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The 25Mg(p, γ )26Al reaction plays an important role in the study of cosmic 1.809 MeV γ -ray as a signature of ongoing nucleosynthesis in the Galaxy. At astrophysical temperature around 0.1 GK, the 25Mg(p, γ )26Al reaction rates are dominated by the 92 keV resonance capture process. We report a precise measurement of the 92 keV 25Mg(p, γ )26Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment (JUNA) facility in the China Jinping Underground Laboratory (CJPL). The resonance strength and ground state feeding factor are determined to be 3.8 ± 0.3 ×10−10 eV and 0.66 ± 0.04 , respectively. The results are in agreement with those reported in the previous direct underground measurement within uncertainty, but with significantly reduced uncertainties. Consequently, we recommend new 25Mg(p, γ )26Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK. The new results indicate higher production rates of 26gAl and the cosmic 1.809 MeV γ -rays. The implication of the new rates for the understanding of other astrophysical situations is also discussed.

The present investigation was conducted to formulate and evaluate gastric-floating controlled release tablets of Ginkgolides. The target tablets were formulated by powder direct compression method combined with hydrophilic polymer, floating assistant agent, and effervescent substance. Formulations were evaluated for in vitro drug release, in vitro floating ability, and in vivo gastro-retentive behavior by gamma scintigraphy technique. The optimized formulations showed good instant and total duration floating properties, and extended drug release characteristic for 12 h. The release behaviors of the tablets were fitted to zero-order model in the coupled action of drug diffusion and matrix erosion mechanism. In vivo behaviors of the tablets were observed at different time intervals from the radiographic pictures of the healthy volunteers and the retention time in the stomach was about 8 h. Results indicated that gastric-floating tablets of the Ginkgolides had the potential for a good gastric residence time and the controlled drug release.

Thermophilic fungus Myceliophthora thermophila has great capacity for biomass degradation and is an attractive option for use as cell factory to produce chemicals directly from renewable polysaccharides, such as starch, rather than monomer glucose. To date, there has been no transcriptomic analysis of this thermophilic fungus on starch. This study determined the transcriptomic profile of M. thermophila responding to soluble starch and a 342-gene set was identified as a “starch regulon”, including the major amylolytic enzyme (Mycth_72393). Its overexpression led to increased amylase activities on starch by 35%. Furthermore, overexpressing the key amylolytic enzyme regulator AmyR in M. thermophila significantly increased amylase activity by 30%. Deletion of amyR by the CRISPR/Cas9 system led to the relief of carbon catabolite repression and 3-fold increased lignocellulase activities on cellulose. This study will accelerate rational fungal strain engineering for biochemical production from biomass substrates such as raw corn starch and even crop straw.

Carbon dots with Nitrogen-doped (N-CDs) were prepared from easy hydrothermal method by broad bean and 1,2-ethanediamine as precursors. The prepared N-CDs were authenticated by ultraviolet–visible (UV–vis) absorption spectra, fluorescence spectra, displayed that the prepared N-CDs owned excellent fluorescence properties. X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR) verified that N-CDs carrying many different hydrophilic groups (for example hydroxyl, carboxyl/carbonyl, amide, amino, etc.) on the surface. Besides, the prepared N-CDs exhibited outstanding advantages including low-toxicity, satisfactory biocompatibility, and excellent chemical stability. More prominently, the prepared N-CDs could sensitively and selectively detect heavy metal Hg2+ ion both in water samples and in HeLa cells.

Porous polyaniline (PANI) with enhanced surface area was obtained using attapulgite (ATP) as a template and then etched with HF acid. Pt-Ag/porous PANI nanocomposites were fabricated successfully via step-by-step electrodeposition method, and then characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), and UV-visible spectrophotometer (UV-visible). The influence of deposition order and deposition laps of Pt, Ag towards glycerol oxidation was also studied. The results showed that when Pt was deposited first then Ag, and the deposition laps of both Pt and Ag were 300 laps, Pt-Ag/porous PANI (300/300) exhibited the best effect. The catalytic activity of Pt-Ag/porous PANI (300/300) was 3.14 times higher than that of the commercial 20 wt.% Pt/C. In addition, the Electrochemical Impedance Spectroscopy (EIS), chronoamperometry and stability testing proved that the Pt-Ag/porous PANI (300/300) modified electrode showed not only excellent electrocatalytic activity but also better poison resistance and good stability towards glycerol oxidation in contrast to other as-prepared composites as well as commercial 20 wt.% Pt/C catalysts, which may be ascribed to high utilization of Pt resulted from porous structure of support and the synergic effect between Pt and Ag.

