Aniline Compounds

苯胺化合物
  • 文章类型: Journal Article
    等离子体材料可以产生强大的电磁场来增强周围分子的拉曼散射,称为表面增强拉曼散射。然而,这些电磁场是异质的,只有分子位于“热点”,占表面积的≈1%,体验有效的增强。在这里,我们提出了图案化的等离子体三聚体,由两侧的一对等离子体二聚体和位于两者之间的陷阱粒子组成,来应对这一挑战。三聚体构型通过化学亲和力选择性地将探针分子引导到“热点”所在的中心陷阱,确保探头和最大场增强位置之间的精确空间重叠。我们研究了Au@Al2O3-Au-Au@Al2O3三聚体的拉曼增强,4-甲基苯硫酚的检测限达到10-14M,4-巯基吡啶,和4-氨基苯硫酚。此外,通过双分析方法证明了单分子SERS灵敏度。受益于这种敏感性,我们的方法用于使用新鲜组织早期检测肺肿瘤。我们的研究结果表明,这种方法对腺癌敏感,但对鳞癌或良性病例不敏感。提供对肺肿瘤亚型之间的区别的见解。
    Plasmonic materials can generate strong electromagnetic fields to boost the Raman scattering of surrounding molecules, known as surface-enhanced Raman scattering. However, these electromagnetic fields are heterogeneous, with only molecules located at the \'hotspots\', which account for ≈ 1% of the surface area, experiencing efficient enhancement. Herein, we propose patterned plasmonic trimers, consisting of a pair of plasmonic dimers at the bilateral sides and a trap particle positioned in between, to address this challenge. The trimer configuration selectively directs probe molecules to the central traps where \'hotspots\' are located through chemical affinity, ensuring a precise spatial overlap between the probes and the location of maximum field enhancement. We investigate the Raman enhancement of the Au@Al2O3-Au-Au@Al2O3 trimers, achieving a detection limit of 10-14 M of 4-methylbenzenethiol, 4-mercaptopyridine, and 4-aminothiophenol. Moreover, single-molecule SERS sensitivity is demonstrated by a bi-analyte method. Benefiting from this sensitivity, our approach is employed for the early detection of lung tumors using fresh tissues. Our findings suggest that this approach is sensitive to adenocarcinoma but not to squamous carcinoma or benign cases, offering insights into the differentiation between lung tumor subtypes.
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  • 文章类型: Journal Article
    背景:在使用第三代TKI奥希替尼治疗的患者中,获得性耐药仍然不可避免地发生。尽管EGFRL718Q突变已被报道为奥希替尼耐药的稀缺机制,先进的治疗策略仍在发展中。在这份报告中,我们纳入了2例奥希替尼后获得EGFRL858R/L718Q突变并被达克替尼克服的患者.
    方法:案例1:一名77岁女性被诊断为IV期肺腺癌。病例2:一名64岁的女性被诊断为IV期肺腺癌。
    方法:病例1:患者诊断为EGFRL858R突变腺癌。从那以后,给予吉非替尼治疗,导致18个月的无进展生存期。根据EGFRT790M突变的检测,将治疗改为奥希替尼,导致24个月的无进展生存期。随后,检测到EGFRL718Q突变。病例2:患者诊断为EGFRL858R突变腺癌。伊克替尼作为一线治疗7个月。基于EGFRT790M突变,奥希替尼作为二线治疗13个月。随后,检测到EGFRL718Q突变。
    方法:病例1:给予达克替尼。案例2:给予达科替尼。
    结果:病例1:无进展生存期为8个月。病例2:无进展生存期为3个月。
    结论:达科替尼是对奥希替尼耐药后EGFRL718Q突变的NSCLC患者的潜在治疗选择。在这种情况下,需要进一步的研究来验证达科替尼的疗效。
    BACKGROUND: Acquired resistance still inevitably occurs in patients treated with third-generation TKI osimertinib. Although the EGFR L718Q mutation has been reported as a scarce mechanism of osimertinib resistance, advanced therapeutic strategies are still in development. In this report, we included 2 cases of patients who acquired EGFR L858R/L718Q mutation after osimertinib and were overcome by dacomitinib.
    METHODS: Case 1: A 77-year-old woman was diagnosed with stage IV lung adenocarcinoma. Case 2: A 64-year-old woman was diagnosed with stage IV lung adenocarcinoma.
