Ginkgo biloba L. exocarp petroleum ether extract inhibits methicillin-resistant Staphylococcus aureus by modulating ion transport, virulence, and biofilm formation in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

As reported in the Ancient Chinese Medicinal Books, Ginkgo biloba L. fruit has been used as a traditional Chinese medicine for the treatment asthma and cough or as a disinfectant. Our previous study demonstrated that G. biloba exocarp extract (GBEE), an extract of a traditional Chinese herb, inhibits the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms. However, GBEE is a crude extract that contains many components, and the underlying mechanisms of purified GBEE fractions extracted with solvents of different polarities are unknown.

AIM OF THE STUDY

This study aimed to investigate the different components in GBEE fractions extracted with solvents of different polarities and their antibacterial effects and mechanisms against MRSA and Staphylococcus haemolyticus biofilms both in vitro and in vivo.

METHODS

The components in different fractions were detected by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). Microbroth dilution assays and time growth curves were used to determine the antibacterial effects of the fractions on 15 clinical bacterial isolates. Crystal violet staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to identify the fractions that affected bacterial biofilm formation. The potential MRSA targets of the GBEE fraction obtained with petroleum ether (PE), denoted GBEE-PE, were screened by transcriptome sequencing, and the gene expression profile was verified by quantitative polymerase chain reaction (qPCR).

RESULTS

HPLC-HRMS analysis revealed that the four GBEE fractions (extracted with petroleum ether, ethyl acetate, n-butanol, and water) contained different ginkgo components, and the antibacterial effects decreased as the polarity of the extraction solvent increased. The antibacterial activity of GBEE-PE was greater than that of the GBEE fraction extracted with ethyl acetate (EA). GBEE-PE improved H. illucens survival and reduced MRSA colonization in model mouse organs. Crystal violet staining and SEM and TEM analyses revealed that GBEE-PE inhibited MRSA and S. haemolyticus biofilm formation. Transcriptional analysis revealed that GBEE-PE inhibits MRSA biofilms by altering ion transport, cell wall metabolism and virulence-related gene expression. In addition, the LO2 cell viability and H. illucens toxicity assay data showed that GBEE-PE at 20 mg/kg was nontoxic.

CONCLUSION

The GBEE fractions contained different components, and their antibacterial effects decreased with increases in the polarity of the extraction solvent. GBEE-PE limited MRSA growth and biofilm formation by affecting ion transport, cell wall synthesis, and virulence-related pathways. This research provides a more detailed overview of the mechanism by which GBEE-PE inhibits MRSA both in vitro and in vivo and suggests that GBEE-PE is a new prospective antimicrobial with the potential to be used in MRSA therapeutics in the future.

[Application of synthetic MRI in predicting isocitrate dehydrogenase 1 genotypes in gliomas]

This study analyzed the clinical and imaging data of 81 glioma patients who underwent brain synthetic MRI and diffusion weighted imaging (DWI) examination in the General Hospital of Ningxia Medical University from August 2020 to September 2021 to explore the value of synthetic MRI relaxation quantitative value in predicting the genotype of isocitrate dehydrogenase 1 (IDH1) in gliomas. There were 44 males and 37 females, those patients with an aged 50.0 (36.5, 59.0) years. The tumor pre-T1, pre-T2, pre-PD, post-T1 and ADC values were obtained by outlining the region of interest (ROI). Univariate analysis was used to compare the differences of parameter values between groups, and the receiver operating characteristic was used to evaluate the diagnostic efficacy of each parameter value in predicting glioma IDH1 genotype. The results showed that the pre-T1 and pre-PD values [M (Q1, Q3)] of IDH1m glioma were lower than those of IDH1w glioma [1 462.75 (1 306.41, 1 567.75) ms vs 1 532.83 (1 434.67, 1 617.67) ms, 84.18 (82.28, 86.41) pu vs 85.85 (84.65, 86.90) pu] (all P<0.05). The post-T1 and ADC values of IDH1m glioma were higher than those of IDH1w glioma [1 054.50 (631.92, 1 262.63) ms vs 669.67 (535.17, 823.33) ms, 1.20 (0.86, 1.35) ×10-3 mm2/s vs 0.80 (0.76, 0.93) ×10-3 mm2/s] (all P<0.05). The AUC of the combined model (pre-T1+pre-PD+post-T1+ADC+Age) is 0.828 (95%CI:0.729-0.903). Synthetic MRI relaxation quantitative values are helpful to distinguish IDH1 genotypes in glioma. The diagnostic efficacy of the multi-parameter combined model based on pre-T1, pre-PD, post-T1, ADC, and age is better than that of the single parameter, and it can be used as an effective strategy to improve the differential diagnosis ability of gliomas molecular markers.

[Thoracoscopic laparoscopy-assisted Ivor-Lewis resection of esophagogastric junction cancer]

