[Treatment strategies for complicated craniocervical junction malformations].

Objective: To explore the treatment strategies for complicated craniocervical junction malformations with diverse clinical and imaging features.

Methods: The clinical data of 67 cases of complicated craniocervical junction malformation treated between January 2000 to December 2010 were retrospectively analyzed. Based on their clinical manifestations and imaging findings, different operative procedures were adopted, including odontoidectomy via transoral transpharyngeal approach (n = 3), occipito-cervical fusion and(or) suboccipital decompression (n = 19) and odontoidectomy via transoral transpharyngeal approach followed by occipito-cervical fusion in two-stage operation (n = 25).

[Development of a membrane inlet-single photon ionization/chemical ionization-mass spectrometer for online analysis of VOCs in water].

A home-made membrane inlet- single photon ionization/chemical ionization- time-of-flight mass spectrometer has been described. A vacuum ultraviolet (VUV) lamp with photon energy of 10.6 eV was used as the light source for single photon ionization (SPI).

[Automatic continuous monitoring of volatile organic compounds using ion mobility spectrometer array].

An ion mobility spectrometer array was designed, in order to broaden the detection range of ion mobility spectrometer and improve the accuracy of compound identification. This instrument was based on the combination of ionization sources of 63Ni positive ion mode, 63Ni negative ion mode and photoionization mode with vacuum UV lamp, and it can continuously monitor the volatile organic compounds in air. With the automatic system of sampling and injection of this instrument, the positive ion of dimethyl sulfoxide and negative ion of dichloromethane were detected simultaneously.

[A novel gas chromatography detector based on ion mobility spectrometry technology and its application].

Ion mobility spectrometry (IMS) is an attractive detector of gas chromatography (GC) due to its high sensitivity, short response time, and comparatively low cost. The hyphenated GC-IMS instrument can simultaneously provide high separation ability of GC and high sensitivity of IMS. In this paper, one setup of a GC-IMS instrument is introduced.

Resolution enhancement of ion mobility spectrometry by improving the three-zone properties of the Bradbury-Nielsen gate.

A simple space compression-dispersion model for ion transport at ambient pressure was mathematically established. On the basis of this model and aided by SIMION simulation, a three-zone theory was proposed to characterize the Bradbury-Nielsen gating electric field features as three zones: the depletion zone, the dispersion zone, and the compression zone. Then, the influences of gating voltage difference increases on the full width at half-maximum of the Cl(-) peak were investigated in detail to verify the theory.

Coupling of stir bar sorptive extraction with single photon ionization mass spectrometry for determination of volatile organic compounds in water.

A home-made stir bar sorptive extraction (SBSE) apparatus was combined to a single photon ionization time-of-flight mass spectrometer (SPI-TOFMS) for rapid and sensitive determination of trace volatile organic compounds (VOCs) in water. The home-made SBSE bar, low-cost and disposable, was used for VOCs extraction. A thermal desorption (TD) device was designed to desorb the analytes from the SBSE bar, and a high throughput interface was developed to transfer the analytes into the ionization chamber of the SPI-TOFMS.

Vacuum ultraviolet lamp based magnetic field enhanced photoelectron ionization and single photon ionization source for online time-of-flight mass spectrometry.

A magnetic field enhanced photoelectron ionization (MEPEI) source combined with single photon ionization (SPI) was developed for an orthogonal acceleration time-of-flight mass spectrometer (oaTOFMS). A commercial radio frequency (rf) powered vacuum ultraviolet (VUV) lamp was used as SPI light source, and the photoelectrons generated by photoelectric effect were accelerated to induce electron ionization (EI). The MEPEI was obtained by applying a magnetic field of about 800 G with a permanent annular magnet.

[Realtime analysis of volatile organic compounds in source water by membrane inlet/time-of-flight mass spectrometry].

To establish an early-warning system for source water pollution accident, a membrane inlet/time-of-flight mass spectrometry technology was applied to a series of pollution scenarios as an online monitoring method for typical volatile organic compounds such as BTEX (benzene, toluene, ethylbenzene and xylene), substituted benzenes, and halogenated aliphatic hydrocarbons. It was shown that this technology can adequately meet the requirements of realtime analysis with short response time to the target organic pollutants (30-70 s for BTEX and 30 s for halogenated aliphatic hydrocarbons) in a linear detecting range of 3-4 magnitudes; the detection limits of BTEX and chlorobenzene were less than 10 microg x L(-1). The results of 52 simulated water pollution accidents in a 30-days' continuous monitoring indicated that the monitoring system was stable with the relative standard deviation less than 5%; the accuracy was acceptable and could be reduced to within 10% by periodical calibrations.

Note: Design and construction of a simple and reliable printed circuit board-substrate Bradbury-Nielsen gate for ion mobility spectrometry.

