[Determination of platinum anticancer drugs in occupational settings by ICP-MS].

Objective: To establish an inductively coupled plasma mass spectrometry (ICP-MS) for platinum antineoplastic drugs in the environment. Methods: The platinum antineoplastic drugs in the environmental table were eluted by wiping and collecting pure water, and the supernatant was taken by centrifugation and inductively coupled plasma mass spectrometry for detection. Results: The concentration range of 0-8.0 µg/L was good, the correlation coefficient was 1.000, the detection limit was 0.0006 µg/L, the lower quantitative limit was 0.002 µg/L, the method precision was between 0.9%-1.3%, and the sample standard recovery rate was between 97.0%-98.5%. Conclusion: This method has low detection limit, high accuracy and precision, and simple sample pretreatment, which is suitable for the determination of platinum antineoplastic drugs in environmental tables.

[Liquid chromatography-tandem mass spectrometry method for the determination of paraquat and diquat in plasma and urine].

Objective: To establish a LC-MS/MS method for determination of paraquat and diquat in plasma and urine samples. Methods: Plasma is precipitated by acetonitrile then diluent with phosphate buffer (pH=7) , urine is diluent with phosphate buffer (pH=7) , then diluent samples extracted with Oasis WCX solid-phase extraction column. Samples were analyzed using LC-MS/MS in multiple reaction monitoring (MRM) mode. The analytical column was XBridge®BEH-HILIC (100 mm×2.1 mm×2.5 µm) and the mobile phase were 100 mmol ammonium formate add 0.5% formic acid and acetonitrile. Paraquat was quantified by internal standard method and diquat by external standard method. Results: The calibration curves of paraquat and diquat were linear in the concentration range of 10.0~120.0 µg/L, the correlation coefficient (r) were 0.9985~0.9994. The limit of detection of paraquat in plasma and urine were 1.98 µg/L and 1.00 µg/L, respectively, the recovery rate were 100.2%~107.3%, the RSD were 1.6%~3.3%. The limit of detection of diquat in plasma and urine were 1.80 µg/L and 2.77 µg/L, respectively, the recovery rate were 85.3%~93.1%, the RSD were 1.8%~5.5%. Conclusion: This method is sensitive and accurate, and can simultaneously determine paraquat and diquat in plasma and urine.

Surfactant-Mediated Epitaxial Growth of Single-Layer Graphene in an Unconventional Orientation on SiC.

We report the use of a surfactant molecule during the epitaxy of graphene on SiC(0001) that leads to the growth in an unconventional orientation, namely R0° rotation with respect to the SiC lattice. It yields a very high-quality single-layer graphene with a uniform orientation with respect to the substrate, on the wafer scale. We find an increased quality and homogeneity compared to the approach based on the use of a preoriented template to induce the unconventional orientation. Using spot profile analysis low-energy electron diffraction, angle-resolved photoelectron spectroscopy, and the normal incidence x-ray standing wave technique, we assess the crystalline quality and coverage of the graphene layer. Combined with the presence of a covalently bound graphene layer in the conventional orientation underneath, our surfactant-mediated growth offers an ideal platform to prepare epitaxial twisted bilayer graphene via intercalation.

[Elemental and isotopic determination of lead in whole blood by ISIS-ICP-MS].

Objective: To establish a method for determination of lead and istope ratios in the blood by ISIS-ICP-MS. Methods: After wet digestion, the blood sample was on-line addition of thallium as internal standard and analyzed by ISIS-ICP-MS. Results: The limit of detection was 0.03 µg/L and the lower limit of quantification was 0.08 µg/L. The detection concentration was 0.45 µg/L and the minimum quantitative concentration was 1.49 µg/L. The relative standard deviations (RSD) were 0.3%~1.7%. The recovery was between 91.0% and 103.4%. The precision of the major lead isotope ratios was better than 0.3%. The calibrated isotope ratios of the standard liquid are close to the certificate. Conclusion: The method has a low detection limit, good precision and high accuracy, it is feasible for determination of lead concentration and isotope ratios in the bloune.

[Determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace by gas chromatography].

