Investigation of ultrafast intermediate states during singlet fission in lycopene H-aggregate using femtosecond stimulated Raman spectroscopy.

The singlet fission process involves the conversion of one singlet excited state into two triplet states, which has significant potential for enhancing the energy utilization efficiency of solar cells. Carotenoid, a typical π conjugated chromophore, exhibits specific aggregate morphologies known to display singlet fission behavior. In this study, we investigate the singlet fission process in lycopene H-aggregates using femtosecond stimulated Raman spectroscopy aided by quantum chemical calculation. The experimental results reveal two reaction pathways that effectively relax the S2 (11Bu+) state populations in lycopene H-aggregates: a monomer-like singlet excited state relaxation pathway through S2 (11Bu+) → 11Bu- → S1 (21Ag-) and a dominant sequential singlet fission reaction pathway involving the S2 (11Bu+) state, followed by S* state, a triplet pair state [1(TT)], eventually leading to a long lifetime triplet state T1. Importantly, the presence of both anionic and cationic fingerprint Raman peaks in the S* state is indicative of a substantial charge-transfer character.

Iodine-Mediated Oxidative Annulation of ß,γ-Unsaturated Hydrazones in Dimethyl Sulfoxide: A Strategy to Build 1,6-Dihydropyridazines and Pyrroles.

Simple, commercially available iodine was successfully employed as a highly efficient and chemoselective catalyst for the oxidative annulation of ß,γ-unsaturated hydrazones to produce 1,6-dihydropyridazines under mild conditions for the first time. Interestingly, when active ß,γ-unsaturated hydrazone compounds containing electron-donating groups, such as furyl, thienyl, and cycloalkyl, were used, pyrroles were obtained. A gram-scale preparation experiment and further derivatization of pyridazines demonstrated the potential applicability of our synthesis method. Experimental studies and density functional theory calculations unveiled the origin of the chemoselectivity determining the formation of different products.

Metabolomics approach to growth-age discrimination in mountain-cultivated ginseng (Panax ginseng C. A. Meyer) using ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry.

Mountain-cultivated ginseng is typically harvested after 10 years, while ginseng aged over 15 years is considered wild ginseng. This study aims to differentiate mountain-cultivated ginseng by age, as the fraudulent practice of selling low-aged cultivated ginseng disguised as high-aged one is damaging the market. In this study, LC-MS analyzed 98 ginseng samples, and multivariate statistical analysis identified patterns between samples to select influential components. Machine learning models were developed to identify ginseng samples of different ages. The untargeted metabolomic analysis clearly divided samples aged 4-20 years into three age groups. Twenty-two potential age-dependent biomarkers were discovered to differentiate the three sample groups. Three machine learning models were used to predict new samples, and the optimal model was selected. Some biomarkers could determine age phases according to the differentiation of mountain-cultivated ginseng samples. These biomarkers were thoroughly analyzed for variation trends. The machine learning models established using the screened biomarkers successfully predicted the age group of new samples.

Investigation of Excited-State Intramolecular Proton Transfer and Structural Dynamics in Bis-Benzimidazole Derivative (BBM).

The bis-benzimidazole derivative (BBM) molecule, consisting of two 2-(2'-hydroxyphenyl) benzimidazole (HBI) halves, has been synthesized and successfully utilized as a ratiometric fluorescence sensor for the sensitive detection of Cu2+ based on enol-keto excited-state intramolecular proton transfer (ESIPT). In this study, we strategically implement femtosecond stimulated Raman spectroscopy and several time-resolved electronic spectroscopies, aided by quantum chemical calculations to investigate the detailed primary photodynamics of the BBM molecule. The results demonstrate that the ESIPT from BBM-enol* to BBM-keto* was observed in only one of the HBI halves with a time constant of 300 fs; after that, the rotation of the dihedral angle between the two HBI halves generated a planarized BBM-keto* isomer in 3 ps, leading to a dynamic redshift of BBM-keto* emission.

Mapping the Complete Photocycle that Powers a Large Stokes Shift Red Fluorescent Protein.

