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Pancreatic cancer is among the leading causes of cancer-related death and remains a formidable therapeutic challenge. To date, surgical resection and chemotherapy have been the standards of care. Methotrexate (MTX), which is recognized as a refractory drug for pancreatic cells, was conjugated to the surface of LiYF4:Ce3+ nanoparticles (NP-MTX) through a photocleavable linker molecule. When LiYF4:Ce3+ NPs are stimulated by X-rays, they emit light, which induces the photocleavage of the photolabile linker molecule to release MTX. MTX can target pancreatic tumors, which overexpress folic acid (FA) receptors and are internalized into the cell through receptor-mediated endocytosis. The synergistic effect of the NP-MTX treatment initiated by X-ray irradiation occurs due to the combination of nanoparticle sensitization and the radiosensitizing chemotherapy of the photocleaved MTX molecule. This dual sensitization effect mediated by NP-MTX enabled 40% dose enhancement, which corresponded with an increase in the generation of cytotoxic cellular reactive oxygen species (ROS) and enhanced S phase arrest within the cell cycle. The delivery of an ultralow radiation dose of 0.1 Gy resulted in the photocleavage of MTX from NP-MTX, and this strategy demonstrated in vivo efficacy against AsPC-1 and PANC-1 xenografted pancreatic tumors.

The increase in energy consumption and lack of long-term sustainability of existing energy sources has been rekindled interests in developing alternate nonpolluting and renewable energy sources. In these aspects, hydrogen has been established as a potential future energy and possibly the best substitute for fossil fuel. The novel feature of the hydrogen is that it can be produced from water using solar energy. Both the energy (solar light) and reactive media (water) are readily available and are renewable. However, to make the hydrogen as a commercial source of energy, it must be produced and made available at low cost without creating any misbalance in global ecology. Photoelectrochemical (PEC) is one of the most attractive methods to produce hydrogen which has high potential in hydrogen economy. A number of semiconductor materials have been investigated to meet the requirement of the PEC. Unfortunately, a stable, efficient light absorption system coupled with favorable semiconductor-redox energy has not yet been discovered. However, the utilization of an oxide semiconductor photocatalyst for water splitting has shown some success. Therefore, this chapter reviews on the TiO2 photocatalyst development for PEC application to split water and yield hydrogen for energy remediation. PEC principal, materials selection, TiO2 photocatalyst, TiO2 nanotubular formation mechanism by anodization method, surface modification, and recent advancement of WO3–TiO2 photocatalyst for PEC are illustrated.

Four series of rodlike racemic Schiff base mesogens possessing different alkyl chains and two types of linkages, ester and alkynyl linkages, were synthesized and applied to induce cubic blue phases (BPs) in simple binary mixture systems. The mesophases of these Schiff base mesogens were confirmed by variable-temperature X-ray diffraction and the characteristic texture from polarized optical microscopy (POM). In general, when chiral additive S-(+)-2-octyl 4-(4-hexyloxybenzoyloxy)benzoate (S811; 20–40 wt %) is added into the rodlike racemic salicylaldimine-based mesogens, the cubic BPs could be observed and its temperature range is larger than 20 K. The widest temperature range of the cubic BP (35 K) can be observed in the blending mixture composed of rodlike racemic salicylaldimine-based mesogen OH-TIn possessing alkynyl linkage and 35–40 wt % S811. However, Schiff base mesogens possessing alkynyl linkage show a direct isotropic to chiral nematic transition when equal amount of chiral dopant is added. Nota...