Objective: To establish a solvent desorption gas chromatographic method for determination of Sevoflurane, Isoflurane and Enflurane in the air of the Workplace. Methods: Sevoflurane, Isoflurane and Enflurane were collected with activated carbon tube and desorbed with dichloromethane, separated with DB-1 capillary columns, and then detected with flame ionization detector. Results: The linearity ranges were 1.9-304.8 µg/ml for Sevoflurane, 2.1-300.4 µg/ml for Isoflurane and 1.7-305.2 µg/ml for Enflurane, The correlation coefficient was both >0.999. Their limits of detection were 0.6 µg/ml, 0.6 µg/ml and 0.5 µg/ml, and Their limits of quatification were 1.9 µg/ml, 2.1 µg/ml and 1.7 µg/ml, and their minimum detectable concentrations were 0.1、0.2 and 0.1 mg/m(3) per 4.5 L of air. Their relative standard deviations (RSD) were 2.5%-3.0%, 2.3%-3.1% and 2.2%-3.0%. The average desorption efficiencies were 101.1%-103.3%, 100.7%-102.7% and 101.0%-102.9%. The sampling efficiency was both 100%. The breakthrough volume of 100 mg actived carbon was 3.7 mg, 3.4 mg and 3.4 mg. Sevoflurane, Isoflurane and Enflurane in activated carbon tube could be kept at least 10 days at room temperature without significant losses. Conclusion: The method shows lower detection limit, high accuracy and precision. It is feasible for determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace.

[Direct determination of manganese in urine by Graphite Furnace Atomic Absorption Spectrometry].

Objective: To establish a method for the determination of manganese in urine by graphite furnace atomic absorption spectrometry (AAS) without the use of matrix modifier. Methods: The urine samples were 5 times diluted with 1% nitric acid then directly determined by AAS. Zeeman was used for background correction. Results: The linear range for determination of manganese in urine was 5~60 µg/L (urine) . The correlation coefficient was greater than 0.995 with the detection limit of 1.5 µg/L and with the lower limit of quantification of 5.0 µg/L. The relative standard deviations (RSDs) of within-run precision was between 1.1%~4.3%, the RSDs of between-run precision was between 3.3%~7.0%. The average recovery was 102.6%. The samples can be stored for 14 days at room temperature, 4℃, -8 ℃ and -35 ℃. Conclusion: The method is feasible for determination of manganese in urine.

[Simultaneous determination of various volatile organic compounds in urine by headspace GC-MS].

Objective: To establish a method for determination of acetone, dichloromethane, hexane, 1, 1, 1-trichloroethane, 1, 2-dichloroethane, benzene, toluene, ethylbenzene etc organic compounds in urine by headspace gas chromatography-mass spectrometry (GC-MS) . Methods: Headspace gases of urine samples were injected into GC and determined by mass. Results: Determination of urine components were in a good linear range in their concentration range of this method. The correlation coefficients were between 0.996 and 1.000 with the detection limits between 0.1 µg/L and 4.5 µg/L, the precisions were between 1.3% and 4.6%, the recovery rates were between 86.2% and 97.4%. Conclusion: This method has the advantages of low detection limits, high accuracy, high precision and simple pretreatment, which is suitable for the determination of the content of various volatile organic compounds in urine.

Atomic Configuration of Point Defect Clusters in Ion-Irradiated Silicon Carbide.

Silicon Carbide (SiC) is a promising cladding material for accident-tolerant fuel in light water reactors due to its excellent resistance to chemical attacks at high temperatures, which can prevent severe accident-induced environmental disasters. Although it has been known for decades that radiation-induced swelling at low temperatures is driven by the formation of black spot defects with sizes smaller than 2 nm in irradiated SiC, the structure of these defect clusters and the mechanism of lattice expansion have not been clarified and remain as one of the most important scientific issues in nuclear materials research. Here we report the atomic configuration of defect clusters using Cs-corrected transmission electron microscopy and molecular dynamics to determine the mechanism of these defects to radiation swelling. This study also provides compelling evidence that irradiation-induced point defect clusters are vacancy-rich clusters and lattice expansion results from the homogenous distribution of unrecovered interstitials in the material.

[Determination of tin dioxide in workplace air by atomic fluorescence spectrometry after alkali fusion].

