UV Response Research Articles

Effect of thickness and reaction media on properties of ZnO thin films by SILAR

Zinc oxide (ZnO) is one of the most promising metal oxide semiconductor materials, particularly for optical and gas sensing applications. The influence of thickness and solvent on various features of ZnO thin films deposited at ambient temperature and barometric pressure by the sequential ionic layer adsorption and reaction method (SILAR) was carefully studied in this work. Ethanol and distilled water (DW) were alternatively used as a solvent for preparation of ZnO precursor solution. Superficial morphology, crystallite structure, optical and electrical characteristics of the thin films of various thickness are examined applying X-ray diffraction (XRD) system, scanning electron microscopy, the atomic force microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, Hall effect measurement analysis and UV response study. XRD analysis confirmed that thin films fabricated using ethanol or DW precursor solvents are hexagonal wurtzite ZnO with a preferred growth orientation (002). Furthermore, it was found that thin films made using ethanol are as highly crystalline as thin films made using DW. ZnO thin films prepared using aqueous solutions possess high optical band gaps. However, films prepared with ethanol solvent have low resistivity (10–2 Ω cm) and high electron mobility (750 cm2/Vs). The ethanol solvent-based SILAR method opens opportunities to synthase high quality ZnO thin films for various potential applications.

Hybrid Graphene-Perovskite Quantum Dot Photodetectors With Solar-Blind UV and Visible Light Response

Hybrid Graphene-Perovskite Quantum Dot Photodetectors With Solar-Blind UV and Visible Light Response

Core-shell PPy@TiO2 enable GO membranes with controllable and stable dye desalination properties

Graphene oxide membranes (GOMs) have great potentials in the high-performance desalination of salty wastewater. However, the low-selectivity and fouling issues are the main obstacles to practical implementation. Although compositing with TiO2 nanoparticles alleviates such problems by regulating membrane structures and photodegrading surface organic filter cakes, the performance is still limited by the intrinsic aggregation feature and narrow UV response range. Here, we functionalize TiO2 nanoparticles with polypyrrole (PPy) to improve their dispersibility and visible-light-driven photodegradation properties. The as-formed core-shell heterostructures (PPy@TiO2) with a large dose are intercalated into GOM, resulting in a large water flux (436.93 Lm−2h−1bar−1) and selective positive dye/negative dye separation with a maximum salt permeation of 97%. Upon the reduction of the dosage, more than 99% of dyes are separated regardless of molecule weights and surface charge polarity although the average water flux is reduced to 5.83 Lm−2h−1bar−1 and the salt rejection rate is increased up to 24%. In addition, the composite membrane with low-dosed PPy@TiO2 photodegrades MB completely within 2 h, while its water permeability and dye rejection performance are maintained after a 5 h filtration process. Our work provides a facile method to develop multi-functional 2D composite membranes with controllable and stable dye desalination performances.

UV-Enabled Multibit Organic Transistor Memory With High Controllability and Stability

An organic field-effect transistor nonvolatile memory with multibit storage capability and selective UV response was demonstrated, which showed good retention for all the memory states. The programming/erasing of the device operating at a low voltage was enabled by solar-blind UV light of 254 nm, and it had no response to 365 nm UV light and visible light. The stepwise switching between the memory states was controlled only by the number of the programming/erasing pulses, rather than by programming/erasing voltage or duration. The multibit memory feature is ascribed to the cumulative and reversible charge trapping in the employed polymer electret layer, and this architecture may offer a promising approach to multibit organic-based memories.

First modification strategy: Ester is better than acid to improve the activity of photocatalyst nano-TiO2