The different crystallographic structures of manganese dioxide (α-MnO 2 , β-MnO 2 , γ-MnO 2 and δ-MnO 2 ) were prepared via simple and feasible methods. Among four crystallographic structures, γ-MnO 2 exhibited the best electrochemical property and was chosen to compound γ-MnO 2 /polyaniline (PANI) composite electrode through in situ synthesis techniques. The as-prepared samples were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). The electrochemical properties of as-prepared samples influenced by the different mass ratios, scan rates, and current densities were mainly investigated by cyclic voltammetry (CV), galvanostatic charge-discharge, electrochemical impedance spectroscopy (EIS), and cycle life, respectively. The results showed that the specific capacitance can be up to 493 F g − 1 as mass ratio of γ-MnO 2 /PANI was 1:5 at current density of 0.5 A g − 1 , suggesting the γ-MnO 2 /PANI (1:5) composite as an electrode material for super capacitors has great development prospects.

Immune checkpoint inhibitors (ICIs), like monoclonal antibodies of PD-1, CTLA-4, and their ligands, are effective only in some populations of patients with cancer, because the immunosuppressive state of the tumor microenvironment (TME) in some patients cannot be effectively reversed after ICI therapy. Sialic acid (SA) receptors in the Siglec family are highly expressed on the surface of tumor-associated macrophages (TAMs) and most have immunosuppressive effects. Therefore, targeting TAMs (the siglec axis) to reverse tumor immunosuppression may provide a new direction for the development of novel tumor immunotherapies. We designed a Zoledronic acid (ZA)-loaded liposome modified by a SA-octadecylamine conjugate (ZA-SL) to act as a novel nanomedicine delivery platform. This platform can efficiently deliver ZA to TAMs through the combination of SA and Siglec-1 and exerts specific cytotoxicity or phenotypic remodeling of M2-like TAMs depending on the drug concentration in TAMs. In vivo experiments showed that ZA-SL had good TAM targeting ability, and after treatment, the S180 tumors of mice were significantly inhibited, and the proportion of M1-like TAMs was significantly higher than that of M2-like TAMs with no significant adverse reactions in mice. Therefore, SA-modified ZA-loaded liposomes may provide a promising strategy for cancer immunotherapy.

DNA based biosensors have become increasingly important in medical diagnostics, genetic and drug screening, and forensics in this post-genomic era. Chemical labeling methods suffer from several drawbacks, which are tedious, cost-expensive and time-consuming, thus the development of simple and general label free strategies is being demanded. The present article introduces a new model of biosensor device based on both metallointercalators and nanomaterials, with the aim of highlighting, in particular, the use of the "label-free" strategy for the construction of simple and inexpensive sensing platforms. In this work, two strategies were developed for designing "label-free" sensors: (1) metallointercalators act as the quencher to nanomaterials; (2) nanomaterials act as the quencher to metallointercalators. These methods take advantage of the sensitive luminescence signal change of metallointercalators or nanomaterials upon analytes binding. By monitoring the luminescence change, we were able to detect metal ions and biomolecules. Compared to other label-free fluorescent methods, these "label-free" DNA biosensors provide fast, simple, economical, sensitive and selective detection of target analytes with specific probes.

A new complex [Ru(bpy) 2 (bppp)] 2 + (bpy = 2,2′-bipyridine, bppp = 12-bromo-pyrido[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline) has been synthesized and characterized. The interaction of the title complex with two different forms of the human telomeric G-quadruplexes DNA was explored by means of CD spectroscopy, CD melting, fluorescent intercalator displacement (FID) and molecular docking studies. Results indicated that [Ru(bpy) 2 (bppp)] 2 + not only induce formation of antiparallel G-quadruplex structure in the absence of metal cations, but also have the ability to stabilize the G-quadruplexes DNA.

