Development of a cost-effective confocal Raman microscopy with high sensitivity.

Confocal Raman microscopy is a powerful technique for identifying materials and molecular species; however, the signal from Raman scattering is extremely weak. Typically, handheld Raman instruments are cost-effective but less sensitive, while high-end scientific-grade Raman instruments are highly sensitive but extremely expensive. This limits the widespread use of Raman technique in our daily life. To bridge this gap, we explored and developed a cost-effective yet highly sensitive confocal Raman microscopy system. The key components of the system include an excitation laser based on readily available laser diode, a lens-grating-lens type spectrometer with high throughput and image quality, and a sensitive detector based on a linear charge-coupled device (CCD) that can be cooled down to -30 °C. The developed compact Raman instrument can provide high-quality Raman spectra with good spectral resolution. The 3rd order 1450 cm-1 peak of Si (111) wafer shows a signal-to-noise ratio (SNR) better than 10:1, demonstrating high sensitivity comparable to high-end scientific-grade Raman instruments. We also tested a wide range of different samples (organic molecules, minerals and polymers) to demonstrate its universal application capability.

Glutamine Synthetase and Glutamate Synthase Family Perform Diverse Physiological Functions in Exogenous Hormones and Abiotic Stress Responses in Pyrus betulifolia Bunge (P.be).

The unscientific application of nitrogen (N) fertilizer not only increases the economic input of pear growers but also leads to environmental pollution. Improving plant N use efficiency (NUE) is the most effective economical method to solve the above problems. The absorption and utilization of N by plants is a complicated process. Glutamine synthetase (GS) and glutamate synthase (GOGAT) are crucial for synthesizing glutamate from ammonium in plants. However, their gene family in pears has not been documented. This study identified 29 genes belonging to the GS and GOGAT family in the genomes of Pyrus betulaefolia (P.be, 10 genes), Pyrus pyrifolia (P.py, 9 genes), and Pyrus bretschneideri (P.br, 10 genes). These genes were classified into two GS subgroups (GS1 and GS2) and two GOGAT subgroups (Fd-GOGAT and NADH-GOGAT). The similar exon-intron structures and conserved motifs within each cluster suggest the evolutionary conservation of these genes. Meanwhile, segmental duplication has driven the expansion and evolution of the GS and GOGAT gene families in pear. The tissue-specific expression dynamics of PbeGS and PbeGOGAT genes suggest significant roles in pear growth and development. Cis-acting elements of the GS and GOGAT gene promoters are crucial for plant development, hormonal responses, and stress reactions. Furthermore, qRT-PCR analysis indicated that PbeGSs and PbeGOGATs showed differential expression under exogenous hormones (GA3, IAA, SA, ABA) and abiotic stress (NO3- and salt stress). In which, the expression of PbeGS2.2 was up-regulated under hormone treatment and down-regulated under salt stress. Furthermore, physiological experiments demonstrated that GA3 and IAA promoted GS, Fd-GOGAT, and NADH-GOGAT enzyme activities, as well as the N content. Correlation analysis revealed a significant positive relationship between PbeGS1.1, PbeGS2.2, PbeNADH-GOGATs, and the N content. Therefore, PbeGS1.1, PbeGS2.2, and PbeNADH-GOGATs could be key candidate genes for improving NUE under plant hormone and abiotic stress response. To the best of our knowledge, our study provides valuable biological information about the GS and GOGAT family in the pear for the first time and establishes a foundation for molecular breeding aimed at developing high NUE pear rootstocks.

In Situ Reconstructing NiFe Oxalate Toward Overall Water Splitting.

