Empirical study and prediction of liquids retention on structured polymer surfaces

Liquids' contact angle hysteresis and critical retention volumes on five commonly used plastics with surface structures were studied. The chevron‐like groove structures, which are orthogonally arranged, make the liquid–solid contact line elongated while the droplet found staying in the Wenzel state. Various dimensions of surface structures were represented by contact length ratio σ. Advancing and receding contact angles of liquids on polymer surfaces with various conditions were reported. Reduced hysteresis H, which links between advancing and receding contact angles, was also studied and found to extend its availability on structured surfaces. The research found that surface structures have linear effects on liquids' advancing contact angles in the range of σ = 1.0 to 1.42. Linear regression analysis was hence proposed to predict advancing contact angles, and the results indicate that approximate 80% of data points have less than 6% error. An empirical model, which adopts liquid–solid surface tension as the source of liquids' retention force, was proposed to estimate liquids' critical retention volumes on inclined surfaces. The proposed model found good agreements with existing experiment data and demonstrated its superiority over previous ones. The present model provides an approach to predict liquids' storage/repellency on structured surfaces when the advancing contact angles are predictable. Copyright © 2016 John Wiley & Sons, Ltd.     

Mononuclear Ni(II)-thiolate complexes with pendant thiol and dinuclear Ni(III/II)-thiolate complexes with Ni...Ni interaction regulated by the oxidation levels of nickels and the coordinated ligands

Compared to [Ni(II)(SePh)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (1a) and [Ni(II)(Cl)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (3a) with a combination of the intramolecular [Ni...H-S] and [Ni-S...H-S] interactions, complexes [NiII(SePh)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (1b) and [Ni(II)(Cl)(P (o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (3b) with intramolecular [Ni...H-S] interaction exhibit lower nu(S-H) stretching frequencies (2137 and 2235 cm(-1) for 1b and 3b vs 2250 and 2287 cm(-1) for 1a and 3a, respectively) and smaller torsion angles (27.2 degrees for 3b vs 58.9 and 59.1 degrees for 1a and 3a, respectively). The pendant thiol interaction modes of 1a, 3a, and 3b in the solid state are controlled by the solvent pairs of crystallization. Oxygen oxidation of dinuclear [Ni(II)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))](2) (4) yielded thermally stable dinuclear [Ni(III)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-mu-S))](2) (5). The two paramagnetic d(7) Ni(III) cores (S = 1/2) with antiferromagnetic coupling (J = -3.13 cm(-1)) rationalize the diamagnetic property of 5. The fully delocalized mixed-valence [Ni(II)-Ni(III)] complexes [Ni2(P(o-C(6)H(3)-3-SiMe(3)-2-S)(3))(2)]- (6) and [Ni(2)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(3))(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SCH(3)))] (7) were isolated upon the reduction of 5 and the methylation of 6, respectively. The electronic perturbation from the sulfur methylation of 6 triggers the stronger Ni...Ni interaction and the geometrical rearrangement from the diamond shape of the [NiS(2)Ni] core to the butterfly structure of [Ni(mu-S)(2)Ni] to yield 7 with Ni...Ni distances of 2.6088(1) A. The distinctly different Ni...Ni distances (2.6026(7) for 5 and 2.8289(15) A for 6) and the coordination number of the nickels indicate a balance of geometrical requirements for different oxidation levels of [PS(3)Ni-NiPS(3)] cores of 5 and 6.     

Charge‐transfer‐to‐solvent absorption spectra of I−(H2O)3–5 at a finite temperature via simulation

Ground‐state equilibrium Born–Oppenheimer molecular dynamics on I^?(H₂O)_3–5 clusters at ～200 K are performed to sample configurations for calculating the charge‐transfer‐to‐solvent (CTTS) absorption spectra for these clusters. When there are more water molecules in clusters, the calculated CTTS spectra are found to become more intense with the absorption maxima shifting to higher energies, which is in agreement with experimental results. In addition, compared with the findings for optimized structures, the absorption energies of the iodide 5p orbitals are red‐shifted at ～200 K because, on average, the distances between the iodide and the dangling hydrogen atoms are increased at finite temperatures which weakens the interactions between the iodide and water molecules in the clusters. Moreover, the number of ionic hydrogen bonds in the clusters are also reduced. However, it is found that all dangling hydrogen atoms must be considered to obtain a good correlation between the CTTS excitation energy and the average distance between the iodide and the dangling hydrogen atoms, which indicates the existence of the strong interactions of the CTTS electron with all of the dangling hydrogen atoms.     

From Chemistry to Translational Medicine: The Application of Proteomics to Cancer Biomarker Discovery and Diagnosis

The study of complex protein mixtures and their interactions in cells and tissues has been difficult due to the tedious process involved in their characterization and analysis. The recent emergence of fast‐evolving and state‐of‐the‐art proteomics methodologies has provided a rapid and scalable platform for understanding the comprehensive proteome profiles from complex whole tissues or cells of various biological sources. Therefore, proteomics has been increasingly valuable to examine real‐time changes in protein expression of various tissues or body fluids from patients with various diseases, especially cancer, resulting in the identification of clinically useful biomarkers for diagnosis, prognosis and disease staging. In this review, we focus on potential biomarkers for (1) Helicobacter pylori‐associated gastric cancer, (2) hepatocellular carcinoma (HCC), and (3) renal cell carcinoma (RCC). In addition to the conventional gel‐based proteomics (1‐D or 2‐D gels), we have utilized a more advanced proteomic approach by incorporating stable isotope dimethyl labelling and shotgun proteomics strategy in combination with nanoliquid chromatography and tandem mass spectrometry (nanoLC‐MS/MS) to better characterize the biomarkers in several cancer tissues. By establishing a high‐throughput proteomics platform based on multiple reaction monitoring (MRM), we have successfully detected and analyzed potential protein markers at low concentrations in various normal and tumor tissues. This platform not only highlights the utility of proteomics for biomarker discovery but also can be uniquely applied to disease‐oriented translational medicine for diagnosis of diverse types of cancers and other diseases.     