An immobilizing conidia approach was used to study the degradation ability of dichlorvos in Trichoderma atroviride T-DNA insertional mutant AMT-28. Beads with 107 immobilized conidia per 100 mL of Na-alginate solution exhibited the highest degradation abilities. The immobilized conidia showed enhanced degradation abilities compared with immobilized or freely suspended mycelia. The immobilized cells kept good storage capacity and reusability. Dichlorvos was confirmed to be completely removed by mycelia of AMT-28 within 7 days using HPLC analysis. The dichlorvos degradation rates in auxotrophic Burk media varied and were significantly affected by nitrogen sources. There was no detectable biosorption and the removal of dichlorvos in AMT-28 was primarily attributed to a kind of Biomineralization process.

Four kinds of reconstituted tobacco sheets were heated in a thermogravimetric analyzer in different atmospheres at the heating rate of 5 °C/min. The curves of thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA) of the reconstituted tobacco sheets were measured and compared. The profiles of the evolving product CO2 were also recorded by the thermogravimetric analyzer coupled to a Fourier transform infrared (TG-FTIR) spectrometer. The results of thermal analysis and the profiles of CO2 showed that the existence of O2 could strongly affect the thermal decomposition of the reconstituted tobacco sheets.

Cyanide binding to fully reduced Pseudomonas aeruginosa cd(1) nitrite reductase (Pa cd(1) NiR) has been investigated for the wild-type enzyme and a site-directed mutant in which the active-site His369 was replaced by Ala. This mutation reduces the affinity toward cyanide (by approximately 13-fold) and especially decreases the rate of binding of cyanide to the reduced d(1) heme (by approximately 100-fold). The crystal structure of wild-type reduced Pa cd(1) NiR saturated with cyanide was determined to a resolution of 2.7 A. Cyanide binds to the iron of the d(1) heme, with an Fe-C-N angle of 168 degrees for both subunits of the dimer and only His369 is within hydrogen bonding distance of the nitrogen atom of the ligand. These results suggest that in Pa cd(1) NiR the invariant distal residue His369 plays a dominant role in controlling the binding of anionic ligands and allow the discussion of the mechanism of cyanide binding to the wild- type enzyme. (c)2002 Elsevier Science (USA).

The fabrication and application of a novel multichannel amperometric detection system (MADS) with chemically modified microelectrodes (CMEs) for liquid chromatography (LC) are described. These CMEs are based on the immobilization of copper tetraaminophthalocyanine(CuTAPc) on platinum (Pt) microelectrodes by cyclic voltammetry (CV). The CMEs show good catalytic activity oxidation of several analytes including thiocompounds. With the multichannel amperometric detection system (MADS) coupled to LC, a three-dimensional hydrodynamic voltammogram (3D HDV) (i.e. current as a function of time and potential) is obtained. The optimum detection potentials of thiocompounds and other analytes at the CMEs are easy to find. The novel multichannel amperometric detector with CMEs shows good stability and reproducibility in detecting the thiocompounds and other analytes in LC. The linear ranges cover over three orders of magnitude and the limits of detection are 10 pmol for cysteine, 16 pmol for glutathione, 16 pmol for N-acetylcysteine, 10 pmol for ascorbic acid and 16 pmol for uric acid. The application of this method with microdialysis sampling and normal sampling in human whole blood assay is successful. The method of LC-MADS with microdialysis sampling is more useful to assay the compounds in the biological matrix.

Nafion/methyl viologen (MV) has been chemically modified on a gold disk microelectrode (GDME). The electrochemistry of the Nafion/MV modified GDME is investigated by cyclic voltammetry (CV). Linear sweep voltammetry (LSV) and differential pulse amperometry (DPA) show that the Nafion/MV modified GDME exhibits very high electrocatalytic activity toward dioxygen reduction with good reproducibility and high sensitivity. The electrocatalytic peak current is found to be linear with the dioxygen concentration in the range of 3.44x10(-7) to 2.59x10(-4) mol l(-1) (at 25 degrees C), with a correlation coefficient of 0.9978. The detection limit (signal/noise=3) is calculated to be 0.19 mumol l(-1). The response time of the microsensor for dioxygen measurement is less than 15 s. For ten parallel measurements for 8.50 mumol l(-1) dioxygen, the relative standard deviation (RSD) is found to be 2.7%. The sensitivity of the microsensor is 0.17 nA mumol(-1) l(-1). This microsensor has been successfully employed to measure the concentration of dioxygen in real samples. The quantity of dioxygen, released from the three kinds of chloroplasts of plant leaves under different illumination, is monitored by the Nafion/MV modified gold microsensor. In order to survey the dioxygen concentration in vivo, a Nafion/MV modified carbon fiber microelectrode (CFME) is fabricated by a modification procedure similar to that of the Nafion/MV GDME. As a preliminary test, the dioxygen levels in the different areas of rat brain are determined by the Nafion/MV modified carbon fiber microsensors. The mechanism of the catalytic reaction is also addressed.