Surface reconstruction plays an essential role in electrochemical catalysis. The structures, compositions, and functionalities of the real catalytic species and sites generated by reconstruction, however, are yet to be clearly understood, for the metastable or transit state of most reconstructed structures. Herein, a series of NiFe oxalates (NixFe1- xC2O4, x = 1, 0.9, 0.7, 0.6, 0.5, and 0) are synthesized for overall water splitting electrocatalysis. Whilst NixFe1-xC2O4 shows great hydrogen evolution reaction (HER) activity, the in situ reconstructed NixFe1-xOOH exhibits outstanding oxygen evolution reaction (OER) activity. As identified by the in situ Raman spectroscopy and quasi-in situ X-ray absorption spectroscopy (XAS) techniques, reconstructions from NixFe1-xC2O4 into defective NixFe1-xOOH and finally amorphous NixFe1-xOOH active species (R-NixFe1-xOOH) are confirmed upon cyclic voltammetry processes. Specifically, the fully reconstructed R-Ni0.6Fe0.4OOH demonstrates the best OER activity (179 mV to reach 10 mA cm-2), originating from its abundant real active sites and optimal d-band center. Benefiting from the reconstruction, an alkaline electrolyzer composed of a Ni0.6Fe0.4C2O4 cathode and an in situ reconstructed R-Ni0.6Fe0.4OOH anode achieves a superb overall water splitting performance (1.52 V@10 mA cm-2). This work provides an in-depth structure-property relationship understanding on the reconstruction of catalysts and offers a new pathway to designing novel catalyst.

LRRC8 complexes are adenosine nucleotide release channels regulating platelet activation and arterial thrombosis.

Platelet shape and volume changes are early mechanical events contributing to platelet activation and thrombosis. Here, we identify single-nucleotide polymorphisms in Leucine-Rich Repeat Containing 8 (LRRC8) protein subunits that form the Volume-Regulated Anion Channel (VRAC) which are independently associated with altered mean platelet volume. LRRC8A is required for functional VRAC in megakaryocytes (MKs) and regulates platelet volume, adhesion, and agonist-stimulated activation, aggregation, ATP secretion and calcium mobilization. MK-specific LRRC8A cKO mice have reduced arteriolar thrombus formation and prolonged arterial thrombosis without affecting bleeding times. Mechanistically, platelet LRRC8A mediates swell-induced ATP/ADP release to amplify agonist-stimulated calcium and PI3K-AKT signaling via P2X1, P2Y 1 and P2Y 12 receptors. Small-molecule LRRC8 channel inhibitors recapitulate defects observed in LRRC8A-null platelets in vitro and in vivo . These studies identify the mechanoresponsive LRRC8 channel complex as an ATP/ADP release channel in platelets which regulates platelet function and thrombosis, providing a proof-of-concept for a novel anti-thrombotic drug target.

Breaking the chain in organ failure: Role of umbilical cord and bone marrow derived mesenchymal stem cells in treatment of severe acute pancreatitis.

Background: Previous studies showed that MSCs could mitigate damage in the pancreas during acute pancreatitis (AP). However, acute mortality associated with AP was more often a result of persistent failure of remote organs, rather than local damage, especially in severe acute pancreatitis (SAP), and the effect of MSCs may vary depending on their origin. Methods: An SAP model was induced in 8-week C57BL/6 J male mice by retrograde injection of 5 % sodium taurocholate solution through the bile duct. SAP mice were divided into the SAP group, UC-MSCs group, and BMSCs group, which were treated with saline, 1 × 106 UC-MSCs, and 1 × 106 BMSCs respectively, through the tail vein. After treatment, serum markers, inflammation, and morphology were assessed in the pancreas, kidneys, lungs, and hearts. Results: MSCs infusion ameliorated the systemic inflammatory response in SAP mice. In the MSCs-treated SAP mice, local tissue injury and inflammation response in the pancreas were alleviated. But more importantly, the renal and lung injury were all significantly and drastically mitigated, and the levels of pro-inflammatory factors such as IL-6, MCP-1, IL-1ß, and TNF-α in the kidney, lung and heart were sharply decreased. In terms of origin, UC-MSCs exhibited superior efficacy compared with BMSCs. Furthermore, compared to the normal control mice, UC-MSCs showed an earlier appearance, higher distribution densities, and longer duration of presence in the injured tissue. Conclusions: This study provides compelling evidence supporting the therapeutic potential of MSCs in SAP treatment and particularly their ability to mitigate multi-organ failure. Our results also suggested that UC-MSCs may offer greater advantages over BMSCs in SAP therapy.

