Publications by authors named "Zehao Wu"

8 Publications

  • Page 1 of 1

Association between Dexamethasone and Delirium in Critically Ill Patients: A Retrospective Cohort Study of a Large Clinical Database.

J Surg Res 2021 Feb 24;263:89-101. Epub 2021 Feb 24.

Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China. Electronic address:

Background: Delirium is a common complication in intensive care unit (ICU) patients, and it can significantly increase the length of hospital stay and cost. Dexamethasone is widely used in various inflammatory diseases and must be used with caution in critically ill patients. Previous studies have shown that the effect of corticosteroid use on the development of delirium in critically ill patients is still controversial, and there is inconclusive conclusion about the effect of dexamethasone on delirium in such patients. Therefore, this study aimed to confirm the effect of dexamethasone use and the dose on the incidence of delirium and patient prognosis in critically ill patients through a large cohort study.

Methods: A retrospective cohort study was conducted using data extracted from the Medical Information Mart for Intensive Care III database, which is a large and freely available database of all 46,476 patients who visited Beth Israel Deaconess Medical Center in Boston, Massachusetts, USA and were admitted to the ICU between 2001 and 2012. The primary outcome was the development of delirium, using multivariate logistic regression analysis to reveal the relationship between dexamethasone and delirium. Secondary endpoints were in-hospital mortality, ICU mortality, total length of stay, and length of ICU stay, and the relationship between dexamethasone and prognosis was assessed with Cox proportional hazards models. Propensity score matching with 1:1 grouping was used to eliminate the effect of confounders on both cohorts. The locally weighted scatter plot smoothing technique was used to investigate the dose correlation between dexamethasone and outcomes, subgroup analysis was used to account for heterogeneity, and different correction models and propensity matching analysis were used to eliminate potential confounders.

Results: Finally, 38,509 patients were included, and 2204 (5.7%) used dexamethasone. No significant statistical difference was observed in basic demographic information after propensity score matching between the two study groups. A significantly higher incidence of delirium (5.0% versus 3.4%, P < 0.001), increased in-hospital mortality (14.9% versus 10.3%, P < 0.001), ICU mortality (9.0% versus 7.5%, P = 0.008), and longer length of stay and ICU stay were observed in patients taking dexamethasone compared with those not taking dexamethasone. Multivariate logistic and Cox regression analyses confirmed that dexamethasone was significantly associated with delirium (adjusted odds ratio = 1.48, 95% confidence interval [CI] = 1.09-2.00, P = 0.012), in-hospital mortality (adjusted hazard ratio = 1.19, 95% CI = 1.02-1.40, P = 0.032), and ICU mortality (adjusted hazard ratio = 1.62, 95% CI = 1.22-2.15, P = 0.001). Compared with critically ill patients using high-dose dexamethasone, the risk of delirium was lower in the dose less than the 10 mg group, and patients using 10-14 mg may be associated with a lower risk of in-hospital death and the least ICU mortality, length of hospital stay, and ICU stay.

Conclusions: This study demonstrated that the use of dexamethasone in critically ill patients exacerbated the occurrence of delirium while increasing the risk of in-hospital death, ICU death, and length of hospital stay, with a lower risk of delirium and a shorter total length of hospital stay with low-dose dexamethasone than with larger doses.
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http://dx.doi.org/10.1016/j.jss.2021.01.027DOI Listing
February 2021

The Size-dependent Cytotoxicity of Amorphous Silica Nanoparticles: A Systematic Review of in vitro Studies.

Int J Nanomedicine 2020 18;15:9089-9113. Epub 2020 Nov 18.

School of Public Health, Capital Medical University, Beijing 100069, People's Republic of China.

With the increasing production and application of engineered amorphous silica nanoparticles (aSiNPs), people have more opportunities to be exposed to aSiNPs. However, the knowledge of its adverse health effects and related mechanisms is still limited, compared with the well-studied crystalline micron-sized silica. Since small differences in the physical-chemical properties of nanoparticles could cause significant differences in the toxic effect, it is important to distinguish how these variations influence the outcoming toxicity. Notably, particle size, as one of the essential characterizations of aSiNPs, is relevant to its biological activities. Thus, the aim of this systematic review was to summarize the relationship between the particle size of aSiNPs and its adverse biological effects. In order to avoid the influence of complicated in vivo experimental conditions on the toxic outcome, only in vitro toxicity studies which reported on the cytotoxic effect of different sizes aSiNPs were included. After the systematic literature retrieval, selection, and quality assessment process, 76 eligible scientific papers were finally included in this review. There were 76% of the studies that concluded a size-dependent cytotoxicity of aSiNPs, in which smaller-sized aSiNPs possessed greater toxicity. However, this trend could be modified by certain influence factors, such as the synthetic method of aSiNPs, particle aggregation state in cell culture medium, toxicity endpoint detection method, and some other experimental conditions. The effects of these influence factors on the size-dependent cytotoxicity of aSiNPs were also discussed in detail in the present review.
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http://dx.doi.org/10.2147/IJN.S276105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7683827PMC
January 2021

Design of a Novel Two-Directional Piezoelectric Energy Harvester With Permanent Magnets and Multistage Force Amplifier.

