Publications by authors named "Tonghui Wang"

12 Publications

  • Page 1 of 1

Resolving Atomic-Scale Interactions in Non-Fullerene Acceptor Organic Solar Cells with Solid-State NMR Spectroscopy, Crystallographic Modelling, and Molecular Dynamics Simulations.

Adv Mater 2021 Nov 24:e2105943. Epub 2021 Nov 24.

University of Lille, CNRS, Centrale Lille Institut, Univ. Artois, UMR 8181, Unité de Catalyse et Chimie du Solide, Lille, F-59000, France.

Fused-ring core non-fullerene acceptors (NFAs), designated "Y-series", have enabled high-performance organic solar cells (OSCs) achieving over 18% power conversion efficiency (PCE). Since the introduction of these NFAs, much effort has been expended to understand the reasons for their exceptional performance. While several studies have identified key optoelectronic properties that govern high PCEs, little is known about the molecular level origins of large variations in performance, spanning from 5 to 18% PCE, e.g., in the case of PM6:Y6 OSCs. Here, we introduce a combined solid-state NMR, crystallography, and molecular modelling approach to elucidate the atomic-scale interactions in Y6 crystals, thin films, and PM6:Y6 bulk heterojunction (BHJ) blends. We show the Y6 morphologies in BHJ blends are not governed by the morphology in neat films or single crystals. Notably, PM6:Y6 blends processed from different solvents self-assemble into different structures and morphologies, whereby the relative orientations of the sidechains and end groups of the Y6 molecules to their fused-ring cores play a crucial role in determining the resulting morphology and overall performance of the solar cells. The molecular-level understanding of BHJs enabled by this approach will guide the engineering of next-generation NFAs for stable and efficient OSCs. This article is protected by copyright. All rights reserved.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.202105943DOI Listing
November 2021

Organic Photovoltaics: Understanding the Preaggregation of Polymer Donors in Solution and Its Morphological Impact.

J Am Chem Soc 2021 02 25;143(4):1822-1835. Epub 2021 Jan 25.

Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0088, United States.

In bulk-heterojunction organic solar cells, it is well established that the active-layer morphology significantly impacts device performance. However, morphology control remains very challenging. An interesting step in that direction was recently provided by the development of polymer donors that display a temperature-dependent aggregation behavior in solution; the aggregation characteristics were found indeed to play a determining role in the eventual active-layer morphology. Here, a combination of thermodynamic analyses, molecular dynamics simulations, and long-range corrected density functional theory calculations enables us (i) to establish the Flory-Huggins interaction parameter, χ, as a useful figure of merit that allows us to integrate the contributions from all inter-related molecular interactions and to describe the extent of polymer preaggregation in solution at room temperature; (ii) to correlate the χ values for various polymer solutions to the extent of polymer aggregation and the morphological characteristics of the active layers; and (iii) to assess how polymer-polymer and polymer-solvent intermolecular interactions contribute to the variations in χ values among different polymer solutions. We have chosen to examine four representative polymer donors (PBT4T-2OD, PBTff4T-2OD, PffBT4T-2OD, and PffBTff4T-2DT) in solution in chlorobenzene or dichlorobenzene. With χ as a robust bridge, our results provide an unprecedented, detailed description of the relationships among intermolecular interactions, extent of polymer solution aggregation, and morphological features of the active layers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.0c09542DOI Listing
February 2021

Application of antibiotics in treatment of coronavirus disease 2019 in a designated hospital.

Zhong Nan Da Xue Xue Bao Yi Xue Ban 2020 May;45(5):571-575

Huoshengshan Hospital, Wuhan 430000.

Objectives: To explore the prescribing habits of doctors, and to provide basis for rational use of antibiotics in clinical practice via investigating and analyzing the applications of antibiotics in treatment of coronavirus disease 2019 (COVID-19) in the designated hospital.

Methods: Specification, quantity, amount, defined daily dose system (DDDs), defined daily dose consumption (DDDc), antibiotics use density (AUD), composition, frequency of use, combined use of antibacterial drugs used in the hospital were analyzed between Feb. 2020 and Mar. 2020.