    METHODS: Case 1: The patient was diagnosed with adenocarcinoma with EGFR L858R mutation. Since then, treatment with gefitinib was administrated, leading to a progression-free survival of 18 months. The treatment was switched to osimertinib based on the detection of EGFR T790M mutation, resulting in a progression-free survival of 24 months. Subsequently, EGFR L718Q mutation was detected. Case 2: The patient was diagnosed with adenocarcinoma with EGFR L858R mutation. Icotinib was used as the first-line treatment for 7 months. Osimertinib was applied as the second-line treatment for 13 months based on the EGFR T790M mutation. Subsequently, EGFR L718Q mutation was detected.
    METHODS: Case 1: Dacomitinib was administered. Case 2: Dacomitinib was administered.
    RESULTS: Case 1:The progression-free survival was 8 months. Case 2: The progression-free survival was 3 months.
    CONCLUSIONS: Dacomitinib is a potential treatment option for NSCLC patients with EGFR L718Q mutation after resistance to Osimertinib. Further research is needed to validate the efficacy of Dacomitinib in this context.
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  • 文章类型: Journal Article
    奥希替尼在EGFRV834L和L858R诊断的NSCLC中导致临床获益。
    Up-front osimertinib leads to clinical benefit in EGFR V834L and L858R comutated NSCLC.
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  • 文章类型: Journal Article
    通过活细胞中敏感的Ca2荧光染料可以方便地监测细胞内Ca2。Gαq涉及脂质信号通路,因此,可以通过细胞内Ca2+成像来研究。在这里,我们描述了测量细胞内Ca2+以研究食管平滑肌细胞中PEG2-EP1活性的方案。比率Fura-2成像提供了定量数据,Fluo-4共聚焦显微成像具有较高的空间分辨率。
    Intracellular Ca2+ can be conveniently monitored by sensitive Ca2+ fluorescent dyes in live cells. The Gαq involved lipid signaling pathways and, thus, can be studied by intracellular Ca2+ imaging. Here we describe the protocols to measure intracellular Ca2+ for studying PEG2-EP1 activity in esophageal smooth muscle cells. The ratiometric Fura-2 imaging provides quantitative data, and the Fluo-4 confocal microscopic imaging has high-spatial resolution.
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  • 文章类型: Journal Article
    背景:表皮生长因子受体(EGFR)基因激活突变的晚期非小细胞肺癌(NSCLC)患者是一个异质性人群,经常发生脑转移(BM)。鉴于新一代靶向疗法在中枢神经系统中的活性,无症状脑转移患者的最佳管理尚不清楚。我们提出了一项个体患者数据(IPD)前瞻性荟萃分析方案,以评估在奥希替尼治疗之前增加立体定向放射外科(SRS)是否会更好地控制颅内转移疾病。这是一个临床相关的问题,将为实践提供信息。
    方法:如果随机对照试验包括由EGFR突变型NSCLC引起的BM患者,并且适合在一线和二线环境中接受奥希替尼(P);SRS比较奥希替尼与单独奥希替尼(I,C)和颅内疾病对照包括作为终点(O)。Medline(Ovid)的系统搜索,Embase(Ovid),Cochrane中央对照试验登记册(中央),CINAHL(EBSCO),PsychInfo,将进行ClinicalTrials.gov和WHO的国际临床试验注册平台的搜索门户。将使用Cochrane协作组织推荐的方法进行IPD荟萃分析。主要结果是颅内无进展生存期,根据神经肿瘤学BM标准的反应评估确定。次要结果包括总生存率,全脑放疗的时间,生活质量,和特别关注的不良事件。将探讨预设亚组之间的效果差异。
    背景:获得每个试验伦理委员会的批准。结果将与临床医生相关,研究人员,决策者和患者,并将通过出版物传播,演示文稿和媒体发布。
    CRD42022330532。
    BACKGROUND: Patients with advanced non-small-cell lung cancer (NSCLC) with activating mutations in the epidermal growth factor receptor (EGFR) gene are a heterogeneous population who often develop brain metastases (BM). The optimal management of patients with asymptomatic brain metastases is unclear given the activity of newer-generation targeted therapies in the central nervous system. We present a protocol for an individual patient data (IPD) prospective meta-analysis to evaluate whether the addition of stereotactic radiosurgery (SRS) before osimertinib treatment will lead to better control of intracranial metastatic disease. This is a clinically relevant question that will inform practice.