Stress-induced cardiac hypertrophy leads to heart failure. Our previous studies demonstrate that insulin-like growth factor-II receptor (IGF-IIR) signaling is pivotal to hypertrophy regulation. In this study, we show a novel IGF-IIR alternative spliced transcript, IGF-IIRα (150 kDa) play a key role in high-salt induced hypertrophy mechanisms. Cardiac overexpression of IGF-IIRα and high-salt diet influenced cardiac dysfunction by increasing pathophysiological changes with up-regulation of hypertrophy markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). We found that, cardiac hypertrophy under high-salt conditions were amplified in the presence of IGF-IIRα overexpression. Importantly, high-salt induced angiotensin II type I receptor (AT1R) up regulation mediated IGF-IIR expressions via upstream mitogen activated protein kinase (MAPK)/silent mating type information regulation 2 homolog 1 (SIRT1)/heat shock factor 1 (HSF1) pathway. Further, G-coupled receptors (Gαq) activated calcineurin/nuclear factor of activated T-cells, cytoplasmic 3 (NFATc3)/protein kinase C (PKC) signaling was significantly up regulated under high-salt conditions. All these effects were observed to be dramatically over-regulated in IGF-IIRα transgenic rats fed with a high-salt diet. Altogether, from the findings, we demonstrate that IGF-IIRα plays a crucial role during high-salt conditions leading to synergistic cardiac hypertrophy.

Photocatalytic organic conversions involving a hydrogen transfer (HT) step have attracted much attention, but the efficiency and selectivity under visible light irradiation still needs to be significantly enhanced. Here we have developed a noble metal-free, basic-site engineered bismuth oxybromide [Bi24O31Br10(OH)] that can accelerate the photocatalytic HT step in both reduction and oxidation reactions, i.e., nitrobenzene to azo/azoxybenzene, quinones to quinols, thiones to thiols, and alcohols to ketones under visible light irradiation and ambient conditions. Remarkably, quantum efficiencies of 42% and 32% for the nitrobenzene reduction can be reached under 410 and 450 nm irradiation, respectively. The Bi24O31Br10(OH) photocatalyst also exhibits excellent performance in up-scaling and stability under visible light and even solar irradiation, revealing economic potential for industrial applications.

Mass production of GO has always been an issue. Generally, there are 3 general methods available, namely Brodie’s, Staudenmaier’s and Hummer’s Method. These three methods differ in the type of oxidation agents used. There are plenty of developed methods to produce GO were reported in the literature including the improved Hummer’s method. This method is associated with the use of mixture of sulphuric acid/phosphoric acid (H2SO4/H3PO4) in 9:1 ratio without the presence of sodium nitrate (NaNO3).The amount of potassium permanganate (KMnO4) was set at 9.0g. This method allows high yield and ease of control. In this reaction, one of the important indicators was the colour changes during the addition of hydrogen peroxide (H2O2) into the mixture. However, with the large amount of KMnO4 added, the colour change was hardly observed. Therefore, one possible way to cope with that was to vary the amount of added KMnO4. Subsequently, the produced GO were characterized by X-Ray diffraction (XRD) and scanning electron microscope (SEM).

Electron density distribution of Di-2-pyrazylamine (Hdpza) is studied both by single-crystal X-ray diffraction method at 100K and theoretical calculation. Structural determination reveals that Hdpza molecules crystalize in a syn-anti conformation with an intramolecular CHN hydrogen bond between two pyrazine rings and then gather together via two intermolecular NHN and CHN hydrogen interaction and ππ stacking interaction between pyrazine rings. Charge density analysis is made in terms of deformation density (Δπ), Laplacian distribution and topological analysis of total electron density based on multipole model and theoretical calculation. The agreement between experiment and theory is good. The topological properties at bond critical points of CC and CN bonds reveal a covalent bond character, and those of intermolecular interactions, such as hydrogen bonds and ππ stacking interactions, reveal a closed-shell interaction. The potential energy curve of Hdpza molecule shows that the syn-anti conformation is the most stable one (global minima) than the other two of syn-syn and anti-anti conformations.

