Identification of the starting reaction position in the hydrogenation of (N-ethyl)carbazole over Raney-Ni

Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393-503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rate-limiting step during the period, in which the conversion of carbazole was less than 40%. The hydrogenation process followed pseudo-first-order kinetics and the hydrogenation activation energies of carbazole and N-ethylcarbazole were 90 kJ/mol and 115 kJ/mol, respectively. The reaction starting position as well as the pathway of the hydrogenation of （N-ethyl）carbazole were investigated by comparing the kinetic characteristics of hydrogen uptake of carbazole and N- ethylcarbazole. The results showed that the reaction was a stepwise hydrogenation process and the first H_2 was added to the C1 = C10 double bond in the hydrogenation.

Air pollution, food production and food security: A review from the perspective of food system

Air pollution negatively impacts food security. This paper reviews the current literature on the relationship between air pollution and food security from the perspective of food system. It highlights that agricultural emissions which substantially contribute to air pollution could happen at every stage along the food supply chain. Meanwhile, air pollution can not only affect plant growth and animal health but also shift market equilibrium of both agro-inputs and outputs in the food supply chain and thereby affect food security indirectly. Furthermore, this study evaluates the effects of agricultural policy and energy policy on food security and air pollution, respectively, and provides an overview of potential policy instruments to reduce air pollution while ensuring food security. Finally, we identify the remaining research and policy issues for further studies, mainly focusing on the study of household＇s bounded rational behaviors and the issue of rural aging population.

1,25-Dihydroxyvitamin D_3 modulates calcium transport in goat mammary epithelial cells in a dose- and energydependent manner

Background： Calcium is a vital mineral and an indispensable component of milk for ruminants. The regulation of transcellular calcium transport by 1,25-dihydroxyvitamin D3 （1,25-（OH）2D3, the active form of vitamin D） has been confirmed in humans and rodents, and regulators, including vitamin D receptor （VDR）, calcium binding protein Dgk （calbindin-Dgk）, plasma membrane Ca2＋-ATPase ] b （PMCAlb）, PMAC2b and Oral1, are involved in this process. However, it is still unclear whether 1,25-（OH）2D3 could stimulate calcium transport in the ruminant mammary gland. The present trials were conducted to study the effect of 1,25-（OH）2D3 supplementation and energy availability on the expression of genes and proteins related to calcium secretion in goat mammary epithelial cells. Methods： An in vitro culture method for goat secreting mammary epithelial cells was successfully established. The cells were treated with different doses of 1,25-（OH）2D3 （0, 0.1, 1.0, 10.0 and 100.0 nmol/L） for calcium transport research, followed by a 3-bromopyruvate （3-BrPA, an inhibitor of glucose metabolism） treatment to determine its dependence on glucose availability. Cell proliferation ratios, glucose consumption and enzyme activities were measured with commercial kits, and real-time quantitative polymerase chain reaction （RT-qPCR）, and western blots were used to determine the expression of genes and proteins associated with mammary calcium transport in dairy goats, respectively. Results： 1,25-（OH）2D3 promoted cell proliferation and the expression of genes involved in calcium transport in a dose-dependent manner when the concentration did not exceed 10.0 nmol/L. In addition, 100.0 nmol/L 1,25-（OH） 2D3 inhibited cell proliferation and the expression of associated genes compared with the 10.0 nmol/L treatment. The inhibition of hexokinase 2 （HK2）, a rate-limiting enzyme in glucose metabolism, decreased the expression of PMCA1 b and PMCA2b at the mRNA and protein levels as well as the transcription of Oral1, indicating that glucose avaitability was required for goat mammary calcium transport. The optimal concentration of 1,25-（OH）2D3 that facilitated calcium transport in this study was 10.0 nmol/L. Conclusions： Supplementation with 1,25-（OH）2D3 influenced cell proliferation and regulated the expression of calcium transport modulators in a dose- and energy-dependent manner, thereby highlighting the role of 1,25-（OH）2D3 as an efficacious regulatory agent that produces calcium-enriched milk in ruminants when a suitable energy status was guaranteed.

Study on Chemisorption, Catalytic Behavior, and Stability of Supported Au Catalyst for the Propylene Epoxidation Reaction

The supported Au/TiO2 and Au/TiO2-SiO2 catalysts were prepared by deposition precipitation method. The TPD study reveals that propylene oxide competes with propylene to be adsorbed on the same adsorptive center-Ti^n＋ site on the surface of the catalyst and that the adisorbing capacity of the catalyst for propylene oxide is larger than that for propylene. Catalytic behavior for propylene epoxidation with H2 and O2 was tested in a micro-reactor. Under typical conditions, the selectivity for propylene oxide is over 87%. The TG curves show that PO successive oxidation cause carbon deposition on the active center and deactivation of the Au catalysts. Because the amounts of Tin＋ site decrease significantly, and consequently the separation between Ti^n＋ sites increases, the Au/TiO2-SiO2 catalyst is more stable than Au/TiO2.

