基于改进YOLOv3-SPP算法的道路车辆检测

针对在城市道路场景下视觉检测车辆时,车辆密集和远处车辆呈现小尺度,导致出现检测精度低或者漏检的问题,提出了一种基于改进的YOLOv3-SPP算法,对激活函数进行优化,以DIOU-NMS Loss作为边界框损失函数,增强网络的表达能力。为提高所提算法对小目标和遮挡目标的特征提取能力,引入空洞卷积模块,增大目标的感受野。实验结果表明,所提算法在检测车辆目标时m AP提高了1.79%,也有效减少了在检测紧密车辆目标时出现的漏检现象。

FOSB、SPP1基因表达对经肝动脉介入化疗栓塞术治疗的中晚期肝癌生存期预测价值

目的探讨骨肉瘤原癌基凶同源物B(FOSB)、分泌性磷蛋白1(SPP 1)基因表达对经肝动脉介入化疗栓塞术治疗的中晚期肝癌患者术后生存期的预测价值。方法回顾性分析2016年1月—2017年10月在西安医学院第一附属医院进行诊治的中晚期肝癌患者115例作为研究对象,根据FOSB、SPP 1基因表达水平分为FOSB高表达组(n=52)、FOSB低表达组(n=63)及SPP 1高表达组(n=89)、SPP 1低表达组(n=26)。同时选取115例健康体检者为健康对照组。分析FOSB、SPP 1表达与中晚期肝癌患者临床病理特征的关系。对纳入研究的患者进行为期60个月的随访,Logistics风险回归模型分析影响患者生存期的危险因素。Kaplan-Meier生存曲线分析FOSB、SPP 1表达水平与患者生存预后的关系。结果肝癌患者外周血单个核细胞中FOSB mRNA表达水平明显低于健康对照组,SPP 1 mRNA表达水平明显高于健康对照组,差异具有统计学意义(P<0.05)。FOSB、SPP 1表达在中晚期肝癌患者肿瘤大小、Child-Pugh分级、淋巴转移、BCLC分期方面比较差异具有统计学意义(P<0.05)。单因素分析结果显示,存活组和死亡组在肿瘤大小、Child-Pugh分级、淋巴转移、BCLC分期、FOSB、SPP 1表达方面比较,差异均具有统计学意义(P<0.05)。肿瘤大小、Child-Pugh分级、淋巴转移、BCLC分期、FOSB低表达、SPP 1高表达均为中晚期肝癌患者生存期的独立危险因素(P<0.05)。随访时间60个月,患者生存率为17.39%(20/115),FOSB高表达组中位生存时间为39.7个月,明显高于FOSB低表达组的19.3个月(P<0.05);SPP 1低表达组中位生存时间为40个月,明显高于SPP 1高表达组的18个月(P<0.05)。结论FOSB在中晚期肝癌患者中表达明显下调,SPP 1表达上调,其对预测中晚期肝癌患者肝动脉介入化疗栓塞术治疗生存期具有一定的价值。FOSB、SPP 1有望成为评估介入术治疗患者预后的潜在指标,可协同肿瘤大小、Child-Pugh分级、淋巴转移、BCLC分期等临床指标预测或评估肝癌患者术后生存情况。

SPP1和PD-L1在子宫内膜癌组织中的表达及其预后价值

目的:分析分泌型磷蛋白1(secreted phosphoprotein 1,SPP1)和程序性死亡蛋白配体1(programmed cell death-ligand 1,PD-L1)在子宫内膜癌(endometrial carcinoma,EC)组织中的表达水平及与预后的关系。方法:通过免疫组织化学方法分析SPP1和PD-L1在84例EC组织和61例正常子宫内膜组织中的表达情况,分析SPP1和PD-L1表达与临床病理特征及预后的关系,利用UALCAN分析工具(https://ualcan.path.uab.edu/)分析癌症基因组图谱(The Cancer Genome Atlas,TCGA)数据库中EC组织SPP1和PD-L1 mRNA的表达及与预后的关系。结果:EC组织SPP1阳性表达率高于正常子宫内膜组织(71.43%vs 36.07%,P=0.001),PD-L1阳性表达率低于正常子宫内膜组织(25.00%vs 42.62%,P=0.025);EC组织中,SPP1阳性表达率与组织学分级相关(P<0.05),PD-L1阳性表达率与淋巴结转移相关(P<0.05),SPP1与PD-L1表达呈正相关(列联系数r=0.237,P=0.026);EC组织中,不同SPP1和PD-L1表达患者总生存期无差异(均P>0.05)。TCGA数据库中生物信息学分析显示EC中SPP1 mRNA表达水平显著高于正常子宫内膜组织(P<0.01),PD-L1 mRNA表达水平与正常子宫内膜组织比较,差异无统计学意义(P=0.057);EC组织SPP1 mRNA和PD-L1 mRNA表达水平呈正相关(r=0.350,P<0.05);不同SPP1和PD-L1表达水平患者总生存期无差异(均P>0.05)。结论:SPP1在EC组织中的表达与PD-L1呈正相关,可能共同参与EC免疫微环境调控,SPP1和PD-L1均不是EC独立预后因子。