IEEE Trans Ultrason Ferroelectr Freq Control 2020 04 29;67(4):840-849. Epub 2019 Nov 29.

This article presents the design and testing of a novel two-directional (2-D) piezoelectric stack-based energy harvester for capturing the mechanical energy from the human footstep. The uniqueness of the harvester lies in the fact that the energy of 2-D excitation is scavenged by a single piezoelectric stack transducer, which can reduce the loss of harvestable energy. The harvester is constructed by the integration of permanent magnets, position protection plates, and multistage force amplification frame. The input force and input displacement are restricted to guarantee the device's safety. The reported multistage force amplification frame with leverage mechanism and bridge-type amplifier enlarges the force acting on the piezoelectric stack, which further improves the power output. A linear guiding mechanism based on leaf flexure is applied to minimize the impact of input forces in other than moving directions. Through analytical modeling, the main architectural parameters of the device are determined. Simulation study with finite-element analysis is conducted to optimize the device parameters for achieving the largest force amplification ratio with a high safety factor. A prototype harvester is fabricated for experimental study. Results demonstrate the feasibility of the developed 2-D piezoelectric stack-based energy harvester.
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http://dx.doi.org/10.1109/TUFFC.2019.2956773DOI Listing
April 2020

High-quality graphene transfer via directional etching of metal substrates.

Nanoscale 2019 Aug;11(34):16001-16006

Center for X-Mechanics and Institute of Applied Mechanics, Zhejiang University, Hangzhou 310012, P. R. China.

Large-scale applications of graphene require its high-efficiency transfer from growth metal substrates to any other substrates of interest. The wrinkles and folds generated during the transfer process of graphene by the well-known poly(methyl methacrylate) (PMMA)-assisted technique is a critical issue. Here, we report an improvement of this method by applying a directional etching process for the removal of the growth Cu substrates, using a pair of electrodes inserted into the etchant with a constant current to form an electrochemical system. The controlled redox reactions between the Cu and the solution environment result in the etching of Cu in a part-by-part manner strictly from one end to the other. The consistency of the Cu etching direction can avoid the formation of an easily destroyable Cu structure and release the stress concentration that is usually generated during the random etching process, and finally yield significantly improved quality of the transferred graphene film with a lowered density of wrinkles, cracks/folds, adlayers, reduced root-mean-square of surface roughness, and increased performance in sheet resistance and carrier mobility.
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http://dx.doi.org/10.1039/c9nr05315hDOI Listing
August 2019

Crack Propagation and Fracture Toughness of Graphene Probed by Raman Spectroscopy.

ACS Nano 2019 Sep 21;13(9):10327-10332. Epub 2019 Aug 21.

Center for X-Mechanics , Zhejiang University , Hangzhou 310012 , P. R. China.

Fracture behaves as one of the most fundamental issues for solid materials. As a one-atom-thick crystal, many aspects in fracture mechanics of graphene are of high significance, such as the crack propagation and its fracture toughness. Here we present a method to study the fracture characteristics of graphene using Raman spectroscopy and designed chemical-vapor-deposited monolayer graphene with preset cracks. The fracture process of graphene was experimentally observed, and its fracture toughness was obtained using Griffith's criterion based on the strain distribution derived from the frequency shifts of Raman bands. The fracture toughness of = 6.1 ± 0.6 MPa[Formula: see text] and = 37.4 ± 6.7 J/m are comparable with the previously reported theoretical and experimental values, and we believe that this simple and easy-to-operate approach of characterizing the fracture of graphene using Raman spectroscopy can also be extended to other two-dimensional materials.
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http://dx.doi.org/10.1021/acsnano.9b03999DOI Listing
September 2019

Evaluation of reporting quality for observational studies using routinely collected health data in pharmacovigilance.

Expert Opin Drug Saf 2018 Jul 12;17(7):661-668. Epub 2018 Jun 12.

a Center for Clinical Epidemiology and Evidence-based Medicine, Beijing Children's Hospital , Capital Medical University, National Center for Children's Health , Beijing , China.

Objectives: To appraise the reporting quality of studies which concerned linezolid-related thrombocytopenia referring to REporting of studies Conducted using Observational Routinely collected health Data (RECORD) statement.

Methods: Medline, Embase, Cochrane library and clinicaltrial.gov were searched for observational studies concerning linezolid-related thrombocytopenia using routinely collected health data from 2000 to 2017. Two reviewers screened potential eligible articles and extracted data independently. Finally, reporting quality assessment was performed by two senior researchers using RECORD statement.