A less laborious, structure-simple, and performance-reliable printed circuit board (PCB) based Bradbury-Nielsen gate for high-resolution ion mobility spectrometry was introduced and investigated. The gate substrate was manufactured using a PCB etching process with small holes (Φ 0.1 mm) drilled along the gold-plated copper lines.

[Monitoring of methyl methacrylate monomer released from autopolymerized denture base polymers during processing using time-of-flight mass spectrometer].

Objective: To analyze the amount and tendency of methyl methacrylate (MMA) released from autopolymerized denture base polymer (self-curing resin) during processing using time-of-flight mass spectrometer (TOF-MS).

Methods: Self-curing resin was mixed in the container using a ratio of 2 g of powder to 1 g of liquid in accordance with the manufacturer's instructions for 40 s as a specimen. The amount of MMA released from the specimen was continuously monitored and simultaneously recorded every minute by TOF-MS since immediately after mixing.

Single photon ionization and chemical ionization combined ion source based on a vacuum ultraviolet lamp for orthogonal acceleration time-of-flight mass spectrometry.

A novel combined ion source based on a vacuum ultraviolet (VUV) lamp with both single photon ionization (SPI) and chemical ionization (CI) capabilities has been developed for an orthogonal acceleration time-of-flight mass spectrometer (oaTOFMS). The SPI was accomplished using a commercial 10.6 eV krypton discharge lamp with a photon flux of about 10(11) photons s(-1), while the CI was achieved through ion-molecule reactions with O(2)(+) reactant ions generated by photoelectron ionization at medium vacuum pressure (MVP).

Increased anxiety-related behaviour in Hint1 knockout mice.

Several reports have implicated a role for the histidine triad nucleotide-binding protein-1 (Hint1) in psychiatric disorders. We have studied the emotional behaviour of male Hint1 knockout (Hint1 KO) mice in a battery of tests and performed biochemical analyses on brain tissue. The behavioural analysis revealed that Hint1 KO mice exhibit an increased emotionality phenotype compared to wildtype (WT) mice, while no significant differences in locomotion or general exploratory activity were noted.

Bipolar ionization source for ion mobility spectrometry based on vacuum ultraviolet radiation induced photoemission and photoionization.

A novel bipolar ionization source based on a commercial vacuum-UV Kr lamp has been developed for ion mobility spectrometry (IMS), which can work in both negative and positive ion mode. Its reactant ions formed in negative ion mode were predominantly assigned to be O(3)(-)(H(2)O)(n), which is different from that of the (63)Ni source with purified air as carrier and drift gases. The formation of O(3)(-)(H(2)O)(n) was due to the production of ozone caused by ultraviolet radiation, and the ozone concentration was measured to be about 1700 ppmv by iodometric titration method.

Membrane-extraction ion mobility spectrometry for in situ detection of chlorinated hydrocarbons in water.

Membrane-extraction ion mobility spectrometry (ME-IMS) has been developed for in situ sampling and analysis of trace chlorinated hydrocarbons in water in a single procedure. The sampling is configured so that aqueous contaminants permeate through a spiral hollow poly(dimethylsiloxane) (PDMS) membrane and are carried away by a vapor flow through the membrane tube. The extracted analyte flows into an atmospheric-pressure chemical-ionization (APCI) chamber and is analyzed in a specially made IMS analyzer.

Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110).

The interface electronic properties of fluorene-1-carboxylic acid (FC-1) adsorbed on Cu(110) have been studied by ultraviolet photoemission spectroscopy (UPS) and first-principles calculations. Both the molecular orbitals and the Cu valence band are significantly modified upon adsorption. FC-1 is chemically bonded to Cu(110) through charge donation and back donation involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the molecule.

The chemisorption of tetracene on Si(100)-2x1 surface.

The adsorption of tetracene on Si(100)-2x1 substrate has been studied by ultraviolet photoemission spectroscopy (UPS). Six features deriving from the organic material are located at 1.22, 2.

[Intracranial aneurysms difficult to be treated by endovascular interventional therapy: report of 27 patients].

Objective: To analyze the characteristics of aneurysms difficult to be treated by endovascular interventional therapy and report the results of operation.

Methods: 27 patients with 33 intracranial aneurysms transferred from the ward of interventional therapy, 7 males and 20 females, aged 47 (27-67), accepted microsurgical operation, The neck, volume, aspect ratio and blood vessel condition of the aneurysms were analyzed.

Results: The aneurysms difficult to be treated by endovascular interventional therapy included those with wide neck (>4 mm), large volume (maximal diameter>or=8 mm), and failure in endovascular maneuvers (because of flexed blood vessel and severe vasospasm).

Interfacial electronic states of tetracene deposited on Si(111).