The rs6576457 G > A variant in the MKRN3 gene promoter significantly increases the risk of central precocious puberty and lung cancer in Hubei Chinese population.

Makorin RING finger protein 3 (MKRN3) is a key inhibitor of the hypothalamic-pituitary-gonadal (HPG) axis. The association between MKRN3 gene variants and central precocious puberty (CPP) has been repeatedly examined. In a recent study, MKRN3 has been assigned a role of tumor suppressor in lung carcinogenesis. Therefore, it is hypothesized that MKRN3 may be the link between CPP and lung cancer (LC), and certain MKRN3 gene variants may affect individuals' susceptibility to CPP and LC. The rs12441287, rs6576457 and rs2239669 in the MKRN3 gene were selected as the target variants. Sanger sequencing was applied to genotype them in two sets of case-control cohorts, namely 384 CPP girls and 422 healthy girls, 550 LC patients and 800 healthy controls. The results showed that rs6576457 but not rs12441287 or rs2239669 was significantly associated with the risk of CPP and LC. Their association with CPP risk was further confirmed in the following meta-analysis. Subsequent functional assays revealed that the rs6576457 genotypes were correlated with differentially expressed MKRN3, and the rs6576457 alleles affected the transcription repressor Oct-1 binding affinity to the MKRN3 promoter. Collectively, the MKRN3 gene rs6576457 may participate in the CPP pathology and LC tumorigenesis in the Hubei Chinese population. However, the present findings should be validated in additional investigations with larger samples from different ethnic populations.

Metabolic reprogramming and immune evasion: the interplay in the tumor microenvironment.

Tumor cells possess complex immune evasion mechanisms to evade immune system attacks, primarily through metabolic reprogramming, which significantly alters the tumor microenvironment (TME) to modulate immune cell functions. When a tumor is sufficiently immunogenic, it can activate cytotoxic T-cells to target and destroy it. However, tumors adapt by manipulating their metabolic pathways, particularly glucose, amino acid, and lipid metabolism, to create an immunosuppressive TME that promotes immune escape. These metabolic alterations impact the function and differentiation of non-tumor cells within the TME, such as inhibiting effector T-cell activity while expanding regulatory T-cells and myeloid-derived suppressor cells. Additionally, these changes lead to an imbalance in cytokine and chemokine secretion, further enhancing the immunosuppressive landscape. Emerging research is increasingly focusing on the regulatory roles of non-tumor cells within the TME, evaluating how their reprogrammed glucose, amino acid, and lipid metabolism influence their functional changes and ultimately aid in tumor immune evasion. Despite our incomplete understanding of the intricate metabolic interactions between tumor and non-tumor cells, the connection between these elements presents significant challenges for cancer immunotherapy. This review highlights the impact of altered glucose, amino acid, and lipid metabolism in the TME on the metabolism and function of non-tumor cells, providing new insights that could facilitate the development of novel cancer immunotherapies.

Cu(I)-Induced 'Click Reaction' Involving Coordination and Covalent Assembly of Hybrid Borates for the Electrocatalytic CO2 Reduction.

The design and synthesis of hybrid borates by the organic ligand modification method are urgent and undeveloped areas of research. It is difficult to directly integrate organoboronic acids within inorganic borate chemistry by adopting the traditional preparation approaches. This work reports a facile synthetic method to synthesize a large family of pyrazole molecule-protected borates in a rapid and precise manner under mild conditions. A unique cyclic eight-membered B4O4-ring has been identified as the cluster core for all these hybrid borates with two different conformations (boat and crown). This strategy can be applied to a system of pyrazolyl molecules to generate such hybrid borates in two independent routes from organoboronic or inorganic boric acids. Furtherly, the mechanism of 'click reaction' between boric acid and pyrazole induced by copper ions has been proposed based on the synthetic conditions and the structure of intermediate. Due to the bimetallic Cu sites and the functional surfaces, these materials can be used as electrocatalysts for CO2 reduction reaction and efficiently enhance the selectivity of HCOOH and C2H4. Our strategy can be regarded as a typical template technique for organic molecule-protected borates.

