Water adsorption on ferroelectric PbTiO (0 0 1) surface: A density functional theory study.

In this work, combining the density functional theory (DFT) calculations and the ab initio molecular dynamics (AIMD) simulations, the water adsorption behavior, including the molecular and the dissociative adsorption on the negatively polarized (0 0 1) surface of ferroelectric PbTiO was comprehensively studied. Our theoretical results show that the dissociative adsorption of water is more energetically favorable than the molecular adsorption on the pristine PbTiO (0 0 1) surface. It has been also found that introducing surface oxygen vacancies (O) can enhance the thermodynamic stability of dissociative adsorption of water molecule.

Ferro/Nonferroelectric Vertical Heterostructure Superlattice as a Visible-Light-Responsive Photocatalyst: A DFT Prediction.

Developing narrow-band-gap ferroelectric semiconducting photocatalysts is a promising strategy for efficient photocatalytic water splitting with high energy conversion efficiency. Within this context, six ferro/nonferroelectric vertical heterostructure superlattices (VHSs) are constructed in this work by stacking ferroelectric SiS or GeS with nonferroelectric layered organic photocatalysts (CN, g-CN, and melon), layer by layer. The geometry and electronic structures of these six VHSs are systematically investigated by density functional theory calculations.

Selective Exposure of Robust Perovskite Layer of Aurivillius-Type Compounds for Stable Photocatalytic Overall Water Splitting.

Aurivillius-type compounds ((Bi O ) (A B O ) ) with alternately stacked layers of bismuth oxide (Bi O ) and perovskite (A B O ) are promising photocatalysts for overall water splitting due to their suitable band structures and adjustable layered characteristics. However, the self-reduction of Bi at the top (Bi O ) layers induced by photogenerated electrons during photocatalytic processes causes inactivation of the compounds as photocatalysts. Here, using Bi TiNbO as a model photocatalyst, its surface termination is modulated by acid etching, which well suppresses the self-corrosion phenomenon.

Non-destructive preservation state estimation of waterlogged archaeological wooden artifacts.

Non-destructive preservation state estimation is an essential prerequisite for the preservation and conservation of waterlogged archaeological wooden artifacts. Herein, Near Infrared (NIR) spectroscopy coupled with orthogonal partial least squares discriminant analysis (OPLS-DA) were applied to assess sixty-four waterlogged archaeological woods collected from seven excavation sites in the period range of 2900 BCE-1912 CE, aiming at developing a non-destructive, accurate and rapid preservation state estimation methodology. The role of non-decayed recent wood of relevant species on preservation state estimation was studied in prior, showing the use of non-decayed recent wood could not improve the predictive ability.

Evaluation of the Deterioration State of Archaeological Wooden Artifacts: A Nondestructive Protocol based on Direct Analysis in Real Time - Mass Spectrometry (DART-MS) Coupled to Chemometrics.

Evaluating the deterioration state of archeological wood is obligatory before the preservation of archeological wooden artifacts. Herein, a nondestructive, accurate, and rapid methodology is first developed via direct analysis in real time-mass spectrometry (DART-MS) with chemometrics to classify archeological wood and recent wood into 3 groups according to their deterioration states. As water in wooden artifacts probably affected the ion fragmentation process during DART-MS, ions responsible for evaluating the deterioration state were separately screened toward waterlogged archeological wood and dried archeological wood by partial least-squares discriminant analysis (PLS-DA).

Discovery of Cisplatin Binding to Thymine and Cytosine on a Single-Stranded Oligodeoxynucleotide by High Resolution FT-ICR Mass Spectrometry.

The clinically widely-used anticancer drug, cisplatin, binds strongly to DNA as a DNA-damaging agent. Herein, we investigated the interaction of cisplatin with a 15-mer single-stranded C,T-rich oligodeoxynucleotide, 5'-CCTTCTTGCTTCTCC-3' (ODN15), using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in conjunction with tandem mass spectrometry (top-down MS). Top-down MS analysis with collision-induced dissociation (CID) fragmentation of the mono-platinated and di-platinated ODN15 provided abundant and informative Pt-containing or Pt-free a/[a - B], w and internal fragments, allowing the unambiguous identification of T, T, C, and T as the platination sites on the cisplatin-ODN15 adducts.

Silver nanoparticles as matrix for MALDI FTICR MS profiling and imaging of diverse lipids in brain.

Owing to the diversity of lipids, profiling and imaging multiple classes of lipids in one analysis by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) is a great challenge. In this work, polyvinylpyrrolidone (PVP) capped silver nanoparticles (AgNPs) was used as the matrix for MALDI MSI for the first time to simultaneously analyze 10 classes of lipids from the brain. This analysis included fatty acids and their derivatives, sterols, CPAs, LPA and PAs, LPE and PEs, LPC and PCs, PS, Cers, SMs, and MAGs and DAGs, and other small metabolites.

Electrospray deposition device used to precisely control the matrix crystal to improve the performance of MALDI MSI.

MALDI MSI has been recently applied as an innovative tool for detection of molecular distribution within a specific tissue. MALDI MSI requires deposition of an organic compound, known as matrix, on the tissue of interest to assist analyte desorption and ionization, in which the matrix crystal homogeneity and size greatly influence the imaging reproducibility and spatial resolution in MALDI MSI. In this work, a homemade electrospray deposition device was developed for deposition of matrix in MALDI MSI.

Combination of ESI and MALDI mass spectrometry for qualitative, semi-quantitative and in situ analysis of gangliosides in brain.