Objective: To investigate the outcome of patients with esophagogastric junction cancer undergoing thoracoscopic laparoscopy-assisted Ivor-Lewis resection. Methods: Eighty-four patients who were diagnosed with esophagogastric junction cancer and underwent Ivor-Lewis resection assisted by thoracoscopic laparoscopy at the National Cancer Center from October 2019 to April 2022 were collected. The neoadjuvant treatment mode, surgical safety and clinicopathological characteristics were analyzed. Results: Siewert type Ⅱ (92.8%) and adenocarcinoma (95.2%) were predominant in the cases. A total of 2 774 lymph nodes were dissected in 84 patients. The average number was 33 per case, and the median was 31. Lymph node metastasis was found in 45 patients, and the lymph node metastasis rate was 53.6% (45/84). The total number of lymph node metastasis was 294, and the degree of lymph node metastasis was 10.6%(294/2 774). Among them, abdominal lymph nodes (100%, 45/45) were more likely to metastasize than thoracic lymph nodes (13.3%, 6/45). Sixty-eight patients received neoadjuvant therapy before surgery, and nine patients achieved pathological complete remission (pCR) (13.2%, 9/68). Eighty-three patients had negative surgical margins and underwent R0 resection (98.8%, 83/84). One patient, the intraoperative frozen pathology suggested resection margin was negative, while vascular tumor thrombus was seen on the postoperative pathological margin, R1 resection was performed (1.2%, 1/84). The average operation time of the 84 patients was 234.5 (199.3, 275.0) minutes, and the intraoperative blood loss was 90 (80, 100) ml. One case of intraoperative blood transfusion, one case of postoperative transfer to ICU ward, two cases of postoperative anastomotic leakage, one case of pleural effusion requiring catheter drainage, one case of small intestinal hernia with 12mm poke hole, no postoperative intestinal obstruction, chyle leakage and other complications were observed. The number of deaths within 30 days after surgery was 0. Number of lymph nodes dissection, operation duration, and intraoperative blood loss were not related to whether neoadjuvant therapy was performed (P>0.05). Preoperative neoadjuvant chemotherapy combined with radiotherapy or immunotherapy was not related to whether postoperative pathology achieved pCR (P>0.05). Conclusion: Laparoscopic-assisted Ivor-Lewis surgery for esophagogastric junction cancer has a low incidence of intraoperative and postoperative complications, high safety, wide range of lymph node dissection, and sufficient margin length, which is worthy of clinical promotion.

Comparison of Clinical Effects of the Modified Masquelet Technique and Kirschner Wire External Fixation-Assisted Autogenous Bone Transplantation in the Treatment of Segmental Metacarpophalangeal Bone Defects

Objective

The present study aims to explore the (1) clinical effects of the modified Masquelet technique, whose improved Masquelet technique innovates the in vitro plasticity of the bone cement module and prefabricated hollow design, and the Kirschner wire external fixation-assisted autologous bone transplantation technique in the treatment of segmental metacarpophalangeal bone defects and (2) the differences between the two techniques.

Methods

The clinical data of 32 patients with segmental metacarpophalangeal bone defects (15 patients treated with the modified Masquelet technique and 17 patients treated with the self-made Kirschner wire external fixation technique) admitted to our department between January 2012 and January 2020 were retrospectively analyzed. The postoperative bone healing time, hand function, and complications were compared between the two groups.

Results

The two groups were comparable; there were no significant differences in age, sex, length of bone defect, and time from injury to operation between the two groups (P > 0.05). All patients were followed up with for 6–24 months (average = 13.7 months), and all patients with segmental metacarpophalangeal bone defects achieved fracture healing. The postoperative hospital stay, fracture healing time, functionary scores of the affected limb, and incidence of severe complications were better in the modified group than in the external fixation group (P < 0.05).

Conclusion

Compared with the Kirschner wire external fixation stent assisted autologous bone transplantation, the improved Masquelet technique has the advantages of simple operation, fast healing, accurate effect, wide indications, and less complications, making it more worthy of clinical promotion.

Temperature-Dependent Tunneling in Furan Oligomer Single-Molecule Junctions

Two commonly observed charge transport mechanisms in single-molecule junctions are coherent tunneling and incoherent hopping. It has been generally believed that tunneling processes yield temperature-independent conductance behavior and hopping processes exhibit increasing conductance with increasing temperature. However, it has recently been proposed that tunneling can also yield temperature-dependent transport due to the thermal broadening of the Fermi energy of the contacts. In this work, we examine a series of rigid, planar furan oligomers that are free from a rotational internal degree of freedom to examine the temperature dependence of tunneling transport directly over a wide temperature range (78-300 K). Our results demonstrate conductance transition from a temperature-independent regime to a temperature-dependent regime. By examining various hopping and tunneling models and the correlation between the temperature dependence of conductance and molecular orbital energy offset from the Fermi level, we conclude thermally assisted tunneling is the dominant cause for the onset of temperature-dependent conductance in these systems.

[Perinatal outcomes on mortality and influencing factors among HIV-infected mothers in Sichuan province]

Objective: To explore the influencing factors on perinatal mortality of pregnant women with HIV infection to reduce the mother-to-child transmission in Sichuan province. Methods: In this study, 4 786 perinatal infants of the HIV-infected pregnant women were included. Related data on perinatal epidemiology was reported by all the 183 medical and health care institutions where the HIV prevention of mother-to-child transmission program was initiated in 2005-2016. Univariate χ(2) test and multivariate logistic regression methods were used to analyze the perinatal mortality outcomes and influencing factors. Results: The overall perinatal mortality rate was 25.7‰ (123/4 786) among HIV-infected pregnant women, with annual downwarding trend (trend χ(2)=32.220, P=0.000). Perinatal mortality rate appeared the highest (χ(2)=4.130, P=0.042), with more fetal deaths and stillbirths and less early neonatal death within 7 days in Liangshan county (χ(2)=29.626, P=0.000). Results from the multivariate logistic regression analysis showed that fewer pregnant numbers would contribute to the, lower perinatal mortality rate (1-2 pregnancies OR=0.417, 95%CI: 0.184-0.943; 3-4 pregnancies OR=0.447, 95%CI: 0.223-0.895). Perinatal deaths were more likely to be prevented if LPV/r protease inhibitor-based triple antiviral therapy was provided (OR=0.530, 95%CI: 0.285- 0.986) or delivery was taken place in the hospital (hospital of municipal-level and above OR=0.222, 95%CI:0.098-0.499; county-level hospital OR=0.282, 95%CI: 0.166-0.480; township-level hospital OR=0.134, 95%CI: 0.031-0.586) among HIV-infected pregnant women. However, premature delivery or neonatal asphyxia would increase the risk of perinatal mortality (premature delivery OR=8.285, 95%CI: 5.073-13.533; neonatal asphyxia OR=9.624, 95%CI: 4.625-20.028). Conclusions: The perinatal mortality rate of HIV-infected pregnant women appeared significantly higher than that in the province or the whole country. Strategies involving LPV/r-based triple antiviral therapy, promotion of hospital delivery, reducing the incidence rates of premature deliveries and neonatal asphyxia, should be strengthened.