It has been a blind spot to compare the modification effect of ester and acid on inorganic photo catalysts. Traditional method is always laborious to realize organic-inorganic combination by the esterification of carboxylic acids with surficial hydroxyls of nano-TiO2. Here, a detailed comparison was conducted using m-dipyridyl benzene skeleton (MPB) molecules containing ester or carboxylic acid groups to modify TiO2 surface with solvothermal method. The result shows that the modification did not affect the crystal structure of TiO2, but formed uniformly distributed organic/inorganic binding sites and non-binding sites on its surface, thus the intrinsic UV response activity of TiO2 can be retained. Combining with the visible light activity of organic/inorganic binding sites, a perfect photogenerated charge transfer system with matching energy levels is constructed, hence the photocatalytic performance is greatly improved. By contrast, the ester derivative of MPB (shorted as EPB) is easier to form stable organic species on the surface of nanoparticles and shows higher catalytic activity than the carboxylic acid derivative of MPB (shorted as APB), thus the study first demonstrated that the low cost and applicable photocatalyst can be obtained with much low dosage of organic modifiers containing ester groups, hence much significant in the design and optimization of catalyst surface. Compared with other reported methods, this modification has the advantages of simple process, low cost, no consumption of precious metals, ease of obtaining high activive and stable catalysts, so it is more prospective in waste water treatment.

Plasmonic Silver Nanoparticle-Mediated Enhanced Broadband Photoresponse of Few-Layer Phosphorene/Si Vertical Heterojunctions.

We report the superior broadband photodetection characteristics of few-layer phosphorene known as black phosphorus (BP) nanosheets integrated with silver nanoparticles (Ag NPs) using vertical heterojunctions on a Si platform. The exfoliation of BP nanosheets and preparation of an Ag NP:BP (Ag-BP) hybrid have been accomplished through environment-friendly and cost-effective chemical routes. The hybrid sample exhibits broadband light absorption with a strong plasmonic peak around ∼425 nm due to the localized surface plasmon resonance (LSPR) of Ag NPs of average size ∼6.0 nm. Spectroscopic analysis of the Ag-BP hybrid ascertains strong light-matter interactions around the LSPR band of Ag NPs. The size-dependent optical response of BP nanostructure/Si state-of-the-art broadband (300-1600 nm) photodiodes has been studied extensively. The enhancement of broadband photoresponse characteristics is demonstrated using the plasmonic Ag-BP 0D-2D hybrid nanostructure compared to pristine BP, where the peak responsivity in the former is shifted to the visible region (∼440 nm) compared to UV response (∼340 nm) of the latter. The tunable spectral responsivity with a peak value of ∼3.2 A/W (@ ∼440 nm and -5 V) for the Ag-BP/Si heterojunction device demonstrates the potential of plasmonic BP hybrids for future nanophotonic devices.

Thermoluminescence Glow Curve Analysis with Variable Concentration of Erbium‐Doped Y2O3 Phosphor

AbstractA series of Y2O3:Er3+ phosphors have been synthesized via combustion synthesis method using urea as a fuel. The prepared samples are characterized by X‐ray diffractometer (XRD) and Fourier transforms infrared spectroscopy (FTIR) techniques. TL glow curves are recorded for Y2O3:Er3+ doped phosphors to study dose dependence, UV response, and heating rate effect. The trapping parameters (μ, E, s) are calculated from Chen's glow peak shape method. TL glow curve is fitted in computerized glow curve deconvolution (CGCD) techniques and are discussed in detail for their possible usage in dosimetry applications.

0D structured Cs4PbI6 single crystals for highly performance UV photodetection

In this work, a high-performance and stable UV photodetector is reported that is based on solution-processed lead bulk Cs4PbI6 single crystals. The Cs4PbI6 single crystals are demonstrated with unique 0D structural and high visible transparent with the wide optical bandgap at 3.46 eV. The crystals exhibit excellent electrical properties with a large μτ value of 9.5 × 10-4 cm2 V-1 and a low trap density of 1.7 × 1010 cm-3. Further, a symmetrical Au-semiconductor-Au structured ultraviolet photodetector based on Cs4PbI6 single crystals has been achieved. The device has been demonstrated with good UV detection performances at 1 V bias: low dark current density of 63.6 nA cm-2, the ratio of the photocurrent to the dark current was about 728 times, fast time profile (response time and recovery time are 11.65 and 12.80 μs, respectively), high UV response (responsivity of 5.07 mA W-1). In addition, the device has good environmental stability under the temperature from 303 K to 404 K and air. This work proves that Cs4PbI6 is a competitive candidate for ultraviolet photon detectors with high detection performance and strong environmental stability.