In recent decades, dependence on fossil fuels resources has shifted into derivation of cellulose based materials to replace the non-renewable resources. Lignocellulosic biomass is the most abundant feedstock on earth and is one of the promising renewable and sustainable resources. In the present study, simple preparation of nanocellulose particles by using ionic liquid (1-butyl-3-methylimidazolium hydrogen sulfate) has been introduced by investigating the influence of reaction temperature (room temperature and heat treated at 90°C). The resultant samples were characterized using X-Ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR). Interestingly, it was found that the high crystallinity sample could be synthesized at temperature of 90°C. The reason might be attributed to ionic liquid enter into the space between cellulose chains and caused cellulose molecules progressively swelled up when heated. Consequently, amorphous regions of cellulose were dissolved by ionic liquid and crystalline parts of cellulose were leave in the cellulose structure. From the XRD data, it could be observed that sharper crystalline peak and higher crystallinity index (CrI) present within heat-treated samples which corresponded to higher crystalline structure of cellulose I. While the broader peak and lower CrI of untreated cellulose samples indicated lower crystalline structure of cellulose I. Pretreatment of cellulose with ionic liquid can provides a facile approach for the preparation of nanocellulose particles with high crystallinity.

The dimeric magnesium(I) compound [{(DipNacnac)Mg}(2)] [1, DipNacnac = (DipNCMe)(2)CH, Dip = 2,6-diisopropylphenyl] has previously been shown to exhibit a non-nuclear attractor (NNA) between the two Mg atoms in the molecular ground state by both experimental and theoretical electron-density studies. To study the stability and characteristics of this topological entity, we have determined the molecular structure of 1 in the pressure range from 0.4 to 1.9 GPa by high-pressure single-crystal X-ray diffraction. The central Mg-Mg bond contracts significantly in this range to 97% of the value at ambient pressure and a temperature of 100 K. High-level single-point theoretical calculations with the resulting atomic coordinates show that the NNA is persistently present in the topology at all pressures and that the difference between the value of the electron density at the NNA and the Mg-NNA bond critical point (bcp) is close to a maximum at the Mg-Mg separation that is found experimentally.

A dimeric molybdenum precursor and nickel ions are used to synthesize a symmetric heteropentanuclear complex, [Mo2NiMo2(tpda)4(NCS)2]. This complex possesses unique structural features, as the four ligands are coordinated to the metal framework in a meso configuration. Furthermore, the central Ni2+ ion is in a high spin state.

High-pressure single crystal X-ray diffraction (HP-SCXRD) measurements have been carried out on the photo-magnetic compound, [Y(DMF)4(H2O)3(μ-CN)Fe(CN)5]·H2O (DMF = dimethyl formamide) (1), in a diamond anvil cell (DAC) at several pressure points up to 7.6 GPa at room temperature. Significant changes are observed in the unit cell parameters accompanying a phase transition at elevated pressure, and the crystal furthermore exhibits a reversible color change. The phase transition involves a change of crystal lattice from monoclinic to triclinic which occurs as the crystal is pressurized above 4 GPa. The b axis, as well as the cell volume, doubles in the triclinic phase. For the data measured at 0.7 GPa full structure determination in the monoclinic cell is possible revealing significant structural changes, that are different from the changes previously observed after UV illumination.

Electron density distribution of 2,2′-dipyridylamine (Hdpa) is studied by single-crystal X-ray diffraction method at 120 K. Structural determination reveals that the conformation of Hdpa molecule is the syn-anti conformation caused by the intramolecular N···H-C hydrogen bond between two pyridine rings. Two Hdpa molecules flock together via two intermolecular N···H-N hydrogen bonds to form a dimer. Bond characterization is made in terms of deformation density (Δρ), topological analysis of total electron density based on multipole model and molecular orbital (DFT) calculation. The agreement between experiment and theory is good. The topological properties of bond critical points at C-C, C-N, N-H and C-H bonds are reasonable and reveal a covalent bond character with the high ρ(rc), negative ∇2ρ(rc) and negative total energy density H((rc) values. A low ρ(rc) and positive ∇2ρ(rc) of bond critical points at N···H bonds reveal a closed-shell interaction for C-H···N and N-H···N hydrogen bonds. The π-delocalization feature around the pyridine ring is also performed by bond ellipticity (ϵ) and fermi-hole distribution.