Phlorizin alleviates deltamethrin-induced oxidative stress in brine shrimp Artemia

Deltamethrin(DEL),a commonly used pyrethroid pesticide,results in higher reactive oxygen species(ROS)levels in aquatic animals,which consequently unbalance the redox state.Phlorizin(PHL)is a flavonoid and a natural product promising to prevent or reduce pesticide-induced oxidative stress.Artemia is a micro-crustacean widely used in marine hatcheries and an experimental aquatic organism for environmental toxicology research.This research aimed to evaluate the toxicity of DEL on Artemia and the antioxidative effect of PHL against the toxicity.Results show that 0.08-mg/mL PHL exerted its antioxidative effects on hatching percentage of the cysts in 24-h incubation and on body length and survival rate of Artemia in 12-d culture.After 12-d culture,12-,24-,and 36-h DEL exposure showed significant drops in SOD,CAT,and GSH-Px enzyme activities,and significant increases in ROS and malondialdehyde(MDA)levels in Artemia(P<0.05).On the contrary,0.08-mg/mL PHL application improved the enzyme activities and decreased the ROS and MDA levels(P<0.05).Moreover,0.08-mg/mL PHL significantly increased mRNA expression levels of Cu/Zn SOD,CAT,GST,HO-1,NQO1,and Nrf2,and decreased mRNA expression level of Keap1 in the DEL-exposed Artemia(P<0.05).Therefore,DEL is toxic to Artemia,while PHL alleviates DEL-induced oxidative damage by possibly regulating the Nrf2signaling pathway.This study provided a theoretical basis for PHL to reduce pesticide-induced toxicity in aquatic animals.

Genetic Diversity of Jute Mallow (Corchorus spp.) Accessions Based on ISSR Markers

Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.

Prevalence and Antibiotic Resistance of Urinary Tract Pathogens, with Molecular Identification of Klebsiella pneumoniae, Klebsiella oxytoca, and Acinetobacter spp., Using Multiplex Real-Time PCR

Urinary tract infections (UTIs) caused by uropathogens are a significant public health problem, and their treatment primarily relies on antibiotic therapy. However, the increasing global development of antibiotic resistance necessitates updating diagnostic techniques to ensure higher sensitivity and specificity, especially with advancements in science and medicine. This study aimed to evaluate the prevalence of UTIs and antibiotic resistance profiles through urine culture, as well as to identify Klebsiella pneumoniae, Klebsiella oxytoca, and Acinetobacter spp. in urine samples using a molecular approach with multiplex real-time PCR. From May 3 to July 25, 2023, at the Pietro Annigoni Biomolecular Research Center (CERBA) and Saint Camille Hospital of Ouagadougou (HOSCO), 209 urine samples collected from patients with suspected UTIs were analyzed using both urine culture and multiplex real-time PCR. Among the 209 patients, 52.15% were male and 47.85% female, with an average age of 46.87 ± 21.33 years. Urine cultures revealed an overall UTI prevalence of 23.44%, with a prevalence of 8.13% in men versus 15.31% in women (P = 0.023). The bacterial prevalence rates were as follows: Escherichia coli (12.92%), Klebsiella spp. (7.18%), Enterobacter cloacae (1.44%), Staphylococcus aureus (0.96%), and other bacteria. Klebsiella spp. demonstrated 100% resistance to Amoxicillin and Amoxicillin/Clavulanic Acid, while Escherichia coli showed 96.2% and 65.4% resistance to Amoxicillin and Amoxicillin/Clavulanic Acid, respectively. PCR analysis of the target bacteria revealed mono-infection prevalence rates of Klebsiella pneumoniae (10.39%), Klebsiella oxytoca (7.79%), and Acinetobacter spp. (7.79%), along with a co-infection prevalence rate of Klebsiella pneumoniae/Acinetobacter spp. (1.30%). This study demonstrated that PCR, with its high sensitivity and specificity, could effectively distinguish Klebsiella pneumoniae from Klebsiella oxytoca and detect Acinetobacter spp. in less than 24 hours—something urine culture alone could not achieve. The relative ease of automating urine PCR testing, combined with its diagnostic accuracy and rapid turnaround time, makes it a valuable addition to modern medical practice for the laboratory diagnosis of UTIs.

