Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion.

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO3-H2SO4-HClO4-HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%-102.3%, Sb: 90.73%-110.0%, Bi: 90.00%-99.67%, Se: 93.33%-110.0%, Ge: 92.26%-104.2%) and precision (RSD%; As: 1.34%-8.96%, Sb: 2.67%-7.10%, Bi: 1.83%-4.58%, Se: 0.36%-3.25%, Ge: 4.41%-8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.

Lead contamination alters enzyme activities and microbial composition in the rhizosphere soil of the hyperaccumulator Pogonatherum crinitum.

Pogonatherum crinitum is a promising lead (Pb) hyperaccumulator; however, the effects of Pb contamination on P. crinitum rhizosphere soil enzymatic activities and microbial composition remain largely unexplored. Thus, an indoor experiment was conducted by cultivating P. crinitum seedlings and exposing them to four Pb concentrations (0, 1,000, 2000 and 3000 mg/kg Pb). Protease, urease, acid phosphatase and invertase activities were determined using standard methods while soil bacterial composition was determined by 16 S rDNA sequencing. The results showed that rhizosphere soil acid phosphatase activity significantly increased with increasing Pb concentration, while urease activity was significantly greater in rhizosphere soil contaminated with 1000 and 2000 mg/kg than in the control. There was a clear shift in bacterial composition during phytoremediation by P. crinitum. Compared to the control, Bacteroidetes was more abundant in all Pb-contaminated soils, Actinobacteria was more abundant in 1000 mg/kg Pb-treated soil, and Firmicutes was more abundant in 3000 mg/kg Pb-treated soil. Positive correlations were observed between dominant bacterial phyla and soil enzyme activities. Metabolic pathways, such as ABC transporter, quinine reductase, and ATP-binding protein were significantly increased in rhizosphere soil bacteria with Pb contamination. In conclusion, Pb contamination differentially influenced the activities of rhizosphere soil enzymes, specifically increasing acid phosphatase and urease activities, and alters the dominance of soil bacteria through up-regulation of genes related to some metabolic pathways. The strong correlations between dominant bacterial phyla and enzymatic activities suggest synergetic effects on the growth of P. crinitum during Pb contamination.

Two lichens differing in element concentrations have similar spatial patterns of element concentrations responding to road traffic and soil input.

Two epiphytic lichens (Xanthoria alfredii, XAa; X. ulophyllodes, XAu) and soil were sampled at three sites with varied distances to a road in a semiarid sandland in Inner Mongolia, China and analyzed for concentrations of 42 elements to assess the contribution of soil input and road traffic to lichen element burdens, and to compare element concentration differences between the two lichens. The study showed that multielement patterns, Fe:Ti and rare earth element ratios were similar between the lichen and soil samples. Enrichment factors (EFs) showed that ten elements (Ca, Cd, Co, Cu, K, P, Pb, S, Sb, and Zn) were enriched in the lichens relative to the local soil. Concentrations of most elements were higher in XAu than in XAa regardless of sites, and increased with proximity to the road regardless of lichen species. These results suggested that lichen element compositions were highly affected by soil input and road traffic. The narrow-lobed sorediate species were more efficient in particulate entrapment than the broad-lobed nonsorediate species. XAa and XAu are good bioaccumulators for road pollution in desert and have similar spatial patterns of element concentrations for most elements as response to road traffic emissions and soil input.

Determination of Elemental Concentrations in Lichens Using ICP-AES/MS.

Lichens are good biomonitors for air pollution because of their high enrichment capability of atmospheric chemical elements. To monitor atmospheric element deposition using lichens, it is important to obtain information on the multi-element concentrations in lichen thalli. Because of serious air pollution, elemental concentrations in thalli of lichens from North China (especially Inner Mongolia, Hebei, Shanxi and Henan province) are often higher than those from other regions, therefore highlighting the necessity to optimize ICP-AES/MS (Inductively coupled plasma-atomic emission spectroscopy/mass spectrometry) for analyzing lichen element content. Based on the high elemental concentrations in the lichen samples, and the differences in the sensitivity and detection limits between ICP-MS and ICP-AES, we propose a protocol for analyzing 31 elements in lichens using ICP-AES/MS. Twenty-two elements (Cd, Ce, Co, Cr, Cs, Cu, K, La, Mo, Na, Ni, Pb, Rb, Sb, Sc, Sm, Sr, Tb, Th, Tl, V and Zn) can be identified by using microwave digestion- ICP-MS, and 9 elements (Al, Ba, Ca, Fe, Mg, Mn, P, S and Ti) by using ashing-alkali fusion digestion- ICP-AES.