The Endoplasmic Reticulum Stress Sensor IRE1α Regulates the UV DNA Repair Response through the Control of Intracellular Calcium Homeostasis

The unfolded protein response is activated by UVB irradiation, but the role of a key mediator, IRE1α, is not clear. In this study, we show that mice with an epidermal IRE1α deletion are sensitized to UV with increased apoptosis, rapid loss of UV-induced cyclopyrimidine dimer‒positive keratinocytes, and sloughing of the epidermis. Invitro, Ire1α-deficient keratinocytes have increased UVB sensitivity, reduced cyclopyrimidine dimer repair, and reduced accumulation of γH2AX and phosphorylated ATR, suggesting defective activation of nucleotide excision repair. Knockdown of XBP1 or pharmacologic inhibition of the IRE1α ribonuclease did not phenocopy Ire1α deficiency. The altered UV response was linked to elevated intracellular calcium levels and ROS, and this was due to dysregulation of the endoplasmic reticulum calcium channel InsP3R. Pharmacologic, genetic, and biochemical studies linked the regulation of the Ins3PR, intracellular calcium, and normal UV DNA damage response to CIB1 and the IRE1α‒TRAF2‒ASK1 complex. These results suggest a model where IRE1α activation state drives CIB1 binding either to the InsP3R or ASK1 to regulate endoplasmic reticulum calcium efflux, ROS, and DNA repair responses after UV irradiation.

Fast-speed self-powered PEDOT:PSS/α-Ga2O3 nanorod array/FTO photodetector with solar-blind UV/visible dual-band photodetection

The α-Ga2O3 nanorod array is grown on FTO by hydrothermal and annealing processes. And a self-powered PEDOT:PSS/α-Ga2O3 nanorod array/FTO (PGF) photodetector has been demonstrated by spin coating PEDOT:PSS on the α-Ga2O3 nanorod array. Successfully, the PGF photodetector shows solar-blind UV/visible dual-band photodetection. Our device possesses comparable solar-blind UV responsivity (0.18 mA/W at 235 nm) and much faster response speed (0.102 s) than most of the reported self-powered α-Ga2O3 nanorod array solar-blind UV photodetectors. And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm. The response time is also much faster than the other non-self-powered β-Ga2O3 DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/α-Ga2O3 heterojunction. The results herein may prove a promising way to realize fast-speed self-powered α-Ga2O3 photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking, imaging, machine vision and communication.

Elevated Central Carbon Metabolism - a Hallmark for Senescent Cells in Aging Human Hematopoietic Stem Cell Compartment

