In JoVE (1)

Other Publications (14)

Articles by Haiqing Lin in JoVE

Other articles by Haiqing Lin on PubMed

Plasticization-enhanced Hydrogen Purification Using Polymeric Membranes

Science (New York, N.Y.). Feb, 2006  |  Pubmed ID: 16456074

Polymer membranes are attractive for molecular-scale separations such as hydrogen purification because of inherently low energy requirements. However, membrane materials with outstanding hydrogen separation performance in feed streams containing high-pressure carbon dioxide and impurities such as hydrogen sulfide and water are not available. We report highly permeable, reverse-selective membrane materials for hydrogen purification, as exemplified by molecularly engineered, highly branched, cross-linked poly(ethylene oxide). In contrast to the performance of conventional materials, we demonstrate that plasticization can be harnessed to improve separation performance.

P38 Mitogen-activated Protein Kinase Inhibition Decreases TNFalpha Secretion and Protects Against Left Ventricular Remodeling in Rats with Myocardial Ischemia

Inflammation. Apr, 2008  |  Pubmed ID: 17943427

The purpose of this study was to test our hypothesis that p38 mitogen-activated protein kinase (p38 MAPK) inhibitor SB203580 may favorably affect tumor necrosis factor alpha (TNFalpha) secretion and left ventricular (LV) remodeling after myocardial ischemia (MI). The left anterior descending coronary artery (LAD) was ligated to produce anterior MI in 40 rats that were randomly divided into two groups: p38i group (n = 24) and MIR group (MI rat models, n = 24). A sham operation group without LAD ligation (Sham, n = 16) was also studied. SB203580 (2 mg/kg) and saline was injected i.p. once every 3 days in the first two groups, respectively. One and six weeks after MI, cardiac function, myocardial fibrosis, the cardiac expressions of phosphorylated p38 MAPK (p-p38 MAPK), TNFalpha, alpha smooth muscle actin (alphaSMA) and collagen I, the ultramicrostructure of the myocardium were examined by echocardiography, histological staining, western blot, immunohistochemical staining, transmission electron microscope (TEM), respectively. Treatments with SB203580 suppressed myocardial fibrosis and LV remodeling, as well as attenuated the expressions of p-p38-MAPK, TNFalpha, alphaSMA and collagen I as compared with the MIR. In conclusion, SB203850 has an effect of inhibiting inflammation-induced fibrosis, which leads to attenuation of LV remodeling.

Effect of Traditional Chinese Medicine Shu-mai-tang on Angiogenesis, Arteriogenesis and Cardiac Function in Rats with Myocardial Ischemia

Phytotherapy Research : PTR. Jan, 2009  |  Pubmed ID: 18814204

Ischemic heart disease is one of the leading causes of morbidity and mortality worldwide. Shu-mai-tang (SMT) is a traditional Chinese medicine for the treatment of ischemic heart disease. To better understand the underlying cardioprotection mechanisms of SMT on myocardial ischemia (MI), the effect of SMT on angiogenesis, arteriogenesis and cardiac function was investigated in a rat model of MI, as well as the potential mechanism. Rats with a ligated left anterior descending coronary artery (MI model) were randomized (24 rats/group) to receive SMT/LY294002 [phosphatidylinositol 3-kinase (PI3K) inhibitor], SMT or no treatment. A sham-operation group was included. It was demonstrated that 2 and 4 weeks after treatment the oral administration of SMT significantly increased capillaries and arterioles, suppressed myocardial fibrosis, as well as significantly increased cardiac phosphorylation of Akt, vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF-BB) levels and functional improvement. PI3K inhibitor down-regulated SMT-induced angiogenesis and arteriogenesis. These novel therapeutic properties of SMT to induce the reconstitution of stable blood supply networks, reverse LV remodeling may offer an alternative therapy for the treatment of ischemic heart disease. The potential mechanism may be that SMT promotes VEGF and PDGF-BB-mediated angiogenesis and arteriogenesis through the PI3K/Akt signaling pathway.

Polymerization of Nitrogen in Cesium Azide Under Modest Pressure

The Journal of Chemical Physics. Jul, 2014  |  Pubmed ID: 25084947

Alkali metal azides can be used as starting materials in the synthesis of polymeric nitrogen, a potential high-energy-density material. The structural evolutionary behaviors of nitrogen in CsN3 have been studied up to 200 GPa using particle swarm optimization structure search combining with density functional theory. Three stable new phases with C2/m, P21/m, and P-1 structure at pressure of 6, 13, and 51 GPa are identified for the first time. The phase transition to chain like structure (P-1 phase) occurs at a modest pressure 51 GPa, the azide ions N3 (-) (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN3 system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp(2) hybridizations. Our study completes the structural evolution of CsN3 under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression.