[Analysis of Cut-off Value in Screening of Thalassemia by Capillary Hemoglobin Electrophoresis for Pregnant Women from Shenzhen Region of China].

OBJECTIVE: To investigate the cut-off value in screening of thalassemia in pregnant women from Shenzhen region by capillary hemoglobin electrophoresis. METHODS: The data of capillary hemoglobin electrophoresis and genetic diagnosis of thalassemia from 2122 examined prenatal women were retrospectively analyzed. Capillary hemoglobin electrophoresis and α-, ß- genetic diagnosis of thalassemia were carried out for every woman. Hemoglobin electrophoresis was performed using Capillarys 2 full-automated electrophoresis instrument. Gap polymerase chain reaction and reverse dot blot were used for genetic diagnosis of thalassemia genotyping test. The cut-off value in screening of thalassemia was determined by receiver operating characteristic curve and next to analyze the value of HbA2 and HbF in screening of thalassemia using the decided cut-off value. RESULTS: The areas under the curve (AUC(Roc)) of HbA2 for diagnosis of α-, ß- thalassemia were 0.75 and 0.981 respectively, and the AUC(Roc) of HbF for diagnosis of ß-thalassemia was 0.787. When HbA2 ≤ 2.55 was taken as the cut-off value of HbA2 for diagnosis of α-thalassemia, the sensitivity, specificity, positive likelihood ratio (LR(+)) and negative likelihood ratio (LR(-)) were 89.5%, 54.8%, 1.98, 0.19 respectively. When HbA2 ≥3.9 was taken as the cut off value of HbA2 for diagnosis of ß-thalassemia, the sensitivity, specificity, LR(+) and LR(-) were 96.1%, 99.8% 480.5, 0.04 respectively. When HbF ≥0.75 was taken as the cut off value of HbF for diagnosis of ß-thalassemia, the sensitivity, specificity, LR(+) and LR(-) were 83.6%, 61.8% respectively. CONCLUSION: The cut-off value in screening of thalassemia by capillarys 2 full automated electrophoresis instrument is different from that of the traditional method of hemoglobin electrophoresis, such as cellulose acetate membrane electrophoresis and agarose gel electrophoresis. Each laboratory should establish their own respective cut off value.

Evaluation of NIN/RPN12 binding protein inhibits proliferation and growth in human renal cancer cells.

The targeted delivery of small interfering RNA (siRNA) to specific tumor tissues and tumor cells remains as one of the key challenges in the development of RNA interference as a therapeutic application. The ribosome assembly factor NIN/RPN12 binding protein (NOB1) has been suggested to be essential for processing of the 20S pre-rRNA to the mature 18S rRNA, and is also reported to participate in proteasome biogenesis. However, it is unclear whether NOB1 is involved in tumor cells growth. The aim of this study was to determine whether the suppression of lentivirus mediated NOB1 siRNA inhibits the growth of human clean cell carcinoma (ccRCC) cells, further focused on NOB1 as a possible therapeutic target for renal cell carcinoma treatment. NOB1 deletion that caused significant decline in cell proliferation was observed in both 786-O and ACHN cell lines as investigated by MTT assay. Further, the number and size of the colonies formed were also significantly reduced in the absence of NOB1. Moreover, NOB1 gene knockdown arrested the cell cycle and inhibited cell cycle-related protein expression. The Kaplan-Meier survival curves revealed that low NOB1 expression was associated with poor prognosis in ccRCC patients. Collectively, these results indicate that NOB1 plays an essential role in renal cell cancer cell proliferation, and its gene expression could be a therapeutic target.

[Signal transducers and activators of transcription-3 modulates human squamous cell carcinoma invasion via targeting mircoRNA-21 in vitro].

