Femtosecond Time-Resolved Observation of Relaxation and Wave Packet Dynamics of the S1 State in Electronically Excited o-Fluoroaniline.

Quantum beat frequency is the basis for understanding interference effects and vibrational wave packet dynamics and has important applications. Using femtosecond time-resolved mass spectrometry and femtosecond time-resolved photoelectron image combined with theoretical calculations, we study the electronic excited-state relaxation of o-fluoraniline molecule and the time-dependent evolution of vibrational wave packets between different eigenstates. After the molecule absorbs a photon of 288.3 nm and is excited to the S1 state, intramolecular vibrational redistribution first occurs on the time scale τ1 = 349 fs, and then the transition to the triplet state occurs through the intersystem crossing on the time scale τ2 = 583 ps, and finally, the triplet state occurs decays slowly through the time scale τ3 = 2074 ps. We find the intramolecular vibrational redistribution is caused by the 00, 10b1 and 16a1 vibrational modes of the Sl state origin. That is, the 288.3 nm femtosecond laser excites the molecule to the S1 state, and the continuous flow of the vibrational wave packet prepares a coherent superposition state of three vibrational modes. Through extracting the oscillation of different peak intensities in the photoelectron spectrum, we observe reversible changes caused by mutual interference of the S1 00, S1 10b1 and S1 16a1 states when the wave packets flow. When the pump pulse is 280 nm, the beat frequency disappears completely. This is explained in terms of increases in the vibrational field density and characteristic period of oscillation, and statistical averaging makes the quantum effect smooth and indistinguishable. In addition, the Rydberg component of the S1 state is more clearly resolved by combining experiment and theory.

Ultrafast conformation-dependent charge transfer in N, N, N', N'-tetramethyl-1,3-propanediamine: Effect of flexible carbon skeleton on electron lone pair interactions.

Flexible three-carbon skeleton makes N, N, N', N'-tetramethyl-1,3-propanediamine (TMPDA) an important diamine system to investigate the conformation-dependent electron lone pair interactions and charge delocalization. The charge transfer process linked to structural motions of the three-carbon skeleton has been monitored in real time by the Rydberg electron binding energy (BE) spectra of TMPDA coupled with quantum chemical calculations. Optical excitation to the 3p state with a 200 nm pump pulse initially generated a localized charge on one of the two nitrogen atoms that may partially transfer to the other one. Rapid internal conversion (IC) from the 3p to 3s state occurred within 430 fs, resulting in an initial charge delocalized 3s_h/3s_l population ratio of 23.6 %/76.4 %. A final 3s_h/3s_l (51.9 %/48.1 %) equilibrium proceeded within about 2.64 ps. The 3s_h (TTTT+, GG'TG+ and G'GG'G+) and 3s_l (GG'GG'+ and GG'G'G+) (see text for structure definitions) are identified as the extended and folded conformers, respectively. Two types of electron lone pair interactions, i.e., through-space interaction (TSI) and through-bond interaction (TBI), are found to coexist in TMPDA to drive charge transfer. The GG'GG'+ and GG'G'G+ structures exhibit TSI, while the TTTT+ structure shows TBI. The GG'TG+ and G'GG'G+ structures exhibit both TSI and TBI. Flexible three-carbon skeleton provide more opportunities for the two N-electron lone pairs to overlap in space (i.e., TSI), making TMPDA to be favorable for the most stably folded conformation.

Dendrimers as Nanocarriers for the Delivery of Drugs Obtained from Natural Products.

Natural products have proven their value as drugs that can be therapeutically beneficial in the treatment of various diseases. However, most natural products have low solubility and poor bioavailability, which pose significant challenges. To solve these issues, several drug nanocarriers have been developed. Among these methods, dendrimers have emerged as vectors for natural products due to their superior advantages, such as a controlled molecular structure, narrow polydispersity index, and the availability of multiple functional groups. This review summarizes current knowledge on the structures of dendrimer-based nanocarriers for natural compounds, with a particular focus on applications in alkaloids and polyphenols. Additionally, it highlights the challenges and perspectives for future development in clinical therapy.

Humoral and cellular immunogenicity and efficacy of a coxsackievirus A10 vaccine in mice.