    METHODS: Randomised controlled trials will be eligible if they include participants with BM arising from EGFR-mutant NSCLC and suitable to receive osimertinib both in the first-line and second-line settings (P); comparisons of SRS followed by osimertinib versus osimertinib alone (I, C) and intracranial disease control included as an endpoint (O). Systematic searches of Medline (Ovid), Embase (Ovid), Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL (EBSCO), PsychInfo, ClinicalTrials.gov and the WHO\'s International Clinical Trials Registry Platform\'s Search Portal will be undertaken. An IPD meta-analysis will be performed using methodologies recommended by the Cochrane Collaboration. The primary outcome is intracranial progression-free survival, as determined by response assessment in neuro-oncology-BM criteria. Secondary outcomes include overall survival, time to whole brain radiotherapy, quality of life, and adverse events of special interest. Effect differences will be explored among prespecified subgroups.
    BACKGROUND: Approved by each trial\'s ethics committee. Results will be relevant to clinicians, researchers, policymakers and patients, and will be disseminated via publications, presentations and media releases.
    UNASSIGNED: CRD42022330532.
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  • 文章类型: Journal Article
    有效消除复杂废水中的重金属对工业废水处理具有重要意义。在这里,制备了Fe3O4-CeO2双金属吸附剂,首次添加H2O2以增强Fe3O4-CeO2对Sb(V)和苯胺气浮法(AAF)复合废水中Sb(V)的吸附。Fe3O4-CeO2具有良好的吸附性能,能在外加磁场下快速分离。在五个吸附/解吸循环后,Fe3O4-CeO2仍保持较好的稳定性。Fe3O4-CeO2在单一Sb(V)中的最大吸附容量,AAF+Sb(V),H2O2+AAF+Sb(V)系统分别为77.33、70.14和80.59mg/g,分别。共存AAF抑制Sb(V)吸附。相反,在AAF+Sb(V)二元体系中,添加H2O2促进Sb(V)的去除,并使Fe3O4-CeO2的吸附量提高了14.90%。H2O2不仅能加快反应速率,而且还将吸附剂的最佳用量从2.0g/L降低到1.2g/L。同时,共存阴离子对Fe3O4-CeO2+H2O2工艺去除Sb(V)影响不大。通过拟二级动力学较好地描述了Sb(V)在三种体系中的吸附行为,暗示化学吸附占主导地位。AAF与Sb(V)的络合阻碍了Fe3O4-CeO2对Sb(V)的吸附。配合物Sb(V)被Fe3O4-CeO2H2O2过程中产生的羟基自由基氧化并分解为游离态。然后游离的Sb(V)主要通过外球络合被Fe3O4-CeO2吸附。本研究为重金属有机物复合废水的处理提供了一种新的策略。
    Effective elimination of heavy metals from complex wastewater is of great significance for industrial wastewater treatment. Herein, bimetallic adsorbent Fe3O4-CeO2 was prepared, and H2O2 was added to enhance Sb(V) adsorption by Fe3O4-CeO2 in complex wastewater of Sb(V) and aniline aerofloat (AAF) for the first time. Fe3O4-CeO2 showed good adsorption performance and could be rapidly separated by external magnetic field. After five adsorption/desorption cycles, Fe3O4-CeO2 still maintained good stability. The maximum adsorption capacities of Fe3O4-CeO2 in single Sb(V), AAF + Sb(V), and H2O2+AAF + Sb(V) systems were 77.33, 70.14, and 80.59 mg/g, respectively. Coexisting AAF inhibited Sb(V) adsorption. Conversely, additional H2O2 promoted Sb(V) removal in AAF + Sb(V) binary system, and made the adsorption capacity of Fe3O4-CeO2 increase by 14.90%. H2O2 could not only accelerate the reaction rate, but also reduce the optimal amount of adsorbent from 2.0 g/L to 1.2 g/L. Meanwhile, coexisting anions had little effect on Sb(V) removal by Fe3O4-CeO2+H2O2 process. The adsorption behaviors of Sb(V) in three systems were better depicted by pseudo-second-order kinetics, implying that the chemisorption was dominant. The complexation of AAF with Sb(V) hindered the adsorption of Sb(V) by Fe3O4-CeO2. The complex Sb(V) was oxidized and decomposed into free state by hydroxyl radicals produced in Fe3O4-CeO2+H2O2 process. Then the free Sb(V) was adsorbed by Fe3O4-CeO2 mostly through outer-sphere complexation. This work provides a new tactic for the treatment of heavy metal-organics complex wastewater.