OBJECTIVE: To establish the method of atomic fluorescence spectrometry (AFS) after alkali fusion for determination of tin dioxide in workplace air. METHODS: Tin dioxide in workplace air was collected with microporous membrane, directly digested by alkali fusion with solid sodium hydroxide heated by electric furnace, and determined by AFS. RESULTS: The linear range of tin dioxide (as Sn) determined by AFS was 1.5~100 µg/L (excluding zero) , and the correlation coefficient was 0.9993. The detection limit of this method was 0.5 µg/L, the lower limit of quantification was 1.5 µg/L, and the minimum detectable concentration was 0.05 mg/m(3) (the volume of the air sample was 75 L) . The relative standard deviation was 1.94%~3.55%, and the average recovery of standard addition was 95.0%~96.0%. CONCLUSION: The method of AFS after alkali fusion for determination of tin dioxide in workplace air is proved to be simple, rapid, sensitive, and accurate, with complete digestion.

Epidemiology of pediatric critically-ill patients presenting to the pediatric emergency department.

This study aimed to analyze the epidemiologic patterns of pediatric critically-ill patients presenting to the emergency department (ED) and the etiologies of intensive care unit (ICU) admission of different age groups.This retrospective study of all children aged less than 18 years presenting with critical illnesses to the ED was conducted in a tertiary medical center in Taiwan from 2003 to 2007. All patients transferred to the ICU from the ED were included without distinction. Demographic data of critically-ill children admitted to the ED and ICU were analyzed. Etiologies of the ICU admissions were analyzed by various age groups.There were 2978 critically-ill children admitted to the ICU from the ED. In 120 pediatric patients with out-of-hospital cardiac arrest, cases with pulseless electrical activity or ventricular fibrillation had higher successful CPR rates than patients with asystole (both p<0.05). In patients admitted to ICUs, complications from the perinatal period, respiratory system diseases, accidental injuries and poisoning were the predominant etiologies respectively in young children (42.5%), school-aged children (38.5%), and adolescents (47.9%). Moreover, the most common of which was respiratory distress syndrome in neonates followed by bacterial pneumonia and status epilepticus.Epidemiologic analysis may provide primary clinicians to identify significant differences in admission rates based on different etiologies of various age groups.

Photodynamic therapy of idiopathic subfoveal choroidal neovascularization in Taiwanese patients: a 2-year follow-up.

AIMS: To study the efficacy of verteporfin photodynamic therapy (VPDT) retrospectively in the treatment of idiopathic subfoveal choroidal neovascularization (ICNV) in an Asian population in correlation with number of treatments and age at treatment. This is the first report to compare the efficacy between single and multiple treatments. METHODS: VPDT was administered according to protocol to 45 eyes in 45 patients aged 18-55 years diagnosed with active subfoveal ICNV between September 2003 and December 2005. In total 28 patients received a single VPDT treatment and the remaining 17 received multiple treatments. Collected measurements of visual acuity (VA) were plotted on a time-course model, and later dichotomized by age (18-45 vs 46-55 years). RESULTS: The 28 patients receiving a single VPDT treatment showed significant improvement in VA at 3-month follow-up. The 17 patients, who did not show improvement after the first treatment, received multiple VPDT treatments. Those patients showed an even clearer trend in VA improvement although significance was detected only at the 24th month. All patients showed a significant improvement in mean VA of 0.46 logMAR (P<0.01 compared to baseline) by the end of the 24-month observation period, although VPDT treatment for subfoveal ICNV appears to stabilize vision more rapidly in younger patients. CONCLUSIONS: ICNV patients who did not benefit from single VPDT treatments could receive multiple treatments, and showed a more significant improvement in visual acuity. These results are the first of their kind in ICNV treatment.

Prediction of protein structure class by coupling improved genetic algorithm and support vector machine.

Structural class characterizes the overall folding type of a protein or its domain. Most of the existing methods for determining the structural class of a protein are based on a group of features that only possesses a kind of discriminative information for the prediction of protein structure class. However, different types of discriminative information associated with primary sequence have been completely missed, which undoubtedly has reduced the success rate of prediction. We present a novel method for the prediction of protein structure class by coupling the improved genetic algorithm (GA) with the support vector machine (SVM). This improved GA was applied to the selection of an optimized feature subset and the optimization of SVM parameters. Jackknife tests on the working datasets indicated that the prediction accuracies for the different classes were in the range of 97.8-100% with an overall accuracy of 99.5%. The results indicate that the approach has a high potential to become a useful tool in bioinformatics.

Creutzfeldt-jakob disease involvement of rolandic cortex: a quantitative apparent diffusion coefficient evaluation.

