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Lead exposure is one of the most concerning public health problems worldwide, particularly among children. Yet the impact of chronic lead exposure on the thyroid status and related intelligence quotient performance among school-age children remained elusive.The aim of this study was to evaluate the influence of lead exposure on the thyroid hormones, amino acid neurotransmitters balances, and intelligence quotient (IQ) among school-age children living nearby a lead-zinc mining site. Other factors such as rice lead levels, mothers' smoking behavior, and diet intake were also investigated.A total of 255 children aged 7-12 years old were recruited in this study. Blood lead level (BLL), thyroid hormones including free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH), and amino acid neurotransmitters such as glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) were measured using graphite furnace atomic absorption spectroscopy (GFAAS), chemiluminescence immunoassay, high performance liquid chromatography (HPLC). Raven's standard progressive matrices (SPM) and the questionnaire were used to determine IQ and collect related influence factors.The average BLL of children was 84.8 μg/L. The occurrence of lead intoxication (defined as the BLL ≥ 100 μg/L) was 31.8%. Serum TSH levels and IQ of lead-intoxicated children were significantly lower than those without lead toxicity. The GABA level of girls with the lead intoxication was higher than those with no lead-exposed group. Correlation analyses revealed that BLL were inversely associated with the serum TSH levels (R= -0.186, p0.05), but positively related with IQ grades (R = 0.147, p0.05). Moreover, BLL and Glu were inversely correlated with IQ. In addition, this study revealed four factors that may contribute to the incidence of lead intoxication among children, including the frequency of mother smoking (OR = 3.587, p0.05) and drinking un-boiled stagnant tap water (OR = 3.716, p0.05); eating fresh fruits and vegetables (OR = 0.323, p0.05) and soy products regularly (OR = 0.181, p0.05) may protect against lead intoxication.Lead exposure affects the serum TSH, GABA levels and IQ of school-aged children. Developing good living habits, improving environment, increasing the intake of high-quality protein and fresh vegetable and fruit may improve the condition of lead intoxication.

In this paper we present new data for the Tianquan (TQ) and Dabure (DB) ocean islands in the western segment of the Longmuco–Shuanghu–Lancangjiang suture zone, northern Tibet, including the results of major and trace element analyses, zircon U–Pb dating, and Hf isotope analyses. Our aim was to assess the genesis of these ocean islands and to consider the implications for the tectonic evolution of the region as a whole. Both TQ and DB retain an ocean-island-type double-layered structure comprising a volcanic basement (basalt and andesite) and an oceanic sedimentary cover sequence (conglomerate, limestone, and chert). The basalts and andesites in the TQ and DB are enriched in light rare earth elements and high field strength elements (Nb, Ta, Zr, Hf, and Ti), yielding chondrite-normalized REE patterns and primitive-mantle-normalized trace element patterns that are similar to those of ocean island basalts. Given the small and generally positive eHf(t) values of the TQ andesites (+ 4.25 to + 6.22) and DB andesites (− 0.59 to + 1.97, mostly > 0), we conclude that the basalts were derived from the partial melting of garnet peridotite in the mantle and that the andesites were formed by fractional crystallization of the mafic parent magma derived from the garnet peridotite mantle. The ascending magmas underwent varying degrees of fractional crystallization but were not contaminated by crustal material. These features indicate that both TQ and DB are typical ocean islands that formed in an ocean basin. Geochemical analyses of cherts from TQ and DB show that they contain terrigenous material, indicating the proximity of a continental margin. The andesites of TQ contain zircons that yield two U–Pb ages of 251 Ma. Given that ages of 246, 247, and 254 Ma had been reported previously, we conclude that TQ formed during the late Permian–Early Triassic. The andesites of DB contain zircons that yield U–Pb ages of 242 and 246 Ma. Taking into account the youngest age of 244 Ma from the DB basalt, we conclude that DB formed during the Middle Triassic. These data, combined with the geological history of the region, indicate that the development of the Longmuco–Shuanghu–Lancangjiang Paleo-Tethys Ocean continued after the early Permian and that the closure of this ocean was diachronous from east to west. The eastern segment of the ocean closed during the Early Triassic; however, the western segment remained at least partially open until the Middle Triassic, although the ocean was relatively small at this time. The ocean finally closed in the Late Triassic.