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  • 文章类型: English Abstract
    Objective: This study aims to evaluate the safety and effectiveness of gilteritinib (Gilt) -based combination therapy bridging allo-HSCT for FLT3-ITD(+) R/R AML. Additionally, it aims to assess the impact of Gilt maintenance therapy on the prognosis of patients after allo-HSCT. Methods: The clinical data of 26 patients with FLT3-ITD(+) R/R AML treated at the First Affiliated Hospital of Soochow University from August 2019 to January 2023 were retrospectively analyzed. The analysis included an assessment of the composite complete remission rate (CRc), overall survival (OS) time, disease-free survival (DFS) time, and adverse events experienced by all enrolled patients. Results: A total of 26 patients with FLT3-ITD(+) R/R AML were enrolled, including 14 men and 12 women with a median age of 38 (18-65) years. A total of 18 cases were refractory, and eight cases were relapsed. The curative effect evaluation conducted between 14 and 21 days showed that the complete remission (CR) rate was 26.9% (7/26), the CR with hematology incomplete recovery was 57.7% (15/26), and the partial response (PR) rate was 7.7% (2/26). The CRc was 84.6% (22/26), and the minimal residual disease (MRD) negativity rate was 65.4%. The 12 month cumulative OS rate for all patients was 79.0%, and the 24 month cumulative OS rate was 72.0%. The median OS time was not determined. The median follow-up time was 16.0 months. Among the patients who responded to treatment, the 12 month cumulative DFS rate was 78.0%, and the 24 month cumulative DFS rate was 71.0%. The median DFS time was not determined. Patients who received allo-HSCT had a median OS time that was significantly longer than those who did not receive allo-HSCT (3.3 months, 95%CI 2.2-4.3 months, P=0.005). The median OS time of patients with or without Gilt maintenance therapy after allo-HSCT was not determined, but the OS time of patients with Gilt maintenance therapy after allo-HSCT treatment was longer than that of patients without Gilt maintenance therapy after allo-HSCT treatment (P=0.019). The FLT3-ITD mutation clearance rate in this study was 38.5%, and the median OS time of patients with FLT3-ITD mutation clearance was not determined but was significantly longer than the median OS of patients without FLT3-ITD mutation clearance (15.0 months; P=0.018). The most common grade 3 and above hematological adverse events of Gilt-based combination therapy included leukopenia (76.9%), neutropenia (76.9%), febrile neutropenia (61.5%), thrombocytopenia (69.2%), and anemia (57.7%). One patient developed differentiation syndrome during oral Gilt maintenance therapy after allo-HSCT treatment, but his condition improved after treatment. Conclusion: The Gilt-based combination therapy is highly effective in treating FLT3-ITD(+) R/R AML. It demonstrates a high CRc, MRD negativity rate, and rapid onset, leading to a significant improvement in patients\' survival. Furthermore, the clearance rate of FLT3-ITD mutation is notably high. Additionally, implementing bridging allo-HSCT and Gilt maintenance therapy after allo-HSCT treatment has considerably enhances patients\' survival. Closely monitoring and managing any adverse event that may occur during treatment are crucial.
    目的: 探讨Gilteritinib(Gilt)为基础的方案桥接异基因造血干细胞移植(allo-HSCT)对伴FMS样酪氨酸激酶3(FLT3)基因内部串联重复(ITD)突变的复发难治性急性髓系白血病(R/R AML)患者的安全性、有效性,以及移植后Gilt维持治疗对FLT3-ITD阳性R/R AML患者预后的影响。 方法: 回顾性分析2019年8月至2023年1月苏州大学附属第一医院收治的26例伴FLT3-ITD突变的R/R AML患者。统计所有纳入患者的复合完全缓解(CRc)率、总生存(OS)期、无病生存(DFS)期和不良反应。 结果: 26例FLT3-ITD突变阳性R/R AML患者中,男14例,女12例,中位年龄38(18~65)岁。难治18例,复发8例。用药第14~21天疗效:完全缓解(CR)率为26.9%(7/26),CR伴血液学不完全恢复(CRi)率为57.7%(15/26),部分缓解(PR)率为7.7%(2/26),CRc率为84.6%(22/26),微小残留病(MRD)转阴率为65.4%。所有患者12、24个月累计OS率分别为79.0%和72.0%。中位OS期未达到。中位随访时间为16.0个月。全部治疗有效患者12、24个月累计DFS率分别为78.0%和71.0%。中位DFS期未达到。接受allo-HSCT的患者中位OS期未达到,较未接受allo-HSCT的患者(3.3个月,95%CI 2.2~4.3个月)显著延长(P=0.005)。移植后是否应用Gilt维持治疗的患者中位OS期均未达到,且移植后维持治疗的患者OS明显优于移植后未进行维持治疗的患者(P=0.019)。本研究中FLT3-ITD基因突变清除率为38.5%,且FLT3-ITD基因突变转阴的患者中位OS期未达到,明显长于未转阴的患者(15.0个月)(P=0.018)。Gilt为基础的方案最常见的3级及以上血液学不良反应包括白细胞减少(76.9%)、中性粒细胞减少(76.9%)、中性粒细胞减少性发热(61.5%)、血小板减少(69.2%)和贫血(57.7%)。其中1例患者在移植后口服Gilt维持治疗时出现分化综合征,治疗后好转。 结论: Gilt为基础的方案桥接allo-HSCT治疗FLT3-ITD突变阳性R/R AML患者的CRc率较高,MRD转阴率也较高,起效迅速,有效延长患者生存期。此外,FLT3-ITD基因突变清除率较高,且桥接移植和移植后Gilt维持治疗明显改善患者生存。治疗过程中不良事件的监测和管理至关重要。.