Microscopic anatomy and ultrastructure of the resin ducts of Ferula ferulaeoides (Steud.) Korov. in Xinjiang

Ferula ferulaeoides (Steud.) Korov. is a perennial herb that belongs to Umbelliferae (Apiaceae). Its resin and roots have extensive commercial and medicinal value in the Xinjiang region. However, the resin-secreting resin ducts (RDs) of F. ferulaeoides have not been studied in detail. This study used optical and transmission electron microscopy to explore the anatomical features, including the distribution, size, and structure, of the RDs among different organs of F. ferulaeoides. The microstructure data revealed that the RDs consisted of a round lumen, a layer of secretory cells, and multiple layers of sheath cells. Notably, the RDs in stem were arranged alternatively in a multilayered ring with vascular bundles of three distinct sizes. The ultrastructural analysis revealed that organelles in the secretory cells potentially play important roles in resin secretion. Those data may be of great significance to understanding the anatomy of the RDs in Ferula L. and Umbelliferae.

[Study on the correlation between prognosis of patients with chronic hepatitis B under interferon treatment and polymorphism of both calcitonin gene related peptide and receptor activity modifying protein 1]

Objective: To analyze the association of two single-nucleotide polymorphisms (SNP) [Calcitonin gene related peptide (CGRP) rs155209 and receptor activity modifying protein 1 (RAMP1) rs3754701] and the prognosis of chronic hepatitis B patients who were under interferon therapy. Methods: A total of 317 patients and their anticoagulant blood samples were collected in this study. The SNPs in the CGRP and region RAMP1 were genotyped using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Logistic regression method was used to assess the results from different phenotypic outcomes between cases and controls, after adjusted for sex and age in co-dominant, dominant and recessive genetic models. Results: Data from this study clearly demonstrated the relevance of CGRP rs155209 and RAMP1 rs3754701 with DNA response and ALT response. RAMP1 rs3754701T was strongly associated with both DNA response and ALT response (OR=2.277, 95%CI: 1.386-3.741, P=0.001; OR=1.694, 95%CI: 1.073-2.675, P=0.024). However, CGRP rs155209C was less prone to DNA response and ALT response (OR=0.150, 95%CI: 0.083-0.271, P<0.001; OR=0.583, 95%CI: 0.367-0.925, P=0.022). Conclusions: Results from our study suggested that both RAMP1 rs3754701 and CGRP rs155209 were associated with the prognosis of patients under interferon therapy in Han population, from the northern parts of China while RAMP1 rs3754701T was a protective factor for both ALT response and DNA response, but CGRP rs155209C carriers were less prone to DNA and ALT responses.

[Surgical treatment for esophageal cancer during the outbreak of COVID-19]

Since December 2019, unexplained pneumonia has appeared in Wuhan City, Hubei Province, and a new type of coronavirus infection was confirmed as COVID-19. COVID-19 spread rapidly nationwide and abroad. The COVID-19 has brought huge impacts to all the people and walks of life, especially to the medical and health systems. It has also brought great challenges to the treatment of patients with cancer. Esophageal cancer is a common malignant tumor in China and most of the patients are in the middle and advanced stage when diagnosed, with immunosuppressive and poor prognosis. The selection of surgical procedures and perioperative managements of esophageal cancer require all thoracic surgeons work together to figure out a reasonable system of surgical treatment and emergency response.

Measuring the expression and activity of the CAT enzyme to determine Al resistance in soybean

To elucidate the mechanism of soybean resistance to Al, physiological and biochemical indices and antioxidant enzyme expression and activities were systematically analyzed in Al-sensitive (Glycine max Merr., Yunnan Province of China, SB) and Al-resistant Dambo (Glycine max Merr., Kyoto of Japan, RB) black soybean plants. According to the results, the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in RB root tips were significantly lower than those in SB root tips, though the opposite results occurred for soluble protein contents. Moreover, the expression and activities of superoxide dismutase (SOD, EC1.15.1.1.1.1.1.1), peroxidase (POD, EC1.11.1.7) and catalase (CAT, EC1.11.1.6) under 0-400 μM Al for 0-96 h were greater in RB than in SB. However, below 100 μM Al, the activities of those enzymes in SB increased with increasing Al concentration and treatment duration, with SOD activity being lowest and CAT activity exceeding that of POD with increasing Al concentration. Overall, enzyme activity in SB treated with Al at concentrations greater than 200 μM was lower than that in the SB control (CK; not treated with Al) and decreased with treatment duration. Additionally, at Al concentrations lower than 200 μM, enzyme activities in RB were significantly greater than those in RB CK and increased with both Al concentration and treatment duration. Moreover, enzyme activity in RB treated with 400 μM Al was slightly greater than that in RB CK. Thus, CAT activity determines soybean resistance to Al. These results indicate that soybean resistance to Al can be enhanced by regulating the expression and activity of antioxidant enzymes to remove H2O2 under Al stress.

[Clinical differences between primary nasopharyngeal NK/T-cell lymphoma and primary nasal cavity NK/T-cell lymphoma with nasopharynx extension]

