Tobacco mosaic virus (TMV) causes significant yield loss in susceptible crops irrigated with contaminated water. However, detection of TMV in water is difficult owing to extremely low concentrations of the virus. Here, we developed a simple method for the detection and quantiifcation of TMV in irrigation water. TMV was reliably detected at concentrations as low as 10 viral copies/μL with real-time PCR. The sensitivity of detection was further improved using polyethylene glycol 6000 (PEG6000, MW 6000) to concentrate TMV from water samples. Among the 28 samples from Shaanxi Province examined with our method, 17 were tested positive after virus concentration. Infectivity of TMV in the original water sample as well as after concentration was conifrmed using PCR. The limiting concentration of TMV in water to re-infect plants was determined as 102 viral copies/mL. The method developed in this study offers a novel approach to detect TMV in irrigation water, and may provide an effective tool to control crop infection.

Objective To detect the serum levels of CC chemokine receptor 2(CCR2)and C-reactive pro-tein(CRP)in stroke patients,and analyze their relationship with the severity of stroke associated pneumonia and their clinical significance.Methods A total of 78 patients with stroke associated pneumonia who were di-agnosed and treated in the hospital from October 2022 to February 2023 were collected as the study group,ac-cording to the severity of pneumonia,the study group was divided into mild group(31 cases),moderate group(29 cases),and severe group(18 cases),78 stroke patients who did not develop pneumonia were included into control group.Pearson method was applied to analyze the correlation between serum CCR2 and CRP levels in stroke associated pneumonia patients.Multivariate Logistic regression was applied to analyze the factors influ-encing the occurrence of stroke associated pneumonia.Receiver operating characteristic(ROC)curve was ap-plied to analyze the diagnostic value of serum CCR2 and CRP for stroke associated pneumonia.Results The National Institute of Health stroke scale(NIHSS)score,serum CCR2,and CRP levels in the study group were obviously higher than those in the control group(P<0.05).The levels of serum CCR2 and CRP increased with the aggravation of pneumonia(P<0.05).The levels of serum CCR2 and CRP in the study group were positively correlated(r=0.799,P<0.05).NIHSS score,CCR2,and CRP levels were risk factors for stroke associated pneumonia in stroke patients(P<0.05).The area under the curve(AUC)for the diagnosis of stroke associated pneumonia using serum CCR2 and CRP alone was 0.873 and 0.888,respectively,and the AUC for the combined detection of the two was 0.936,the combined detection of the two was superior to the individual detection of serum CCR2 and CRP(Zcombination-CCR2=1.987,Zcombination-CRP=1.832,P=0.041,0.047).Conclusion Serum CCR2 and CRP are closely related to the severity of stroke associated pneumonia,and their combined detection has high diagnostic value for stroke associated pneumonia.

Objective: To evaluate the efficiency of maxillary expansion with clear aligners and to analyze the possible influence factors. Methods: Thiry-one clear aligner cases (Invisalign) with maxillary expansion were enrolled in this study. The three-dimensional (3D) digital models of pre-treatment, planned in Clincheck software and post-treatment were collected. Upper dental arch width, buccal inclination of posterior teeth, and the expansion efficiency (expansion acquired/expansion planned) were measured and calculated. The impact of factors such as planned buccal inclination, planned expansion amount, attachment, and the mode of expansion on the expansion efficiency were analyzed. Results: The increases of upper arch width in canine, 1st and 2nd premolar, 1st and 2nd molar were (2.0±1.3), (2.8±1.5), (3.0±1.4), (1.8±1.0) and 0.5 (0.1, 1.1) mm, with their efficiency of 68%, 70%, 68%, 55% and 29%, respectively. The posterior teeth showed significantly more buccal inclination than the planned position (P<0.05). However, the most buccally inclined tooth detected in 1st molars was only 3.1°±3.9°. When the planned inter-molar width increase was less than 2 mm (n=15), the expansion efficiency of premolars was higher compared with those cases with the planned inter-molar width increase more than 2 mm (n=16, P<0.05). The planned buccal inclination, attachments, and the expansion mode had no significant effect on the expansion efficiency (P>0.05). Conclusions The expansion of maxillary arch with clear aligners was achieved by the buccal movement of the posterior teeth with limited buccal inclination. The efficiency of expansion declines from 1st premolars to second molars. The planned inter-molar width had a significant influence on the efficiency of premolar expansion.