A Control Algorithm for the Optimization of Batch Reactor-Based Processes

Levenberg-Marquardt(LM)algorithm is applied for the optimization of the heat transfer of a batch reactor.The validity of the approach is verified through comparison with experimental results.It is found that the mathematical model can properly describe the heat transfer relationships characterizing the considered system,with the error being kept within±2℃.Indeed,the difference between the actual measured values and the model calculated value curve is within±1.5℃,which is in agreement with the model assumptions and demonstrates the reliability and effectiveness of the algorithm applied to the batch reactor heat transfer model.Therefore,the present work provides a theoretical reference for the conversion of practical problems in the field of chemical production into mathematical models.

Properties and nucleotide sequence of linear plasmid-like DNA pC4 from mitochondria of Cucumis sativus

Four kinds of mitochondrial plasmid-like DNAs, designated pC1, pC2, pC3 and pC4, were detected in Cucumis sativus Jinyan No. 4. The electron microscopy observation showed that pC4 was linear conformation. Complete sequence of pC4 was cloned into pUC19 with E. coli JM109 as host. Sequence analysis revealed that pC4 was 370 bp long, the shortest one among all the reported mitochondrial plasmid-like DNAs. pC4 was AT rich. It contained terminal direct repeat sequence (35 bp in length)as well as many short direct and inverted repeats. ORFs in pC4 were short. pC4 was found to be homologous to nuclear DNAs, but lack homology with main mitochondrial and chloroplast DNAs. pC4-homologous sequence also occurred in nuclear genome of Jinyan No. 7 which contained no mitochondrial plasmid-like DNAs. The hybridization pattern of Jinyan No. 7 was slightly different from that of Jinyan No. 4. This suggested that pC4 occurred at the forepart of Cucumis sativus species divergence and integrated into the nuclear genome,

Epidemiological characteristics of ventilator-associated pneumonia in neurosurgery:A 10-year surveillance study in a Chinese tertiary hospital

Background Ventilator-associated pneumonia(VAP)is a significant and common health concern.The epidemiological landscape of VAP is poorly understood in neurosurgery patients.This study aimed to explore the epidemiology of VAP in this population and devise targeted surveillance,treatment,and control efforts.Methods A 10-year retrospective study spanning 2011 to 2020 was performed in a large Chinese tertiary hospital.Surveillance data was collected from neurosurgical patients and analyzed to map the demographic and clinical characteristics of VAP and describe the distribution and antimicrobial resistance profile of leading pathogens.Risk factors associated with the presence of VAP were explored using boosted regression tree(BRT)models.Results Three hundred ten VAP patients were identified.The 10-year incidence of VAP was 16.21 per 1000 ventilation days.All-cause mortality was 6.1%.The prevalence of gram-negative bacteria,fungi,and gram-positive bacteria among the 357 organisms isolated from VAP patients was 86.0%,7.6%,and 6.4%,respectively;most were multidrug-resistant organisms.Acinetobacter baumannii,Klebsiella pneumoniae,and Pseudomonas aeruginosa were the most common pathogens.The prevalence of carbapenem-resistant A.baumannii,P.aeruginosa,and K.pneumoniae was high and increased over time in the study period.The BRT models revealed that VAP was associated with number of days of ventilator use(relative contribution,47.84±7.25),Glasgow Coma Scale score(relative contribution,24.72±5.67),and tracheotomy(relative contribution,21.50±2.69).Conclusions Our findings provide a better understanding of the epidemiology of VAP and its risk factors in neurosurgery patients.