In this paper we present new major and trace element chemical data, zircon U–Pb age data, and zircon Hf isotopic compositions for the Dong Co granodiorites (DGs) that were emplaced directly in the Dong Co ophiolites (DOs) in the middle segment of the Bangong–Nujiang suture zone (BNSZ), northern Tibet. We use these new data to discuss the genesis of the DGs and implications for the evolution of the region. The DGs have high contents of SiO 2 , Al 2 O 3 , Na 2 O, and Sr, high values of Mg # , low contents of Yb and Y, and markedly high Sr/Y ratios, indicating an adakitic affinity, and we show that they were derived from the partial melting of subducted oceanic crust. The DGs contain large numbers of inherited zircons that have similar shapes and peak ages to the detrital zircons in the accretionary wedge graywackes that surround the DGs, suggesting that many of these sediments were assimilated during the formation of the DGs. Five DG samples yield the youngest zircon U–Pb ages of 155–160 Ma, indicating that the DGs formed during the Late Jurassic. Based on the present results and regional geological data, we infer that the Bangong–Nujiang oceanic lithosphere was subducted northwards beneath the Southern Qiangtang terrane during the formation of a continental arc system during the Late Jurassic. The Bangong–Nujiang oceanic lithosphere retreated rapidly after its initial subduction, and the Southern Qiangtang terrane to the north of the Bangong–Nujiang Ocean acquired a massive amount of new oceanic material in the form of an accretionary wedge. This wedge, which included the DOs and the Mugagangri Group, became sufficiently large (both in size and width) for arc-type magmas (DGs) to develop within it during the Late Jurassic.

The effects of replacing sandstone with incineration bottom ash and different water-to-cement ratios and aggregate sizes in pervious concrete bricks preparation were investigated. Among the various permeable brick specimens, the compressive strengths of 11 different mix proportions exceeded that of traditional red bricks (by 14 MPa), and was maximum for the specimen with bottom ash aggregate size #4 and a water-to-cement ratio 0.55. The permeability coefficients, although smaller than that of general pervious concrete, were within general permeable pavement specifications (10−2 cm/s). Therefore, it is recommended for general bicycle ways, sidewalks, and landscaping, not roads with high traffic flow.

We conducted in situ U–Pb analyses of zircons from three basalts and one gabbro from the Zhonggang oceanic island, one basalt from the Zhaga oceanic island, and one gabbro from the Kangqiong ophiolite (all located in the middle segments of the Bangong–Nujiang suture zone of Tibetan Plateau), as well as in situ Hf isotope analyses of zircons from one gabbro from the Zhonggang oceanic island to constrain the tectonic evolution of the Bangong–Nujiang Neo-Tethys ocean. All samples contain numerous inherited zircons, and all the zircons contain magmatic oscillatory zoning and have Th/U ratios exceeding 0.4. Moreover, the average ΣREE content of these zircons is less than 2000 ppm, and they display clear negative Eu and variable positive Ce anomalies, indicating a magmatic origin. LA–ICP–MS U–Pb dating of the zircons revealed three clear peaks in the age distribution, at 248–255, 162–168, and 117–120 Ma; Lu–Hf isotopic analyses of zircons from the gabbro of the Zhonggang oceanic island yielded a 269 Ma crust–mantle separation age. Taking into account the regional geology, previous data, and our new analyses, we infer that the middle and western segments of the Bangong–Nujiang Neo-Tethys ocean had initially opened in the late Permian (254–269 Ma) and that the ocean opened substantially between the late Permian and the Early Triassic (248–255 Ma). In addition, we infer that the initiation of subduction of the Bangong–Nujiang Neo-Tethys ocean took place at ~ 162–168 Ma, which is Middle Jurassic. The 117–120 Ma age is the time when the oceanic islands and ophiolites were formed, indicating that the Bangong–Nujiang Neo-Tethys ocean was, to some extent, still open at that time.

