We study the propagation and injection models of cosmic rays using the latest measurements of the boron-to-carbon ratio and fluxes of protons, helium, carbon, and oxygen nuclei by the Alpha Magnetic ...Spectrometer and the Advanced Composition Ex- plorer at top of the Earth, and the Voyager spacecraft outside the heliosphere. The Advanced Composition Explorer (ACE) data during the same time interval of the AMS-02 data are extracted to minimize the complexity of the solar modulation effect. We find that the cosmic ray nucleus data favor a modified version of the diffusion-reacceleration scenario of the propagation. The diffusion coefficient is, however, required to increase moderately with decreasing rigidity at low energies, which has interesting implications on the particle and plasma interaction in the Milky Way. We further find that the low rigidity (< a few GV) injection spectra are different for different compositions. The injection spectra are softer for lighter nuclei. These results are expected to be helpful in understanding the acceleration process of cosmic rays.
Solar energy‐driven conversion of CO2 into fuels with H2O as a sacrificial agent is a challenging research field in photosynthesis. Herein, a series of crystalline porphyrin‐tetrathiafulvalene ...covalent organic frameworks (COFs) are synthesized and used as photocatalysts for reducing CO2 with H2O, in the absence of additional photosensitizer, sacrificial agents, and noble metal co‐catalysts. The effective photogenerated electrons transfer from tetrathiafulvalene to porphyrin by covalent bonding, resulting in the separated electrons and holes, respectively, for CO2 reduction and H2O oxidation. By adjusting the band structures of TTCOFs, TTCOF‐Zn achieved the highest photocatalytic CO production of 12.33 μmol with circa 100 % selectivity, along with H2O oxidation to O2. Furthermore, DFT calculations combined with a crystal structure model confirmed the structure–function relationship. Our work provides a new sight for designing more efficient artificial crystalline photocatalysts.
COF catalysts: A series of crystalline covalent organic frameworks (COFs) was designed and applied for CO2 photoreduction coupled with H2O photooxidation, in the absence of photosensitizers and sacrificial agents. This approach gives a more straightforward and clear understanding of the structure–function relationship of artificial photosynthesis.
Given the wavelength dependence of tissue transparency and the requirement for sufficiently low background autofluorescence, the development of fluorescent dyes with excitation and emission maxima ...beyond 700 nm is highly desired, but it is a challenging task. Herein, a new class of fluorescent dyes, named sulfone-rhodamines (SO2Rs), was developed on the basis of the one-atom replacement of the rhodamine 10-position O atom by a sulfone group. Such a modification makes their absorption and emission maxima surprisingly reach up to 700–710 and 728–752 nm, respectively, much longer than their O-, C-, and Si-rhodamine analogs, due to the unusual d*−π* conjugation. Among these dyes, SO 2 R4 and SO 2 R5, bearing disubstituted meso-phenyl groups, show the greatest potentials for bioimaging applications in view of their wide pH range of application, high photostability, and big extinction coefficients and fluorescence quantum yields. They could quickly penetrate cells to give stable NIR fluorescence, even after continuous irradiation by a semiconductor laser, making them suitable candidates for time-lapse and long-term bioimaging applications. Moreover, they could specifically localize in lysosomes independent of alkylmorpholine targeted group, thus avoiding the problematic alkalization effect suffered by most LysoTrackers. Further imaging assays of frozen slices of rat kidney reveal that their tissue imaging depth is suprior to the widely used NIR labeling agent Cy5.5.
Although the prognostic value of blood creatinine levels in patients with paraquat (PQ) poisoning has been studied for a long time, the results are still controversial. Therefore, we performed the ...first meta-analysis to comprehensively assess the value of blood creatinine in predicting the prognosis of patients with PQ poisoning. We searched PubMed, EMBase, Web of Science, ScienceDirect, Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal Database, and China Online Journals to identify all relevant papers published up to June 2022. Data were extracted for pooled analysis, heterogeneity testing, sensitivity analysis, publication bias analysis, and subgroup analysis. Ultimately, 10 studies involving 862 patients were included. The I2 of diagnostic odds ratio (DOR), sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of this study were all greater than 50%, which showed the existence of heterogeneity in this study, and a random effects model was used for the combination of the above five effect sizes. Pooled analysis showed a high predictive value of blood creatinine for prognosis of PQ poisoning pooled DOR:22.92, 95% confidence interval (CI):15.62-33.65, P < 0.001. The combined sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 86% (95% CI: 0.79-0.91), 78% (95% CI: 0.69-0.86), 4.01 (95% CI: 2.81-5.71), and 0.17 (95% CI: 0.12-0.25), respectively. Deeks publication bias test revealed there was publication bias. Sensitivity analysis showed no significant differences in the estimates of impact. Serum creatinine is an effective predictor of mortality in patients with PQ poisoning.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Herein, we describe a practical protocol for efficient, mild, visible‐light‐induced three‐component intermolecular trifluoromethyl‐alkenylation reactions of unactivated alkenes. The protocol has good ...functional group tolerance and a broad substrate scope. Using this protocol, we not only introduced a trifluoromethyl group into alkenes but also converted unactivated alkenes to styrene‐based activated alkenes, in addition to accomplishing late‐stage functionalization of pharmaceutical intermediates.