Case Report: Clinical effect of combining auricular cartilage, full-thickness auricular skin graft, and local flap from the right nasal ala in complex nasal defect reconstruction.

The aim of this report was to evaluate the efficacy of nasal reconstruction using auricular cartilage combined with auricular full-thickness skin graft and a local flap from the right nasal ala for correcting complex nasal defects, and its impact on the patient's quality of life and psychological well-being. We present the case of a 50-year-old female with a severe nasal deformity due to a car accident, characterized by a missing right alar flap and an exposed right nostril. The patient underwent nasal reconstructive surgery using auricular cartilage combined with an auricular full-thickness skin graft and a local flap from the right nasal ala. Detailed records of the patient's postoperative recovery, surgical outcomes, and satisfaction were made at follow-up. The survival rate of the grafted skin and flaps on the nasal ala, septum, and dorsum was high. The reconstructed right nasal ala closely resembled the left, and the patient was very satisfied. In patients with complex nasal deformities, nasal reconstruction using ear cartilage combined with auricular full-thickness skin grafts and local flaps can achieve satisfactory aesthetic and functional outcomes. The high level of postoperative satisfaction suggests that this technique significantly improves patients' quality of life and psychological well-being.

Omega-3 PUFAs slow organ aging through promoting energy metabolism.

Energy metabolism disorder, mainly exhibiting the inhibition of fatty acid degradation and lipid accumulation, is highly related with aging acceleration. However, the intervention measures are deficient. Here, we reported Omega-3 polyunsaturated fatty acids (Omega-3 PUFAs), especially EPA, exerted beneficial effects on maintaining energy metabolism and lipid homeostasis to slow organ aging. As the endogenous agonist of peroxisome proliferator-activated receptor α (PPARα), Omega-3 PUFAs significantly boosted fatty acid ß-oxidation and ATP production in multiple aged organs. Consequently, Omega-3 PUFAs effectively inhibited age-related pathological changes, preserved organ function, and retarded aging process. The beneficial effects of Omega-3 PUFAs were also testified in mfat-1 transgenic mice, which spontaneously generate abundant endogenous Omega-3 PUFAs. In conclusion, our study innovatively demonstrated Omega-3 PUFAs administration in diet slow aging through promoting energy metabolism. The supplement of Omega-3 PUFAs or fat-1 transgene provides a promising therapeutic approach to promote healthy aging in the elderly.

Dietary antioxidant and inflammatory potential in asthmatic patients and its association with all-cause mortality.

BACKGROUND: The occurrence and progression of asthma can be influenced by the components in food. Our study aims to determine whether dietary antioxidant and inflammatory potential are associated with the risk of mortality in asthma patients. METHODS: Participants from the 2001-2018 National Health and Nutrition Examination Survey (NHANES) aged 20 years and older with a diagnosis of asthma were included. Mortality status was obtained according to death certificate records from the National Death Index. The antioxidant and inflammatory potential of the diet was assessed using two widely used and dependable indices, Composite Dietary Antioxidant Index (CDAI) and Dietary Inflammatory Index (DII). Restricted cubic spline (RCS) regression was used to analyze the non-linear relationship between the two indexes and mortality. Multivariable Cox proportional risk models were used to estimate hazard ratio and 95% confidence intervals for mortality. Finally, the relationship between CDAI and DII was analyzed. RESULTS: A total of 4698 NHANES participants represented 23.2 million non-institutionalized residents of the US were enrolled in our study. Patients with higher CDAI or lower DII exhibited longer survival times. RCS regression showed a linear relationship of CDAI or DII with mortality. In the Cox regression, both crude and adjusted models demonstrated that higher CDAI or lower DII was linked to a reduced risk of all-cause mortality. Similar associations were found in subgroup analysis. Finally, a negative relationship was found between CDAI and DII. CONCLUSION: Reducing pro-inflammatory or increasing antioxidant diets could reduce all-cause mortality among adult asthma patients.