We present new zircon U–Pb dates, major and trace element chemistry, and Hf isotopic compositions for bimodal volcanic rocks of the Maierze Group (MG) in the Maierze area of the Southern Qiangtang–Baoshan block, northern Tibet. We discuss the implications of these data for the evolution of this region. The MG bimodal volcanic rocks consist of basalts and dacites that yield LA-ICP-MS zircon U–Pb ages of 122 and 120 Ma, respectively. The MG basalts have light rare earth element (LREE)-enriched chondrite-normalized REE patterns (LaN/YbN = 13–14), high Ti/V ratios (45–64), high Zr (190–270 ppm) and Nb (22–41 ppm) concentrations, and Zr/Y ratios (7–9) that are similar to those of within-plate basalts. The MG basalts also have low MgO and total Fe2O3 (TFe2O3) concentrations, significant enrichments in the LREE and the light ion lithophile elements (LILEs; Rb, Ba, Th, U and Pb), and weak depletions in the high field strength elements (HFSE; Nb, Ta, and Ti), all of which are clearly evident in primitive-mantle-normalized multi-element variation diagrams. The MG dacites are more enriched in the LILE (e.g., Rb, Ba, Th, U, K, and Pb) and more depleted in the HFSE (e.g., Nb, Ta, and Ti) than the MG basalts. Moreover, the dacites have variable zircon eHf(t) values (− 6.3 to + 6.3). These features indicate that the parental magma for the MG basalts was likely derived from an enriched lithospheric mantle source that was contaminated by subduction-related fluids or melts. In contrast, the MG dacites were derived from mixing of the MG basaltic magma with a second magma derived from partial melting of the continental crust. The geochemical and Hf isotopic characteristics of the MG bimodal volcanic rocks suggest that they formed during the initial stages of development of a back-arc basin. From south to north, the Bangong–Nujiang suture zone, the Duolong gold-rich porphyry copper deposit, and the Maierze bimodal rocks are interpreted to represent a remnant of a complete volcanic arc system that comprises the Bangong–Nujiang Ocean, an island arc, and a back-arc basin, respectively. The fact that this volcanic arc system was still active during the Early Cretaceous indicates that closure of the Bangong–Nujiang Ocean occurred later than the previously suggested period of between the Late Jurassic and Early Cretaceous.

In this study, the electrospinning technique was applied to fabricate biocompatible membranes composed of PLLA (poly-L-lactic acid) and chitosan. With high porosity and interconnected structure, the electrospun membranes were suitable scaffolds for cell or tissue growth. In preparations, injection rate, polymer concentration and applied voltage were varied to investigate their effects on electrospun fibers. The morphology of the electrospun membranes were observed by scanning electron microscopy (SEM). The microphotography indicated that the structures including bead, bead-in-string and nanofibers with different diameters would be controlled by adjusting the above variables. The diameter of strings is about 50 nm and the diameter of beads is ranged from 400 nm to 2 μm, depending on preparation conditions. There was the critical range in the above parameters for the formation of homogeneous nanofibers. Outside the critical range, the bead-on-a-string structures became significant instead. From in vitro experiments, the biocompatibility of electrospun membranes was analyzed by culturing osteoblastic cells with electrospun membranes and dense films. When the osteoblastic cells are cultured with nano-fibrous membranes, the cell density was higher and the secretion of fibril was more significant compared with the cells cultured on dense films. The results indicated that the biocompatibility of PLLA and chitosan would be improved by changing their topography from smooth surface into nano-scaled structures. It manifested the potential of electrospinning technique for biomedical applications.

This article describes the anatomy of the cervical spine and the most common types of fractures associated with the cervical spine. Cervical spinal cord syndromes are also reviewed because such syndromes discovered during neurologic examinations frequently provide the first clue that there is an underlying spinal cord injury. Because most associated maxillofacial and spinal injuries occur in the setting of motor vehicle accidents, it is particularly important for the maxillofacial surgeon to be cognizant of the injuries, particularly in the context of the need for facial/cranial surgery. Appropriate measures are necessary to immobilize or fixate the spine before surgery to avoid exacerbating the spinal injury.

The liquefaction resistance of the soils used to be estimated through the in situ tests, such as standard penetration test and cone penetration test; or by means of cyclic triaxial test in laboratory. However, both in situ tests and cyclic triaxial test are time-consuming and costly; this study introduces a quick and cost-effective method to evaluate the liquefaction resistance of soils under certain confining pressure in laboratory. A particular device modified from the conventional triaxial compression test apparatus, namely “Triaxial Cone Penetration Test”, was developed to obtain the peak values of cone resistance in soils so as to correlate the liquefaction resistance of the reclaimed soils evaluated by cyclic triaxial tests. The test result indicates a good correlation between the peak value of cone resistance and the corresponding cyclic stress ratio (CSR) at the state of initial liquefaction, in which the correlation for loose samples is better than that for dense samples. Besides, both peak values of cone resistance and corresponding CSR increase with fine content of soils reaches 10% and decreased with fine content varying between 10% and 50%. By examining the compositions of the soils with scanning electron microscopy and X-ray diffraction, it is found that the proportion and characteristics of the fines plays an important role on the liquefaction resistance of the reclaimed soils.