Objective: To investigate the clinical and prognostic differences between primary nasopharyngeal natural killer (NK)/T-cell lymphoma (NP NKTCL) and extranodal NK/T-cell lymphoma of the nasal cavity with nasopharynx extension (N-NP NKTCL). Methods: A total of 89 patients with NP NKTCL and 113 patients with N-NP NKTCL from January 2000 to June 2015 were retrospectively analyzed. Clinical and pathological features, treatment responses and prognosis were compared between the two groups. Results: NP NKTCL patients showed similar clinicopathological features with those with N-NP NKTCL, except that the former had a relative low proportion of elevated lactate dehydrogenase (LDH) levels (28.1% vs. 41.6%; P=0.001). Both of two groups presented with high proportion of cervical lymph node involvement (55.1% and 42.5%; P=0.076). The 5-year overall survival (OS) rates in these two groups were 63.2% and 54.6%, respectively, whereas 5-year progress-free survival (PFS) rates were 50.7% and 45.6%, respectively. For the patients with stage Ⅰ and Ⅱ, the 5-year OS and PFS rates in these two groups were 68.8% and 55.7% as well as 55.6% and 47.2%, respectively. These were no statistically significant differences between two groups (all P>0.05). The complete response (CR) rate after initial chemotherapy in NP NKTCL group was 43.8%, which was significant higher than that of 19.6% in N-NP NKTCL group (P=0.006). Additionally, the CR rate after primary radiotherapy was 63.4% and 62.7%, respectively (P=0.629). The NP NKTCL patients with stage Ⅰ and Ⅱ who accepted radiotherapy with or without chemotherapy had similar survival times with chemotherapy alone, showing the 5-year OS rates of 70.5% and 33.3% (P=0.238), as well as the 5-year PFS rates of 56.7% and 33.3%, respectively (P=0.431). Similar results were found in N-NP NKTCL group, the 5-year OS rates for patients with radiotherapy with or without chemotherapy and chemotherapy alone were 57.4% and 33.3% (P=0.246), while the 5-year PFS rates were 49.3% and 16.7% (P=0.177), respectively. Besides, the relapse pattern of NP NKTCL and N-NP NKTCL groups was also similar, mainly involving the distant extra-nodal organs followed by lymph nodes. Conclusion: The patients with N-NP NKTCL and NP NKTCL showed similar clinical and prognostic features, however, the initial response to chemotherapy was different.

[Screening of the SETX gene in sporadic amyotrophic lateral sclerosis patients of Chinese origin]

Objective: To investigate all coding regions of amyotrophic lateral sclerosis (ALS)-related gene Senataxin (SETX) in sporadic amyotrophic lateral sclerosis patients of Chinese origin. Methods: From January 2010 to December 2014, the peripheral venous blood samples and clinical data were collected from 311 patients with sporadic amyotrophic lateral sclerosis (SALS) and 311 healthy controls who were of Chinese ancestry from the Department of Neurology, Chinese PLA General Hospital.Genomic DNA was extracted from peripheral venous blood of all participants using standard methods. The coding regions of SETX were amplified by polymerase chain reaction (PCR) and screened for mutations using next-generation sequencing technology. The online software SIFT and PolyPhen-2 were used to analyze the conservation of an altered amino acid and predict the potential pathogenicity of identified mutations. The SPSS 22.0 software was used to analyze the clinical feature of all participants. Results: Tenkinds of rare and one novel nonsynonymous mutations were identified and were absent in 311 controls. Twelve (3.86%) patients carried one SETX gene mutation. Five (1.61%) out of above-mentioned 12 patients carried highly pathogenic mutations including p. Pro1868Leu (c.5603G>A), p. Pro1331Leu (c.3992G>A), p. Glu756Val (c.2267T>A), p. Leu564Val (c.1690A>C), and p. Asn144Ser (c.431T>C). Patients carried SETX mutations were not different from other patients in onset age. Conclusion: Mutations in SETX are likely to be a pathogenesis for Chinese sporadic amyotrophic lateral sclerosis.

[Study on the characters of wideband tympanometry in newborns with normal hearing]

Objective:The aim of this study is to establish the characteristic of wideband tympanometry (WBT) in neonates with normal hearing. Method:Ninety newborn babies (149 ears) who had received rooming in care and passed hearing screening were randomly selected to test WBT. The screening programme consisted of distortion product otoacoustic emissions (DPOAE) and tympanometry at 1 kHz. The eigenvalue of ear canal volume, middle ear resonance frequency and acoustic absorptivity were obtained initially to explore the influence of gender and mode of delivery on the eigenvalues. Result:①Ear canal volume: The ear canal volume varied within (0.50±0.12)ml. The statistically significant correlationwas observed between ear canal volume and gender as well as the way of delivery (P<0.01). ②Resonance frequency: the resonant frequency distributed from 128 Hz to 642 Hz (mean 328.2±125.76 Hz). No statistically significant correlation (P>0.05) was observed between resonance frequency and gender as well as the way of delivery. ③Frequency wideband absorbance function: the shape of the curve showed two peaks and two troughs. The three most values were located in 1 296 Hz, 2 000 Hz and 5 339 Hz. No statistically significant correlation (P>0.05) was observed between acoustic absorptivity and gender as well as way of delivery. Conclusion:Resonance frequency and frequency acoustic absorptivity functions of newborns are different from adults. It is necessary to establish the normal reference value of WBT for newborns in China in order to promote this technique in the clinic.

Prevalence of pathogenicity island ETT2 in Escherichia coli isolated from piglets with diarrhea in northeast of China

Our aim was to investigate the prevalence of the pathogenicity island ETT2 and to examine the relationship between the ETT2 locus and other virulence factors in Escherichia coli (E. coli) isolated from piglets with diarrhea. A total of 354 E. coli strains isolated from scouring piglets were tested using PCR for the presence of the ETT2 locus. The E. coli strains were also analyzed for enterotoxins, fimbriae, non-fimbrial adhesin, Shiga toxins, pathogenicity islands, α-haemolysin (hlyA), afa8 gene cluster and autotransporter protease (sepA) genes. The results showed that 215 (60.7%) of the isolates possessed the ETT2 island. In 215 ETT2-positive E. coli strains, the virulence genes found were EAST1 (27.0%), irp2 (18.6%), paa (15.4%), STb (7.9%), LT (6.5%), ler (4.7%), hlyA (3.7%), AIDA-I (3.7%), K88 (3.7%), eae (3.3%), STa (2.8%), afaD (1.4%), afaE (1.4%), K99 (0.9%) and sepA (0.47%), respectively, and the isolates could be assigned into 25 different virulence factor patterns. In 139 ETT2-negative E. coli strains, the virulence genes detected were EAST1 (38.9%), paa (14.4%), STb (11.5%), AIDA-I (10.1%), irp2 (7.9%), sepA (2.16%), LT (0.7%), STa (0.7%), eae (0.7%), ler (0.7%), hlyA (0.7%) and K88 (0.7%), respectively, and the isolates could be classified into 13 different virulence factor patterns. Moreover, the occurrence of LT gene of ETT2-positive E. coli strains was far more than that of ETT2-negative E. coli strains.