Structure-Function Assessment of Mannosylated Poly(β-amino Esters) Upon Targeted Antigen Presenting Cell Gene Delivery

Biomacromolecules. May, 2015  |  Pubmed ID: 25848953

Antigen presenting cell (APC) gene delivery is a promising avenue for modulating immunological outcomes toward a desired state. Recently, our group developed a delivery methodology to elicit targeted and elevated levels of APC-mediated gene delivery. During these initial studies, we observed APC-specific structure-function relationships with the vectors used during gene delivery that differ from current non-APC cell lines, thus, emphasizing a need to re-evaluate vector-associated parameters in the context of APC gene transfer. Thus, we describe the synthesis and characterization of a second-generation mannosylated poly(β-amino ester) library stratified by molecular weight. To better understand the APC-specific structure-function relationships governing polymeric gene delivery, the library was systematically characterized by (1) polymer molecular weight, (2) relative mannose content, (3) polyplex biophysical properties, and (4) gene delivery efficacy. In this library, polymers with the lowest molecular weight and highest relative mannose content possessed gene delivery transfection efficiencies as good as or better than commercial controls. Among this group, the most effective polymers formed the smallest polymer-plasmid DNA complexes (∼300 nm) with moderate charge densities (<10 mV). This convergence in polymer structure and polyplex biophysical properties suggests a unique mode of action and provides a framework within which future APC-targeting polymers can be designed.

Stabilization of Fullerene-like Boron Cages by Transition Metal Encapsulation

Nanoscale. Jun, 2015  |  Pubmed ID: 26007319

The stabilization of fullerene-like boron (B) cages in the free-standing form has been long sought after and a challenging problem. Studies that have been carried out for more than a decade have confirmed that the planar or quasi-planar polymorphs are energetically favored ground states over a wide range of small and medium-sized B clusters. Recently, the breakthroughs represented by Nat. Chem., 2014, 6, 727 established that the transition from planar/quasi-planar to cage-like Bn clusters occurs around n = ∼38-40, paving the way for understanding the intriguing chemistry of B-fullerene. We herein demonstrate that the transition demarcation, n, can be significantly reduced with the help of transition metal encapsulation. We explore via extensive first-principles swarm-intelligence based structure searches the free energy landscapes of B24 clusters doped by a series of transition metals and find that the low-lying energy regime is generally dominated by cage-like isomers. This is in sharp contrast to that of bare B24 clusters, where the quasi-planar and rather irregular polyhedrons are prevalent. Most strikingly, a highly symmetric B cage with D3h symmetry is discovered in the case of Mo or W encapsulation. The endohedral D3h cages exhibit robust thermodynamic, dynamic and chemical stabilities, which can be rationalized in terms of their unique electronic structure of an 18-electron closed-shell configuration. Our results indicate that transition metal encapsulation is a feasible route for stabilizing medium-sized B cages, offering a useful roadmap for the discovery of more B fullerene analogues as building blocks of nanomaterials.

Mercury Under Pressure Acts As a Transition Metal: Calculated from First Principles

Angewandte Chemie (International Ed. in English). Aug, 2015  |  Pubmed ID: 26136387

The inclusion of Hg among the transition metals is readily debated. Recently, molecular HgF4 was synthesized in a low-temperature noble gas but the potential of Hg to form compounds beyond a +2 oxidation state in a stable solid remains unresolved. We propose high-pressure techniques to prepare unusual oxidation states of Hg-based compounds. Using an advanced structure search algorithm and first-principles electronic structure calculations, we find that under high pressure Hg in Hg-F compounds transfers charge from the d orbitals to the F, thus behaving as a transition metal. Oxidizing Hg to +4 and +3 yielded the thermodynamically stable compounds HgF4 and HgF3. The former consists of HgF4 planar molecules, a typical geometry for d(8) metal centers. HgF3 is metallic and ferromagnetic owing to the d(9) configuration of Hg, with a large gap between its partially occupied and unoccupied bands under high pressure.

Designing Ultrathin Film Composite Membranes: the Impact of a Gutter Layer

Scientific Reports. Oct, 2015  |  Pubmed ID: 26456377

Industrial membranes comprised of a thin selective layer (<100 nm) requires a gutter layer (<100 nm) between the selective layer and the porous support to achieve high permeance for gas separation. The gutter layer materials must be carefully chosen to enhance overall membrane performance, i.e., high permeance and high selectivity. However, the experimental determination of the optimum gutter layer properties is very challenging. Herein we address this need using a three dimensional (3D) computational model to systematically determine the effects of the gutter layer thickness and permeability on membrane performance. A key finding is that the introduction of a gutter layer between the selective layer and porous support can enhance the overall permeance of the penetrant by up to an order of magnitude, but this gain is accompanied by an undesired decrease in selectivity. The analysis also shows for the first time that a maximum increase in permeance with negligible decrease in selectivity is realized when the thickness of the gutter layer is 1-2 times the pore radius. The modeling approach provides clear and practical guidelines for designing ultrathin multilayer composite membranes to achieve high permeance and selectivity for low-cost and energy-efficient molecular separations.