Large Stokes shift (LSS) red fluorescent proteins (RFPs) are highly desirable for bioimaging advances. The RFP mKeima, with coexisting cis- and trans-isomers, holds significance as an archetypal system for LSS emission due to excited-state proton transfer (ESPT), yet the mechanisms remain elusive. We implemented femtosecond stimulated Raman spectroscopy (FSRS) and various time-resolved electronic spectroscopies, aided by quantum calculations, to dissect the cis- and trans-mKeima photocycle from ESPT, isomerization, to ground-state proton transfer in solution. This work manifests the power of FSRS with global analysis to resolve Raman fingerprints of intermediate states. Importantly, the deprotonated trans-isomer governs LSS emission at 620 nm, while the deprotonated cis-isomer's 520 nm emission is weak due to an ultrafast cis-to-trans isomerization. Complementary spectroscopic techniques as a table-top toolset are thus essential to study photochemistry in physiological environments.

Structural Revision of Guttiferone F and 30-epi-Cambogin.

Guttiferone F, a natural polyprenylated polycyclic acylphloroglucinol, was originally assigned as the 30-epimer of garcinol by NMR data analyses. Conversion of guttiferone F in the presence of acid afforded its cyclized form (2a), which was previously assigned as 30-epi-cambogin. However, the absolute configurations of guttiferone F and 2a have not been determined. Reinvestigation of the structures of those two compounds, using X-ray and NMR data analyses and chemical transformation, revealed that the original assignment of the C-30 absolute configuration in guttiferone F and 2a should be inverted. Guttiferone F is indeed garcinol, and 2a, which was previously identified as 30-epi-cambogin, is cambogin.

Polycyclic polyprenylated acylphloroglucinol congeners from Garcinia yunnanensis Hu with inhibitory effect on α-hemolysin production in Staphylococcus aureus.

α-Hemolysin (Hla) is an extracellular protein secreted by methicillin-resistant Staphylococcus aureus (MRSA) strains that plays a critical role in the pathogenesis of pulmonary, intraperitoneal, intramammary, and corneal infections, rendering Hla a potential therapeutic target. In this study, 10 unreported polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives, garciyunnanins C-L (1-10), with diverse skeletons, were isolated from Garcinia yunnanensis Hu. The structures of these new compounds were determined by HRMS, NMR, electronic circular dichroism (ECD) calculations, single-crystal X-ray diffraction, and biomimetic transformation. Garciyunnanins C and D (1 and 2) were found to be potent Hla inhibitors in the anti-virulence efficacy evaluation against MRSA strain.

Uncariitannin, a polyphenolic polymer from Uncaria gambier, attenuates Staphylococcus aureus virulence through an MgrA-mediated regulation of α-hemolysin.

A global transcriptional regulator, MgrA, was previously identified as a key determinant of virulence in Staphylococcus aureus. An 80% EtOH extract of Uncaria gambier was found to attenuate the virulence of S. aureus via its effects on MgrA. Using bioassay-guided fractionation, a polyphenolic polymer, uncariitannin, was found to be the main bioactive constituent of the extract, and its structure was characterized using spectral and chemical analysis. The molecular weight and polydispersity of uncariitannin were determined by gel permeation chromatography-refractive index-light scattering analysis. An electrophoretic mobility shift assay showed that uncariitannin could effectively inhibit the interaction of MgrA with DNA in a dose-dependent manner. Treatment with uncariitannin could decrease the mRNA and protein levels of Hla in both the S. aureus Newman and USA300 LAC strains. Further analysis of Hla expression levels in the Newman ΔmgrA and Newman ΔmgrA/pYJ335-mgrA strains indicated that uncariitannin altered Hla expression primarily in an MgrA-dependent manner. A mouse model of infection indicated that uncariitannin could attenuate MRSA virulence. In conclusion, uncariitannin may be a potential candidate for further development as an antivirulence agent for the treatment of S. aureus infection.

Enhanced high-order harmonic generation from spatially prepared filamentation in argon.

We experimentally demonstrate enhanced high-order harmonic generation (HHG) from spatially prepared filamentation in Argon. Upon shifting the focus position of an elliptically polarized laser pulse over the filament induced by a linearly polarized laser pulse, an obvious enhancement of harmonic yield by nearly one order of magnitude is observed. The result could be interpreted in terms of the double contributions from both the excited states of target atom and the phase-matching effect of harmonic beam. In contrast to the enhancement phenomena, an obvious suppression of harmonic yield is also presented, which could be attributed to both the ground-state depletion and the plasma effect.

Spatially and spectrally resolved quantum-path tracing in high-order harmonic generation.