Comprehensive proteomic studies of HSC derived from bone marrow of healthy human subjects (n = 59) in different age groups (range: 20 - 72 years) showed that aging HSCs are characterized not only by myeloid lineage skewing, senescence associated secretory phenotype (SASP), accumulation of reactive oxygen species (ROS), anti-apoptosis, but prominently by elevated glycolysis, glucose uptake, and accumulation of glycogen. This is caused by a subset of HSC that has become more glycolytic than others and not on a per cell basis. Subsequent comparative transcriptome studies of HSCs from human subjects >60 years versus those from <30 years have confirmed this association of elevated glycolysis with aging transcriptome signature.Provided with this background and based on glucose metabolism levels, we have developed a method to isolate human HSCs (CD34+ cells) from bone marrow into three distinct subsets with high, intermediate, and low glucose uptake (GU) capacity (GU high, GU inter, GU low). For human subjects >60 years old (n=9), the proportions of these subsets are: GU high= 5.4+3.5 %, GU inter= 66.4+22.5 %, GU low= 28.2+21.7 %. For subjects <30 years (n=5), the proportions are GU high= 1.7+1.5 %, GU inter= 66.5+36.9 %, GU low= 31.8+36.7. Single-cell RNA-sequencing (scRNA-seq) studies and gene ontology analysis of biological processes revealed that, compared to the GU inter and GU low subsets, the GU high cells showed a significantly higher expression of genes involved in myeloid development, inflammation response (AIF1, CASP2, ANXA1, ZFP36), anti-apoptosis (GSTP1, NME1, BCL2, DMNT1, BAX), cell cycle checkpoint (MCL1, CDK1, CDK4, EIF5A), histone regulation (BCL6, EGR1, KDM1A, MLLT3), b-galactosidase, and significantly lower expressions of genes involved in lymphoid development, and of MDM4, MDM2, FOXP1, SOX4, RB1. Functional studies indicated that the glycolytic enzymes were elevated in elderly HSCs, and the GU low subset corresponded to primitive and more pluripotent HSCs than the GU interand GU high subsets. Pathway analyses have then demonstrated that the GU high subset is associated with up-regulated p53 as well as JAK/STAT signaling pathways, characteristic of senescent HSCs observed in murine models. Applying Gene Set Enrichment Analysis (GSEA) algorithms, we have compared the scRNA-seq data of CD34+ cells derived from young (<30 years) versus older (>60 years) subjects, as well as the scRNA-seq data from GU high subset versus GU inter and GU lowsubsets from each individual subject (n = 6). The results are shown in Figure 1. In analogy to the comparison between old (>60 years) versus young (<30 years) HSCs (CD34+ cells), GSEA of the GU high versus GU inter and GU low subsets shows the same pattern of changes - significant upregulation of gene-set expressions for (a) inflammatory response (b) G2M checkpoint, (c) MTORC1, (d) ROS, (Fig. 1B), (e) allograft rejection; and down-regulation of gene-set expressions for (f) pluripotency, (g) androgen response, (h) UV response (Fig. 1C) as well as (i) interferon-a induction during SARS-CoV2-infection (data not shown in Fig. 1). Thus, our novel findings of elevated glycolysis coupled with significant activation of MTORC1 in the senescent cells of the HSC compartment have provided evidence for the important role of calorie restriction (CR) for healthy aging of HSCs. In numerous animal models, aging has been shown to be driven by the nutrient-sensing MTORC1 network. In animal models of aging, CR has been reported to deactivate the MTOR pathway, thus slowing aging and delaying diseases of aging.Conclusion: In a series of multi-omics studies, we have demonstrated that the GU high subset is identical to the senescent cells (SCs) in human HSC compartment. Studies in animal models have shown that SCs in murine bone marrow are responsible for driving the aging process, and elimination of this subset by inhibitors of anti-apoptotic factors is able to rejuvenate hematopoiesis in mice. Our present results have provided cellular and molecular evidence that SCs in human HSC compartment are also dependent on anti-apoptotic factors, elevated MTORC1 as well as increased glycolysis for survival. Inhibition of MTORC1 or glycolysis, either by specific inhibitors or by CR, may eliminate senescent HSCs and promote rejuvenation of human hematopoiesis. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A compound post-column re-focusing approach in supercritical fluid chromatography

Supercritical-fluid chromatography (SFC) is regaining popularity in various fields of analytical chemistry owning to significant advances in instrumentation made in the past decade. However, due to the CO2 based mobile phase and the high flow rates often employed, detection of trace amounts of analytes and coupling with certain detectors or other chromatography techniques are still difficult under many circumstances. In this study we propose a post-column re-focusing approach for SFC analysis to achieve not only signal enhancement in UV-Vis detection, but also actual concentration enhancement of the analyte. By heart-cutting and transporting a selected fraction from the SFC flow into a trapping column with a flushing solvent, re-focusing of the collected analytes can be achieved by re-mobilization with another solvent once the depressurized CO2 is eliminated. By carefully selecting the trapping stationary phase and the two solvents, signal-enhancement ratios between 2.2 and 6.4 were realized for four representative compounds eluting with very different percentages of SFC modifier (methanol). The actual concentration enhancement was lower (ratios between 1.7 to 2.9), because the UV response of the analytes was found to differ significantly under SFC and LC conditions.

Refining models of archaic admixture in Eurasia with ArchaicSeeker 2.0

We developed a method, ArchaicSeeker 2.0, to identify introgressed hominin sequences and model multiple-wave admixture. The new method enabled us to discern two waves of introgression from both Denisovan-like and Neanderthal-like hominins in present-day Eurasian populations and an ancient Siberian individual. We estimated that an early Denisovan-like introgression occurred in Eurasia around 118.8–94.0 thousand years ago (kya). In contrast, we detected only one single episode of Denisovan-like admixture in indigenous peoples eastern to the Wallace-Line. Modeling ancient admixtures suggested an early dispersal of modern humans throughout Asia before the Toba volcanic super-eruption 74 kya, predating the initial peopling of Asia as proposed by the traditional Out-of-Africa model. Survived archaic sequences are involved in various phenotypes including immune and body mass (e.g., ZNF169), cardiovascular and lung function (e.g., HHAT), UV response and carbohydrate metabolism (e.g., HYAL1/HYAL2/HYAL3), while “archaic deserts” are enriched with genes associated with skin development and keratinization.