Effect of dissolved organic nitrogen on the bloom of Prorocentrum donghaiense and Karenia spp. in the East China Sea coastal waters

Understan ding the mechanism of harmful algal bloom formation is vital for effectively preventing algal bloom outbreaks in coastal environments.Karenia spp.blooms in the East China Sea show a significant correlation with nutrient regimes.However,the impact of key components of nutrients,especially dissolved organic nitrogen(DON),on the blooms of Karenia spp.is not clear.Quantitative research is still lacking.In this study,the cruise observations,field mesocosm-flask culture experiments,and a multinitrogen-tri-phytoplankton-detritus model(NTPD) are combined to reveal the quantitative influence of nutrient regimes on the shift of Prorocentrum donghaiense and Karenia spp.in the East China Sea.It has a synchronism rhythm of diatom-P.donghaienseKarenia spp.-diatom loop in the field culture experiment,which is consistent with the results of the cruise observation.The results showed that the processes of terrigenous DON(TeDON) and dissolved inorganic nitrogen(DIN:NO_(3)^(-)-N,NH_(4)^(+)-N) absorption promoted P.donghaiense to become the dominant algae in the community;whereas the processes of DON from P.donghaiense absorption promoted Karenia spp.to become the dominant algae in ambient DIN exhaustion.In addition,the three-dimensional fluorescence components of humus C,tyrosine and fulvic acid can indicate the processes of growth and extinction of P.donghaiense and Karenia spp.,respectively.This study infers that P.donghaiense and Karenia spp.regime shift mechanism associated with the nutrient regime in coastal waters,which provides a scientific basis for the environmental management of coastal eco system health.

Strawberry (Fragaria spp.): Cultivation, Production, Consumption, and Marketing in Cameroon

Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.

Botulinum toxin type A-targeted SPP1 contributes to neuropathic pain by the activation of microglia pyroptosis

BACKGROUND Neuropathic pain(NP)is the primary symptom of various neurological condi-tions.Patients with NP often experience mood disorders,particularly depression and anxiety,that can severely affect their normal lives.Microglial cells are as-sociated with NP.Excessive inflammatory responses,especially the secretion of large amounts of pro-inflammatory cytokines,ultimately lead to neuroinflam-mation.Microglial pyroptosis is a newly discovered form of inflammatory cell death associated with immune responses and inflammation-related diseases of the central nervous system.METHODS Two models,an in vitro lipopolysaccharide(LPS)-stimulated microglial cell model and a selective nerve injury model using BTX-A and SPP1 knockdown treatments,were used.Key proteins in the pyroptosis signaling pathway,NLRP3-GSDMD,were assessed using western blotting,real-time quantitative polymerase chain reaction,and immunofluorescence.Inflammatory factors[interleukin(IL)-6,IL-1β,and tumor necrosis factor(TNF)-α]were assessed using enzyme-linked immuno-sorbent assay.We also evaluated microglial cell proliferation and apoptosis.Furthermore,we measured pain sensation by assessing the delayed hind paw withdrawal latency using thermal stimulation.RESULTS The expression levels of ACS and GSDMD-N and the mRNA expression of TNF-α,IL-6,and IL-1βwere enhanced in LPS-treated microglia.Furthermore,SPP1 expression was also induced in LPS-treated microglia.Notably,BTX-A inhibited SPP1 mRNA and protein expression in the LPS-treated microglia.Additionally,depletion of SPP1 or BTX-A inhibited cell viability and induced apoptosis in LPS-treated microglia,whereas co-treatment with BTX-A enhanced the effect of SPP1 short hairpin(sh)RNA in LPS-treated microglia.Finally,SPP1 depletion or BTX-A treatment reduced the levels of GSDMD-N,NLPRP3,and ASC and suppressed the production of inflammatory factors.CONCLUSION Notably,BTX-A therapy and SPP1 shRNA enhance microglial proliferation and apoptosis and inhibit microglial death.It improves pain perception and inhibits microglial activation in rats with selective nerve pain.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