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  • 文章类型: Journal Article
    农药和有机砷化合物的使用及其对环境的毒性影响的惊人增长激发了我们开发一种选择性和高灵敏度的传感器来检测这些污染物。在这里,一个生物友好的,低成本铝基发光金属有机框架(1\')基荧光材料被证明有助于通过快速监测和量化长期建立的农药(戊二氢萘)和广泛使用的有机砷饲料添加剂(roxarsone)来维持水质。溶剂热合成了吡啶官能化的多孔铝基金属有机骨架(Al-MOF)。激活后,与其他竞争性分析物相比,它用于快速(<10s)和选择性关闭检测罗沙松和二甲双胍。这是第一个基于MOF的可循环使用的传感器,该传感器具有极低的检测限(LOD,14.4nM)。已成功验证了检测各种蔬菜和食品提取物中二甲戊灵的实时有效性。此外,roxarsone的水相可回收检测具有超低的检测限(13.1nM),使其成为实时应用的潜在候选者。罗沙酮和二甲戊灵的检测限低于现有的基于发光材料的传感器。此外,证明了在不同环境水和宽pH范围内检测罗沙酮的回收率。此外,制备了一种廉价且生物友好的1\'@壳聚糖@纸带复合材料,并成功地将其用于对二甲萘林和罗沙松的动手检测。系统地检查了在存在二甲戊灵和罗沙松的情况下1\'的关闭行为,并在多个实验证据的帮助下提出了合理的机理途径。
    An alarming increase in the use of pesticides and organoarsenic compounds and their toxic impacts on the environment have inspired us to develop a selective and highly sensitive sensor for the detection of these pollutants. Herein, a bio-friendly, low-cost Al-based luminescent metal-organic framework (1\')-based fluorescent material is demonstrated that helps in sustaining water quality by rapid monitoring and quantification of a long-established pesticide (pendimethalin) and a widely employed organoarsenic feed additive (roxarsone). A pyridine-functionalized porous aluminum-based metal-organic framework (Al-MOF) was solvothermally synthesized. After activation, it was used for fast (<10 s) and selective turn-off detection of roxarsone and pendimethalin over other competitive analytes. This is the first MOF-based recyclable sensor for pendimethalin with a remarkably low limit of detection (LOD, 14.4 nM). Real-time effectiveness in detection of pendimethalin in various vegetable and food extracts was successfully verified. Moreover, the aqueous-phase recyclable detection of roxarsone with an ultralow detection limit (13.1 nM) makes it a potential candidate for real-time application. The detection limits for roxarsone and pendimethalin are lower than the existing luminescent material based sensors. Furthermore, the detection of roxarsone in different environmental water and a wide pH range with a good recovery percentage was demonstrated. In addition, a cheap and bio-friendly 1\'@chitosan@paper strip composite was prepared and successfully employed for the hands-on detection of pendimethalin and roxarsone. The turn-off behavior of 1\' in the presence of pendimethalin and roxarsone was examined systematically, and plausible mechanistic pathways were proposed with the help of multiple experimental evidences.