We experimentally demonstrate the macroscopic evolution of quantum-path distributions in harmonic emission with spatial and spectral resolution from an argon gas jet, and obviously observe that the spatial profiles of harmonics are gradually split into two components (the red and blue shifts) when the driving laser intensity is increased. Moreover, the red and blue shifts in quantum-path distributions are experimentally traced and clarified in the spatial and spectral domain by choosing the focal position. These results give a more comprehensive understanding and therefore a better control of harmonic emission.

Observation of CEP effect via filamentation in transparent solids.

We report on the first direct observation of carrier-envelope-phase (CEP) effect during the interaction between few-cycle laser pulses and bulk solid materials. Using 2-cycle mid-infrared laser pulses with stabilized CEP, the CEP effect of tunneling ionization during the laser filamentation in a fused silica is revealed. The phase variation of the accompanying supercontinuum (SC) emission with filamentation at different CEPs of laser pulses can be measured by means of spectral interference technique, as a direct manifestation of the strong field tunneling ionization dynamics in transparent solids.

Investigation of Ultrafast Configurational Photoisomerization of Bilirubin Using Femtosecond Stimulated Raman Spectroscopy.

Phototherapy is an efficient and safe way to reduce high levels of free 4Z,15Z-bilirubin (ZZ-BR) in the serum of newborns. The success of BR phototherapy lies in photoinduced configurational and structural isomerization processes that form excretable isomers. However, the physical picture of photoinduced photoisomerization of ZZ-BR is still unclear. Here, we strategically implement tunable femtosecond stimulated Raman spectroscopy and several time-resolved electronic spectroscopies, assisted by quantum chemical calculations, to dissect the detailed primary configurational isomerization dynamics of free ZZ-BR in organic solvents. The results of this study demonstrate that upon photoexcitation, ultrafast configurational isomerization proceeds by a volume-conserving "hula twist", followed by intramolecular hydrogen-bond distortion and large-scale rotation of the two dipyrrinone halves of the ZZ-BR isomer in a few picoseconds. After that, most of the population recovers back to ZZ-BR, and a very small amount is converted into stable BR isomers via structural isomerization.

Predictive value of urinary cell cycle arrest biomarkers for all cause-acute kidney injury: a meta-analysis.

The cell cycle arrest markers tissue inhibitor metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) have been identified as potential biomarkers of acute kidney injury (AKI) in critically ill adults in intensive care units and cardiac surgery-associated AKI (CSA-AKI). However, the clinical impact on all-cause AKI remains unclear. Here, we report a meta-analysis performed to evaluate the predictive value of this biomarker for all-cause AKI. The PubMed, Cochrane, and EMBASE databases were systematically searched up to April 1, 2022. We used the Quality Assessment Tool for Diagnosis Accuracy Studies (QUADAS-2) to assess the quality. We extracted useful information from these studies and calculated the sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). Twenty studies with 3625 patients were included in the meta-analysis. The estimated sensitivity of urinary [TIMP-2] × [IGFBP7] in the diagnosis of all-cause AKI was 0.79 (95% CI 0.72, 0.84), and the specificity was 0.70 (95% CI 0.62, 0.76). The value of urine [TIMP-2] × [IGFBP7] in the early diagnosis of AKI was assessed using a random effects model. The pooled positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 2.6 (95% CI 2.1, 3.3), 0.31 (95% CI 0.23, 0.40), and 8 (95% CI 6, 13), respectively. The AUROC was 0.81 (95% CI 0.78-0.84). No significant publication bias was observed in eligible studies. Subgroup analysis indicated that the diagnostic value was related to the severity of AKI, time measurement, and clinical setting. This study shows that urinary [TIMP-2] × [IGFBP7] is a reliable effective predictive test for all cause-AKI. However, whether and how urinary [TIMP-2] × [IGFBP7] can be used in clinical diagnosis still requires further research and clinical trials.

The dataset of Japanese patents and patents' holding firms in green vehicle powertrains field.

