitro transcription assays showed that the mutant RNA polymerase RpoB114 was defective in transcribing the two major promoters of the rpoD operon specifically. The effects of these rpoB mutations on gene expression are discussed.

Interaction of Gal repressor with inducer and operator: induction of gal transcription from repressor-bound DNA

Gal repressor inhibits transcription from the gal promoter (P1) when it binds to the cognate operator (O(E)). The repression is relieved by the presence of the inducer D-galactose. Compared with its interaction with free repressor, D-galactose binds to the repressor-operator complex with 10-fold reduced affinity as determined by fluorescence enhancement measurements. Thermodynamic analysis and fluorescence anisotropy showed that the stability of the repressor-operator complex is reduced by only 7-fold by the presence of the inducer in the complex. The formation of the inducer-repressor-operator ternary complex has been confirmed by CD spectral analysis. Fluorescence spectroscopy and energy transfer experiments suggest that individual allosteric effects of the two ligands, inducer and operator, on Gal repressor are responsible for the slightly weakened stability of the ternary complex compared with the stability of the inducer-repressor and repressor-operator complexes. In vitro transcription results demonstrated full derepression of transcription of the P1 promoter under conditions in which the concentrations of the inducer-repressor binary complex are severalfold higher than the dissociation constant of the inducer-repressor-operator ternary complex into inducer-repressor and free DNA. These results strongly suggest that the inducer binding to the repressor-operator complex does not lead to dissociation of the repressor from the operator during transcription induction. Because Gal repressor inhibits transcription by modulating the alpha subunit of the P1-bound RNA polymerase, we conclude that the inducer binding to the operator-bound repressor only allosterically relieves the inhibitory effect of repressor on RNA polymerase without dissociating the repressor from DNA.

The non-inducible nature of super-repressors of the gal operon in Escherichia coli

We isolated and characterized mutant repressors (GalR) of the gal operon in Escherichia coli. These repressors (super-repressors), called GalRs, have a non-inducible phenotype. Repression of the gal operon by super-repressors cannot be lifted by inducer. The mutant galR genes, galRs, have been cloned and the mutational changes determined. Two of them, galRuv7s and galR78s, were located in the proposed sugar binding domains of the repressor. The repressor from wild-type (galR+), as well as from mutant galRuv7s, was purified and characterized biochemically. The results showed that, like wild-type GalR+, GalRuv7s binds to DNA normally and represses transcription from the P1 promoter and stimulates that from the P2 promoter of the gal operon. Nevertheless, compared to GalR+, GalRuv7s is much less sensitive to the presence of the inducer, D-galactose. The affinity of D-galactose to GalRuv7s is 10 to 30-fold lower, as measured by the effect of the inducer on GalR tryptophan fluorescence; GalR complexes with DNA and on GalR repression of transcription. Our results suggest that the super-repressor phenotype of GalRuv7s is because of a defect in D-galactose binding rather than a defect in the ligand-induced allosteric change or increased affinity for the operator.

How a mutation in the gene encoding sigma 70 suppresses the defective heat shock response caused by a mutation in the gene encoding sigma 32

In Escherichia coli, transcription of the heat shock genes is regulated by sigma 32, the alternative sigma factor directing RNA polymerase to heat shock promoters. sigma 32, encoded by rpoH (htpR), is normally present in limiting amounts in cells. Upon temperature upshift, the amount of sigma 32 transiently increases, resulting in the transient increase in transcription of the heat shock genes known as the heat shock response. Strains carrying the rpoH165 nonsense mutation and supC(Ts), a temperature-sensitive suppressor tRNA, do not exhibit a heat shock response. This defect is suppressed by rpoD800, a mutation in the gene encoding sigma 70. We have determined the mechanism of suppression. In contrast to wild-type strains, the level of sigma 32 and the level of transcription of heat shock genes remain relatively constant in an rpoH165 rpoD800 strain after a temperature upshift. Instead, the heat shock response in this strain results from an approximately fivefold decrease in the cellular transcription carried out by the RNA polymerase holoenzyme containing mutant RpoD800 sigma 70 coupled with an overall increase in the translational efficiency of all mRNA species.

A mutant sigma 32 with a small deletion in conserved region 3 of sigma has reduced affinity for core RNA polymerase

sigma 70, encoded by rpoD, is the major sigma factor in Escherichia coli. rpoD285 (rpoD800) is a small deletion mutation in rpoD that confers a temperature-sensitive growth phenotype because the mutant sigma 70 is rapidly degraded at high temperature. Extragenic mutations which reduce the rate of degradation of RpoD285 sigma 70 permit growth at high temperature. One class of such suppressors is located in rpoH, the gene encoding sigma 32, an alternative sigma factor required for transcription of the heat shock genes. One of these, rpoH113, is incompatible with rpoD+. We determined the mechanism of incompatibility. Although RpoH113 sigma 32 continues to be made when wild-type sigma 70 is present, cells show reduced ability to express heat shock genes and to transcribe from heat shock promoters. Glycerol gradient fractionation of sigma 32 into the holoenzyme and free sigma suggests that RpoH113 sigma 32 has a lower binding affinity for core RNA polymerase than does wild-type sigma 32. The presence of wild-type sigma 70 exacerbates this defect. We suggest that the reduced ability of RpoH113 sigma 32 to compete with wild-type sigma 70 for core RNA polymerase explains the incompatibility between rpoH113 and rpoD+. The rpoH113 cells would have reduced amounts of sigma 32 holoenzyme and thus be unable to express sufficient amounts of the essential heat shock proteins to maintain viability.