OBJECTIVE: To investigate the effect and mechanism of signal transducers and activators of transcription 3 (STAT-3) modulates human tongue squamous cell carcinoma invasion ability via targeting mircoRNA-21. METHODS: Tscca and Tca8113P160 human tongue squamous cell carcinoma cell lines were used.WP1066 (STAT-3 inhibitor) , the small molecule inhibitor of STAT-3 was used to suppress the STAT-3 expression. The half maximal inhibitory concentration (IC50 value) of WP1066 in the two cell lines was determined by methyl thiazolyl tetrazolium (MTT) assay. The expression level of STAT-3 and phosphorylation of STAT-3 (pSTAT-3) was examined by Western blotting. Real-time PCR was used to detect the mircoRNA-21 expression after treated with WP1066. Matrigel matrix and transwell assay were used to determine cancer cell colony formation and invasion ability after treated with WP1066. Tumor invasion related proteins in Tscca and Tca8113P160 cell lines were measured by Western blotting. Luciferase reporter gene assay was conducted to detect the relationship between STAT-3 and mircoRNA-21. RESULTS: The IC50 to WP1066 in Tscca cell was 3.1 and 3.5 µmol/L for Tca8113P160 cell respectively. STAT-3/pSTAT-3 protein level was suppressed significantly (Tscca: STAT-3: F = 887.154, P = 0.000; pSTAT-3: F = 332.212, P = 0.000; Tca8113P160: STAT-3: F = 322.895, P = 0.000; pSTAT-3:F = 788.357, P = 0.000). mircoRNA-21 expression was down-regulated (Tscca:F = 32.157, P = 0.000; Tca8113P160: F = 11.349, P = 0.007). The diameters of culture clone in cell treated with WP1066 were less than control groups (Tscca:F = 15.751, P = 0.004; Tca8113P160: F = 12.964, P = 0.007). The number of tongue cancer cell migrating through the transwell membrane in WP1066 treated group was less than in control groups (Tscca: F = 1688.926, P = 0.000; Tca8113P160: F = 327.528, P = 0.000). In addition, MMP-2/9 protein expression was decreased in both of the cell lines treated with WP1066, while TIMP-3 was up regulated dramatically. STAT-3 could modulate mircoRNA-21 directly. CONCLUSIONS: Reduction of STAT-3 can inhibit tongue cancer cell invasion ability via targeting mircoRNA-21.

[Research progress on the biology and epidemiology of Cyclospora cayetanensis].

Cyclosporiasis is one of the emerging parasitic diseases. Cyclospora cayetanensis is so far the only species infecting humans in the Cyclospora genus. This paper reviews mainly the biological characteristics of C. cayetanensis and the current epidemiology status of human infection.

Nuclear deformation during breast cancer cell transmigration.

Metastasis is the main cause of cancer mortality. During this process, cancer cells dislodge from a primary tumor, enter the circulation and form secondary tumors in distal organs. It is poorly understood how these cells manage to cross the tight syncytium of endothelial cells that lines the capillaries. Such capillary transmigration would require a drastic change in cell shape. We have therefore developed a microfluidic platform to study the transmigration of cancer cells. The device consists of an array of microchannels mimicking the confined spaces encountered. A thin glass coverslip bottom allows high resolution imaging of cell dynamics. We show that nuclear deformation is a critical and rate-limiting step for transmigration of highly metastatic human breast cancer cells. Transmigration was significantly reduced following the treatment with a protein methyltransferase inhibitor, suggesting that chromatin condensation might play an important role. Since transmigration is critical for cancer metastasis, this new platform may be useful for developing improved cancer therapies.

Effect on multifocal electroretinogram in persistently elevated intraocular pressure by erigeron breviscapus extract.

AIM: To observe the effect on multifocal electroretinogram (mfERG) in persistently elevated intraocular pressure (IOP) by erigeron breviscapus extract (also named Dengzhanhua in Chinese) in rat models. METHODS: The rat models with persistently elevated IOP were established by the method of Akira. Then, erigeron breviscapus extract was given for one month to observe the effect on mfERG in persistently elevated IOP in rats. RESULTS: As elevated IOP went on, the mfERG changes were mainly in weaken of reaction density with progressive development. After intervention of erigeron breviscapus extract, the total peak latency of P1 wave had recovered to some extent and the difference was significant when compared with control group (P<0.05); the total response density and P1 wave response density in second circle had risen noticeably, which had significant differences than those of control group (P<0.05). CONCLUSION: Erigeron breviscapus extract can improve the impaired visual function of persistently elevated IOP in rats, suggesting that this extract is the effective part of erigeron breviscapus for optic neuroprotection.

[Evaluation of right ventricular function of patients with intraoperative device closure of atrial septal defect by ultrasonic Doppler tissue imaging].

OBJECTIVE: To study the application of Doppler tissue imaging (TDI) in the assessment of right ventricular function of patients with intraoperative device closure of atrial septal defect (ASD). METHODS: A total of 48 ASD patients, 18 males and 30 females, were selected for intraoperative device closure. The mean age was 31 +/- 16 years old. Color Doppler echocardiographic instrument (Sonos 4500) was employed to perform the Doppler tissue imaging before and at 3-5 days after operation. The parameters included: (1) Time and peak speed of systolic motion of anterior tricuspid valve annulus (TDI-TS, TDI-PVS), early diastole motion time (TDI-TE) and late diastolic motion time (TDI-TA) and peak speed of early and late diastolic motion (TDI-PVE, TDI-PVA), interval between the early diastolic motion and late diastolic motion (TDI-TE-A); (2) Peak speed of systolic, early diastolic and late diastolic motions of the middle lateral and basic lateral walls of right ventricle. RESULTS: The TDI-PVS (0.16 +/- 0.05) m/s in post-operation was decreased than TDI-PVS (0.20 +/- 0.04) m/s in pre-operation and TDI-PVA (0.12 +/- 0.03) m/s in post-operation was decreased than TDI-PVA (0.16 +/- 0.02) m/s in pre-operation apparently (P < 0.01). The TDI-TS (231 +/- 36) msec in post-operation were shorter than TDI-TS (265 +/- 24) msec in pre-operation (P < 0.01). Peak spead of Systolic, early diastolic and late diastolic motions of middle lateral and basic lateral walls of right ventricle declined post-operatively (P < 0.01). CONCLUSION: TDI is an effective method to evaluate the function of right ventricle quantitatively in patients with intraoperative device closure of ASD.