High-Performance Polymers for Membrane CO2 /N2 Separation

Chemistry (Weinheim an Der Bergstrasse, Germany). Nov, 2016  |  Pubmed ID: 27539399

This Concept examines strategies to design advanced polymers with high CO2 permeability and high CO2 /N2 selectivity, which are the key to the success of membrane technology for CO2 capture from fossil fuel-fired power plants. Specifically, polymers with enhanced CO2 solubility and thus CO2 /N2 selectivity are designed by incorporating CO2 -philic groups in polymers such as poly(ethylene oxide)-containing polymers and poly(ionic liquids); polymers with enhanced CO2 diffusivity and thus CO2 permeability are designed with contorted rigid polymer chains to obtain high free volume, such as polymers with intrinsic microporosity and thermally rearranged polymers. The underlying rationales for materials design are discussed and polymers with promising CO2 /N2 separation properties for CO2 capture from flue gas are highlighted.

Structurally Defined 3D Nanographene Assemblies Via Bottom-Up Chemical Synthesis for Highly Efficient Lithium Storage

Advanced Materials (Deerfield Beach, Fla.). Dec, 2016  |  Pubmed ID: 27723130

Functionalized 3D nanographenes with controlled electronic properties have been synthesized through a multistep organic synthesis method and are further used as promising anode materials for lithium-ion batteries, exhibiting a much increased capacity (up to 950 mAh g(-1) ), three times higher than that of the graphite anode (372 mAh g(-1) ).

Combination Therapy with L-arginine and α-PD-L1 Antibody Boosts Immune Response Against Osteosarcoma in Immunocompetent Mice

Cancer Biology & Therapy. Feb, 2017  |  Pubmed ID: 28045576

L-arginine supplementation was recently proved to promote the function of immune cells, especially T-cells, by facilitating T-cell proliferation, differentiation and survival in vivo. Cytotoxic CD8(+) plays a crucial role in modulating anti-cancer response mediated by the immune system, but was restricted by exhaustion. Thus, we hypothesized that L-arginine, in combination with α-PD-L1 antibody, may provide a favored environment for T-cell response against osteosarcoma. Immunocompetent BALB/c mouse models bearing orthotopic and metastatic osteosarcoma were established to validate this conjecture. We found that L-arginine significantly elevated the number of splenic CD8(+) T-cells, the level of serum interferon-γ, and CD8(+) T-cell infiltration. Furthermore, α-PD-L1 antibody protected these amplified CD8(+) T-cells from exhaustion, and therefore strengthened the secretion of interferon-γ, granzyme B and perforin by these T-cells. As a result, this combination treatment strategy significantly prolonged survival of osteosarcoma bearing mice, suggesting that L-arginine supplementation in combination with α-PD-L1 antibody may be a promising method for osteosarcoma patients.

One-Step Assembly of Molecular Separation Membranes by Direct Atomizing Oligomers

ACS Applied Materials & Interfaces. Feb, 2017  |  Pubmed ID: 28051848

Polymeric membranes are important materials for efficient sieving of targeted components at the molecular level and have made significant advancement in many industrial applications such as biofuel production, water purification, fuel combustion, and carbon dioxide capture. Although their separation efficiencies have been widely investigated, lack of more efficient, greener, and lower-cost membrane fabrication mechanisms is still a major hurdle for mass production, because the conventional membrane-making process is always time-consuming, highly inefficient, and consumes a large amount of organic solvents. Herein we report a one-step assembly concept capable of directly processing low-viscosity oligomers into polymer-based molecular separation membranes in an ultrafast and green manner. This process was implemented by alternate atomizing-depositing of low-viscosity oligomers and reaction auxiliary agents onto a rotating support and followed by an ultrafast interfacial reaction under solvent-free conditions. Without the need for dissolution processing of polymer, solvent evaporation, and any post-treatments, the whole technological process could be accomplished within a few seconds/minutes, which is 2-3 orders of magnitude faster than conventional solution-coating technologies. The universality of this facile approach has also been demonstrated by successfully producing various defect-free polymeric membranes and homodispersed nanohybrid membranes with excellent and stable performance for bioalcohol production and recovery of different trace organics from dilute solutions.

Room Temperature Multiferroicity in Hydrogenated Triapentafulvalene and Pentaheptafulvalene Oligomers

The Journal of Chemical Physics. Feb, 2017  |  Pubmed ID: 28249414

To search for new organic multiferroics, we perform a systematic study on the magnetic and ferroelectric properties of fused triapentafulvalene and pentaheptafulvalene oligomers (n = 2-6), by using the density functional theory and quantum Monte Carlo method. It is found that the oligomers without hydrogenation always lie in the spin singlet (nonmagnetic) state, while a selective hydrogenation of carbon atoms at the ends of oligomers can result in the spin triplet (ferromagnetic) state, which is tens to hundreds meV lower than the nonmagnetic state. The formation of ferromagnetism can be attributed to the hydrogenation-induced near degeneracy between the highest occupied and lowest unoccupied molecular orbitals. Simultaneously, there exists a finite dipole moment in the ferromagnetic state, due to the breaking of the inversion symmetry of oligomers. Our results imply that the hydrogenated triapentafulvalene and pentaheptafulvalene oligomers could be promising candidates in the development of room temperature organic multiferroics.

Membranes with Surface-Enhanced Antifouling Properties for Water Purification

Membranes. Mar, 2017  |  Pubmed ID: 28273869

Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted.

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