Coxsackievirus A10 (CV-A10) has become one of the major pathogens of hand, foot and mouth disease (HFMD), and studies on the vaccine and animal model of CV-A10 are still far from complete. Our study used a mouse-adapted CV-A10 strain, which was lethal for 14-day-old mice, to develop an infected mouse model. Then this model was employed to establish an actively immunized-challenged mouse model to evaluate the efficacy of a formaldehyde-inactivated CV-A10 vaccine, which was prepared from a Vero cell-adapted strain. CV-A10 vaccine at a dose of 0.5 or 2.0 µg was inoculated intraperitoneally in neonatal Kunming mice on the third and ninth day. Then the mice were challenged on day 14. The survival rate of mice immunized with 0.5 or 2.0 µg vaccine were 90% and 100%, respectively, while all Alum-inoculated mice died. Compared to those in the two vaccinated groups, the Alum-inoculated mice showed severe pathological damage, strong viral protein expression and high viral loads. The antisera from vaccinated mice showed high level of neutralizing antibodies against CV-A10. Meanwhile, three potential T cell epitopes located at the carboxyl-terminal regions of the VP1 and VP3 were identified and exhibited CV-A10 serotype-specific. The humoral and cellular immunogenicity analysis showed that immunization with two doses of the vaccine elicited CV-A10 specific neutralizing antibody and T cell response in BALB/c mice. Collectively, these findings indicated that this actively immunized-challenged mouse model will be invaluable in future studies on CV-A10 pathogenesis and evaluation of vaccine candidates.

PHD3 as a Prognosis Marker and its Relationship with Immune Infiltration in Lung Adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is a highly heterogeneous malignant tumor. Therefore, it is necessary to find predictive biomarkers related to the prognosis and immune infiltration of lung adenocarcinoma, which may provide an effective theoretical basis for its clinical treatment. OBJECTIVE: This study aimed to evaluate whether the expression level of PHD3 in lung adenocarcinoma (LUAD) is related to immunity. METHODS: PHD3 expression was analyzed by the ONCOMINE, TIMER, UALCAN, and GEPIA databases. The correlations between clinical information and PHD3 expression were analyzed by the LinkedOmics database. Then, we evaluated the influence of PHD3 on the survival of LUAD patients using Kaplan-Meier Plotter and HPA database. We explored the correlation between PHD3 and tumor immunity using TIMER and the correlation module of TISDIB. Finally, we used the cBioportal database to analyze PHD3 mutations in LUAD. RESULTS: Comprehensive analysis displayed PHD3 expression to be clearly higher in LUAD compared to adjacent normal tissues. PHD3 expression was identified to be positively associated with tumor purity, histological type, and later pathological stage. Survival curve results revealed the high expression of PHD3 in LUAD patients to be accompanied by a poor prognosis. Further study indicated PHD3 to be significantly related to a variety of tumor immune cells and molecules. Moreover, among the LUAD cases with gene alteration of PHD3, amplification was the most common of all alteration types. CONCLUSION: PHD3 may be used as a biomarker for survival and immunotherapy of LUAD.

TurboHawk plaque rotation system for treatment of arteriosclerosis occlusion in lower extremities: A pilot retrospective study.

ABSTRACT: This pilot study retrospectively assessed the feasible efficacy of TurboHawk plaque rotation system (THPRS) for treatment of arteriosclerosis occlusion in lower extremities (AOLE).A total of 36 eligible patients with AOLE were included in this pilot retrospective study. We divided all those patients into a treatment group and a control group, each group 18 patients. All patients in both groups administered conventional therapy. Additionally, all patients in the treatment group received THPRS, while all patients in the control group received percutaneous transluminal angioplasty (PTA) and percutaneous transluminal stenting (PTS). All outcomes were evaluated and analyzed at 3-month after surgery.At 3-month postsurgery, there were not significant statistical differences in clinical manifestations (intermittent claudication, P = .49; resting pain, P = .28), ankle brachial index change (P = .07), 6-minute walk distance (P = .43), and complications between 2 groups.This pilot study did not show better outcome improvement of THPRS for patients with AOLE. We cautiously draw the present conclusion, because it suffers from several major restrictions. Thus, further studies with larger sample size and longer term follow-up are still needed to warrant the current conclusion.

Glycemic control by umbilical cord-derived mesenchymal stem cells promotes effects of fasting-mimicking diet on type 2 diabetic mice.