A new chemically modified electrode (CME) was found to be comparable to a glassy carbon electrode in terms of the eletrocatalytic effect of Cobalt Hexacyanoferrate (CoHCF) towards thiolcompounds (glutathione (GSH), cysteine (Cys), N -acetylcysteine (NAC)). Polynuclear CoHCF thin films are electrodeposited on a glassy carbon electrode by potential cycling between 1.2 V and −0.2 V versus Ag/AgCl in a fresh modification solution containing 0.5 mmol/l K 3 Fe(CN)6 and 1 mmol/l CoCl 2 in 0.1 mol/l KH 2 PO 4 (pH = 3.0). Combined with liquid chromatography, the CoHCF CME exhibits a good linear relationship between the concentration and the current responses of GSH (5.0 × 10 −6 –1.0 × 10 −4 mol/l), Cys (1.5 × 10 −6 –2.0 × 10 −4 mol/l), and NAC (3.0 × 10 −6 –1.0 × 10 −4 mol/l). The detection limits were 2.5 × 10 −6 mol/l for GSH, 1.0 × 10 −6 mol/l for Cys and 1.5 × 10 −6 mol/l for NAC. We coupled the microdialysis sampling technique with liquid chromatography-electrochemical detection (LC-ECD) and successfully determined glutathione in the brain of a freely moving rat.

A new type of chemically modified electrode (CME) was fabricated by electrodeposition of palladium(II)-substituted Dawson type heptadecatungstodiphosphate, K 8 [P 2 W 17 O 61 Pd(H 2 O)] (abbreviated as P 2 W 17 Pd in the following), onto a carbon fiber microelectrode (CFME). A pair of waves was observed on the P 2 W 17 Pd CFME, which is ascribed to the redox process of the palladium center in the heteropolytungstate. After continuous potential scanning for 30 min in a pH 4.0 buffer, 92% of the original electrode response remained for the P 2 W 17 Pd CFME. The P 2 W 17 Pd CFME had high electrocatalytic activity for nitrite reduction and exhibited good reproducibility and stability. The catalytic peak current was found to be linear with the nitrite concentration in the range of 1.0×10 −7 ∼1.2×10 −3 mol l −1 (at 25°C) with a correlation coefficient of 0.9886. The detection limit (signal/noise=3) was found to be 2.0×10 −8 mol l −1 . The response time of the microsensor for nitrite measurement was less than 15 s. For 10 parallel measurements of 1.0×10 −5 mol l −1 nitrite, the relative standard deviation (RSD) was found to be 4.5%. The sensitivity of the microsensor was 0.57 nA (μmol l −1 ) −1 . The P 2 W 17 Pd CME was applied successfully as an electrochemical detector (ECD) to determine the nitrite level in rat brain by flow injection analysis (FIA) coupled with microdialysis sampling. The linear range was over three orders of magnitude and the detection limit was 3.0 pmol for nitrite determination. The mechanism of the catalytic reaction was also addressed.

A potassium salt of palladium(II)-substituted Keggin type heteropolytungstate, K 6 [(H 2 O)PdSiW 11 O 39 ] (abbreviated as PdSiW 11 in the following), was used to fabricate a new kind of chemically modified electrode (CME) by potential scanning on the surface of glassy carbon electrode. Characterization of this modified electrode was conducted by Fourier transform infrared reflection absorption spectroscopy (FTIRRAS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). FTIRRAS and XPS showed that the species on the electrode surface sustained the same Keggin type structure as that of the heteropolytungstate in buffer solution. A couple of waves was observed on the PdSiW 11 CME, which was assigned to the redox process of the palladium center in the heteropolytungstate. This CME had high electrocatalytic activity towards nitrite reduction and exhibited good reproducibility and stability. The catalytic peak current was found to be linear with the nitrite concentration in the range 1–20 mmol/l with a correlation coefficient of 0.998. The PdSiW 11 CME is successfully applied as an electrochemical detector to monitor nitrite in flow injection analysis (FIA). The linear range is over three orders of magnitude and the detection limit is 24.0 pmol for nitrite determination. The relative standard deviation (RSD) for ten successive measurements of 1.0 mmol/l nitrite in FIA is found to be 3.3%.