In copper leadframe fabrication process, anti-oxidant agent is a common chemical solution used to easily protect oxidize surface like copper bond pad surface. There are varieties of anti-oxidant solution available in the market. However, only certain group of anti-oxidant chemical solution can be applied on the copper leadframe or bond pad surface. This is mainly due to the specific and unique anti-tarnish properties, such as low evaporation point and high adhesion strength on specific metal or polymer surface. The application of this anti-oxidant in copper leadframe or bond pad application leads to some challenges like difficulty to examine or ensure the homogeneity of the coating thickness. Besides, in flip chip die bonding process, insufficient removal of the anti-oxidant protecting layer from the copper bond pad surface will cause copper pillar chip bonding quality issue, due to the organic residue left on the bond pad surface, which inhibits the intermetallic formation and contributes to solder voiding issue. Therefore, to accurately examine the existence of the anti-oxidant characteristics, high end analytical tools like X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) had been applied in this study. From the analysis, the properties of chemical bonding state on the anti-oxidant and coating thickness had been successfully determined. In term of verifying the coating thickness, a single analytical tool like XPS may not be able to provide an accurate information, due to the tool depth profiling setting. Therefore, a complimentary analytical tool like TEM is more suitable to be used to examine the nano thickness level anti-oxidant coating.

INTRODUCTION Smoke-free workplace legislation often exempts certain venues. Do smoking (exempted) and nonsmoking (nonexempted) catering premises' workers in Hong Kong report different perceptions of risk from and reactions to nearby smoking as well as actual exposure to secondhand smoke (SHS)? METHODS In a cross-sectional survey of 204 nonsmoking catering workers, those from 67 premises where smoking is allowed were compared with workers from 36 nonsmoking premises in Hong Kong on measures of perceptions of risk and behavioral responses to self-reported SHS exposure, plus independent exposure assessment using urinary cotinine. RESULTS Self-reported workplace SHS exposure prevalence was 57% (95% CI = 49%-65%) in premises prohibiting and 100% (95% CI = 92%-100%) in premises permitting smoking (p < .001). Workers in smoking-permitted premises perceived workplace air quality as poorer (odds ratio [OR] = 9.3, 95% CI = 4.2-20.9) with higher associated risks (OR = 3.7, 95% CI = 1.6-8.6) than workers in smoking-prohibited premises. Workers in smoking-prohibited premises were more bothered by (OR = 0.2, 95% CI = 0.1-0.5) and took more protective action to avoid SHS (OR = 0.2, 95% CI = 0.1-0.4) than workers in smoking-permitted premises. Nonwork exposure was negatively associated with being always bothered by nearby smoking (OR = 0.3, 95% CI = 0.1-0.9), discouraging nearby smoking (OR = 0.5, 95% CI = 0.2-1.1), and discouraging home smoking (OR = 0.4, 95% CI = 0.2-0.9). Urinary cotinine levels were inversely related to workers' avoidance behavior but positively related to their perceived exposure-related risks. CONCLUSIONS Different workplace smoking restrictions predicted actual SHS exposure, exposure-related risk perception, and protective behaviors. Workers from smoking-permitted premises perceived greater SHS exposure-related risks but were more tolerant of these than workers in smoking-prohibited premises. This tolerance might indirectly increase both work and nonwork exposures.

Titanate and titania (TiO 2 ) nanotubes were synthesized by hydrothermal method. The effect of NaOH to TiO 2 ratio, reaction temperature, reaction time and annealing temperature on the formation of nanotubes was investigated using X-ray diffraction, field emission microscope and Transmission electron microscope. Titanate nanotubes with 10 nm diameter was formed for NaOH to TiO 2 ratio >27 treated at 110 °C for 24 h. Increasing the synthesis temperature to 150 °C, the titanate nanotubes transformed to anatase phase and it was found minimum of 15 h is required for completing transformation from nanoparticles to nanotubular structure. With increasing annealing temperature, titanate nanotubes undergo dehydration and form anatase phase. Besides, the sintegration of the nanotubes was observed at 500 °C and the structure completely converted to nanoparticles at 600 °C. The photocatalytic activity of the sample was evaluated by degradation of methyl orange aqueous solution. The results indicate the photocatalytic activity of titanate is low and once the formation of anatase phase begins with increasing temperature, the photocatalytic activity increases dramatically. However, the deterioration in the tubular structure and increase in oxygen vacancies which act as a recombination centre of electron–holes with increasing annealing temperature need to be controlled to avoid the reduction in the photocatalytic behavior of anatase phase.