[Characteristics of repetitive nerve stimulation in 53 cases of amyotrophic lateral sclerosis]

Objective: To investigate the feature of repetitive nerve stimulation (RNS) in patients with amyotrophic lateral sclerosis (ALS) and correlation between RNS and clinical features and electromyography (EMG) findings of the corresponding muscle. Methods: Needle EMG and RNS were performed in 53 patients with ALS, who were recruited into Department of Neurology of Chinese PLA general hospital during April to December in 2016. Decrement of the compond muscle action potential (CMAP) in response to RNS of different nerves and stimulus frequencies was compared. The effects of gender, age of onset, disease duration, region of onset, ALS functional rating scale-revised (ALSFRS-R) and rate of disease progression (ΔFS) on the decrement were analyzed. Results: 49.1% of patients with ALS had decremental responses to low frequency RNS (LF-RNS) in accessory nerve, which was lower in ulnar nerve (4.3%) and common peroneal nerve (2.6%). Decremental responses of accessory nerve at 3 Hz were observed in 49.1% of patients with ALS, more frequent than 30.2% at 1 Hz. None of the patients had increased responses to high frequency RNS. Patients with upper-limb-onset, longer disease duration and lower ALSFRS-R tended to have more frequent decrement of CMAP in response to RNS. The decrement with LF-RNS of accessory nerve was in concert with neurogenic damage of sternocleidomastoid muscle with needle EMG (r=0.365, P=0.007). There were 3 patients who had decremental responses to LF-RNS in accessory nerve without clinical involvement and neurogenic damage of sternocleidomastoid muscle. Conclusions: There is significant decrement of CMAP in response to LF-RNS of accessory nerve in patients with ALS, which may reveal neuromuscular junction (NMJ) impairment. It may indicated a dying-back pattern of disease progression which derived from motor neuron terminal or NMJ to neuronal soma that some patients with ALS have decremental responses in RNS without clinical involvement and neurogenic damage of sternocleidomastoid muscle.

Syntheses, structural characterisation and electronic structures of ferrocenyl-osmafuran heterobinuclear organometallic complexes

The electron transfer through the backbone of metallafurans was studied by spectroelectrochemistry and theoretical calculation.

[Clinical outcome of intramyocardial dissecting hematoma after acute myocardial infarction]

Objective: To observe the clinical outcome of intramyocardial dissecting hematoma (IDH) after acute myocardial infarction (MI). Methods: The clinical characteristics and outcomes of nine patients with IDH after acute MI in Beijing Anzhen Hospital from 2010 to 2014 were retrospectively assessed, and all the patients were followed up. Results: The mean age of nine IDH patients (7 males, 2 females) was (61±5) years. One patient was diagnosed as right ventricular IDH and died before surgery because of deteriorated cardiac and renal failure. Eight patients were diagnosed as left ventricular IDH, among whom 1 patient died of perioperative bleeding. The other 7 patients survived, among whom 5 cases were treated medically and 2 cases accepted surgical treatment. After 2-6 years of follow-up, the survived patients had no other complications. Conclusion: IDH after acute MI was a rare clinical event with a high mortality, and improvement of recognition of this rare condition may reduce its mortality, especially the right ventricular IDH.

Emulating Anyonic Fractional Statistical Behavior in a Superconducting Quantum Circuit

Anyons are exotic quasiparticles obeying fractional statistics, whose behavior can be emulated in artificially designed spin systems. Here we present an experimental emulation of creating anyonic excitations in a superconducting circuit that consists of four qubits, achieved by dynamically generating the ground and excited states of the toric code model, i.e., four-qubit Greenberger-Horne-Zeilinger states. The anyonic braiding is implemented via single-qubit rotations: a phase shift of π related to braiding, the hallmark of Abelian 1/2 anyons, has been observed through a Ramsey-type interference measurement.

Multimedia fate and source apportionment of polycyclic aromatic hydrocarbons in a coking industry city in Northern China

A steady state Level III fate model was established and applied to quantify source-receptor relationship in a coking industry city in Northern China. The local emission inventory of PAHs, as the model input, was acquired based on energy consumption and emission factors. The model estimations were validated by measured data and indicated remarkable variations in the paired isomeric ratios. When a rectification factor, based on the receptor-to-source ratio, was calculated by the fate model, the quantitatively verified molecular diagnostic ratios provided reasonable results of local PAH emission sources. Due to the local ban and measures on small scale coking activities implemented from the beginning of 2004, the model calculations indicated that the local emission amount of PAHs in 2009 decreased considerably compared to that in 2003.

Predictors of survival in Chinese patients with lupus nephritis

The current study was to determine the predictors of survival in 491 Chinese patients with lupus nephritis (LN). All patients were evaluated and consecutively followed up from 2003 to 2010. The female: male ratio was 9.5:1, with a median age of 31.1 ± 12 years. Forty-nine (10.0%) patients were lost to follow-up and 47 (10.3%) patients died. The overall cumulative probability of survival at 5, 10, 15 and 20 years by Kaplan-Meier analysis was 88%, 77%, 53% and 45%, respectively. The log-rank test showed that the probability of survival was significantly decreased in the late-onset patients (≥50 years) ( P = 0.036), patients with hypoproteinaemia (≤35 g/l) ( P = 0.014), patients with increased creatinine (≥1.5 mg/dl) ( P = 0.002) and patients with massive proteinuria (≥3.5 g/24 h) ( P = 0.009). However, the probability of survival was significantly higher in patients treated with hydroxychloroquine (HCQ) ( P = 0.003) than those not treated with it. Based on a multivariate model, increased creatinine (hazard ratio (HR) = 2.041; P = 0.017) and proteinuria ≥3.5 g/24hours (HR=1.716; P = 0.016) were independent risk factors. Glucocorticoid (HR = 0.457; P = 0.01) and HCQ (HR=0.197; P = 0.026) were independent protective factors. Our findings suggest that renal dysfunction and massive proteinuria are independent risk factors for mortality. HCQ could improve the survival of patients with LN.