Results: A total of 25 antibiotic drugs in 12 categories were used. The total cost for antibiotic drugs was 1 million 238 thousand yuan, in which quinolone accounts for 48%, the third generation cephalosporin/lactamase inhibitors accounts for 15.86%, antifungals accounts for 14.17%, oxazolidone accounts for 13.46%, and carbapenms account for 12.73%. The top three drugs of DDDs and AUD were moxifloxacin hydrochloride tablets, moxifloxacin hydrochloride and sodium chloride injection, cefoperazone sodium and sulbactam sodium for injection. The proportion of patients who had been used more than two kinds of antibiotics was 22.36%.

Conclusions: Broad-spectrum, high-potency antibiotics are used at the beginning of COVID-19 treatment. The varieties of antibiotics meet the requirements of the management of antibiotics, and the utilization rate of antibiotics and the cost proportion of antibiotics in COVID-19 patients are within a reasonable range.In the future, for the treatment of COVID-19, we should continue to summarize the experience, improve the strategies, and rationally apply antibiotics on the basis of guidelines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.11817/j.issn.1672-7347.2020.200291DOI Listing
May 2020

Stochastic growth pattern of untreated human glioblastomas predicts the survival time for patients.

Sci Rep 2020 04 20;10(1):6642. Epub 2020 Apr 20.

Department of Mathematical Sciences, New Mexico State University, 1780 E University Ave, Las Cruces, NM, 88003, USA.

Glioblastomas are highly malignant brain tumors. Knowledge of growth rates and growth patterns is useful for understanding tumor biology and planning treatment logistics. Based on untreated human glioblastoma data collected in Trondheim, Norway, we first fit the average growth to a Gompertz curve, then find a best fitted white noise term for the growth rate variance. Combining these two fits, we obtain a new type of Gompertz diffusion dynamics, which is a stochastic differential equation (SDE). Newly collected untreated human glioblastoma data in Seattle, US, re-verify our model. Instead of growth curves predicted by deterministic models, our SDE model predicts a band with a center curve as the tumor size average and its width as the tumor size variance over time. Given the glioblastoma size in a patient, our model can predict the patient survival time with a prescribed probability. The survival time is approximately a normal random variable with simple formulas for its mean and variance in terms of tumor sizes. Our model can be applied to studies of tumor treatments. As a demonstration, we numerically investigate different protocols of surgical resection using our model and provide possible theoretical strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-63394-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7171128PMC
April 2020

Making the A Priori Procedure Work for Differences Between Means.

Educ Psychol Meas 2020 Feb 14;80(1):186-198. Epub 2019 May 14.

New Mexico State University, Las Cruces, NM, USA.

Previous researchers have proposed the a priori procedure, whereby the researcher specifies, prior to data collection, how closely she wishes the sample means to approach corresponding population means, and the degree of confidence of meeting the specification. However, an important limitation of previous research is that researchers sometimes are interested in differences between means, rather than in the means themselves. To address this limitation, we propose additional equations that expand the a priori procedure to handle differences between means, both in matched and in independent samples. Finally, implications are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0013164419847509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6943990PMC
February 2020

From a Sampling Precision Perspective, Skewness Is a Friend and Not an Enemy!

Educ Psychol Meas 2019 Feb 3;79(1):129-150. Epub 2018 Apr 3.

New Mexico State University, Las Cruces, NM, USA.

Two recent publications in advocated that researchers consider using the a priori procedure. According to this procedure, the researcher specifies, prior to data collection, how close she wishes her sample mean(s) to be to the corresponding population mean(s), and the desired probability of being that close. A priori equations provide the necessary sample size to meet specifications under the normal distribution. Or, if sample size is taken as given, a priori equations provide the precision with which estimates of distribution means can be made. However, there is currently no way to perform these calculations under the more general family of skew-normal distributions. The present research provides the necessary equations. In addition, we show how skewness can increase the precision with which locations of distributions can be estimated. This conclusion, based on the perspective of improving sampling precision, contrasts with a typical argument in favor of performing transformations to normalize skewed data for the sake of performing more efficient significance tests.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0013164418764801DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318746PMC
February 2019

Manipulating the Alpha Level Cannot Cure Significance Testing.