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  • 文章类型: Journal Article
    肺癌是最常见和最致命的癌症之一。临床前模型对于研究考虑肿瘤遗传学的新疗法和组合至关重要。我们已经从具有不同遗传背景的细胞系中建立了表达荧光素酶基因的细胞系,常见于肺腺癌患者。我们通过测试这些品系对多种药物的反应来表征这些品系。因此,我们开发了非小细胞肺癌原位临床前小鼠模型,其移植效率非常高.这些模型可以轻松监测肿瘤的生长,特别是对治疗的反应,以及肿瘤细胞在体内的传播。我们表明,奥希替尼(第三代酪氨酸激酶抑制剂靶向突变的EGFR)和贝伐单抗(抗血管生成靶向VEGF)的联合治疗可以对EGFR突变的肿瘤产生有益的治疗效果。我们还表明,在奥希替尼治疗的肿瘤中加入阿法替尼导致肿瘤生长抑制。使用司美替尼或辛伐他汀没有观察到这种效果。因此,这些临床前小鼠模型可以测试创新的治疗组合,也是研究抗性机制的首选工具。
    Lung cancer is one of the most common and deadliest cancers. Preclinical models are essential to study new therapies and combinations taking tumor genetics into account. We have established cell lines expressing the luciferase gene from lines with varied genetic backgrounds, commonly encountered in patients with pulmonary adenocarcinoma. We have characterized these lines by testing their response to multiple drugs. Thus, we have developed orthotopic preclinical mouse models of NSCLC with very high engraftment efficiency. These models allow the easy monitoring of tumor growth, particularly in response to treatment, and of tumor cells dissemination in the body. We show that concomitant treatment with osimertinib (3rd generation tyrosine kinase inhibitor targeting mutated EGFR) and bevacizumab (anti-angiogenic targeting VEGF) can have a beneficial therapeutic effect on EGFR-mutated tumors. We also show that the addition of afatinib to osimertinib-treated tumors in escape leads to tumor growth inhibition. No such effect is observed with selumetinib or simvastatin. These preclinical mouse models therefore make it possible to test innovative therapeutic combinations and are also a tool of choice for studying resistance mechanisms.
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  • 文章类型: Journal Article
    化合物特定同位素分析(CSIA)是跟踪受污染地点有机化学物质原位转化的既定工具。在这项工作中,我们评估了多元素CSIA评估2,3-二氯苯胺(2,3-DCA)生物降解的潜力,这是一种主要的工业原料。使用受控的实验室实验,我们决定,第一次,在混合富集培养的好氧2,3-DCA生物降解过程中,碳(<0.5‰)和氢(<10‰)的同位素分馏和显着的逆氮同位素分馏(>10‰)。2,3-DCA的谷氨酸缀合物作为反应中间体的初步鉴定表明,最初的多步酶促反应可能是限速的。谷氨酸加合物的形成会增加N原子的键能,因此可能解释了观察到的反N同位素分馏。相应的氮富集因子为+6.8±0.6‰。该值用于研究受污染地点的原位2,3-DCA生物降解,现场样品中的碳和氮同位素特征表明天然微生物的有氧过程相似。在Rayleigh模型在处理受污染地下水的试点湿地中的适用性的假设下,生物降解的程度估计高达80-90%。这项研究提出了多元素CSIA作为研究地下水和地表水中2,3-DCA命运的新应用,并提供了对生物降解途径的见解。
    Compound-specific isotope analysis (CSIA) is an established tool to track the in situ transformation of organic chemicals at contaminated sites. In this work, we evaluated the potential of multi-element CSIA to assess biodegradation of 2,3-dichloroaniline (2,3-DCA), which is a major industrial feedstock. Using controlled laboratory experiments, we determined, for the first time, negligible carbon (<0.5‰) and hydrogen (<10‰) isotope fractionation and a significant inverse nitrogen isotope fractionation (>10‰) during aerobic 2,3-DCA biodegradation by a mixed enrichment culture. The tentative identification of a glutamate conjugate of 2,3-DCA as a reaction intermediate indicates that the initial multistep enzymatic reaction may be rate-limiting. The formation of the glutamate adduct would increase the bond energy at the N atom, thus likely explaining the observed inverse N isotope fractionation. The corresponding nitrogen enrichment factor was +6.8 ± 0.6‰. This value was applied to investigate the in situ 2,3-DCA biodegradation at a contaminated site where the carbon and nitrogen isotope signatures from field samples suggested similar aerobic processes by native microorganisms. Under the assumption of the applicability of the Rayleigh model in a pilot wetland treating contaminated groundwater, the extent of biodegradation was estimated to be up to 80-90%. This study proposes multi-element CSIA as a novel application to study 2,3-DCA fate in groundwater and surface water and provides insights into biodegradation pathways.
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