A Global Identification of Protein Disulfide Isomerases from 'duli' Pear (Pyrus betulaefolia) and Their Expression Profiles under Salt Stress.

Protein disulfide isomerases (PDIs) and PDI-like proteins catalyze the oxidation and reduction in protein disulfide bonds, inhibit aggregation of misfolded proteins, and participate in isomerization and abiotic stress responses. The wild type 'duli' pear (Pyrus betulaefolia) is an important rootstock commonly used for commercial pear tree grafting in northern China. In this study, we identified 24 PDI genes, named PbPDIs, from the genome of 'duli' pear. With 12 homologous gene pairs, these 24 PbPDIs distribute on 12 of its 17 chromosomes. Phylogenetic analysis placed the 24 PbPDIs into four clades and eleven groups. Collinearity analysis of the PDIs between P. betulaefolia, Arabidopsis thaliana, and Oryza sativa revealed that the PbPDIs of 'duli' pear show a strong collinear relationship with those from Arabidopsis, a dicot; but a weak collinear relationship with those from rice, a monocot. Quantitative RT-PCR analysis showed that most of the PbPDIs were upregulated by salt stress. Identification and expression analysis of 'duli' pear PbPDIs under salt stress conditions could provide useful information for further research in order to generate salt-resistant rootstock for pear grafting in the future.

M2 macrophage infusion ameliorates diabetic glomerulopathy via the JAK2/STAT3 pathway in db/db mice.

Objectives: To explore the therapeutic effects of M2 macrophages in diabetic nephropathy (DN) and their mechanism.Methods: We infused M2 macrophages stimulated with IL-4 into 10-week-old db/db mice once a week for 4 weeks through the tail vein as M2 group. Then we investigated the role of M2 macrophages in alleviating the infammation of DN and explored the mechanism.Results: M2 macrophages hindered the progression of DN, reduced the levels of IL-1ß (DN group was 34%, M2 group was 13%, p < 0.01) and MCP-1 (DN group was 49%, M2 group was 16%, p < 0.01) in the glomeruli. It was also proven that M2 macrophages alleviate mesangial cell injury caused by a high glucose environment. M2 macrophage tracking showed that the infused M2 macrophages migrated to the kidney, and the number of M2 macrophages in the kidney reached a maximum on day 3. Moreover, the ratio of M2 to M1 macrophages was 2.3 in the M2 infusion group, while 0.4 in the DN group (p < 0.01). Mechanistically, M2 macrophages downregulated Janus kinase (JAK) 2 and signal transducer and activator of transcription (STAT) 3 in mesangial cells.Conclusions: Multiple infusions of M2 macrophages significantly alleviated inflammation in the kidney and hindered the progression of DN at least partially by abrogating the M1/M2 homeostasis disturbances and suppressing the JAK2/STAT3 pathway in glomerular mesangial cells. M2 macrophage infusion may be a new therapeutic strategy for DN treatment.

Identification of Aggregation Pheromone as an Attractant for Odontothrips loti, A Serious Thrips Pest on Alfalfa.