基于SPPs的二维多凹槽结构MIM波导透射特性的研究

不规则结构对波导的传播特性有着很大的影响,但对于MIM(Metal-Insulator-Metal,金属-介质-金属型)波导双边矩形槽并添加多凹槽结构对传播特性的影响方面的研究尚少。在研究内嵌凹槽位置对MIM波导透射特性影响的基础上,提出了在双矩形波导模型基础的内部添加多凹槽结构来影响波导的透射特性,并对波长与透射的关系及不同凹槽位置、不同凹槽数目的电场模图进行了对比分析。在凹槽位置改变时,Fano共振峰位置发生了移动,在小波长区域共振峰的数目也有所改变。随着上凹槽位置的增大,最大透射峰位置发生了蓝移,透射强度也有一定的增强;增加凹槽对数,得到波长与透射特性的关系曲线发生了改变,随着凹槽对数的增加,Fano共振峰的位置发生了一定的红移,且在小波长600~1 000 nm区域,Fano共振峰数目及透射峰值均发生了变化。这些研究结果可为预测金属缝隙波导制备过程中小尺度、多凹槽局部缺陷结构对其传播特性的影响提供理论依据。

差分码偏差产品对BDS-3多频SPP影响分析

为分析不同差分码偏差(differential code bias,DCB)产品对BDS-3多频伪距单点定位(single point positioning,SPP)的影响,基于IGS跟踪站实测数据,对比分析CAS产品、DLR产品、GBM产品解算B1C/B2a、B1I/B3I、B1C/B2a/B3I、B1I/B2a/B3I伪距单点定位精度的影响。试验结果表明:采用CAS产品解算BDS-3双频和三频伪距单点定位精度较优;采用DLR产品解算B1I/B3I和B1I/B2a/B3I伪距单点定位精度较优,但低于CAS产品;采用DLR产品和GBM产品解算B1C/B2a和B1C/B2a/B3I伪距单点定位精度较差,E、N、U 3个方向精度均低于7 m;无论采用哪种产品,三频伪距单点定位精度均优于双频伪距单点定位精度,且提升量较优。

SPP1、OLR1在宫颈癌的表达及临床意义

观察SPP1(分泌型磷酸蛋白1)、OLR1(氧化低密度脂蛋白受体1)在正常宫颈及宫颈癌中的表达情况,探讨二者与宫颈癌相关临床病理资料及预后的关系。方法 选取2021年01月至2023年01月就诊于包头市肿瘤医院的48例宫颈癌患者为病例组,获取同一时间就诊于该院的48例正常宫颈组织为对照组。应用免疫组化法检测SPP1、OLR1在上述两组的表达情况,初步探讨SPP1和OLR1与宫颈癌患者的关系及二者之间的相关性;采用生物信息学分析对比宫颈癌及正常宫颈中SPP1、OLR1的表达,并分析其与宫颈癌患者生存预后的关系。结果 癌组织中SPP1、OLR1阳性表达率高于正常组织(P<0.05);SPP1的表达与癌组织淋巴结转移、分化程度及FIGO具有相关性(P<0.05);OLR1的表达与癌组织淋巴结转移和分化程度具有相关性(P<0.05);在癌组织中,SPP1和OLR1的表达呈正相关(r=0.423,P=0.007)。与SPP1低表达相比,高表达患者的生存率更低(P<0.05);宫颈癌患者的预后不良与SPP1、OLR1的T分期、N分期相关(P<0.05)。结论 宫颈癌组织的发生发展可能与SPP1、OLR1密不可分,检测这两种蛋白对宫颈癌的发生、发展及预后有一定的帮助。