Development of a Dinitrosyl Iron Complex Molecular Catalyst into a Hydrogen Evolution Cathode

Despite extensive efforts, the electrocatalytic reduction of water using homogeneous/heterogeneous Fe, Co, Ni, Cu, W, and Mo complexes remains challenging because of issues involving the development of efficient, recyclable, stable, and aqueous‐compatible catalysts. In this study, evolution of the de novo designed dinitrosyl iron complex DNIC‐PMDTA from a molecular catalyst into a solid‐state hydrogen evolution cathode, considering all the parameters to fulfill the electronic and structural requirements of each step of the catalytic cycle, is demonstrated. DNIC‐PMDTA reveals electrocatalytic reduction of water at neutral and basic media, whereas its deposit on electrode preserves exceptional longevity, 139 h. This discovery will initiate a systematic study on the assembly of [Fe(NO)₂] motif into current collector for mass production of H₂, whereas the efficiency remains tailored by its molecular precursor [(L)Fe(NO)₂].     

Dirhodium-catalyzed phenol and aniline oxidations with T-HYDRO. Substrate scope and mechanism of oxidation

Dirhodium caprolactamate, Rh(2)(cap)(4), is a very efficient catalyst for the generation of the tert-butylperoxy radical from tert-butyl hydroperoxide, and the tert-butylperoxy radical is a highly effective oxidant for phenols and anilines. These reactions are performed with 70% aqueous tert-butyl hydroperoxide using dirhodium caprolactamate in amounts as low as 0.01 mol % to oxidize para-substituted phenols to 4-(tert-butyldioxy)cyclohexadienones. Although these transformations have normally been performed in halocarbon solvents, there is a significant rate enhancement when Rh(2)(cap)(4)-catalyzed phenol oxidations are performed in toluene or chlorobenzene. Electron-rich and electron-poor phenolic substrates undergo selective oxidation in good to excellent yields, but steric influences from bulky para substituents force oxidation onto the ortho position resulting in ortho-quinones. Comparative results with RuCl(2)(PPh(3))(3) and CuI are provided, and mechanistic comparisons are made between these catalysts that are based on diastereoselectivity (reactions with estrone), regioselectivity (reactions with p-tert-butylphenol), and chemoselectivity in the formation of 4-(tert-butyldioxy)cyclohexadienones. The data obtained are consistent with hydrogen atom abstraction by the tert-butylperoxy radical followed by radical combination between the phenoxy radical and the tert-butylperoxy radical. Under similar reaction conditions, para-substituted anilines are oxidized to nitroarenes in good yield, presumably through the corresponding nitrosoarene, and primary amines are oxidized to carbonyl compounds by TBHP in the presence of catalytic amounts of Rh(2)(cap)(4).     

Potential energy surface of O2-(H2O) and factors controlling water-to-O2- binding motifs

The potential energy surface (PES) of O(2)(-)(H(2)O) is investigated by varying the interoxygen distance of O(2)(-) via ab initio calculations with a large basis set. Although two stationary points, C(s) and C(2v) conformers, are found along the interoxygen-distance coordinate, only the C(s) conformer is identified as a minimum-energy species. We find a critical distance, r(c), separating these two conformers in the PES. The C(s) conformer prevails at interoxygen distances of O(2)(-) that are less than r(c), while the C(2v) conformer dominates at the distances larger than r(c). The structural features of these two conformers are also discussed. Although the water deformation energy is shown to be the stabilization source responsible for the prevalence of the C(s) cluster conformer at the interoxygen distances of O(2)(-) less than r(c), the ionic hydrogen bonding is the major driving force for transformation of the water binding motif from C(s) to C(2v) when the interoxygen distance of O(2)(-) increases.     

High-speed droplet generation on demand driven by pulse laser-induced cavitation

We report on a pulse laser-driven droplet generation (PLDG) mechanism that enables on-demand droplet generation at rates up to 10,000 droplets per second in a single-layer PDMS-based microfluidic device. Injected droplet volumes can be continuously tuned between 1 pL and 150 pL with less than 1% volume variation.     

Interrupted Fischer Indolization Approach toward the Communesin Alkaloids and Perophoramidine

A concise approach toward the total synthesis of the communesin alkaloids and perophoramidine is reported. The strategy relies on the use of the interrupted Fischer indolization to build the tetracyclic indoline core of the natural products. Studies to probe the scope and limitations of this plan are presented. Although the methodology does not tolerate a C8-allyl substituent en route to the challenging vicinal quaternary stereocenters, variation at C7 and on the C ring is permitted.     

A refined cellular automaton model to rectify impractical vehicular movement behavior

When implementing cellular automata (CA) into a traffic simulation, one common defect yet to be rectified is the abrupt deceleration when vehicles encounter stationary obstacles or traffic jams. To be more in line with real world vehicular movement, this paper proposes a piecewise-linear movement to replace the conventional particle-hopping movement adopted in most previous CA models. Upon this adjustment and coupled with refined cell system, a new CA model is developed using the rationale of Forbes’ et al. car-following concept. The proposed CA model is validated on a two-lane freeway mainline context. It shows that this model can fix the unrealistic deceleration behaviors, and thus can reflect genuine driver behavior in the real world. The model is also capable of revealing Kerner’s three-phase traffic patterns and phase transitions among them. Furthermore, the proposed CA model is applied to simulate a highway work zone wherein traffic efficiency (maximum flow rates) and safety (speed deviations) impacted by various control schemes are tested.