Front Psychol 2018 15;9:699. Epub 2018 May 15.

Consejo Nacional de Investigaciones Científicas y Técnicas, Mar del Plata, Argentina.

We argue that making accept/reject decisions on scientific hypotheses, including a recent call for changing the canonical alpha level from = 0.05 to = 0.005, is deleterious for the finding of new discoveries and the progress of science. Given that blanket and variable alpha levels both are problematic, it is sensible to dispense with significance testing altogether. There are alternatives that address study design and sample size much more directly than significance testing does; but none of the statistical tools should be taken as the new magic method giving clear-cut mechanical answers. Inference should not be based on single studies at all, but on cumulative evidence from multiple independent studies. When evaluating the strength of the evidence, we should consider, for example, auxiliary assumptions, the strength of the experimental design, and implications for applications. To boil all this down to a binary decision based on a -value threshold of 0.05, 0.01, 0.005, or anything else, is not acceptable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpsyg.2018.00699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962803PMC
May 2018

Ultrathin nanoporous membranes for insulator-based dielectrophoresis.

Nanotechnology 2018 Jun 12;29(23):235704. Epub 2018 Mar 12.

Department of Chemical Engineering, University of Rochester, NY, United States of America.

Insulator-based dielectrophoresis (iDEP) is a simple, scalable mechanism that can be used for directly manipulating particle trajectories in pore-based filtration and separation processes. However, iDEP manipulation of nanoparticles presents unique challenges as the dielectrophoretic force [Formula: see text] exerted on the nanoparticles can easily be overshadowed by opposing kinetic forces. In this study, a molecularly thin, SiN-based nanoporous membrane (NPN) is explored as a breakthrough technology that enhances [Formula: see text] By numerically assessing the gradient of the electric field square [Formula: see text]-a common measure for [Formula: see text] magnitude-it was found that the unique geometrical features of NPN (pore tapering, sharp pore corner and ultrathin thickness) act in favor of intensifying the overall [Formula: see text] A comparative study indicated that [Formula: see text] generated in NPN are four orders of magnitude larger than track-etched polycarbonate membranes with comparable pore size. The stronger [Formula: see text] suggests that iDEP can be conducted under lower voltage bias with NPN: reducing joule heating concerns and enabling solutions to have higher ionic strength. Enabling higher ionic strength solutions may also extend the opportunities of iDEP applications under physiologically relevant conditions. This study also highlights the effects of [Formula: see text] induced by the ion accumulation along charged surfaces (electric-double layer (EDL)). EDL-based [Formula: see text] exists along the entire charged surface, including locations where geometry-based iDEP is negligible. The high surface-to-volume ratio of NPN offers a unique platform for exploiting such EDL-based DEP systems. The EDL-based [Formula: see text] was also found to offset the geometry-based [Formula: see text] but this effect was easily circumvented by reducing the EDL thickness (e.g. increasing the ionic strength from 0.1 to 100 mM). The results from this study imply the potential application of iDEP as a direct, in-operando antifouling mechanism for ultrafiltration technology, and also as an active tuning mechanism to control the cut-off size limit for continuous selectivity of nanomembrane-based separations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1361-6528/aab5f7DOI Listing
June 2018

Quantitative relations between interaction parameter, miscibility and function in organic solar cells.

Nat Mater 2018 03 5;17(3):253-260. Epub 2018 Feb 5.

Department of Physics and ORaCEL, North Carolina State University, Raleigh, NC, USA.