Bio-P-02 - Genetic expression profile in the prognosis of mycosis fungoides

We present a historic cohort study with 57 patients diagnosed with mycosis fungoides in early stages during the years 1999 to 2002. Our group performed a cDNA microarray on the diagnosis skin biopsies samples with the CNIO (oncologic investigation national center of Spain) Onco-Chip. This chip includes 6386 cancer-related clones. Since the samples were processed in two deferent years the initial set of 57 patients was divided in two groups of 29 and 28 patients due to the heterogeneity of the sample array results. The patients had a medium of 14 years of follow-up and were divided in two groups: progression (development of tumor, nodes, erythroderma, blood involvement or metastasis) and no progression. And we performed volcano pot analysis and GSEA to determine whether there are different genes expressions at diagnosis that determine prognosis. Several pathways were up and down regulated differently in patients progressing. We performed a GSEA analysis with the following results. Pathways related with progression: CXCR4 pathway (p=0.000) Normalized Enrichment Score (NES) 1.91 and FDR 0.027; genes: BCAR1, PXN, PIK3CA, PTK2, PIK3R1, PRKCA, HRAS, RAF1, CXCL12, PIK3C2G, GNB1. Other pathways with p<5% were: ERK5 pathway p=0.035, NES 1.15, FDR 0.92; genes: PIK3CA, PIK3R1, HRAS, RPS6KA1, SHC1. AKT pathway p=0.049, NES 1.52, FDR 0.70; genes: PIK3CA, PIK3R1, GHR, CASP9, YWHAH. Cytokine pathway p=0.034, NES 1.49, FDR 0.66; genes: SOCS6, SOD2, CCL2. PIK 3-CL1 pathway p=0.035, NES 1.39, FDR 0.63; genes: PIK3CA and PIK3CD INFAR1 pathway p=0.012, NES –1.51, FDR 1; genes: IFNAR1, JAK1, IFNAR2. P53 pathway p=0.032, NES –1.48, FDR 1; genes: MDM2, ABCB1, TP53. Pathways related with no progression: lymphocyte pathway p=0.000, FDR 0.31 NES –1.67; genes: ITGA, ITGB1, SELL, SELP. UV response pathway p=0.007, NES 1.62, FDR 0.40; genes: NTRK3, CCNE1, RAB27A, LYN, CEBPG, IL6ST, GAL, PSMC3, RRAD, ATF3, SOD2, BAK1, STIP1, GCH1, BMP2, PRKCD, RFC4, E2F2, IRF1, RASGRP1, BTG3, CDKN1C, ATP6V1F, CHKA, EIF5, POLE3, CDC5, UROD, CDC34, NR4A1, ENO2, JUNB, SLC6A8, DNAJB1, IGFB2, CDK2, PPIF, ABCB1, RXRB, PPT1, SPOP, KIT, MET, EIF5, FURIN. Other pathway with p<5% was: ERK pathway p=0.048, NES –1.48, FDR 0.93; genes: SRC, NGFB, HRAS; IGF1R, RPS6KA1, MYC, EGFR, RAF, SHC1, PDGFRA, GNB1, STAT3, NGFR, ITGB1, GNAS. We also performed a volcano pot study that showed overexpression of PPP1R3C a gene related with the mTOR pathway in the progression cases. Although our sample size was limited, we believe that pathways related with JAK/STAT, PIK/AKT/mTOR, MAPK, and cellular cycle can be differentially expressed in patients that have progression of the disease from the early stages of mycosis fungoides. Further studies are necessary to validate our results.