A Novel Aptamer Lateral Flow Strip for the Rapid Detection of Gram-positive and Gram-negative Bacteria

Diseases caused by foodborne pathogens are one of the main burdens of public health and seriously hinder global social and economic development.In this research,a novel lateral flow strip was successfully constructed for the simultaneous detection of Gram-positive and Gram-negative bacteria based on the fluidity and color aggregation effect of Au nanoparticles(AuNPs).The lateral flow strip first combined ampicillin(AMP)antigens with AuNPs to form AuNPs-AMP antigens as the first recognition molecule.Then vancomycin specifically recognizing Gram-positive bacteria,and aptamers specifi-cally recognizing Gram-negative bacteria were used as the second recognition molecules.Finally,Gram-positive bacteria and Gram-negative bacteria were detected rapidly using this sandwich mode.The strip can rapidly test the samples within 5 min.Using a lateral flow strip detector,the limit of detection was 4 CFU/mL,and the recovery rates in honey samples were 78.2-88.6%.The lateral flow strip constructed can detect foodborne pathogens quickly,accurately and e fficiently,which is of great significance for food safety detection.

Safety and clinical efficacy of sintilimab (anti-PD-1) in pediatric patients with advanced or recurrent malignancies in a phase I study

The aim of this phase I study is to evaluate,for the first time,the safety and efficacy of sintilimab in pediatric patients diagnosed with advanced or recurrent malignancies.During the dose escalation phase,patients received a single intravenous infusion of sintilimab at varying doses of 1,3,and 10 mg/kg.The primary endpoints included the identification of dose-limiting toxicities(DLTs)as well as the evaluation of safety and tolerance.Secondary endpoints focused on assessing objective response rate(ORR),progression-free survival(PFS),and overall survival(OS).A total of 29 patients were enrolled,including 10 individuals diagnosed with Hodgkin lymphoma(HL)and 19 patients with various other tumor categories.Notably,diverse pathological types such as thymoma,choroid plexus carcinoma,and NK/T-cell lymphoma were also included in the study cohort.By the safety data cutoff,most adverse events were grade 1 or 2,with grade 3 or higher treatment-related adverse events(TRAE)occurring in 10%of patients.Among the 27 evaluated subjects,four achieved confirmed complete response(CR)while seven patients exhibited confirmed partial response(PR).Additionally,seven patients maintained disease(SD)during the study period.Notably,sintilimab demonstrated remarkable tolerability without DLTs and exhibited promising anti-tumor effects in pediatric HL.Whole-exome sequencing(WES)was conducted in 15 patients to assess the mutational landscape and copy number variation(CNV)status.The completion of this phase I study establishes the foundation for potential combination regimens involving sintilimab in childhood cancer treatment.The trial is registered on ClinicalTrials.gov with the identifier NCT04400851.

重症急性胰腺炎死亡风险因素分析及风险评估模型建立

目的:回顾性分析重症急性胰腺炎(SAP)患者死亡的危险因素,构建预后分析模型,进一步为SAP临床诊疗提供参考。方法:选取2017年9月至2022年9月于大连医科大学附属第二医院重症医学科接受诊治的88例SAP患者作为研究对象,根据患者出院后1个月的生存情况,将其分为存活组(51例)和死亡组(37例)。比较两组患者的临床资料,采用多因素logistic回归分析探讨影响SAP死亡的风险因素并构建SAP风险评估模型。采用受试者工作特征(ROC)曲线和曲线下面积判断模型的准确性。结果:两组患者血肌酐、血尿素氮、血淀粉酶、血脂肪酶、丙氨酸转氨酶(ALT)、天冬氨酸氨基转移酶(AST)、开展早期肠内营养、采取液体负平衡疗法、应用西维来司他钠治疗、总住院时间、ICU入住时间、急性病生理学和长期健康评价(APACHE)Ⅱ评分、序贯器官衰竭估计(SOFA)评分、改良CT评分及改良Marshall评分比较,差异均有统计学意义(P均<0.05)。进一步行多因素logistic回归分析发现液体负平衡疗法[比值比(OR)=0.045,95%置信区间(CI)(0.003,0.722),P=0.029]是影响SAP患者死亡的保护因素,改良CT评分[OR=2.393,95%CI(1.021,5.609),P=0.045]、改良Marshall评分[OR=2.992,95%CI(1.105,9.194),P=0.014]是影响SAP患者死亡的危险因素。回归模型对存活情况的预测正确率为94.4%,对死亡情况的预测正确率为90.3%,整体预测的正确率为92.5%。ROC曲线分析结果显示,其曲线下面积为0.978,95%CI为0.949~1.000(P<0.001)。结论:改良CT评分、改良Marshall评分是影响SAP患者死亡的危险因素,液体负平衡疗法是其保护因素,可降低SAP患者的病死率,应用所构建的SAP预后模型可有效地进行风险评估。