Analysis of prognosis-related factors in patients with invasive cervical adenocarcinoma

OBJECTIVE

To explore the prognostic related factors in patients with cervical adenocarcinoma.

METHODS

Clinical and pathological data were retrospectively analyzed in 144 patients with cervical adenocarcinoma between 1995 and 2004.

RESULTS

Five-year survival rates were 80.1%, 59.7%, 6.3 % and 0.0%, respectively, in patients with Stage I, II, III and IV cervical adenocarcinoma, and the overall 5-year survival rate was 59.0%. Univariate analysis indicated poor prognosis in non-exophytic tumor, tumor diameter > 4 cm, advanced clinical stage, mucinous adenocarcinoma and clear cell carcinoma, or poorly differentiated tumor. The prognosis was related to lymph node metastasis and deep myometrial invasion. Multivariate analysis indicated that besides clinical stage, myometrial invasion and lymph node metastasis, tumor shape was also an independent prognostic related factor.

CONCLUSION

The prognosis is associated with tumor shape besides pre-confirmed clinical stage, myometrial invasion and lymph node metastasis. Ovarian preservation in young women remains to be further explored.

Preliminary evaluation on the use of homing pigeons as a biomonitor in urban areas

This study evaluates the usefulness of homing pigeons as a biomonitor of polycyclic aromatic hydrocarbons (PAHs) in urban environments. The mean concentrations of total PAHs in liver and lung tissues were greater in pigeons from Beijing compared to pigeons from Chengdu, however, this difference was only statistically significant for PAH concentrations in liver tissue (P < 0.05). Similarly, the severity of anthracosis or pneumoconiosis in lung tissue and hepatitis in liver tissue was greater in pigeons from Beijing compared to pigeons from Chengdu. Low molecular weight PAHs dominated the contribution of individual PAHs in both tissues. Significant differences (P < 0.05) were observed for most low and moderate molecular weights PAHs in liver and for some low and high molecular weights PAHs in lung between the two cites. The profile patterns of individual PAHs were similar between lung tissue of pigeons and between local ambient airs in summer for both cities, whereas the profile patterns between liver tissue and pigeon food were less similar. These data suggest that homing pigeons may be of value as a biomonitor of environmental pollution in urban areas.

Organochlorine pesticide residuals in chickens and eggs at a poultry farm in Beijing, China

Chicken organs, animal feed, droppings, and ambient air were sampled at a farm in Beijing to determine the concentrations of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDTs). Mean fresh weight concentrations of HCHs and DDTs were 0.122+/-0.061 ng/g and 0.051+/-0.038 ng/g in the muscles. These values are 1-2 orders of magnitude lower than those reported in China in 1980. Contaminated feed was the main source of HCHs and DDTs. Only 12.8% of HCH and 3.3% of DDT of the amount consumed were excreted. Accumulated quantities of HCHs and DDTs increased during growth. However, concentrations of HCHs and DDTs did not increase because of dilution from rapid growth. Based on the observed residual levels in mature chicken and the average diet of residents of China, the contributions from chicken and egg consumption to per capita daily intake of HCHs and DDTs were 487% and 88% of those of fish consumption.

Spatial and temporal variations and possible sources of dichlorodiphenyltrichloroethane (DDT) and its metabolites in rivers in Tianjin, China

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.

Partitioning and source diagnostics of polycyclic aromatic hydrocarbons in rivers in Tianjin, China

Water, suspended particulate matter (SPM), and sediment samples were collected from ten rivers in Tianjin and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), dissolved organic carbon (DOC), particulate organic carbon (POC) in SPM and total organic carbon (TOC) in sediment. The behavior and fate of PAHs influenced by these parameters were examined. Generally, organic carbon was the primary factor controlling the behavior of the 16 PAH species. Partitioning of PAHs between SPM and water phase was studied, and K(OC) for some PAH species were found to be significantly higher than the predicted values. The source of PAHs contamination was diagnosed by using PAH isomer ratios. Coal combustion was identified to be a long-term and prevailing contamination source for sediment, while sewage/wastewater source could reasonably explain a short-term PAHs contamination of SPM.

N-Amidothiourea based PET chemosensors for anions

Neutral N-amidothiourea based PET anion sensors bearing a pyrene fluorophore, 1-3, were synthesized and their fluorescent response toward anions was assessed. The anion quenching and binding constants were found to be much higher than those of the corresponding PET sensors bearing a simple thiourea receptor despite a higher oxidation potential of the electron donor and a relatively longer spacer (CH(2))(3) between the signal reporter and binding receptor in 1-3. This was explained in terms of a much more substantial increase in the electron donating ability of amidothiourea upon anion binding.

In vitro and in vivo activities of HQQ-3, a new triazole antifungal agent

The activity of HQQ-3, a new triazole antifungal agent, was evaluated and compared with those of fluconazole, ketoconazole and terbinafine in vitro and with fluconazole in vivo. HQQ-3 exhibited potent in vitro activity against clinically important fungi. The activity of HQQ-3 against Candida spp. was superior to those of fluconazole and terbinafine and comparable or superior to that of ketoconazole. HQQ-3 retained potent activity against Candida albicans strains with low levels of susceptibility to fluconazole (fluconazole MIC80s range, 4 to >64 microg/ml). Against Cryptococcus neoformans and filamentous fungi, the activity of HQQ-3 was superior to that of fluconazole. HQQ-3 also exhibited potent in vivo activity against murine systemic infections caused by C. albicns and C. krusei. The 50% effective doses against these infections were 0.12 to 1.9 mg/kg of body weight. These result suggest that HQQ-3 may be useful in the treatment of candidiasis.