智能手机BDS-3/GPS数据质量及SPP性能分析

使用可观测到BDS-3 B1I/B1C/B2a频率和GPS L1/L5频率的智能手机Xiaomi 11(青春版)作为研究对象,分别进行静态实验和不同场地的动态实验,分析手机输出的三频BDS和双频GPS原始观测数据质量及单频SPP性能。实验结果表明,智能手机的GNSS天线成本低致使其信号质量不佳,其中GPS L1频率和BDS B1C频率抗干扰性较强:BDS B1C频率定位结果在静态和动态实验中均较为稳定;GPS L1频率定位结果在动态实验中优于GPS L5频率,在静态实验中略差于GPS L5频率。

鸭SPP1基因的生物信息学分析、原核表达及其在鸭胚胎期骨骼肌中表达规律研究

分泌型焦磷酸蛋白1(SPP1)是一种具有多种功能的分泌型酸性糖蛋白,在肌肉发育过程中具有重要的调控作用,但SPP1基因在鸭骨骼肌中的结构和功能尚不明确。本研究选择胚胎期第17天(E17 d)、第21天(E21 d)、第24(E24 d)和第27天(E27 d)北京鸭和汉中麻鸭胸肌及腿肌组织作为实验材料,克隆了SPP1基因的CDS区序列并对该序列进行分析,进一步诱导基因表达,采用SDS-PAGE检测表达蛋白。同时采用qPCR方法分析SPP1基因在胚胎期北京鸭与汉中麻鸭胸肌和腿肌组织中的相对表达。结果表明:SPP1基因开放阅读框大小为915 bp,编码304个氨基酸,是有SP型信号肽的亲水性不稳定蛋白,无跨膜结构,有磷酸化和糖基化位点。qPCR结果表明,北京鸭骨骼肌SPP1的表达量在E27 d达到最高;而汉中麻鸭胸肌SPP1在E17 d的表达量最高,在E21 d的腿肌中表达量最高。在胚胎期北京鸭与汉中麻鸭骨骼肌的比较中,汉中麻鸭胸肌SPP1基因在E17 d时的表达量显著高于北京鸭,而在E27 d则低于北京鸭。北京鸭腿肌SPP1在E17 d和E27 d的表达量均高于汉中麻鸭,而在E21 d和E24 d则均低于汉中麻鸭。本研究揭示了鸭SPP1基因的结构及该基因在北京鸭和汉中麻鸭骨骼肌中的表达规律,为鸭生长发育的调控机制研究提供一定的参考。

基于YOLOv3-SPP的遥感图像目标检测压缩模型

近年来,卷积神经网络模型已被广泛应用于遥感图像目标检测任务中,但自然场景图像与遥感图像的目标特性存在差异,针对自然场景设计的模型往往难以在遥感图像任务中取得良好的效果。同时,很多遥感图像处理任务需要在星载、机载等资源有限的平台中进行,难以部署参数量、计算量大的复杂模型。针对以上问题,本文对在自然场景中性能优异的YOLOv3-SPP模型进行适应性改进及参数压缩。首先,对原始的L1范数剪枝算法进行改进,提出基于L1范数和均值差的加权剪枝算法,能够更好地保留重要的通道。其次,对剪枝后的子网集合进行快速评估,选取评估结果最好的子网进行微调。在预训练和微调阶段,本文将SPP模块中的最大池化层替换为softmax加权池化层,着重突出深层网络中权重较大的特征,提高了模型的检测精度。本文在多个公开遥感数据集上进行实验,结果表明改进的YOLOv3-SPP模型在遥感目标检测任务上具有更好的性能,同时本文的剪枝算法可以在相同的参数压缩比例条件下,降低模型的性能损失。

城市复杂环境下不同加权模型对动态SPP定位性能影响分析

城市复杂环境下,由于建筑物的遮挡,卫星定位严重受到非视距信号的影响。测量值随机误差加权模型是卫星定位的关键环节,它能够合理地分配各卫星在解算中所起作用的大小。因此,加权模型常用于缓解非视距信号对卫星定位的影响。本文针对目前主流的多种加权模型进行了系统总结和阐述,比较和分析了城市复杂环境下不同加权模型对卫星动态单点定位的影响。试验结果表明,各加权模型均能够在一定程度上提高定位精度,其中综合加权模型具有最优的性能表现。