Four simple rodlike Schiff base mesogens with tolane moiety were synthesized and applied to stabilize cubic blue phases (BPs) in simple binary mixture systems for the first time. When the chiral additive ISO(6OBA)2 or R811 was added into a chiral salicylaldimine-based compound, the temperature range of the cubic BP could be extended by more than 20 °C. However, when the chiral Schiff base mesogen was blended with chiral dopant possessing opposite handedness, S811, BPs could not be observed. Interestingly, the widest temperature range of the cubic BPs (∼35 °C) could be induced by adding the rodlike chiral dopant R811 or S811 into the rodlike racemic Schiff base mesogen with hydroxyl group. On the basis of our experimental results and molecular modeling, the appearance and temperature range of the BPs are affected by the dipole moment and the biaxiality of the molecular geometry. Accordingly, we demonstrated that the hydroxyl group and the methyl branch in this type of Schiff base mesogen play an important role in the stabilization of BPs.

The mixed-valence complex Fe3 O(cyanoacetate)6 (H2 O)3 (1) has been studied by single-crystal X-ray diffraction analysis at pressures up to 5.3(1) GPa and by (synchrotron) Mossbauer spectroscopy at pressures up to 8(1) GPa. Crystal structure refinements were possible up to 4.0(1) GPa. In this pressure range, 1 undergoes two pressure-induced phase transitions. The first phase transition at around 3 GPa is isosymmetric and involves a 60° rotation of 50 % of the cyanoacetate ligands. The second phase transition at around 4 GPa reduces the symmetry from rhombohedral to triclinic. Mossbauer spectra show that the complex becomes partially valence-trapped after the second phase transition. This sluggish pressure-induced valence-trapping is in contrast to the very abrupt valence-trapping observed when compound 1 is cooled from 130 to 120 K at ambient pressure.

We demonstrate the concept of Pb2+ cation sensing using the emissive Ir(III) complex (1) based on the associated decrease of room-temperature phosphorescence upon forming the 1:1 adduct 1-Pb2+. Complex 1 bears two cyclometalated N-phenyl pyrazoles with pyrazoles residing at the mutual trans dispositions as well as one 3,5-di(pyridyl) pyrazolate chelate. X-ray structural analyses on the adduct 1-Pb2+ confirm the key function of 3,5-di(pyridyl) pyrazolate as it forms chelate interaction with the metal analytes, while quenching of phosphorescent emission is probably due to the Pb2+ induced perturbation, which increases the intersystem crossing to another lower-lying triplet state for the host chromophore via an enhanced spin–orbit coupling.

Formation of voids at the interface between Cu/Cu3Sn or within Cu3Sn phase can be observed when Sn plated on electrolytic copper surface is subjected to High Temperature Storage of 150°C for 1000 hours. In this study, acid copper plating system consists of organic additives was used for the copper plating process. Without copper plating additives brightener and leveller, minimum voids were distributed uniformly at Cu3Sn phase. Addition of SPS or brightener to the system without leveller or PEG showed the density of voids became more and distributed along the Cu/Cu3Sn interface. However, when leveller been introduced to the system containing the brightener, the cross section showed the voids were reduced and uniformly distributed along the Cu3Sn layer.

Leadframe fabrication process normally involves additional thin film metal layer plating on the bulk copper substrate surface for wire bond purpose. The recent commonly adopted plating materials are silver, tin, and copper flake. To assess the thickness quality, the conventional X-section methods involving grinding and polishing process are utilized. However, the process may lead to inaccurate results, which stems from the occurrence of sample preparation artifact, such as smearing effect attributable to the grinding or polishing process. Thus, alternative advanced methods are developed for assessing the thin film metal layer thickness, such as Focus Ion Beam (FIB), SIMS profiling or XPS, readily available in worldwide market. However, these alternative measurement services are very costly and time consuming per sample measure. To cater the cost and long sample preparation time due to the abovementioned advanced methods, an Energy Dispersive X-ray (EDX) can be applied. In this study, the newly invented methodology breakthrough had been validated by applying EDX for the first time on known bulk elemental analysis purpose. EDX feature is not only useful for elemental analysis but also applicable for thin film-metal layer thickness measurement and bulk material densification determination. A promising result was observed from the detailed experiment work through applying EDX in this evaluation.