Although it is known that molecular interactions govern morphology formation and purity of mixed domains of conjugated polymer donors and small-molecule acceptors, and thus largely control the achievable performance of organic solar cells, quantifying interaction-function relations has remained elusive. Here, we first determine the temperature-dependent effective amorphous-amorphous interaction parameter, χ(T), by mapping out the phase diagram of a model amorphous polymer:fullerene material system. We then establish a quantitative 'constant-kink-saturation' relation between χ and the fill factor in organic solar cells that is verified in detail in a model system and delineated across numerous high- and low-performing materials systems, including fullerene and non-fullerene acceptors. Our experimental and computational data reveal that a high fill factor is obtained only when χ is large enough to lead to strong phase separation. Our work outlines a basis for using various miscibility tests and future simulation methods that will significantly reduce or eliminate trial-and-error approaches to material synthesis and device fabrication of functional semiconducting blends and organic blends in general.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41563-017-0005-1DOI Listing
March 2018

Electrokinetically controlled fluid injection into unicellular microalgae.

Electrophoresis 2017 10 10;38(20):2587-2591. Epub 2017 May 10.

Department of Chemical Engineering, University of Rochester, Rochester, NY, USA.

Electrokinetically controlled microinjection is reported as an effective transport mechanism for microinjection into the wild-type strain of the widely studied model microalga Chlamydomonas reinhardtii. A microinjection system using glass capillary pipettes was developed to capture and impale the motile cells. To apply an electric field and induce electrokinetic flow (e.g., electrophoresis and electroosmosis), an electrode was inserted directly into the solution inside the impaling injection pipette and another electrode was inserted into the external cell media. The viability of the impaled cells was confirmed for more than an hour under 0.01 V using the fluorescein diacetate/propidium iodide dual fluorescent dye based assay. The viability was also found to increase almost logarithmically with decreasing voltage and to depend strongly on the solution within the injection pipette. Successful electrokinetic microinjection into cells was confirmed by both an increase in cell volume under an applied voltage and electric field dependent delivery of fluorescent fluorescein molecules into an impaled cell. Our study offers novel opportunities for quantitative delivery of biomolecules into microalgae and advancing the research and development of these organisms as biosynthetic factories.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/elps.201600548DOI Listing
October 2017

HER2 somatic mutations are associated with poor survival in HER2-negative breast cancers.

Cancer Sci 2017 Apr 21;108(4):671-677. Epub 2017 Apr 21.

Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Breast Center, Peking University Cancer Hospital and Institute, Beijing, China.

It is well documented that human epidermal growth factor receptor 2 (HER2) overexpression/amplification is associated with poor survival in breast cancer patients. However, it is largely unknown whether HER2 somatic mutations are associated with survival in HER2-negative breast cancer patients. Here, we identified HER2 somatic mutations in tumors from 1348 unselected breast cancer patients by sequencing the entire HER2 coding region. All of these mutations were tested for in corresponding blood samples to determine whether they were somatic or germline mutations. We further investigated the associations between HER2 somatic mutations and recurrence-free survival and distant recurrence-free survival in this cohort of patients. We found that 27 of 1348 (2.0%) of these patients carried a HER2 somatic mutation. In vitro experiments indicated that some of the novel mutations and those with unknown functions increased HER2 activity. HER2 status was available for 1306 patients, and the HER2 somatic mutation rates in HER2-positive (n = 353) and HER2-negative breast cancers (n = 953) were 1.4% and 2.3%, respectively. Among the HER2-negative patients, those with a HER2 somatic mutation had a significantly worse recurrence-free survival (unadjusted hazard ratio = 2.67; 95% confidence interval, 1.25-5.72, P = 0.002) and distant recurrence-free survival (unadjusted hazard ratio = 2.50; 95% confidence interval, 1.10-5.68, P = 0.004) than those with wild-type HER2. Taken together, our findings suggested that HER2 somatic mutations occur at a higher frequency in HER2-negative breast cancer, and HER2-negative breast cancer patients with these mutations have poor survival. Therefore, HER2-negative patients with a HER2 somatic mutation are potentially good candidates for HER2-targeted therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cas.13182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406600PMC
April 2017
-->