Odontothrips loti (Haliday) (Thysanoptera: Thripidae) is one of the most serious pests on alfalfa, causing direct damage by feeding and indirect damage by transmitting plant viruses. This damage causes significant loss in alfalfa production. Semiochemicals offer opportunities to develop new approaches to thrips management. In this study, behavioral responses of female and male adults of O. loti to headspace volatiles from live female and male conspecifics were tested in a Y-tube olfactometer. The results showed that both male and female adults of O. loti were attracted to the odors released by conspecific males but not those released by females. Headspace volatiles released by female and male adults were collected using headspace solid-phase microextraction (HS-SPME). The active compound in the volatiles was identified by gas chromatography-mass spectrometry (GC-MS). The analysis showed that there was one major compound, (R)-lavandulyl (R)-2-methylbutanoate. The attractive activity of the synthetic aggregation pheromone compound was tested under laboratory and field conditions. In an olfactometer, both male and female adults showed significant preference for synthetic (R)-lavandulyl (R)-2-methylbutanoate at certain doses. Lures with synthetic (R)-lavandulyl (R)-2-methylbutanoate significantly increased the trap catches of sticky white traps at doses of 40-80 µg in the field. This study confirmed the production of aggregation pheromone by O. loti male adults and identified its active compound as (R)-lavandulyl (R)-2-methylbutanoate, providing a basis for population monitoring and mass trapping of this pest.

Safety profiles of doxycycline, minocycline, and tigecycline in pediatric patients: a real-world pharmacovigilance analysis based on the FAERS database.

Introduction: Recently, the rise of antibiotic resistance has prompted a reconsideration of tetracyclines. However, existing studies are inadequate in assessing the pediatric safety of this class of antibiotics. To address the gap, our study aims to comprehensively assess the safety of tetracyclines in children. Methods: Adverse event (AE) reports from January 2005 to September 2023 were obtained from the U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database, and reporting odds ratio (ROR) was performed to identify potential risk signals in children under 18 years old who were administered any of the three tetracyclines: doxycycline, minocycline, and tigecycline. Results: A total of 1903 AE cases were included in our study: 782 for doxycycline, 981 for minocycline, and 140 for tigecycline. Doxycycline and tigecycline were predominantly associated with "general disorders and administration site conditions" and "gastrointestinal disorders," while minocycline was more frequently linked to "skin and subcutaneous tissue disorders" and "gastrointestinal disorders." Psychiatric risks predominantly included depression, suicidal ideation, and suicide attempt. In the category of skin and subcutaneous tissues, 30.88% of the minocycline-induced drug reaction with eosinophilia and systemic symptoms (DRESS) cases resulted in death, alongside a high occurrence of co-occurring AEs such as multiple organ dysfunction syndrome, Type 1 Diabetes Mellitus (T1DM), and autoimmune thyroiditis. As for the endocrine system, both doxycycline and minocycline were found to potentially increase the risk of thyroid dysfunction. For children under the age of 8, doxycycline was associated with tooth discoloration (N = 7, ROR = 20.11%, 95% CI: 9.48-42.67), although it remained unclear whether the discoloration was permanent. Conclusion: Our findings indicated that for pediatric patients, the majority of results were in line with the prescribing information and previous studies, and minocycline tended to cause more frequent and severe AEs than doxycycline. However, it is noteworthy that exceptions were found for psychiatric disorders and thyroid dysfunction associated with doxycycline, which are not mentioned in its FDA prescribing information. Additionally, further safety studies on tigecycline are still needed for children. When prescribing tetracyclines to pediatric patients, a careful risk-benefit assessment is crucial.

Enhancing CO2 electroreduction to ethylene via microenvironment regulation in boron-imidazolate frameworks.

Using the structure-induced effect of KBH(mim)3 ligand, four 2-dimensional (2D) boron imidazolate frameworks with identical body framework and different dangling monocarboxylate ligands, have been synthesized. Electrocatalytic results indicate that the surrounding microenvironment regulation could effectively affect the activity and selectivity towards C2H4. BIF-151 showed the highest electrocatalytic performances with the Faraday efficiency (FE) of 25.94% for C2H4 at -1.4 V vs. RHE.

[Exploration and practice of ideological and political education in instrumental analysis courses: a case study on chromatography course teaching].