The compound trans-4,4'-azo-1,2,4-triazole (atrz) is a planar molecule with two planar triazole rings bridged by an azo group. The molecule is a good donor ligand and has an interesting π-delocalized character. In addition, intermolecular interactions in the crystalline state through π-π stacking are found between triazole rings with a very short inter-planar distance of 3.17 Å. The electron density distribution is obtained from both high resolution X-ray diffraction data at 100 K and density functional theory (DFT) calculations using the ωB97X-D functional. Bond characterization is performed in terms of the charge density distribution and the associated topological properties. The Laplacian distribution around each atom reveals the shape of the valence-shell charge concentration and demonstrates a sp(2) hybrid orbital shape for each atom in the molecule. The π-delocalization of the planar molecule is further illustrated by the Fermi-hole distribution. The weak intermolecular π-π interactions and hydrogen bonds are further illustrated by the Hirshfeld surface. The energies of weak intermolecular π-π interactions and hydrogen bonds have been calculated using ωB97X-D/6-311++G(3df,2p) at experimental geometry.

Workers in the catering industry are at greater risk of exposure to secondhand smoke (SHS) when smoke-free workplace policies are not in force. We determined the exposure of catering workers to SHS in Hong Kong and their risk of death from heart disease and lung cancer. Nonsmoking catering workers were provided with screening at their workplaces and at a central clinic. Participants reported workplace, home, and leisure time exposure to SHS. Urinary cotinine was estimated by enzyme immunoassay. Catering facilities were classified into three types: nonsmoking, partially restricted smoking (with nonsmoking areas), and unrestricted smoking. Mean urinary cotinine levels ranged from 3.3 ng/ml in a control group of 16 university staff through 6.4 ng/ml (nonsmoking), 6.1 ng/ml (partially restricted), and 15.9 ng/ml (unrestricted smoking) in 104 workers who had no exposures outside of work. Workers in nonsmoking facilities had exposures to other smoking staff. We modeled workers' mortality risks using average cotinine levels, estimates of workplace respirable particulates, risk data for cancer and heart disease from cohort studies, and national (US) and regional (Hong Kong) mortality for heart disease and lung cancer. We estimated that deaths in the Hong Kong catering workforce of 200,000 occur at the rate of 150 per year for a 40-year working-lifetime exposure to SHS. When compared with the current outdoor air quality standards for particulates in Hong Kong, 30% of workers exceeded the 24-h and 98% exceeded the annual air quality objectives due to workplace SHS exposures.

Topological analyses of experimental and theoretical calculated electron densities of 1,3,5,7-tetra-tert-butyl-s-indacene provide bond characterizations of the chemical bond and of the π-delocalization. A weak C sp 3 —H...H—C sp 2 -type intramolecular dihydrogen interaction (DHI) is identified through this analysis.

The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.

A combined experimental and theoretical electron density study of the shortest trichromium metal wire, Cr3(dpa)4Cl2·(C2H5OC2H5)(x)(CH2Cl2)(1-x) (1, dpa = bis(2-pyridyl)amido), is reported. High resolution X-ray diffraction data has been collected both at 100 K using a conventional X-ray source (DS1) and at 15 K using a synchrotron X-ray source (DS2). The linear chromium string is terminated by Cl(-) ions at both ends, and each Cr atom is also coordinated by four N atoms from bridging dpa ligands. The two Cr-Cr bond distances are unequal at 100 K (with d(Cr1-Cr2) being 0.029 A shorter than d(Cr2-Cr3)) but at 15 K they are almost equal (0.002 A difference). Analysis of the slightly elongated thermal ellipsoids of the Cr2 atom suggests that it is not due to disorder, but the presence of a shallow potential energy surface. Laplacian maps clearly show local valence shell charge concentration (VSCC) in the electron density along the bisector of the equatorial Cr-N bonds. Integration over the atomic basins indicates that Cr2 has smaller atomic charge and volume than Cr1 and Cr3. The topological characterization of the Cr-Cr bonds indicates partly covalent characters with electron density at the bond critical point of ∼0.3 e A(-3) and negative total energy density. The delocalization index of Cr-Cr is 0.8 for Cr1-Cr2 and 0.08 for Cr1-Cr3. Second-order perturbation analysis shows high stabilization energy of the Cr-Cr bonds (E(2) ∼ 190 kcal mol(-1)). Delocalization indices and source function and natural bond orbital analyses are all indicative of localized Cr-Cr bonding interactions.