根际溶磷伯克霍尔德菌Paraburkholderia spp.对马尾松苗的促生作用

为筛选溶磷效果较好的根际细菌(phosphate-solubilizing rhizobacteria,PSB),并明确其对马尾松苗的促生效果和作用机制。利用土壤稀释平板法进行PSB菌株的分离和纯化,通过形态学和16S rDNA分子测序等方法进行PSB菌株的鉴定,最后将PSB菌株接种至马尾松苗,培养60 d后测定马尾松苗生长、生理、苗根际土壤理化性质和根际细菌群落结构和组成。结果表明:由马尾松根际土中分离获得溶磷能力较强的3个PSB菌株WJ10、WJ25和WJ41均为伯克霍尔德菌Paraburkholderia spp.;3个PSB菌株对磷酸铝的增溶能力最强,其次是磷酸三钙、磷酸氢钙和磷酸铁;盆栽试验表明,3个PSB菌株均可促进幼苗的生长,其中WJ25对苗高、根长的促进效果最明显,WJ41和WJ10次之。3个PSB菌株对苗促生的主要机制包括,PSB提高了马尾松苗的根系活力、叶绿素b、可溶性蛋白等生长指标及氮、磷和钾等养分含量;同时,提升了根际土有效磷、速效钾、活性氮、土壤养分含量、土壤酶活性;此外,3个PSB菌株的添加还影响了马尾松苗根际细菌群落的组成和多样性,促进了Bacillus、Nitrosospira、Gemmata和Cytophaga等有益菌在根际土壤中的显著富集。综上,本研究筛选获得的3个溶磷伯克霍尔德菌,它们能够通过调控植物生理及改变根际微环境从而促进马尾松苗的生长。通过本研究,为马尾松根际溶磷细菌菌肥的开发和应用提供了理论依据。

基于YOLOv3-spp的汽车轮毂表面缺陷检测算法研究与分析

针对传统人工检测方法效率低且准确率不高等问题,提出一种基于YOLOv3-spp网络的自动缺陷检测方法。首先通过图像切片提取缺陷区域,然后将提取的缺陷图片经过数据增强后组成数据集并以此训练YOLOv3-spp网络,接着对比分析了不同深度学习网络及数据集筛选方法对轮毂表面缺陷的检测效果。实验结果表明:在工业现场采集的数据集上,训练好的YOLOv3-spp神经网络可以准确地定位,并识别出点状、线性、油泥油漆、针孔4类缺陷,其平均准确率分别为84.5%、93.4%、95.4%和89.5%,检测速度达到35 ms/幅,满足检测的实时性要求,且检测准确率优于Faster R-CNN和SSD两种常用神经网络。

无效基因fruitless参与卤虫Artemia franciscana的生殖调控研究

fruitless(fru)是在昆虫与甲壳动物求偶、交配行为以及生殖发育过程中发挥关键作用的基因。卤虫不仅是水产育苗的重要开口饲料,而且是生物学研究的重要实验生物。本实验通过对卤虫Artemia franciscana转录组的筛选,获得了fru基因的开放阅读框(ORF)并进行生物信息学分析,利用qPCR技术研究了它在卤虫生殖腺发育的不同阶段的表达情况,最后利用RNAi显微注射技术,深入探索了它的功能。经过生物信息学分析,fru基因的ORF长度为1215 bp,其中包含了404个氨基酸,其分子量和等电点分别为45.19 kDa和5.28,属于酸性亲水性蛋白,且不含信号肽和跨膜结构;结构域预测显示fru存在BTB_POZ和HTH两个结构域,二级结构主要由α-螺旋和无规则卷组成,三级结构与其对应。qPCR结果显示,fru基因的表达量在卵囊的晚期胚胎中表现出明显的增加趋势,其表达量显著高于其他发育阶段(P<0.01);而在精巢的未成熟期,fru基因的表达量也有所增加,其表达量显著高于成熟早期、中期和晚期(P<0.01)。经过RNA干扰,我们发现fru基因的表达量有了显著的下降(P<0.01),并且经过受到干扰的雌虫后代都为休眠卵。这表明fru基因对于A.franciscana的生殖和发育有着重要的影响,甚至可能是影响卤虫繁殖方式的关键因素。通过本次研究,我们获得了关于fru基因在卤虫生殖发育中的作用及其相关分子机制的重要信息,可以帮助我们更好地理解这一重要的生物学过程。