Instrumental analysis is an important professional course for many chemistry majors. Its teaching content is rich, diverse and is closely related to daily life. Moreover, this course contains a large number of ideological and political resources. This study investigates chromatography technology in instrumental analysis as an example, focusing on aspects such as chromatography knowledge, solution preparation, standard operations, and guided experiments, to deeply explore the elements of ideological and political education and organically integrate them into the teaching of instrumental analysis courses. Academic teaching of professional knowledge increases the diversity and richness of the teaching content and enhances the innovative skills of the students. In addition, this teaching method can inspire students to establish life goals and great ideals, with the aim of ultimately cultivating moral people.

Endoplasmic reticulum-targeted fluorescent probe with aggregation-induced emission features for imaging peroxynitrite in drug-induced liver injury model.

Drug-induced liver injury (DILI) poses a severe threat to public health. Endoplasmic reticulum (ER) stress contributes significantly to DILI pathogenesis, with peroxynitrite (ONOO-) identified as a pivotal indicator. However, the temporal and spatial fluctuations of ONOO- associated with ER stress in the pathogenesis of DILI remain unclear. Herein, a novel ER-specific near-infrared (NIR) probe (QM-ONOO) with aggregation-induced emission (AIE) features for monitoring ONOO- fluctuations in DILI was elaborately constructed. QM-ONOO exhibited excellent ER-targeting specificity, a large Stoke's shift, and a low detection limit (26.9 nM) toward ONOO-. QM-ONOO performed well in imaging both exogenous and endogenous ONOO- in HepG2 cells. Furthermore, molecular docking calculations validated the ER-targeting mechanism of QM-ONOO. Most importantly, using this probe allowed us to intuitively observe the dynamic fluctuations of ONOO- during the formation and remediation processes of DILI in the acetaminophen (APAP)-induced mouse model. Consequently, this work provides a promising tool for in-depth research of ONOO- associated pathological processes in DILI.

Exogenous GA3 Enhances Nitrogen Uptake and Metabolism under Low Nitrate Conditions in 'Duli' (Pyrus betulifolia Bunge) Seedlings.

'Duli' (Pyrus betulifolia Bunge) is one of the main rootstocks of pear trees in China. Gibberellin (GA) is a key plant hormone and the roles of GA in nitrate (NO3-) uptake and metabolism in plants remain unclear. In this study, we investigated the effects of exogenous GA3 on the N metabolism of 'Duli' seedlings under NO3- deficiency. The results showed that exogenous GA3 significantly improves 'Duli' growth under NO3- deficiency. On the one hand, GA3 altered the root architecture, increased the content of endogenous hormones (GA3, IAA, and ZR), and enhanced photosynthesis; on the other hand, it enhanced the activities of N-metabolizing enzymes and the accumulation of N, and increased the expression levels of N absorption (PbNRT2) and the metabolism genes (PbNR, PbGILE, PbGS, and PbGOGAT). However, GA3 did not delay the degradation of chlorophyll. Paclobutrazol had the opposite effect on growth. Overall, GA3 can increase NO3- uptake and metabolism and relieve the growth inhibition of 'Duli' seedlings under NO3- deficiency.

Effect of Si and Holding Time on Ti2Al20La Phase in Al-Ti-La Intermediate Alloy.

The effects of holding time and Si on the content, shape size and structure of Ti2Al20La phase in Al-Ti-La intermediate alloy were investigated by an X-ray diffractometer, scanning electron microscope and transmission electron microscope. The results show that the volume fraction and aspect ratio of Ti2Al20La phase in Al-Ti-La intermediate alloy decrease significantly, from 21% and 2.3 without Si addition to 4% and 2.0 with the addition of 2.3 wt.% Si at a holding time of 15 min at 750 °C, respectively. The Si element will attach to the Ti2Al20La phase and form La-Si binary phase at the grain boundary of α-Al. With the increase of holding time from 15 min to 60 min, the content of Ti2Al20La phase in the alloy gradually decreases and the size decreases significantly. Meanwhile, Al11La3 will dissolve and disappear, while the content of La-Si binary phase increases, and part of Ti2Al20La phase transforms into Ti2(Al20-x,Six)La phase.