In 2020, the Government of Japan declared "2050 carbon neutral" and launched a long-term strategy to create a "virtuous cycle of economy and environment". Japanese firms possess many technologies that contribute to decarbonization, which is important to expand investment for Green Technology (environmental technology) development. As automobiles are major contributors to greenhouse gas emissions [1], the technological shift towards vehicle powertrain systems is an attempt to lower problems like emissions of carbon dioxide, nitrogen oxides [2]. On the other hand, patent data are the most reliable business performance for applied research and development activities when investigating the knowledge domains or the technology evolution (Wand, 1997). Our paper describes a Japanese patents dataset of the vehicle powertrain systems for hybrid electric vehicle (HEV), battery electric vehicle (BEV) and fuel cell electric vehicles (FCEV). In this paper we create a method of bombinating international patent classification (IPC) and keywords to define "green" patents in vehicle powertrains field, using patent data which were applied to Japan Patent Office recorded on EPO's PATSTAT database during 2010∼2019 year. When analyze patents, it is necessary to consider the social situation of each country including language background, we collect patents description documents (abstracts and titles) not only written in English but also in Japanese. Finally, we build a database includes 6025 green patents' description documents and 266 patents' holding firms. With which we then identify 3756 HEV patents, 1716 BEV patents, and 553 FCEV patents. Data about patent holding firms is also appended. The full dataset may be useful to researchers who would like to do further search like natural language processing and machine learning on patent description documents, statistical data analysis for empirical economics.

Two Novel Phenylpropanoid Trimers From Ligusticum chuanxiong Hort With Inhibitory Activities on Alpha-Hemolysin Secreted by Staphylococcus aureus.

The emergence of antibiotic resistance in Staphylococcus aureus has necessitated the development of innovative anti-infective agents acting on novel targets. Alpha-hemolysin (Hla), a key virulence factor of S. aureus, is known to cause various cell damage and death. In this study, with bioassay-guided fractionation, a pair of unusual epimeric lignan trimers, ligustchuanes A and B (1 and 2), were isolated from the rhizomes of Ligusticum chuanxiong Hort, together with two known phthalides being identified by UPLC-QTOF-MS. To the best of our knowledge, trimers with rare C8-C9″-type neolignan and ferulic acid fragments have not been identified in any natural product. Both of them were isolated as racemic mixtures, and their absolute configurations were determined by comparing experimental and calculated ECD spectra after enantioseparation. Ligustchuane B exhibited an outstanding inhibitory effect on α-hemolysin expression in both MRSA USA300 LAC and MSSA Newman strains at concentrations of 3 and 6 µM, respectively. Notably, a mouse model of infection further demonstrated that ligustchuane B could attenuate MRSA virulence in vivo.

The anti-infective activity of Salvia miltiorrhiza against Staphylococcus aureus by attenuating accessory gene regulator system-mediated virulence.

Due to the rapid evolution of antibiotic resistance in Staphylococcus aureus, antivirulence therapy may be a promising alternative for the effective control of the spread of resistant pathogens. The Chinese Materia Medica has been widely used for the treatment of diseases and production of health foods, and it remains a valuable resource for the discovery of compounds possessing antivirulence activity. Through a Caenorhabditis elegans infection model, an EtOAc-soluble fraction of 80% EtOH extract of Salvia miltiorrhiza Bunge (SMEA) was found to possess potential anti-infective activity against S. aureus. Then, several in vitro assays indicated that SMEA had robust antivirulence activity at the dose of 400 µg mL-1, reducing hemolytic activity and α-hemolysin expression in S. aureus. Furthermore, at 100 mg kg-1, SMEA reduced abscess formation in the main organs of mice challenged with S. aureus. In order to identify the bioactive components of SMEA and investigate the mechanisms underlying the antivirulence activity, SMEA was separated using bioassay-guided fractionation. As a result, eight compounds were identified in SMEA. Among them, tanshinone IIB (TNB) showed strong antivirulence activity both in vitro and in vivo. Furthermore, at 24 µg mL-1, TNB significantly reduced the expression of RNAIII and psmα, indicating that the mechanism underlying TNB activity was related to the accessory gene regulator quorum sensing system. In conclusion, TNB's antivirulence properties make it a promising candidate for drug development against S. aureus infections.

Prenylated xanthones and biphenyls from Garcinia esculenta with antistaphylococcal activity.

One new xanthone, (±) garciesculenxanthone C (1), two new biphenyls, garciesculenbiphenyls A (2) and B (3), together with two known compounds, doitungbiphenyl B (4) and morusignin D (5), were isolated from Garcinia esculenta. The structures of new compounds were elucidated by spectroscopic analysis, and the absolute configuration of (±) garciesculenxanthone C (1) was assigned by a modified Mosher's method. All isolates were evaluated for their antistaphylococcal activities against Staphylococcus aureus Newman, USA300 LAC, USA400 MW2, and Mu50 strains. Among these, (±) garciesculenxanthone C (1) showed the best antistaphylococcal activity, and its effect was determined to be bactericidal by time-kill experiment.