Fabricating solar cells with tandem structure is an efficient way to broaden the photon response range without further increasing the thermalization loss in the system. In this work, a tandem organic ...solar cell (TOSC) based on highly efficient nonfullerene acceptors (NFAs) with series connection type is demonstrated. To meet the different demands of front and rear sub‐cells, two NFAs named F‐M and NOBDT with a whole absorption range from 300 to 900 nm are designed, when blended with wide bandgap polymer poly(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo1,2‐b:4,5‐b′dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo1′,2′‐c:4′,5′‐c′dithiophene‐4,8‐dione)) (PBDB‐T) and narrow bandgap polymer PTB7‐Th, respectively, the PBDB‐T: F‐M system exhibits a high Voc of 0.98 V and the PTB7‐Th: NOBDT system shows a remarkable Jsc of 19.16 mA cm−2, which demonstrate their potential in the TOSCs. With the guidance of optical simulation, by systematically optimizing the thickness of each layer in the TOSC, an outstanding power conversion efficiency of 14.11%, with a Voc of 1.71 V, a Jsc of 11.72 mA cm−2, and a satisfactory fill factor of 0.70 is achieved; this result is one of the top efficiencies reported to date in the field of organic solar cells.
A non‐fullerene tandem organic solar cell (OSC) with high efficiency is fabricated. Two non‐fullerene acceptors named F‐M and NOBDT with a whole absorption range from 300–900 nm are designed for the front and rear sub‐cell respectively; the tandem cell based on them demonstrates an outstanding PCE of 14.11%, which is among the top PCEs in the field of OSCs.
•Effects of raw materials, processing factors and environment on air entrainment in fresh concrete are reviewed.•The testing methods of air void system in concrete at fresh and hardened states are ...summarized.•Effects of air entrainment on properties of concrete at fresh and hardened states are reviewed.
The presence of the stable and adequate air-void system in fresh and hardened concretes are crucial to many properties, such as resistance against freeze and thaw cycle, workability/rheology, pumpability, strength, and fire resistance of concrete. This paper presents a critical review of the air-void system in fresh and hardened concretes and its effects on various properties. The air entrainment mechanisms and testing methods for air void system were first reviewed. Although the air void system can be measured by different methods, the measurement of the air void system in fresh concrete is still challenging. The influence of air void parameters on the workability and rheology of concrete was then discussed. In the hardened state, the effect of air entrainment on compressive strength, freeze-thaw resistance, and fire resistance was illustrated. Moreover, the effect of binder, chemical admixture, mixing time, vibration, pumping, temperature, and low atmospheric pressure on the parameters of the air-void system were reviewed in detail. In the end, the future researches on this topic are also recommended.
Herein, we report a method that combines hydrogen atom transfer and photoredox catalysis to achieve the dehydrogenative difluoroallylation of amides, ethers, and alkyl aldehydes. This operationally ...convenient method transforms a broad scope of substrates into the corresponding gem-difluoroalkenes via the construction of C(sp3)–C(sp3) or C(sp3)–C(sp2) bonds. Excellent functional group compatibility and high selectivity make this method have a wide range of substrate types and render it suitable for late-stage modification of pharmaceutical intermediates.
Probes to dye for: Rhodamine‐inspired Si‐pyronine, Si‐rhodamine, Te‐rhodamine, and Changsha NIR dyes have been developed recently. These dyes show fluorescence in the far‐red to near‐infrared region, ...while retaining the advantages of the original rhodamines, such as high fluorescence quantum yield, tolerance to photobleaching, good water solubility, and exhibit great potential for biological application.
Quinolones and isoquinolones are of particular importance to pharmaceutical industry due to their diverse biological activities. However, their synthetic protocols were limited by high toxicity, high ...energy consumption, poor functional group tolerance and noble metal catalyst. This study concerns the development of a series of TEMPO@PCN‐222 (TEMPO: 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy; PCN: porous coordination network) composite photocatalysts by coordinating different amount of 4‐carboxy‐TEMPO with the secondary building units of PCN‐222. Upon visible‐light irradiation, photogenerated holes in the highest occupied molecular orbital of PCN‐222 can smoothly transfer to TEMPO, which can significantly boost the photosynthesis of bioactive (iso)quinolones from readily available N‐alkyl(iso)quinolinium salts. TEMPO@PCN‐222 exhibits an outstanding catalytic stability and substrate tolerance with a 1‐methyl‐2‐quinolinone yield of 86.7 %, over four times that with PCN‐222 (21.4 %). This work provides a new route to construct composite photocatalysts from abundant starting materials for efficient photosynthesis of high value‐added chemicals.
Shedding light on photocatalysis: A TEMPO@MOF composite exhibits high activity, superior cycling stability, good functional group tolerance, and mild reaction conditions for the photocatalytic oxidation of N‐alkyl(iso)quinolinium salts to afford bioactive (iso)quinolones. This work provides a new route to construct composite photocatalysts from abundant starting materials for efficient photosynthesis of high value‐added chemicals.
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