Results: Of 25 included studies, 11 (44.0%) mentioned the type of data in the title and/or abstract. In 38 items derived from RECORD statement, the median number of items reported in the included studies was 22 (inter-quartile range 18-27). Inadequate reporting issues were discovered in the following aspects: validation studies of the codes or algorithms, study size estimation, quantitative variables, subgroup statistical methods, missing data, follow-up/matching or sampling strategy, sensitivity analysis and cleaning methods, funding and role of funders and accessibility of protocol, raw data.

Conclusion: This study provides the evidence that the reporting quality of post-marketing safety evaluation studies conducted using routinely collected health data was often insufficient. Future stakeholders are encouraged to endorse the RECORD guidelines in pharmacovigilance.
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http://dx.doi.org/10.1080/14740338.2018.1484106DOI Listing
July 2018

Inflammation-coagulation response and thrombotic effects induced by silica nanoparticles in zebrafish embryos.

Nanotoxicology 2018 06 14;12(5):470-484. Epub 2018 Apr 14.

a Department of Toxicology and Sanitary Chemistry, School of Public Health , Capital Medical University , Beijing , P.R. China.

Nowadays, nanotechnology environmental health and safety (nanoEHS) is gaining attention. We previously found that silica nanoparticles (SiNPs) could induce vascular endothelial damage. However, the subsequent toxicologic response to SiNPs-induced endothelial damage was still largely unknown. In this study, we explored the inflammation-coagulation response and thrombotic effects of SiNPs in endothelial cells and zebrafish embryos. For in vitro study, swollen mitochondria and autophagosome were observed in ultrastructural analysis. The cytoskeleton organization was disrupted by SiNPs in vascular endothelial cells. The release of proinflammatory and procoagulant cytokines including IL-6, IL-8, MCP-1, PECAM-1, TF and vWF, were markedly elevated in a dose-dependent manner. For in vivo study, based on the NOAEL for dosimetry selection, and using two transgenic zebrafish, Tg(mpo:GFP) and Tg(fli-1:EGFP), SiNPs-induced neutrophil-mediated inflammation and impaired vascular endothelial cells. With the dosage higher than NOAEL, SiNPs significantly decreased blood flow and velocity, exhibiting a blood hypercoagulable state in zebrafish embryos. The thrombotic effect was assessed by o-dianisidine staining, showed that an increasing of erythrocyte aggregation occurred in SiNPs-treated zebrafish. Microarray analysis was used to screen the possible genes for inflammation-coagulation response to SiNPs in zebrafish, and the JAK1/TF signaling pathway was further verified by qRT-PCR and Western blot assays. For in-deepth study, il6st was knocked down with specific morpholinos. The whole-mount in situ hybridization and qRT-PCR analysis showed that the expression jak1 and f3b were attenuated in il6st knockdown groups. In summary, our data demonstrated that SiNPs could induce inflammation-coagulation response and thrombotic effects via JAK1/TF signaling pathway.
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http://dx.doi.org/10.1080/17435390.2018.1461267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6157531PMC
June 2018

Can statistic adjustment of OR minimize the potential confounding bias for meta-analysis of case-control study? A secondary data analysis.

BMC Med Res Methodol 2017 12 29;17(1):179. Epub 2017 Dec 29.

Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University, Beijing, China.

Background: Different confounder adjustment strategies were used to estimate odds ratios (ORs) in case-control study, i.e. how many confounders original studies adjusted and what the variables are. This secondary data analysis is aimed to detect whether there are potential biases caused by difference of confounding factor adjustment strategies in case-control study, and whether such bias would impact the summary effect size of meta-analysis.

Methods: We included all meta-analyses that focused on the association between breast cancer and passive smoking among non-smoking women, as well as each original case-control studies included in these meta-analyses. The relative deviations (RDs) of each original study were calculated to detect how magnitude the adjustment would impact the estimation of ORs, compared with crude ORs. At the same time, a scatter diagram was sketched to describe the distribution of adjusted ORs with different number of adjusted confounders.

Results: Substantial inconsistency existed in meta-analysis of case-control studies, which would influence the precision of the summary effect size. First, mixed unadjusted and adjusted ORs were used to combine individual OR in majority of meta-analysis. Second, original studies with different adjustment strategies of confounders were combined, i.e. the number of adjusted confounders and different factors being adjusted in each original study. Third, adjustment did not make the effect size of original studies trend to constringency, which suggested that model fitting might have failed to correct the systematic error caused by confounding.

Conclusions: The heterogeneity of confounder adjustment strategies in case-control studies may lead to further bias for summary effect size in meta-analyses, especially for weak or medium associations so that the direction of causal inference would be even reversed. Therefore, further methodological researches are needed, referring to the assessment of confounder adjustment strategies, as well as how to take this kind of bias into consideration when drawing conclusion based on summary estimation of meta-analyses.
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http://dx.doi.org/10.1186/s12874-017-0454-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5747180PMC
December 2017