Tracking Ultrafast Structural Dynamics in a Dual-Emission Anti-Kasha-Active Fluorophore Using Femtosecond Stimulated Raman Spectroscopy.

The anti-Kasha process provides the possibility of using high-energy excited states to develop novel applications. Our previous research (Nature communications, 2020, 11, 793) has demonstrated a dual-emission anti-Kasha-active fluorophore for bioimaging application, which exhibits near-infrared emissions from the S1 state and visible anti-Kasha emissions from the S2 state. Here, we applied tunable blue-side femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy, assisted by quantum calculations, to reveal the anti-Kasha dual emission mechanism, in which the emergence of two fluorescing states is due to the retardation of internal conversion from the S2 state to the S1 state. It has been demonstrated that the facts of anti-Kasha high-energy emission are commonly attributed to a large energy gap between the two excited states, leading to a decrease in the internal conversion rate due to a poor Franck-Condon factor. In this study, analysis of the calculation and FSRS experimental results provide us further insight into the dual-emission anti-Kasha mechanism, where the observation of hydrogen out-of-plane Raman modes from FSRS suggested that, in addition to the energy-gap law, the initial photoinduced molecular conformational change plays a key role in influencing the rate of internal conversion.

Tracking Ultrafast Fluorescence Switch-On and Color-Tuned Dynamics in Acceptor-Donor-Acceptor Chromophore.

Understanding how the conformational change of conjugated molecules with acceptor-donor-acceptor (A-D-A) architecture affects their physical and optoelectronic properties is critical for determining their ultimate performance in organic electronic devices. Here, we utilized femtosecond transient absorption, time-resolved upconversion photoluminescence spectroscopy, and tunable femtosecond-stimulated Raman spectroscopy, aided by quantum chemical calculations, to systematically investigate the excited state structural dynamics of the intramolecular charge transfer of the tetramethoxy anthracene-based fluorophore 2,3,6,7-tetramethoxy 9,10-dibenzaldehydeanthracene (AnDA) and its derivative 2,3,6,7-tetramethoxy 9,10-diphenylanthracene (TMDPAn) in chloroform. In the AnDA molecule, the tetramethoxy anthracene and benzaldehyde moieties exhibit a strong ability to donate and withdraw electrons. Upon photoexcitation, AnDA shows intriguing ultrafast fluorescence switch-on and red shift dynamics on charge transfer states, and the temporal evolution of AnDA recorded by ultrafast spectroscopy reveals a dynamic picture of two-step intramolecular charge transfer assisted by ultrafast conformational changes and solvation processes. Removing the aldehyde group from TMDPAn significantly decreases the electron pulling capacity of the phenyl unit and disables charge transfer characteristics.

Multiorgan toxicity induced by EtOH extract of Fructus Psoraleae in Wistar rats.

BACKGROUND: The fruits of Psoralea corylifolia L. (Fructus Psoraleae, FP) has a long history and a wide range of applications in the treatment of osteoporosis and leukoderma. Although it is well known that FP could cause hepatotoxicity and reproductive toxicity, less is known about its potential toxicity on multiple organs. PURPOSE: This study aims to determine the multiorgan toxicity of EtOH extract of FP (EEFP) and to investigate the underlying mechanisms through a systematic evaluation in Wistar rats. STUDY DESIGN AND METHODS: Wistar rats were orally administered with the EEFP at doses of 1.5, 1.0 and 0.5 g/kg for 28 days. Histopathologic and clinicopathologic analyses were performed, and the hormone levels in serum and the mRNA levels of enzymes related to the production of steroid hormones in adrenal glands were detected. The area of each band of adrenal glands and the steroid levels in the adrenal glands were also measured. RESULTS: After the treatment, both the histopathologic and clinicopathologic examination showed that EEFP caused liver, prostate, seminal vesicle and adrenal gland damage. Among the enzymes involved in the regulation of adrenal steroid hormone production, NET, VMAT2, and CYP11B1 were upregulated, while CYP17A1 was downregulated. Among the adrenal steroid hormones, COR and NE were upregulated, while levels of DHT and serum ACRH and CRH decreased. CONCLUSION: Our results indicated that adrenal gland, prostate, and seminal vesicles could also be the target organs of FP-induced toxicity. Abnormal enzyme and hormone production related to the hypothalamic pituitary adrenal (HPA) axis caused by the EEFP may be the potential toxic mechanism for changes in the adrenal gland and secondary sex organs of male rats.