Charge density study of a mixed-valence tri-cobalt compound, Co3(μ-admtrz)4(μ-OH)2(CN)6·2H2O (1) (admtrz = 3,5-dimethyl-4-amino-1,2,4-triazole), is investigated based on high resolution X-ray diffraction data and density functional theory (DFT) calculations. The molecular structure of this compound contains three cobalt atoms in a linear fashion, where two terminal ones are Co(III) at a low-spin (LS) state and a central one is Co(II) at a high-spin (HS) state with a total spin quantum number, S(total), of 3/2. It is centrosymmetric with the center of inversion located at the central Co atom (Co2). The Co2 ion is linked with each terminal cobalt (Co1) ion through two μ-admtrz ligands and a μ-OH ligand in a CoN4O2 coordination, where the Co1 is bonded additionally to three CN ligands with CoN2OC3 coordination. The combined experimental and theoretical charge density study identifies the different characters of two types of cobalt ions; more pronounced charge concentration and depletion features in the valence shell charge concentration (VSCC) are found in the Co(III) ion than in the Co(II) ion, and d-orbital populations also show the difference. According to topological properties associated with the bond critical point (BCP), the Co1-C(N) bond is the strongest among all the Co-ligand bonds in this compound; the Co-O is stronger than Co-N bond. Again Co1-O is stronger than Co2-O, so as the Co1-N being stronger than Co2-N bond. The electronic configuration of each type of Co atom is further characterized through magnetic measurement, Co-specific X-ray absorption near edge spectroscopy (XANES), and X-ray emission spectra (XES).

Based on several studies, package delamination caused by copper oxide is one of the most common IC packaging defects detected in backend assembly processes. The possible root causes for the copper oxide formation could be due to leadframe surface oxidation, incompatible process temperature and ineffectiveness of surface cleaning prior to molding. In order to effectively investigate the contribution of copper oxide formation to package delamination, this study have been initiated with the application of relevant reliability stress tests and surface interface analytical techniques. Reliability stress test of HTS was carried out to accelerate the copper oxide formation after molding and the delamination occurrence being monitored by SAM scanning after defined stress test intervals. To further on the study, a detailed elemental low KeV EDX analysis was performed to assess the delaminated interfaces after mechanical decapsulation of the failure units. In addition, AES analysis including depth profiling was also applied to determine the copper oxide layer. A good correlation of copper oxide formation to package delamination was demonstrated and inappropriate temperature used in wirebonding clamping was identified to be the most probable root cause of the package delamination.