Gangliosides are a family of complex lipids that are abundant in the brain. There is no doubt the investigations about the distribution of gangliosides in brian and the relationship between gangliosides and Alzheimer's disease is profound. However, these investigations are full of challenges due to the structural complexity of gangliosides.

Modified Ilioinguinal Approach to Treat Pelvic or Acetabular Fractures: A Retrospective Study.

The aim of this study was to evaluate the potential advantages and clinical results of a modified minimally invasive ilioinguinal approach for the treatment of acetabular or pelvic fractures to the results obtained using a standard ilioinguinal approach. Forty-six patients who were diagnosed as having anterior column acetabular fractures or anterior pelvic ring fractures underwent open reduction and internal fixation through 2 different surgical approaches between June 2008 to June 2012 in our trauma center was studied. The modified ilioinguinal group included 20 patients and the other 26 patients were in the standard ilioinguinal approach group.

A uniform 2,5-dihydroxybenzoic acid layer as a matrix for MALDI-FTICR MS-based lipidomics.

A very uniform 2,5-dihydroxybenzoic acid (DHB) layer was for the first time constructed and used as a matrix for matrix-assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) for quickly exploring the changes in lipids within biological systems. Lipid extracts from biological samples were dissolved in chloroform and deposited onto the DHB layer. Benefiting from the insolubility of DHB in chloroform, the uniform matrix crystals were still maintained, and more importantly, the lipid analytes were distributed homogeneously on the layer, which significantly increased the reproducibility of analysis using MALDI-FTICR MS.

Prenatal and postnatal lead exposure and cognitive development of infants followed over the first three years of life: a prospective birth study in the Pearl River Delta region, China.

Purpose: Our pilot studies showed that there was a significant relationship between low cord blood levels and scores of neonatal behavioral neurological assessment. The study was further to probe the adverse cognitive effects induced by low-level lead exposure during prenatal and postnatal period.

Method: Totally 362 mothers with their infants located the PRD, Guangdong, China participated in the study during their stay in these center: 141 in the high lead group [umbilical-cord blood lead levels (UCBLLs)≥3.

Mass spectrometry methodology in lipid analysis.

Lipidomics is an emerging field, where the structures, functions and dynamic changes of lipids in cells, tissues or body fluids are investigated. Due to the vital roles of lipids in human physiological and pathological processes, lipidomics is attracting more and more attentions. However, because of the diversity and complexity of lipids, lipid analysis is still full of challenges.

Lead exposure at each stage of pregnancy and neurobehavioral development of neonates.

Purpose: Our pilot studies showed that there was a significant relationship between blood lead levels of women at the first trimester and scores of neonatal behavioral neurological assessment (NBNA). This study went further (1) to determine particular neurotoxicity during a specific trimester, (2) to analyze "safe" levels of Pb in neonates, and (3) to identify influencing factors for prenatal Pb exposure.

Method: A total of 415 mothers with newborn located Shenzhen, Guangdong, China participated in the study: 219 in the high lead group [blood lead levels (BLLs) at first trimester≥4.

Polystyrene spheres-assisted matrix-assisted laser desorption ionization mass spectrometry for quantitative analysis of plasma lysophosphatidylcholines.

The quantitative analysis by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) is a challenge due to the poor reproducibility originating from the heterogeneity of the matrix-analyte crystals. Polystyrene (PS) colloidal spheres have superior monodispersed property and can self-assemble to form photonic crystals. With the assistance of PS spheres, a uniform matrix-analyte cocrystal was constructed for the quantitative analysis of plasma lysophosphatidylcholines (LPCs).

2,3,4,5-Tetrakis(3',4'-dihydroxylphenyl)thiophene: a new matrix for the selective analysis of low molecular weight amines and direct determination of creatinine in urine by MALDI-TOF MS.

Small organic matrixes are still the most commonly used ones in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) because of their advantages of high sensitivity, convenience, and cost-effectiveness. However, due to the matrix interference in the low mass region, the direct analysis of low molecular weight amines in complex surroundings with conventional organic matrixes remains a challenge. Here, a new Brønsted-Lowry acid compound 2,3,4,5-tetrakis(3',4'-dihydroxylphenyl)thiophene (DHPT) was designed, synthesized, and applied as a matrix for analysis of low molecular weight amines by MALDI-TOF MS.

Matrix-assisted laser ablation production of gold cluster ions from Au-coated photonic crystals.

A new strategy was explored to generate pure gold cluster ions, Au(n)(+/-), from gold films deposited on solid substrates via a matrix-assisted laser ablation technique. The gold films deposited on SiO(2)-particle-assembled photonic crystals were demonstrated to be the most ideal compared with the films deposited on various glass slides. Dropped with a matrix of 2-(4-hydroxyphenylazo) benzoic acid and bombarded by nitrogen pulse laser (355 nm), they could release a series of Au(n)(+) with n more than 110 or Au(n)(-) with n more than 60 according to the data obtained by inline time-of-flight mass spectrometry.

A novel strategy for MALDI-TOF MS analysis of small molecules.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) does not work efficiently on small molecules (usually with molecular weight below 500 Da) because of the interference of matrix-related peaks in low m/z region. The previous methods developed for this problem focused on reducing the peaks caused by the traditional matrices. Here, we report a novel strategy to analyze small molecules in a high and interference-free mass range by using metal-phthalocyanines (MPcs) as matrices which should be capable of forming matrix-analyte adducts.