BACKGROUND: Previous reports have suggested that abnormally reduced water diffusivity and T2 prolongation involving cerebral gray matter in patients with early sporadic Creutzfeldt-Jakob disease (sCJD) involves all areas of neocortex with similar frequency, except for primary sensorimotor cortex (Rolandic cortex) and visual cortex. Rolandic cortex often appears to be spared even in the presence of extensive surrounding neocortical signal intensity abnormality in adjacent frontal and parietal gray matter. A quantitative apparent diffusion coefficient (ADC) analysis was designed to investigate whether this unusual pattern results from pathophysiologic sparing of Rolandic cortex or from reduced conspicuity of signal intensity abnormality on MR imaging echo-planar diffusion-weighted images (epiDWI) related to unknown underlying features of Rolandic cortex. METHODS: ADC maps were derived from epiDWI of 6 patients with sCJD and 8 control patients. Bilateral regions of interest were manually selected in precentral gyri, superior frontal gyri, postcentral gyri, supramarginal gyri, thalamus, putamen, and caudate nuclei. ADC and relative ADC (rADC) values were calculated for each region of interest. RESULTS: Patients with CJD had significantly lower ADC values than control patients in all areas (P < or = 0.05). The trend toward decreased ADC values in the deep nuclei correlates well with previously published reports. rADC were not significantly different between CJD and control groups in any area (P > 0.25 in all cases). CONCLUSION: Quantitative ADC measurements in patients with early sCJD demonstrate a similar degree of reduced water diffusivity in the primary somatosensory cortex as in other neocortical areas, despite the normal appearance of these areas on visual inspection of epiDWI.

Central adenoid cystic carcinoma of the mandible manifesting as an endodontic lesion.

AIM: To present a case of adenoid cystic carcinoma (ACC) in the mandible, and manifesting as a periapical lesion. SUMMARY: A 56-year-old male suffered from pain around the right mandibular first molar for approximately 1 week. Oral examination revealed that the involved tooth was restored by a full coverage crown with no obvious abnormalities. A periapical radiograph revealed two ill-defined radiolucencies associated with the tooth, one over the mesial and another over the distal roots of the tooth; incomplete root filling and furcation involvement also being noted. The affected tooth was extracted based on the clinical impression of apical periodontitis. The surrounding tissue of the root apex was curetted and sent for histopathological examination, which revealed ACC. KEY LEARNING POINTS: Adenoid cystic carcinoma affecting the mandible may mimic a periapical lesion. Proper diagnosis of such a lesion is dependent on thorough clinical, radiographic and microscopic examinations. Such a case highlights the benefits of biopsy and histological examination of collected tissues. Diagnosis of lesions in the mandible should include salivary gland tumours.

Pleomorphic adenoma with extensive necrosis: report of two cases.

Pleomorphic adenoma (PA) is the most common neoplasm for both the major and minor salivary glands. While PA is occasionally associated with cystic change or hemorrhage necrosis, spontaneous infarction appears to be very uncommon. We report two unusual cases of extensive necrosis of PA; one occurred in the palate with the necrotic tumor mass slipping into the oral cavity. This phenomenon, possibly associated with incision biopsy, has never been described previously. A second case, arising in the parotid with spontaneous tumor necrosis, poses some dilemma in differential diagnosis.

Dissecting the pet18 mutation in Saccharomyces cerevisiae: HTL1 encodes a 7-kDa polypeptide that interacts with components of the RSC complex.

The yeast pet18 mutant exhibits three distinct phenotypes: temperature-sensitive lethality, failure to maintain a dsRNA virus, and respiration deficiency. We have isolated a yeast mutant, H53, with phenotypes identical to those of pet18. Based on PCR and Southern hybridization analysis, H53 was found to result from a large chromosomal deletion extending from YCR019w to YCR028c on chromosome III. Genetic analysis was carried out on H53 to correlate individual loci with each of the observed phenotypes. Disruption of YCR020c-a/MAK31 brought about a loss of dsRNA without affecting the temperature sensitive phenotype. The loss of YCR020w-b/HTL1, which encodes a hypothetical protein of 78 amino acids in length, was shown to be responsible for the temperature-sensitive lethality of the H53 mutant. Using immunoblotting, we demonstrated that a 7-kDa protein was indeed expressed in wild-type yeast, but not in a HTL1 deletion mutant. Moreover, the significance of HTL1 was investigated by isolating genes that are functionally associated with HTL1. We demonstrated that Rsc8p interacts physically with Htl1p, and that the genes RSC3, STH1 and RSC30 interact with HTL1. Thus, HTL1 may play a role in the function of the RSC complex.