BACKGROUND: Hepatic steatosis is a big hurdle to treat type 2 diabetes (T2D). Fasting-mimicking diet (FMD) has been shown to be an effective intervention in dyslipidemia of T2D. However, fasting may impair the normal glucose metabolism. Human umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation has been discovered to regulate immune reactions and reduce hyperglycemia in diabetes. However, the effect of UC-MSCs on improving the lipid metabolism disorder is not quite satisfactory. We have investigated the efficacy comparison and interaction between FMD and UC-MSC infusion, aiming to establish effective T2D therapies and explore its mechanism. METHODS: C57/BL6 mice were fed with high-fat diet (HFD) to induce a diet-induced obese (DIO) mouse model. Leptin receptor-deficient (db/db) mice were used for follow-up experiments. DIO or db/db mice were divided into 4 groups: phosphate buffer saline (PBS), UC-MSCs, FMD, and UC-MSCs + FMD. At the end of the study period, mice were fasted and sacrificed, with the measurement of physiological and biochemical indexes. In addition, the fresh liver, skin, and white adipose tissue were analyzed by histology. RESULTS: FMD restored the lipid metabolism in DIO mice, whereas its capacity to rescue hyperglycemia was uncertain. Infusion of UC-MSCs was effective in T2D glycemic control but the impact on dyslipidemia was insufficient. Furthermore, both the glucose and the lipid alterations of DIO and db/db mice recovered after UC-MSCs combined with FMD. It was proved that UC-MSCs promoted FMD effects on ameliorating hyperglycemia and restoring the lipid metabolism in T2D mice, while FMD had little promotion effect on UC-MSCs. Mechanistically, we discovered that UC-MSC infusion significantly modulated systematic inflammatory microenvironment, which contributed to concerted actions with FMD. CONCLUSIONS: We established a strategy that combined UC-MSC infusion and FMD and was effective in treating T2D, which provided potential approaches for developing novel clinical T2D therapies.

Enhanced Optical Absorption and Interfacial Carrier Separation of CsPbBr3/Graphene Heterostructure: Experimental and Theoretical Insights.

Controlling effective separation of carriers at the interface is a key element to realize highly efficient halogenated perovskite-based optoelectronic devices. Here, a comprehensive study of interfacial properties for CsPbBr3 nanocrystals (NCs)/graphene heterostructure is performed by the combination of theoretical and experimental methods. Enhanced visible light absorption is observed experimentally in the CsPbBr3 NCs/graphene heterostructure. The strong photoluminescence quenching phenomenon and improved photoresponse prove the efficient interfacial charge transfer from the perovskite CsPbBr3 NC layer to the graphene side. Significantly, theoretical calculations suggest that an intrinsic built-in electric field, pointing from graphene toward CsPbBr3, promotes the separation of photoinduced carriers at the CsPbBr3 NCs/graphene interface and simultaneously inhibits the recombination of electron-hole pairs. Thus, the high optoelectronic performance can be obtained in the CsPbBr3 NCs/graphene heterostructure, as shown in our experiment. Moreover, the CsPbBr3 NCs/graphene heterostructure exhibits smaller effective mass than that of CsPbBr3 NCs, indicating that the heterostructure does possess a high carrier mobility, which can further accelerate the separation of photogenerated carriers. Furthermore, the calculated results reveal that, accounting for the presence of the stronger built-in electric field, larger band bending value, and smaller effective mass, the PbBr2/graphene interface can realize the separation of the photoinduced carriers more effectively than the CsBr/graphene interface and thus more efficiently facilitate electron transfer from the perovskite optical absorber side to the graphene electronic transport side. Our findings provide valuable insight into perovskite/graphene-based photodetector devices via the interface engineering project.

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Reducing the application of chemical fertilizer and increasing fertilizer efficiency can contribute to the sustainable development of agriculture. To evaluate the impacts of N fertilizer reduction and biochar application on soil organic carbon active components and mineralization in yellow soil, an experiment was carried out with five different substitution rates of chemical N fertilizer by biochar under the same rate of N input, i.e., 0, 10%, 20%, 30%, 40% (CK, T1-T4). The results showed that chemical N fertilizer reduction combined with biochar application could significantly improve soil organic carbon (SOC), the magnitude of which was proportional to the amount of biochar application. Under the condition of 20% substitution rate (T2), soil microbial biomass carbon (MBC) and readily oxidized carbon (ROC) were the highest with 293.68 mg·kg-1 and 250.00 mg·kg-1, respectively, but the concentration of soil dissolved organic carbon (DOC) was the lowest. SOC mineralization rate reached the highest on the third day of incubation. Then, it decreased rapidly in the early period (day 3 of incubation to day 6), decreased slowly in the middle period (day 6 of incubation to day 18), and stabilized in the later period (day 18 of incubation to day 30). There was a logarithmic relationship between mineralization rate of soil organic carbon and incubation time. SOC cumulative mineralization amount and cumulative mineralization rate were the lowest in the T2 treatment with 0.66-0.86 g·kg-1 and 2.9%-4.0%, respectively. As the substitution rate of chemical N fertilizer by biochar increased, rice yield increased firstly and then decreased. Rice yield in the T2 treatment was the highest, which increased by 13.4% compared with the CK. The substitution of 20% chemical N fertilizer with biochar (5 t·hm-2) could effectively improve the contents of SOC, MBC, ROC, and rice yield, reduce the cumulative mineralization amount of organic carbon and cumulative mineralization rate, and enhance the capacity of soil carbon sequestration. Hence, it could be the most effective fertilizer practice for improving soil fertility and rice yield in paddy field of yellow soil in Guizhou Province.