Faculty Bibliography

The flow and heat transfer characteristics of TiO₂-water nanofluids with different nanoparticle mass fractions in a spirally fluted tube and a smooth tube are experimentally investigated at different Reynolds numbers. The effects of pH values and doses of dispersant agent on the stability of TiO₂-water nanofluids are discussed. The effects of nanoparticle mass fractions and Reynolds numbers on Nusselt numbers and frictional resistance coefficients in the spirally fluted tube and the smooth tube are also investigated. It is found that TiO₂-water nanofluids in the spirally fluted tube have a larger enhancement than that in the smooth tube. The heat transfer enhancement and the increase in frictional resistance coefficients of TiO₂-water nanofluids in the spirally fluted tube and the smooth tube for laminar flow and turbulent flow are compared. It is found that there are a larger increase in heat transfer and a smaller increase in frictional resistance coefficients for turbulent flow than that for laminar flow of TiO₂-water nanofluids in the spirally fluted tube. The comprehensive evaluations for the thermo-hydraulic performance of TiO₂-water nanofluids in the smooth tube and spirally fluted tube are also discussed.

The extended-spectrum beta-lactamase (ESBL)- and Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae represent serious and urgent threats to public health. In a retrospective study of multidrug-resistant K. pneumoniae, we identified three clinical isolates, CN1, CR14 and NY9, carrying both blaCTX-M and blaKPC genes. The complete genomes of these three K. pneumoniae isolates were de novo assembled by using both short- and long-read whole-genome sequencing. In CR14 and NY9, blaCTX-M and blaKPC were carried on two different plasmids. In contrast, CN1 had one blaKPC-2 and three copies of blaCTX-M-15 integrated in the chromosome, for which the blaCTX-M-15 genes were linked to an insertion sequence ISEcp1, whereas blaKPC-2 gene was in the context of a Tn4401a transposition unit conjugated with a PsP3-like prophage. Intriguingly, downstream of the Tn4401a-blaKPC-2-prophage genomic island, CN1 also carried a Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-cas array with four spacers targeting a variety of K. pneumoniae plasmids harboring antimicrobial resistance genes. Comparative genomic analysis revealed that there were two subtypes of Type I-E CRISPR-cas in K. pneumoniae strains; and suggested that the evolving CRISPR-cas with its acquired novel spacer might have induced the mobilization of antimicrobial resistance genes from plasmids into chromosome. The integration and dissemination of multiple copies of blaCTX-M and blaKPC from plasmids to chromosome depicts the complex pandemic scenario of multidrug-resistant K. pneumoniae Additionally, the implications from this study also raise concern for the application of a CRISPR-cas strategy against antimicrobial resistance.

BACKGROUND:We investigated risk factors for decreased lung function among Chinese island residents (≥30 years) to determine the relationship between metabolic syndrome (MS) and decreased lung function. METHODS:From October 17, 2011 to November 1, 2011, 2607 residents aged ≥30 years who lived on the Huangqi Peninsula of Fujian were enlisted by random cluster sampling. They completed a questionnaire designed according to the Burden of Obstructive Lung Disease (BOLD) questionnaire, and underwent physical examination, blood test, and lung function evaluation. We constructed spirometric prediction equations for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), determined the lower limits of normal for FVC, FEV1 and FEV1/FVC, and examined the relationship between lung function and MS. RESULTS:Prediction equations for normal island residents were as follows: FVC (L) = -0.023 × age (years) + 0.042 × height (cm) + 0.641 × weight (kg) - 3.607 (males); FVC (L) = -0.017 × age (years) + 0.030 × height (cm) + 0.009 × weight (kg) - 1.741 (females); FEV1 (L) = -0.023 × age (years) + 0.040 × height (cm) + 0.010 × weight (kg) - 2.999 (males); FEV1 (L) = -0.017 × age (years) + 0.026 × height (cm) + 0.007 × weight (kg) -1.135 (females). The odds ratio for MS for increased risk of decreased FVC was 4.623 (95%CI =3.626-5.894, P<0.001), and for increased risk of decreased FEV1 was 3.043 (95%CI =2.447-3.785, P<0.001). CONCLUSIONS:MS is a risk factor for decreased lung function in island residents ≥30 years old.

OBJECTIVE To evaluate the use of a perianal swab to detect CDI. METHODS A perianal swab was collected from each inpatient with a positive stool sample for C. difficile (by polymerase chain reaction [PCR] test) and was tested for C. difficile by PCR and by culture. The variables evaluated included demographics, CDI severity, bathing before perianal swab collection, hours between stool sample and perianal swab, cycle threshold (Ct) to PCR positivity, and doses of CDI treatment before stool sample and before perianal swab. RESULTS Of 83 perianal swabs, 59 (71.1%) tested positive for C. difficile by PCR when perianal swabs were collected an average of 21 hours after the stool sample. Compared with the respective stool sample, the perianal sample was less likely to grow C. difficile (P=.005) and had a higher PCR Ct (P<.001). A direct, significant but weak correlation was detected between the Ct for a positive perianal sample and the respective stool sample (r=0.36; P=.006). An inverse dose relationship was detected between PCR positivity and CDI treatment doses before perianal swab collection (P=.27). CONCLUSION Perianal swabs are a simple method to detect C. difficile tcdB gene by PCR, with a sensitivity of 71%. These data were limited because stool samples and perianal swabs were not collected simultaneously. Compared with stool samples, the perianal Ct values and culture results were consistent with a lower bacterial load on the perianal sample due to the receipt of more CDI treatment before collection or unknown factors affecting perianal skin colonization. Infect Control Hosp Epidemiol 2017;38:658-662.

In 2014 the United States experienced a nationwide outbreak of Enterovirus D68 (EV-D68) infection. There were no confirmed cases of EV-D68 in 2015 and CDC was only aware of limited sporadic EV-D68 detection in the US in 2016. In this report, we analyzed 749 nasopharyngeal (NP) specimens collected in 2015 and 2016 from patients in the Lower Hudson Valley, New York using a previously validated EV-D68-specific rRT-PCR assay. EV-D68 was detected in none of 199 NP specimens collected in 2015, and in one of 108 (0.9%) samples from January to May and 159 of 442 (36.0%) samples from July to October 2016. Complete EV-D68 genome sequences from 22 patients in 2016 were obtained using a metagenomic next-generation sequencing assay. Comparative genome analysis confirmed that a new EV-D68 strain belonging to subclade B3, with 3.2-4.8% divergence in nucleotide from subclade B1 strains identified during the 2014 US outbreak, was circulating in the US in 2016 and caused an outbreak in the Lower Hudson Valley, New York with 160 laboratory-confirmed cases. Our data highlight the genetic variability and capacity in causing outbreak by diverse EV-D68 strains, and the necessity of awareness and more surveillance on their active circulation worldwide.