Short-term dynamic change of gill copper in common carp, Cyprinus carpio, evaluated by a sequential extraction

Dynamic changes in Cu speciation and its binding to fish gills were investigated by exposing common carp (Cyprinus carpio) to a 1 mg/1 Cu solution for 7 hours. Cu speciation in the bulk solution and fish gill microenvironment was calculated using general chemical equilibrium modeling. A sequential extraction procedure using distilled water, magnesium dichloride (1.0 mol/1), and acetic acid (10%) was used to characterize the Cu associated with the fish gills. Cu residual in the gill tissue was measured after the sequential extraction. Changes in total Cu concentration, pH, and dissolved organic carbon (Doc) in the bulk solution were recorded during the experimental period and calculated for the fish gill microenvironment. Cu-hydroxide species and Cu2 were dominant Cu species in both bulk solution and the fish gill microenvironment, whereas increased Cu-mucus was found in the fish gill microenvironment. DOC in the exposure medium, assumed to arise from mucus release, also increased and complexed Cu in solution. Forty-three percent of the Cu associated with the gills was readily water extractable, with an additional 22% exchangeable with Mg2+ or protons. Only 35% of the Cu accumulated within the gill tissues. The binding of Cu to the fish gills reached apparent equilibrium after 3 hours of exposure. Furthermore, the amount of water-extractable Cu within the gills showed significant correlation to the concentration of Cu predicted to be complexed with calculated free mucus in the gill microenvironment.

Distribution of sorbed phenanthrene and pyrene in different humic fractions of soils and importance of humin

Contributions of fulvic-humic acids (FA/HA) and humin (HM) to sorption of phenanthrene (PHE) and pyrene (PYR) in a soil were differentiated using a humic separation procedure after multi-concentration sorption experiments. It was found that the amount of solutes in FA/HA did not change significantly after 48 h, while that in HM increased continuously and slowly up to the end of the experimental period (720 h), indicating that HM was the main region for slow sorption. Based on the fitting results using Freundlich equation, it was found that nonlinearity of both solutes was greater in HM than in FA/HA, consistent with the sorption characteristics of individually extracted HA and HM in a separate experiment. The observed nonlinearity of the solute distribution was confirmed by using three other soil samples with organic carbon contents ranging from 0.7 to 7.9%. Distribution dynamics of PHE and PYR among various fractions were also discussed.

Geostatistical analysis and kriging of Hexachlorocyclohexane residues in topsoil from Tianjin, China

A previously published data set of HCH isomer concentrations in topsoil samples from Tianjin, China, was subjected to geospatial analysis. Semivariograms were calculated and modeled using geostatistical techniques. Parameters of semivariogram models were analyzed and compared for four HCH isomers. Two-dimensional ordinary block kriging was applied to HCH isomers data set for mapping purposes. Dot maps and gray-scaled raster maps of HCH concentrations were presented based on kriging results. The appropriateness of the kriging procedure for mapping purposes was evaluated based on the kriging errors and kriging variances. It was found that ordinary block kriging can be applied to interpolate HCH concentrations in Tianjin topsoil with acceptable accuracy for mapping purposes.

Accumulation and distribution of polycyclic aromatic hydrocarbons in rice (Oryza sativa)

Various tissues of rice plants were sampled from a PAH contaminated site in Tianjin, China at different growth stages of the ripening period and analyzed for PAHs. PAHs were much higher in roots than in the exposed tissues. Grains and internodes accumulated much smaller amounts of PAHs than leaves, hulls or ear axes. No specific gradient trends along roots, stem, ear axes, and grains were observed, suggesting that systematic translocation among them is unlikely. Over the ripening period, PAH concentrations were increased in rice roots and decreased in most above-ground tissues. Significant correlations between PAH and lipid contents can only be observed during full mature stage. The spectra of individual PAH compounds in rice organs including roots were similar to those in air, rather than those in soil. There was also a significant correlation between bioconcentration factor (BCF, plant over air) and octanol/air partitioning coefficient (Koa).

Particle size distributions of polycyclic aromatic hydrocarbons in rural and urban atmosphere of Tianjin, China

The size distributions of 16 polycyclic aromatic hydrocarbons (PAHs) and particle mass less than 10 microm in aerodynamic diameter (Dp) were measured using a nine-stage low-volume cascade impactor at rural and urban sites in Tianjin, China in the winter of 2003-2004. The particles exhibited the trimodal distribution with the major peaks occurring at 0.43-2.1 and 9.0-10.0 microm for both urban and rural sites. The concentrations of the total PAH (sum of 16 PAH compound) at rural site were generally less than those of urban site. Mean fraction of 76.5% and 63.9% of the total PAH were associated with particles of 0.43-2.1 microm at rural and urban sites, respectively. Precipitation, temperature, wind speed and direction were the important meteorological factors influencing the concentration of PAHs in rural and urban sites. The distributions of PAHs concentration with respect to particle size were similar for rural and urban samples. The PAHs concentrations at the height of 40 m were higher than both of 20 and 60 m at urban site, but the mass median diameter (MMD) of total PAH increased with the increasing height. The mid-high molecular weight (278 >or= MW >or= 202) PAHs were mainly associated with fine particles (Dp <or= 2.1 microm), whereas low molecular weight (128 >or=MW >or=178) PAHs were distributed in both of fine and coarse particle. The fraction of PAHs associated with coarse particles (Dp>2.1 microm) decreased with increasing molecular weight. The relatively consistent distribution of PAHs seemed to indicate the similar combustion source of PAHs at both of rural and urban sites. The fine differences of concentration and distribution of PAHs at different levels at urban site suggested that the different source and transportation path of particulate PAHs.