昆虫共生菌的次级代谢产物研究进展

微生物与昆虫的共生是一种普遍现象,昆虫种类繁多,与昆虫共生的微生物也多种多样。昆虫共生菌是活性次生代谢产物的重要来源。本文对自2008年以来已报道的177个昆虫共生菌的次级代谢产物进行了统计和分析,结果表明:61.6%的化合物为新天然产物(生物碱类新化合物最多),其中,约75%的新化合物来源于昆虫共生真菌,25%来源于细菌;醌酮类化合物是昆虫共生菌源天然产物的主要结构类型,占23.2%;47.5%的化合物具有显著的抗肿瘤、抗菌、除草和抗氧化等生物活性,且化合物中的主要活性类型是抗菌和抗肿瘤活性,活性范围覆盖面最广的结构类型是生物碱类。以上结果表明昆虫共生菌的次级代谢产物是先导性化合物的重要来源且具有丰富的生物活性类型。本文以天然产物的结构分类为切入点,结合其研究菌株来源、生物活性等进行综述,旨在为充分挖掘昆虫共生菌次级代谢产物提供重要参考。

土壤中四溴双酚A不可提取态残留的降解转化

四溴双酚A(tetrabromobisphenol A, TBBPA)在各种氧化还原状态土壤中均可形成大量的不可提取态残留(nonextractable residues, TBBPA-NER).然而TBBPA-NER在环境中的稳定性和生物可利用性目前还鲜见报道.本研究以TBBPA在淹水条件和有氧条件下分别形成的不可提取态残留(即flooded-nonextractable residues, F-NER和oxicnonextractable residues, O-NER)为研究对象,分析了有氧条件下F-NER的归趋,以及土壤氧化还原状态改变下, FNER和O-NER环境行为的差异;同时研究了水稻根系分泌物对上述过程的影响.结果显示,有氧条件连续培养231 d中, F-NER在土壤中发生了缓慢的生物转化.尽管F-NER在土壤中释放出的可提取态量很低(1%~6%),但是矿化>10%,且酯键和醚键结合部分有所消减.土壤氧化还原状态的改变(即0~50 d有氧, 50~103 d淹水, 103~231 d有氧)对F-NER的矿化影响很小;而TBBPA-NER在土壤中的降解转化受形成条件影响较大,表现为有氧-淹水-有氧培养下F-NER的矿化量,以及释放量均显著高于O-NER. F-NER受环境因素的影响更大,水稻根系分泌物抑制了FNER在有氧环境下的矿化,而淹水条件促进了F-NER的释放产物在土壤中的累积.结果证明,土壤中添加根系分泌物以及氧化还原状态转变等,在不同程度上影响了两种NER在土壤中的生物转化.

Effects of Cu^(2+)and humic acids on degradation and fate of TBBPA in pure culture of Pseudomonas sp.strain CDT

Soil contamination with tetrabromobisphenol A（TBBPA） has caused great concerns;however, the presence of heavy metals and soil organic matter on the biodegradation of TBBPA is still unclear. We isolated Pseudomonas sp. strain CDT, a TBBPA-degrading bacterium, from activated sludge and incubated it with ^（14）C-labeled TBBPA for 87 days in the absence and presence of Cu^（2＋）and humic acids（HA）. TBBPA was degraded to organic-solvent extractable（59.4% ± 2.2%） and non-extractable（25.1% ± 1.3%） metabolites,mineralized to CO_2（4.8% ± 0.8%）, and assimilated into cells（10.6% ± 0.9%） at the end of incubation. When Cu^（2＋）was present, the transformation of extractable metabolites into non-extractable metabolites and mineralization were inhibited, possibly due to the toxicity of Cu^（2＋）to cells. HA significantly inhibited both dissipation and mineralization of TBBPA and altered the fate of TBBPA in the culture by formation of HA-bound residues that amounted to 22.1% ± 3.7% of the transformed TBBPA. The inhibition from HA was attributed to adsorption of TBBPA and formation of bound residues with HA via reaction of reactive metabolites with HA molecules, which decreased bioavailability of TBBPA and metabolites in the culture. When Cu^（2＋）and HA were both present, Cu^（2＋）significantly promoted the HA inhibition on TBBPA dissipation but not on metabolite degradation. The results provide insights into individual and interactive effects of Cu^（2＋）and soil organic matter on the biotransformation of TBBPA and indicate that soil organic matter plays an essential role in determining the fate of organic pollutants in soil and mitigating heavy metal toxicity.