A combined experimental and theoretical charge density study on a quintuply bonded dichromium complex, Cr(2)(dipp)(2) (dipp = (Ar)NC(H)N(Ar) and Ar = 2,6-i-Pr(2)-C(6)H(3)), is performed. Two dipp ligands are bridged between two Cr ions; each Cr atom is coordinated to two N atoms of the ligands in a linear fashion. The Cr atom is in a low oxidation state, Cr(I), and in low coordination number condition, which stabilizes a metal-metal multiple bond, in this case, a quintuple bond. Indeed, it gives an ultrashort Cr-Cr bond distance of 1.7492(1) Å in the complex. The bond characterization of such a quintuple bond is undertaken both experimentally by high-resolution single-crystal X-ray diffraction and theoretically by density functional calculation (DFT). Electron densities are depicted via deformation density and Laplacian distributions. Bond characterizations of the complex are presented in terms of topological properties, Fermi hole function, source function (SF), and natural bonding orbital (NBO) analysis. The electron density at the Cr-Cr bond critical point (BCP) is 1.70 e/Å(3), quite a high value for metal-metal bonding and mainly contributed from the metal ion itself. The quintuple bond is confirmed with one σ, two π, and two δ interactions by NBO analysis and Fermi hole function. The molecular orbitals (MOs) illustrate that five bonding orbitals are predominantly contributed from the 3d orbitals of the Cr(I) ion. The effective bond order from NBO analysis is 4.60. The detail comparison between experiment and theory will be given. Additionally, three closely related complexes are calculated for systematic comparison.

8,8′-(1,4,10,13-Tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene)diquinolin-7-ol (TDBQ) was synthesized and proved to recognize Hg2+via reducing Hg2+ to Hg+, forming a unique Hg22+–TDBQ complex.

Cyn d Bd46K, a 46-kD component of Bermuda grass (Cynodon dactylon) pollen, had been identified as an allergenic constituent. In the present study two-dimensional (2D) gel electrophoresis illustrated the presence of five acidic isoforms in Cyn d Bd46K, and this molecule was purified by monoclonal antibody (MAb) affinity chromatography for further characterization. Using a digoxigenin-labeled lectin-binding assay, the elucidating protein was disclosed to be a glycoprotein with terminal mannose. The involvement of a carbohydrate moiety in the allergenicity and antigenicity of the elucidated molecule was demonstrated with sodium-periodate-treated Cyn d Bd46K, which reduced binding to its specific MAb and human IgE. We were unable to identify the N-terminal amino acid sequences of Cyn d Bd46K, but some internal amino acid sequences were disclosed by microsequencing some fragments cleaved by Achromobacter protease I and fractionated by reversed-phase column chromatography. The amino acid sequences of 4 identified Cyn d Bd46K internal peptide fragments were found to be 25–71% identical with that of cytochrome c oxidase III from corn grass pollen. The present study provided important information for future experiments on the molecular cloning of the elucidated allergen.

A "pillar-free", highly porous metalloporphyrinic framework (UNLPF-1) exhibiting eclipsed porphyrin arrays has been constructed from an octacarboxylate ligand connected with paddlewheel secondary building units. UNLPF-1 possesses two types of open metal sites and exhibits an efficient selectivity toward capture of CO2 over N2.

One-dimensional nanotube systems with high surface-to-volume ratios possess unique properties and are thus utilized in various applications. In this study, self-organized TiO2 nanotubes were prepared by anodization of a Ti foil in glycerol containing 5 wt% ammonium fluoride (NH4F) and 6 wt% ethylene glycol (EG). The surface morphology, average inner diameter, and average length of the nanotubes varied with the electrochemical anodization parameters. Nanotubes with uniform surface morphologies, an average diameter of 85 nm, and an average length of 1.1 µm were obtained at 30 V for 1 h. The as-prepared nanotubes were amorphous but they crystallized in the anatase phase after heating at about 400 °C for 2 h in an argon atmosphere. The photocatalytic activity of the TiO2 nanotubes was evaluated through the degradation of methyl orange (MO) and by investigating their bactericidal effect. Optimum photocatalysis of MO was achieved at a kinetic rate constant of 10 3 min 1 . Furthermore, cell viability rapidly decreased on UV illumination and complete killing was achieved at 60 min in the presence of TiO2 nanotubes. For biomedical applications, the cellular activity on TiO2 nanotubes was determined using PA6 cells. Higher cellular activities were achieved using the anatase phase of 85-nm-diameter nanotubes than the amorphous phase. Photoelectrochemical hydrogen generation was investigated using nanotube photoanodes in 1 M potassium hydroxide (KOH) containing 1 wt% EG and xenon lamp. The maximum photocurrent density was 0.55 mA/cm 2 . These findings demonstrate that TiO2 nanotubes are promising for use in multifunctional applications.