Jian Gao

Jian Gao

Doctor of Philosophy

About

24
Publications
5,238
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690
Citations

Publications

Publications (24)
Article
Assaying for enzymatic activity is a persistent bottleneck in biocatalyst and drug development. Existing high‐throughput assays for enzyme activity tend to be applicable only to a narrow range of biochemical transformations, whereas universal enzyme characterization methods usually require chromatography to determine substrate turnover, greatly dim...
Article
Full-text available
There is a dynamic reciprocity between plants and their environment: soil physiochemical properties influence plant morphology and metabolism, and root morphology and exudates shape the environment surrounding roots. Here, we investigate the reproducibility of plant trait changes in response to three growth environments. We utilized fabricated ecos...
Article
Full-text available
Background Producing valuable fuels and chemicals from lignin is a key factor for making lignocellulosic biomass economically feasible; however, significant roadblocks exist due to our lack of detailed understanding of how lignin is enzymatically depolymerized and of the range of possible lignin fragments that can be produced. Development of suitab...
Article
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Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microb...
Article
Nanostructure-initiator mass spectrometry (NIMS) is a laser desorption/ionization analysis technique based on the vaporization of a nanostructure trapped liquid 'initiator' phase. Here we report an intriguing relationship between NIMS surface morphology and analyte selectivity. Scanning electron microscopy and spectroscopic ellipsometry were used t...
Article
Biological assays often require expensive reagents and tedious manipulations. These shortcomings can be overcome using digitally operated microfluidic devices that require reduced sample volumes to automate assays. One particular challenge is integrating bioassays with mass spectrometry based analysis. Towards this goal we have developed μNIMS, a h...
Article
Nanostructure-Initiator Mass Spectrometry (NIMS) is a matrix-free desorption/ionization technique with high sensitivity for small molecules. Surface preparation has relied on hydrofluoric acid (HF) electrochemical etching which is undesirable given the significant safety controls required in this specialized process. In this study, we examine a con...
Article
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Cost-effective hydrolysis of biomass into sugars for biofuel production requires high-performance low-cost glycoside hydrolase (GH) cocktails that are active under demanding process conditions. Improving the performance of GH cocktails depends on knowledge of many critical parameters, including individual enzyme stabilities, optimal reaction condit...
Conference Paper
Full-text available
We study exciton coupling and interconversion between neutral and charged states of different spin in pi-stacked conjugated polymer aggregates. Rigorous self-assembly approaches are used to prepare aggregate nanofibers that permit reliable control of polymer chain conformational and packing (intra- and interchain) order within these structures. Exc...
Article
Charge transfer doping efficiencies of π-stacked poly(3-hexylthiophene) (P3HT) aggregate nanofibers are studied using spectroscopic and electron microscopy probes. Solution dispersions of self-assembled P3HT nanofibers are doped in the ground electronic state by adding varying amounts (w/w%) of the strong charge transfer dopant 2,3,5,6-tetrafluoro-...
Article
New structure-function correlations are revealed in poly(3-alkyl-thienylenevinylene) (P3ATV) derivatives using resonance Raman spectroscopy techniques. P3ATVs are prototype conjugated polymers that have received increased attention recently due to reports of efficient singlet fission following excitation of the lowest energy allowed (1Bu) excited s...
Article
Photoluminescence (PL) of single poly(3-hexylthiophene) (P3HT) J-aggregate nanofibers (NFs) exhibit strong quenching under intensity-modulated pulsed excitation. Initial PL intensity (I0) decays to steady state levels (ISS) typically within ~1-10 μs and large PL quenching depths (I0/ISS >2) are observed for ~70% of these NFs. Similar studies of pol...
Article
Resonance Raman spectroscopy was used to identify ordered and disordered conformers of poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) blended with the electron acceptor [6,6]-phenyl C-61 butyric acid methyl ester (PCBM) in bulk heterojunction (BHJ) solar cells where PCBM intercalates into PBTTT side groups. We show that the...
Article
Full-text available
The effect of the strong electron acceptor, 2,3,5,6-tetra?uoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), on poly (3-hexylthiophene) (P3HT) aggregates is studied. F4-TCNQ is commonly used as a dopant for P3HT, however, relatively little is currently known about its affect on polymer conformation and packing. Resonance Raman and optical spectra of...
Article
The doping efficiencies of regioregular (r-Re) and regiorandom (r-Ra) poly(3-hexylthiophene) (P3HT) with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) were studied in solution using electron paramagnetic resonance (EPR), 19F NMR, optical absorption, and Raman spectroscopy. EPR spectra of doped r-Re P3HT possess significantly larger...
Article
Full-text available
Resonance Raman spectra of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester blend thin films display progressions of overtone and combination bands (up to two harmonics) involving the dominant symmetric C=C backbone stretching mode of P3HT that encode excited state vibrational displacements and dynamics information. Cont...
Article
Syntheses for a set of new ligands containing one or two carbamoylmethylphosphine oxide (CMPO) fragments appended to pyridine and pyridine N-oxide platforms are described. Molecular mechanics analyses for gas phase lanthanide-ligand interactions for the pyridine N-oxides indicate that the trifunctional NOPOCO molecules, 2-{[Ph2P(O)][C(O)NEt2]C(H)}C...
Article
Nanofibers (NFs) of the prototype conjugated polymer, poly(3-hexylthiophene) (P3HT), displaying H- and J-aggregate character are studied using temperature- and pressure-dependent photoluminescence (PL) and transient absorption (TA) spectroscopy. Single J-aggregate NF spectra show a decrease of the 0-0/0-1 vibronic intensity ratio from ~2.0 at 300K...
Article
Nanoparticles of poly(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine) [PFB] and poly(9,9-dioctylfluorene-co-benzothiadiazole) [F8BT] (1:1 w/w) were studied using scanned probe and single particle spectroscopy techniques. Photoluminescence (PL spectra of ∼58 and ∼100 nm PFB/F8BT nanoparticles show efficient energy...
Article
Here, we report an unusual oxidation-induced photoluminescence (PL) turn-on response of a poly(3-alkoxythiophene), poly(3-{2-[2-(2-ethoxyethoxy)ethoxy]ethoxy}thiophene) (PEEEET). PEEEET shows a significantly red-shifted absorption spectrum compared to polyalkylthiophenes and is almost non-fluorescent (quantum yield < 1%) in its pristine state. The...
Article
Poly(3-hexylthiophene) (P3HT) nanofibers (NF) displaying J-aggregate exciton coupling behavior are encapsulated with the amphiphilic block copolymer (BCP), poly(3-hexyl-thiophene)-block-poly(ethylene-glycol), (PHT20-b-PEG108). Encapsulation results in the formation of hierarchical superstructures and the BCP coating is expected to exert a mild chem...
Article
Full-text available
Optical emission spectra of poly[2-methoxy-5-[3('),7(')-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) in dilute solutions exhibit a vibronic progression interval (∼1225 cm(-1)) that does not correspond to any ground state vibrational mode frequency. This phenomenon is assigned as the missing mode effect (MIME) in which five key displaced poly...

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