[ICP-AES determination of Cu2+, Pb2+ and Cd2+ with adsorption behavior of potassium hexatitanate whisker].

A new method for the determination of free Cu2+, Pb2+ and Cd2+ in environmental sample using potassium hexatitanate whisker as a solid-phase extractant and inductively coupled plasma-atomic emission spectrometry (ICP-AES) as a sensitive detector has been developed. The adsorption rate of Cu2+, Pb2+ and Cd2+ by potassium hexatitanate whisker was 98% at pH 5.0, and Cu2+, Pb2+ and Cd2+ could be eluted from potassium hexatitanate whisker with HNO3 (C: 3 mol x L(-1)). The Cu2+, Pb2+ and Cd2+ in environmental samples were preconcentrated with potassium hexatitanate whisker and determined by ICP-AES, the detection limits of Cu2+, Pb2+ and Cd2+ (3sigma, n = 9) were 0.007 1, 0.006 8 and 0.007 1 microg x mL(-1), and the relative standard deviations (RSD) were 0.63%, 0.61% and 0.50%, respectively. The method was applied to the determination of analytes in real samples, such as chrysanthemum and loquat leaf. And good results were obtained (recoveries were 90%-102.9%). The results obtained indicate that the potassium hexatitanate whisker has good regenerate capability.

[Flame atomic absorption spectrometry determination of cadmium in environmental water with preconcentration and separation by sodium trititanate whisker].

Sodium tertitanate whisker is a new material for preconcentration. The adsorption properties of sodiium trititanate whisker for Cd(II) were studied and a new method for preconcentration and separation of Cd(II) was proposed. The adsorption rate of Cd(II) by sodium trititanate whisker was 98% at pH 5.0 and Cd(II) could be eluted from sodium trititanate whisker with hydrochloric acid (C: 0.1 mol x L(-1)). The Cd(II) in environmental water was preconcentrated with sodium trititanate whisker and determined by flame atomic absorption spectrometry (FAAS). The detection limit (3sigma, n = 9) was 3.1 ng x L(-1), and the relative standard deviation (RSD) was 2.6%. The response of proposed method is linear in the concentration range of 0.01-1.0 microg x mL(-1) of Cd(II). The method was applied to the determination of analytes in real samples, such as Changjiang River water, Canal water, Yudai River water etc. Good results were obtained (relative standard deviations were 1.5%-4.7%, while recoveries were 98%-102.0%).

[Expression of mGluR1 at primary visual cortex of monocular deprivation amblyopia rat and the observing of ultrastructure].

OBJECTIVE: To explore the regulation of expression of mGluR1 and the changes of neuron ultrastructure at primary visual cortex of monocular deprivation amblyopia rat within cortical period. METHODS: Taking randomized concurrent controlled trail. Establishing the model of monocular deprivation amblyopia rat. After proving the model successful by PVEP, all of the rats were randomly divided into three groups: normal visual cortex, experimental visual cortex and experimental opposite visual cortex. Immunocytochemical technology, electron microscope, photography microscope, computer image analysis, SPSS 11.5 and ANOV were used to get the results. RESULTS: Compared with the layer IV of normal visual cortex and experimental opposite visual cortex, the area of immunopositive neurons in layer IV of experimental visual cortex are deficiency, there is significant difference between them (P < 0.01). There are no significant differences between the other four corresponding layers (P > 0.05). Morphological abnormals were found in layer IV of experimental visual cortex by observing of ultrastructure. CONCLUSION: The expression of mGluR1 in layer IV of primary visual cortex of monocular deprivation amblyopia is reduced. There are morphological abnormals happened in layer IV of primary visual cortex of monocular derivation amblyopia. Reduced afference of nerve pulse because of monocular deprivation leads to the expression deficiency of mGluR1 in layer IV of the primary visual cortex, then synaptic plasticity happened, then neurons atrophy occurred may be one of the etiopathogenesis of amblyopia.