Toward integration of comparative genetic, physical, diversity, and cytomolecular maps for grasses and grains, using the sorghum genome as a foundation.

The small genome of sorghum (Sorghum bicolor L. Moench.) provides an important template for study of closely related large-genome crops such as maize (Zea mays) and sugarcane (Saccharum spp.), and is a logical complement to distantly related rice (Oryza sativa) as a "grass genome model." Using a high-density RFLP map as a framework, a robust physical map of sorghum is being assembled by integrating hybridization and fingerprint data with comparative data from related taxa such as rice and using new methods to resolve genomic duplications into locus-specific groups. By taking advantage of allelic variation revealed by heterologous probes, the positions of corresponding loci on the wheat (Triticum aestivum), rice, maize, sugarcane, and Arabidopsis genomes are being interpolated on the sorghum physical map. Bacterial artificial chromosomes for the small genome of rice are shown to close several gaps in the sorghum contigs; the emerging rice physical map and assembled sequence will further accelerate progress. An important motivation for developing genomic tools is to relate molecular level variation to phenotypic diversity. "Diversity maps," which depict the levels and patterns of variation in different gene pools, shed light on relationships of allelic diversity with chromosome organization, and suggest possible locations of genomic regions that are under selection due to major gene effects (some of which may be revealed by quantitative trait locus mapping). Both physical maps and diversity maps suggest interesting features that may be integrally related to the chromosomal context of DNA-progress in cytology promises to provide a means to elucidate such relationships. We seek to provide a detailed picture of the structure, function, and evolution of the genome of sorghum and its relatives, together with molecular tools such as locus-specific sequence-tagged site DNA markers and bacterial artificial chromosome contigs that will have enduring value for many aspects of genome analysis.

Locus-specific contig assembly in highly-duplicated genomes, using the BAC-RF method.

Polyploidy, the presence of multiple sets of chromosomes that are similar but not identical, complicates both chromosome walking and assembly of sequence-ready contigs for many plant taxa including a large number of economically-significant crops. Traditional 'dot-blot hybridization' or PCR-based assays for identifying BAC clones corresponding to a mapped DNA landmark usually do not provide sufficient information to distinguish between allelic and non-allelic loci. A restriction fragment matching method using pools of BAC DNA in combination with dot-blots reveals the locus specificity of individual BACs that correspond to multi-locus DNA probes, in a manner that can efficiently be applied on a large scale. This approach also provides an alternative means of mapping DNA loci that exploits many advantages of 'radiation hybrid' mapping in taxa for which such hybrids are not available. The BAC-RF method is a practical and reliable approach for using high-density RFLP maps to anchor sequence-ready BAC contigs in highly-duplicated genomes, provides an alternative to high-density robotic gridding for screening BAC libraries when the necessary equipment is not available, and permits the expedient isolation of individual members of multigene or repetitive DNA families for a wide range of genetic and evolutionary investigations.

Detailed alignment of saccharum and sorghum chromosomes: comparative organization of closely related diploid and polyploid genomes.

The complex polyploid genomes of three Saccharum species have been aligned with the compact diploid genome of Sorghum (2n = 2x = 20). A set of 428 DNA probes from different Poaceae (grasses) detected 2460 loci in F1 progeny of the crosses Saccharum officinarum Green German x S. spontaneum IND 81-146, and S. spontaneum PIN 84-1 x S. officinarum Muntok Java. Thirty-one DNA probes detected 226 loci in S. officinarum LA Purple x S. robustum Molokai 5829. Genetic maps of the six Saccharum genotypes, including up to 72 linkage groups, were assembled into "homologous groups" based on parallel arrangements of duplicated loci. About 84% of the loci mapped by 242 common probes were homologous between Saccharum and Sorghum. Only one interchromosomal and two intrachromosomal rearrangements differentiated both S. officinarum and S. spontaneum from Sorghum, but 11 additional cases of chromosome structural polymorphism were found within Saccharum. Diploidization was advanced in S. robustum, incipient in S. officinarum, and absent in S. spontaneum, consistent with biogeographic data suggesting that S. robustum is the ancestor of S. officinarum, but raising new questions about the antiquity of S. spontaneum. The densely mapped Sorghum genome will be a valuable tool in ongoing molecular analysis of the complex Saccharum genome.