Polynuclear indium(III) hexacyanoferrate(II, III) thin films are electrodeposited on a glassy carbon (GC) electrode through potential cycling between 1.1 and 0.0 V vs. SCE in a fresh modification solution containing potassium, indium(III) and hexacyanoferrate(III) ions. During the negative scans, the cationic In 3+ species interact with the simultaneously generated anionic Fe(CN) 4− 6 to yield a sparingly soluble mixed-valent coating on the electrode. Coated with Nafion film, the chemically modified electrode (CME) shows a better stability. The CME shows a single set of reversible, well-defined peaksc significantly separated from the solution responses. The apparent surface coverage is found to be 6.3×10 −9 mol/cm 2 . This CME exhibits an efficient catalytic activity towards the rapid oxidation of thiocompounds in cyclic voltammetry. Cysteine (Cys), glutathione (GSH), 6-thiopurine (6-TP) and methimazole (MMI) have good and stable current responses at the CME in liquid chromatography with electrochemical detection (LC–ECD). The linear ranges are over three orders of magnitude and the detection limits are 1.6 pmol for Cys, 20 pmol for GSH, 20 pmol for 6-TP and 1.6 pmol for MMI. The method has been successfully applied to assess the purity of methimazole, the contents of cysteine in human urine and other thiocompounds in artificial urines.

Direct reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film was observed in this work. The redox potential E0' = 0.46 V vs. NHE for first primary donor redox couple P/P+ was accurately measured from reversible CV or SWV peaks, which were quite close to those obtained from optic redox titration method. Reaction center (RC) in film was found re-constituted in such an ordered way that the orientation of RC favored the electron transfer in film. Thus, the protein electroactivity seems to be turned on in this artificial biomimic thin film. Furthermore, RC in the film features a photo-induced redox-peak fluctuation, suggesting an intact and functional state for RC in such film. Redox peaks were also found dependent of pH, implying a proton-coupled electron transfer occurring in film. Charge recombination was observed accompanied with change of electrochemical driving force. Electrochemical model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fits SWV experimental data at different pulse height and frequency.

An electrochemical microsensor, constructed by chemical modification of Nafion, poly(vinyl pyridine) (PVP), palladium and iridium oxide onto a platinum microelectrode, has been developed for the determination of nitric oxide (NO). This microsensor exhibits excellent catalytic activity toward NO oxidation, which is confirmed by differential pulse voltammetry. Cyclic voltammetry and differential pulse amperometry are also performed to measure NO. The catalytic peak current is found to be linear with the NO concentration in the range 5.8×10 −8 –6.4×10 −6 mol/l, with a correlation coefficient of 0.9985. The detection limit of the microsensor is 1.5×10 −8 mol/l. In addition, the microsensor is also very selective with respect to interferents such as ascorbic acid, dopamine, and nitrite.

Redox electrochemistry of Keggin type iridium-substituted heteropolytungstate anions, [H 2 OIr IV XW 11 O 39 ] n − (X=B, n = 5; X=Si, Ge, n = 4;X=P, n = 3), have been investigated in acetonitrile and aqueous solutions using cyclic voltammetry. In acetonitrile solutions, these heteropolyanions exhibit two-step one-electron reduction processes. These redox waves are ascribed to theW(VI→V) processes of the heteropolytungstate framework. The slope of a plot of standard redox potentials against the ionic charge is evaluated. In acid buffer solutions (pH 1.0 ∼ 6.0), all these anions exhibit two pairs of reversible, one-electron redox peaks. One pair is assigned to the Ir IV center and another (at more negative potential) is attributed to electron addition and removal from the tungsten-oxo framework that comprises the structure of each anion. These iridium-substituted heteropolyanions are shown to be excellent catalysts for the electroreduction of nitrite ion. The unsubstituted parent anions show no catalytic activity. The catalytic mechanism involves the rapid formation of a nitrosyl complex with of the Ir III form the catalyst, which seems to depend on the electron configuration of Ir III and the inorganic structure of the iridium-substituted heteropolytungstates. The pH dependence of the rate constant for the catalytic reaction shows that nitrous acid is the reactive form of the nitrite ion atpH