Electrochemical Preparation of ZnO/PEDOT‐Type Conducting Polymers Composites for Ultraviolet Photodetector

AbstractGenerally, the ultraviolet photodetector devices based on ZnO/PEDOT composites were fabricated by spin coating of PEDOT solutions on ZnO nanorods array, which needs the polymer disperesed in solvent. In this paper, an electrochemical deposition method was proposed for the prepparation of ZnO/PEDOT‐type conducting polymers composites for ultraviolet photodetector. The poly(3,4‐proplene‐dioxythiophene) (PProDOT) and poly(3,4‐ethylenedioxy‐thiophene)(PEDOT) were selected as PEDOT‐type conducting polymers. The structure of composite materials was characterized by UV‐vis, XRD, Raman, SEM,EDS and XPS analysis. The effects of different polymers on the UV sensing ability of ZnO nanorods were studied. The structural results showed that the composites were successfully prepared by electrochemical deposition method indicating that the electrochecmial method was an effective way to prepraration of this type composites.The photoelectric performance test showed that the structure of the polymer chain affected the responsiveness of the materials, and the response time of ZnO/PProDOT was 14 s shorter than that of ZnO/PEDOT, and it displayed an excellent long‐term stability. After deposition of PProDOT, the UV responsivity of ZnO nanorods was increased from 2.5 A W−1 to 27.5 A W−1, and the external quantum efficiency and detectivity were significantly improved, implying that the PProDOT can be ideal candidate material for ultraviolet photodetector.

Characterization of Molecular Subtypes in Head and Neck Squamous Cell Carcinoma With Distinct Prognosis and Treatment Responsiveness.

Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive malignancies with complex phenotypic, etiological, biological, and clinical heterogeneities. Previous studies have proposed different clinically relevant subtypes of HNSCC, but little is known about its corresponding prognosis or suitable treatment strategy. Here, we identified 101 core genes from three prognostic pathways, including mTORC1 signaling, unfold protein response, and UV response UP, in 124 pairs of tumor and matched normal tissues of HNSCC. Moreover, we identified three robust subtypes associated with distinct molecular characteristics and clinical outcomes using consensus clustering based on the gene expression profiles of 944 HNSCC patients from four independent datasets. We then integrated the genomic information of The Cancer Genome Atlas (TCGA) HNSCC cohort to comprehensively evaluate the molecular features of different subtypes and screen for potentially effective therapeutic agents. Cluster 1 had more arrested oncogenic signaling, the highest immune cell infiltration, the highest immunotherapy and chemotherapeutic responsiveness, and the best prognosis. By contrast, Cluster 3 showed more activated oncogenic signaling, the lowest immune cell infiltration, the lowest immunotherapy and chemotherapy responsiveness, and the worst prognosis. Our findings corroborate the molecular diversity of HNSCC tumors and provide a novel classification strategy that may guide for prognosis and treatment allocation.

Necklace-like hybrid nanofiber as an enhanced and recyclable intrinsic photocatalyst for tetracycline removal and hydrogen evolution

Recycling of nanophotocatalyst in slurry system is still a challenge due to its powder form. Here, polyacrylonitrile with nanophotocatalyst (CdS, Cd@TiO2, and CdS@void@TiO2, respectively) and vanadyl acetylacetonate as a potential oxidant was electrospun into nanofiber membrane. After sintering and acidification, polypyrrole (PPy) was coated via V5+ oxidation polymerization, and the necklace-like nanofiber photocatalyst (nanophotocatalyst@PPy NFs) was yielded. After calcination and PPy covering, nanophotocatalyst@PPy NFs with ternary heterojunctions have the narrow energy gap of ~1.6 eV and broad response in UV and visible light region. The maximum removal efficiency of the nanophotocatalyst@PPy NF can reach up to ~77% for tetracycline, and H2 evolution rate raises up to 654.7 μmol h−1 g−1. With the protection of PPy covering, nanophotocatalyst@PPy NFs possess outstanding resistance to photocorrosion. As a recyclable fiber-form photocatalyst, our nanophotocatalyst@PPy NFs with commendable photocatalytic activity and stable performance as well as easy handling and recycling show great promise for environmental remediation.