The interfacial electronic states of tetracene on Si(111) 7x7 substrate were studied by using ultraviolet photoelectron spectroscopy (UPS). After deposition of tetracene on the Si(111) 7x7 surface, the features originating from the tetracene molecule appear at 1.55, 3.

[The effect of resolution on the measurement of carbon bisulfide by DOAS].

Featuring excellent response characteristics and detection sensitivity and with much lower operational cost, differential optical absorption spectroscopy (DOAS) can be a powerful tool to trace the concentration variation of carbon bisulfide (CS2), a kind of poisonous gas with bad smell. In the DOAS measurement, the accuracy of the carbon bisulfide results is determined by the selected spectral resolution. The present paper focuses on the effect of resolution on the detected characteristic absorption structure of CS2 and the variation in differential cross section of CS2 with the change in resolution, from which the effect of resolution on the detection limit of CS2 is deduced.

Quartz crystal microbalance sensor array for the detection of volatile organic compounds.

A sensor array system consisting of five quartz crystal microbalance (QCM) sensors (four for measuring and one for reference) and an artificial neural network (ANN) method is presented for on-line detection of volatile organic compounds. Three ionic liquids, 1-butyl-3-methylimidazolium chloride (C(4)mimCl), 1-butyl-3-methylimidazolium hexafluorophosphate (C(4)mimPF(6)), 1-dedocyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C(4)mimNTf(2)), and silicone oil II, which is widely used as gas chromatographic stationary phase, have been selected as sensitive coatings on the quartz surface allowing the sensor array effective to identify chemical vapors, such as toluene, ethanol, acetone and dichloromethane. The success rate for the qualitative recognition reached 100%.

[Research on cluster-assistant multiple ionization of acetonitrile by intense nanosecond laser].

To further investigate the relation between cluster and multi-charged ions, the photo-ionization of acetonitrile molecular beam carried by helium was studied by time-of-flight mass spectrometry using 25 ns, 532 nm and 1 064 nm Nd-YAG laser with an intensity of 10(10) W x cm(-2). When the effused beam of CH3CN at a pressure of about 11 kPa was irradiated by a 532 nm laser, only a few mono-charged ions appeared in the mass spectrum and were clearly resolved, While the pulsed molecular beam seeded in 0.15 MPa He, multi-charged species appeared between H+ and C+, and parent ions containing one or more acetonitrile molecules were also discovered.

Histidine triad nucleotide-binding protein 1 up-regulates cellular levels of p27KIP1 by targeting ScfSKP2 ubiquitin ligase and Src.

The one or more underlying mechanisms of the tumor suppressing activity of the histidine triad nucleotide-binding protein 1 (HINT1) are not well defined. In this study we found that HINT1 regulates cellular levels of the cyclin-dependent kinase inhibitor p27(KIP1) through multiple mechanisms. Increased expression of HINT1 increases cellular levels of p27(KIP1), and HINT1 knockdown with small hairpin RNA leads to decreased cellular levels of p27(KIP1).

HINT1 inhibits beta-catenin/TCF4, USF2 and NFkappaB activity in human hepatoma cells.

In this study we explored the relevance of Hint, a novel tumor suppressor gene, to human hepatoma. The human hepatoma cell lines Hep3B and HepG2 express very low levels of the HINT1 protein but the Huh7 cells express a relatively high level. In Hep3B and HepG2 cells, but not in Huh7 cells, the promoter region of Hint1 is partially methylated and treatment with 5-azadcdeoxycytidine increased expression of the HINT1 protein and Hint1 mRNA in Hep3B and HepG2 cells.

Silencing of Hint1, a novel tumor suppressor gene, by promoter hypermethylation in hepatocellular carcinoma.

The Hint1 protein, a member of the histidine triad (HIT) family, is highly conserved in diverse species and ubiquitously expressed in mammalian tissues. Previous studies in mice provided evidence that Hint1 may be haploinsufficient with respect to its function as a tumor suppressor. In the present study, we investigated the aberrant methylation of Hint1 and explored possible relationships between aberrant methylation and clinicopathological features in hepatocellular carcinoma (HCC).

Dopant-enhanced atmospheric pressure glow discharge ionization source for ion mobility spectrometry.

A dopant-enhanced atmospheric pressure direct current glow discharge ionization source for ion mobility spectrometry (APDCGD-IMS) has been described. It is shown that the ion intensity can be greatly increased by addition of species with ionization energy lower than that of buffer gas when the direction of the electric field between the target electrode and the extraction electrode was opposite to that of the drift field. With N(2) as the buffer gas, adding O(2) (or air), acetone, and CH(2)Cl(2) with certain concentration can enhanced the ion intensity more than one order of magnitude, and for O(2), it was found that the enhancement depending on both the concentration of O(2) and the flow rate of the carrier gas, and the largest enhancements of the signal intensity for electron in negative mode and reaction ion in positive mode reached at O(2) concentration about 1.