This paper aims to develop a decision-making tool that can be used by government agencies in planning for flood emergency logistics. In this article, the flood emergency logistics problem with uncertainty is formulated as two stochastic programming models that allow for the determination of a rescue resource distribution system for urban flood disasters. The decision variables include the structure of rescue organizations, locations of rescue resource storehouses, allocations of rescue resources under capacity restrictions, and distributions of rescue resources. By applying the data processing and network analysis functions of the geographic information system, flooding potential maps can estimate the possible locations of rescue demand points and the required amount of rescue equipment. The proposed models are solved using a sample average approximation scheme. Finally, a real example of planning for flood emergency logistics is presented to highlight the significance of the proposed model as well as the efficacy of the proposed solution strategy.

Phenolphthalein indicator has traditionally been used to determine the depth of carbonation in concrete. This investigation uses the thermalgravimetric analysis (TGA) method, which tests the concentration distribution of Ca(OH)2 and CaCO3, while the X-ray diffraction analysis (XRDA) tests the intensity distribution of Ca(OH)2 and CaCO3. The Fourier transformation infrared spectroscopy (FTIR) test method detects the presence of C–O in concrete samples as a basis for determining the presence of CaCO3. Concrete specimens were prepared and subjected to accelerated carbonation under conditions of 23 °C temperature, 70% RH and 20% concentration of CO2. The test results of TGA and XRDA indicate that there exist a sharp carbonation front. Three zones of carbonation were identified according to the degree of carbonation and pH in the pore solutions. The TGA, XRDA and FTIR results showed the depth of carbonation front is twice of that determined from phenolphthalein indicator.

This paper presents a seismic wave energy-based method with back-propagation neural networks to assess the liquefaction probability. An empirical equation and Fourier spectrum of acceleration are employed, respectively, to calculate the seismic wave energy. Discriminant analysis is used to determine the equation of the boundary curve separating the data points with and without liquefaction. The proposed method shows capability in evaluating the probability of soil liquefaction based on the boundary curve and a logarithm normal distribution.

Median grain size is often used as a representing size in the calculation of sediment transport. But, it may not meet the physical mean of sediment transport completely. Comparison is made on the median grain size and the grain size weighting by percentage retained. Two grain sizes are calculated on the basis of the numerous grain size distributions of bed material collected from offshore western Taiwan. It is shown that the grain size weighting by percentage retained is better than the median grain size to represent the various grain sizes of bed material. In addition, the percentage finer of the grain sizes that takes into consideration of the the weighting of the percentage retained is introduced to investigate the influences of grain sizes of bed material on water depth.

The tyrosine at position 60 of the Flp recombinase of the Saccharomyces cerevisiae plasmid, 2 μ circle, is invariant among site-specific recombinases of the “yeast plasmid family”. Alterations of this residue give rise to Flp variants that show no recombination activity when assayed in vivo in Escherichia coli. Upon purification, they bind substrate, execute DNA cleavage and catalyze recombination. The efficiency of strand cleavage follows the order: Flp(Y60F) > Flp > Flp(Y60S) > Flp(Y60D); efficiency of recombination between Flp sites on a linear substrate and a circular one follows the order: Flp > Flp(Y60F) > Flp(Y60S) > Flp(Y60D). Methylation footprints of the DNA-protein complexes formed by two of the Flp variants, Flp(Y60S) and Flp(Y60D), do not show hypermethylation of the G residues within the substrate core that is characteristic of complexes formed by wild-type Flp. The third variant, Flp(Y60F), causes significant distortion (although less than wildtype Flp) of the substrate core, as indicated by enhanced G-methylation. Binding profiles with circularly permuted substrates indicate that Flp(Y60S) and Flp(Y60D), but not Flp(Y60F), are defective in bending substrate DNA. In recombination between two Flp half-sites, the variant proteins are significantly more active than in normal full-site recombination.

A combination of site-directed mutagenesis and amino acid sequence analysis identifies Tyr-343 of Flp recombinase as the residue that covalently attaches to DNA during the strand-cleavage step of recombination. This residue is part of the invariant His-Arg-Tyr triad of the Int family of recombinases. Tyr-343 is located in a highly protease-accessible (and hence "open") region of Flp. This placement may provide the conformational flexibility required for the dual role of Tyr-343 in recombination: nicking of the DNA strands to initiate recombination and joining of the nicked strands across partner substrates to complete recombination. In-frame insertion of a few amino acids close to Tyr-343 (and to its amino-terminal side) does not affect substrate recognition by Flp but abolishes its catalytic function.