Quality analysis of Ziziphi Spinosae Semen extracts based on high performance liquid chromatography quantitative fingerprint and ultra-high performance liquid chromatography-tandem mass spectrometry quantification

酸枣仁具有显著的改善睡眠和抗焦虑等作用,其提取物在助眠类功能食品开发中应用前景广阔。但目前市场上酸枣仁提取物质量参差不齐,缺乏统一标准,企业在使用时面临较大的质量风险,因此亟须建立一种准确、全面的内控质量评价方法。针对酸枣仁提取物中黄酮和皂苷两类主要活性成分紫外响应差异巨大且水提物中皂苷成分含量低的问题,该研究建立了酸枣仁水提物HPLC定量指纹图谱方法,共标定了8个共有峰。通过对照品指认、文献比对以及高效液相色谱-四极杆飞行时间质谱数据解析,8个共有峰均为黄酮类化合物,该方法可同时实现7种黄酮成分的半定量对比分析和斯皮诺素的含量测定;采用超高效液相色谱-三重四极杆质谱,在正离子模式下,以多反应监测扫描方式可实现酸枣仁皂苷A和B的含量测定;最终以雷达图展现上述10种成分的半定量和定量数据。应用上述方法,该研究对比分析了实验室自制的3批酸枣仁水提物和15家供应商的15批提取物样品。结果显示,实验室自制的3批酸枣仁水提物虽然原料来自不同饮片企业,但总体差异性不大,而不同厂家提供的酸枣仁提取物样品成分含量差异巨大,提示不同厂家存在辅料稀释、理枣仁掺假和醇提或纯化富集等情况。该法为企业制定内控质量标准和筛选合格供应商提供了依据。

Narrow-Band 311 nm Ultraviolet-B Radiation Evokes Different Antioxidant Responses from Broad-Band Ultraviolet.

Supplemental narrow-band 311 nm UV-B radiation was applied in order to study the effect of this specific wavelength on tobacco as a model plant. UV-B at photon fluxes varying between 2.9 and 9.9 μmol m−2 s−1 was applied to supplement 150 μmol m−2 s−1 photosynthetically active radiation (PAR) for four hours in the middle of the light period for four days. Narrow-band UV-B increased leaf flavonoid and phenolic acid contents. In leaves exposed to 311 nm radiation, superoxide dismutase activity increased, but phenolic peroxidase activity decreased, and the changes were proportional to the UV flux. Ascorbate peroxidase activities were not significantly affected. Narrow-band UV-B caused a dose-dependent linear decrease in the quantum efficiency of photosystem II, up to approximately 10% loss. A parallel decrease in non-regulated non-photochemical quenching indicates potential electron transfer to oxygen in UV-treated leaves. In addition to a flux-dependent increase in the imbalance between enzymatic H2O2 production and neutralization, this resulted in an approximately 50% increase in leaf H2O2 content under 2.9–6 μmol m−2 s−1 UV-B. Leaf H2O2 decreased to control levels under higher UV-B fluxes due to the onset of increased non-enzymatic H2O2- and superoxide-neutralizing capacities, which were not observed under lower fluxes. These antioxidant responses to 311 nm UV-B were different from our previous findings in plants exposed to broad-band UV-B. The results suggest that signaling pathways activated by 311 nm radiation are distinct from those stimulated by other wavelengths and support the heterogeneous regulation of plant UV responses.

Mapping the landscape of chromatin dynamics during na\xefve CD4+\u2009T-cell activation

T-cell activation induces context-specific gene expression programs that promote energy generation and biosynthesis, progression through the cell cycle and ultimately cell differentiation. The aim of this study was to apply the omni ATAC-seq method to characterize the landscape of chromatin changes induced by T-cell activation in mature naïve CD4+ T-cells. Using a well-established ex vivo protocol of canonical T-cell receptor signaling, we generated genome-wide chromatin maps of naïve T-cells from pediatric donors in quiescent or recently activated states. We identified thousands of individual chromatin accessibility peaks that are associated with T-cell activation, the majority of which were annotated intronic and intergenic enhancer regions. A core set of 3268 gene promoters underwent chromatin remodeling and concomitant changes in gene expression in response to activation, and were enriched in multiple pathways controlling cell cycle regulation, metabolism, inflammatory response genes and cell survival. Leukemia inhibitory factor (LIF) was among those factors that gained the highest accessibility and expression, in addition to IL2-STAT5 dependent chromatin remodeling in the T-cell activation response. Using publicly available data we found the chromatin response was far more dynamic at 24-h compared with 72-h post-activation. In total 546 associations were reproduced at both time-points with similar strength of evidence and directionality of effect. At the pathways level, the IL2-STAT5, KRAS signalling and UV response pathways were replicable at both time-points, although differentially modulated from 24 to 72 h post-activation.