Synergistic control of dual cross-linking strategy toward tailor-made hydrogels

Simple, efficient and accurate controllable systems for materials are becoming more essential, in response to the explosively growing demands in the fields of chemistry and material science. Herein, tailored hydrogels are explored depending on synergistic regulation of p H-responsive chemical networks with an "on/off" function and physical networks with dynamic selfoptimized arrangement. Thiol-disulfide exchange reaction endows hydrogels with controlled architectures while hydrogen bondstrengthened 2-ureido-4[1H]-pyrimidinone(UPy) moieties contributes a significant increase in mechanical strengths. The integration of that dual cross-linking(DC) network ensures the hydrogels with customized structure and enhanced mechanical property. Such controllably strategy is universally applicable and will open a new avenue to flexibly fabricate desired hybrid hydrogels with distinctive features and functions for their potential applications.

Quantum dot biosensor combined with antibody and aptamer for tracing food-borne pathogens

Due to the increasing number of food-borne diseases,more attention is being paid to food safety.Food-borne pathogens are the main cause of food-borne diseases,which seriously endanger human health,so it is necessary to detect and control them.Traditional detection methods cannot meet the requirements of rapid detection of food due to many shortcomings,such as being time-consuming,laborious or requiring expensive instrumentation.Quantum dots have become a promising nanotechnology in pathogens tracking and detection because of their excellent optical properties.New biosensor detection methods based on quantum dots are have been gradually developed due to their high sensitivity and high specificity.In this review,we summarize the different characteristics of quantum dots synthesized by carbon,heavy metals and composite materials firstly.Then,attention is paid to the principles,advantages and limitations of the quantum dots biosensor with antibodies and aptamers as recognition elements for recognition and capture of food-borne pathogens.Finally,the great potential of quantum dots in pathogen detection is summarized.

Outcomes of Burkitt lymphoma with bone marrow involvement or Burkitt leukemia in Chinese children

Importance Burkitt lymphoma with bone marrow involvement and Burkitt leukemia behave aggressively.Thus far,there are limited data concerning survival and toxicity in Chinese children with Burkitt lymphoma or Burkitt leukemia who have undergone treatment with the non-Hodgkin’s lymphoma Berlin-Frankfurt-Münster-90/95(NHL-BFM-90/95)protocol.Objective To analyze outcomes and toxicity in pediatric patients who exhibit Burkitt lymphoma with bone marrow involvement or Burkitt leukemia following treatment with the NHL-BFM-90/95 protocol.Methods Patients aged<18 years with bone marrow involvement/leukemia who were treated with the NHL-BFM-90/95 protocol,with or without rituximab,in Sun Yat-Sen University Cancer Center from April 2004 to December 2018 were included in this retrospective analysis.Results Twenty-five patients were eligible.Burkitt lymphoma with bone marrow involvement and Burkitt leukemia were present in 10 and 15 patients,respectively.Central nervous system infiltration was not observed in any patients.All patients underwent chemotherapy involving NHL-BFM-90/95 protocol.Six courses of treatment were administered to each patient(v-AA-BB-CC-AA-BB-CC).The BFM-90/95 plus rituximab protocol was administered to 13 patients.The median follow-up interval was 31.9 months(range,2.5–158 months).Of the 25 patients,four died:three died of tumor progression and one died of therapy abandonment after relief of tumor lysis syndrome.The estimated 5-year event-free survival and overall survival rates were both 85.8%±5.0%.Interpretation Chinese pediatric patients who exhibit Burkitt lymphoma with bone marrow involvement or Burkitt leukemia can achieve optimal treatment outcomes and exhibit good tolerance when using the NHL-BFM-90/95 protocol.

Ring Opening of N-Sulfonyl Aziridines by Amines in Silica-Water

Ring opening reactions of N-sulfonyl aziridines by primary and secondary amines in silica gel(SG)-water system were achieved,which provided a mild,practical and environmentally benign method to synthesize mono-and bis-sulfonyl substituted amines.When primary and secondary amines were used in excess,they reacted with N-sulfonyl aziridines smoothly at room temperature,mainly affording 1∶1 ring opening products.Reactions of primary amines with 2 equiv.of aziridines produced 2∶1 ring opening products.Some 1∶1 products can be cyclized with CS2 to synthesize N-sulfonyl cyclothioureas also in water.