Modeling the dynamic changes in concentrations of gamma-hexachlorocyclohexane (gamma-HCH) in Tianjin region from 1953 to 2020

A level IV fugacity model was used to simulate the dynamic changes of gamma-hexachlorocyclohexane (gamma-HCH) concentrations in environmental media in Tianjin, China. A similar model (level III) was previously used and validated under steady state conditions; this paper explores its dynamic behavior. Application of the level IV fugacity model has been validated using independently observed gamma-HCH concentrations in various media during the early 1980s and during 2001. Sensitivity analysis was conducted using coefficient-of-variation normalized sensitivity coefficients. The model was also subject to uncertainty analysis using Monte Carlo simulation. It was found that concentrations of gamma-HCH reached within 95% of their steady-state levels in all media after less than 15 years. Around one order-of-magnitude decreases in gamma-HCH concentrations in various media occurred between 1993 and 2001. We project that gamma-HCH concentrations will decrease another 1.7-1.9 orders of magnitude to reach 1.1 (0.9-1.2) x 10(-14), 2.7 (2.5-3.0) x 10(-10), 1.2 (1.1-1.3) x 10(-7), and 6.1 (5.4-6.8) x 10(-8) mol/m(3), in air, water, soil, and sediment, respectively, by 2020. The sensitivities and true uncertainty of the model are discussed.

Source diagnostics of polycyclic aromatic hydrocarbons based on species ratios: a multimedia approach

Often, the sources of polycyclic aromatic hydrocarbons (PAHs) in environmental media can be identified by comparing the ratios of concentrations of selected pairs of PAH congeners in the source emissions to the ratios in the contaminated environmental media. However, these ratios can be altered significantly due to differences in the transport of the PAH compounds in a multimedia environment. To examine such changes, a fugacity model was applied to PAH ratios in a model environment. A linear relationship between the rate of emission and the bulk media concentration was identified for each PAH compound in an environmental medium at steady state and was quantified by a receptor-to-source ratio (RRS). It was demonstrated that the RRS values of the two congeners usually differ significantly. Consequentially, PAH ratios changed remarkably from the source emissions to various environmental media. A site-specific rectification factor (RF) was defined as the ratio of the two RRS values of the paired congeners for a specific PAH ratio in a given medium, which can be applied to account for the ratio changes in a multimedia environment. The PAH ratio changes were further verified with the surface soil data collected from Tianjin, China, and the observed changes of PAH ratios were compared favorably with the model predictions. The sensitivity analysis revealed that PAH ratios of the low molecular weight compounds were less stable. The most influential parameters controlling PAH ratios were those pertaining to dry precipitation, surface-to-air diffusion, degradation in air and water, and exchange between water and sediment.

Human exposure and health risk of alpha-, beta-, gamma- and delta-hexachlorocyclohexane (HCHs) in Tianjin, China

The dynamic exposures to HCHs of individuals born between the years 1913 and 1993 in Tianjin have been simulated by connecting a fugacity model (IV) with a multimedia exposure model. Ingestion is the most important pathway for human beings to take up HCHs, and concentrations in the human body correlate with body weight changes. Accumulations of HCHs were derived assuming that the degradation in human body behaved linearly. The health risk of exposure to HCHs was measured using cancer risk and loss of life expectancy (LLE), and LLE was modified from its original definition to incorporate a dynamic calculation that takes variances in exposure into account. Monte-Carlo simulations were run to analyze the uncertainties of the model.

Organochlorine pesticides in agricultural soil and vegetables from Tianjin, China

Samples of eight types of vegetables, the rhizosphere soils, and bulk soils were collected from two sites (A and B) in Tianjin, China for the determination of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDXs). The average concentrations of total HCHs and DDXs in the bulk soils were 3.6 and 80.1 ng/g for site A and 102 and 235 ng/g for site B, respectively. Relative accumulations of HCHs and DDXs in the rhizosphere soil from site A but not site B were demonstrated. The concentrations of total HCHs and DDXs in vegetable roots were 3.6-60 and 4.2-73 ng/g for site A and 15-152 and 7.1-136 ng/g for site B, respectively. Difference in bioaccumulation among various vegetables, especially between tuber and fibrous vegetables was significant. DDXs in spinach and cauliflower from site B and lindane (gamma-HCH) in cauliflower from both sites and violet from site B exceeded the maximum residual limits. Linear correlation of log-transformed HCHs and DDXs contents between the vegetable roots and the rhizosphere soils suggests the direct uptake of HCHs and DDXs.

Contamination of rivers in Tianjin, China by polycyclic aromatic hydrocarbons

Tianjin urban/industrial complex is highly polluted by some persistent organic pollutants. In this study, the levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were tested in sediment, water, and suspended particulate matter (SPM) samples in 10 rivers in Tianjin. The total concentration of 16 PAHs varied from 0.787 to 1943 microg/g dry weight in sediment, from 45.81 to 1272 ng/L in water, and from 0.938 to 64.2 microg/g dry weight in SPM. The levels of PAHs in these media are high in comparison with values reported from other river and marine systems. Variability of total concentrations of PAHs in sediment, water, and SPM from nine different rivers is consistent with each other. No obvious trends of total PAHs concentration variations were found between upstream and downstream sediment, water, and SPM samples for most rivers, which indicate local inputs and disturbances along these rivers. The spatial distributions of three-phase PAHs are very similar to each other, and they are also similar to those found in topsoil. However, their chemical profiles are significantly different from that of topsoil. The change of profiles is consistent with the different aqueous transport capability of 16 PAHs. Low molecular weight PAHs predomination suggests a relatively recent local source and coal combustion source of PAHs in the study area.

Development ofN-Benzamidothioureas as a New Generation of Thiourea-Based Receptors for Anion Recognition and Sensing

A series of neutral N-(substituted-benzamido)-N'-phenylthioureas (substituent = p-OC(2)H(5), p-CH(3), m-CH(3), H, p-Cl, p-Br, m-Cl, and p-NO(2)) were designed as anion receptors, in which the thiourea binding site was attached to the benzamido moiety via an N-N bond. The absorption spectra of these N-benzamidothioureas in acetonitrile peaked at ca. 270 nm were found to show unprecedented red shifts by 7 373 to 14 325 cm(-1) in the presence of anions such as AcO(-), F(-), and H(2)PO(4)(-). Under the same conditions, the classic neutral thiourea receptors, N-(substituted-phenyl)-N'-phenylthioureas, showed absorption spectral shifts in most cases of less than 800 cm(-1) with one exception of 6501 cm(-1). Control experiments, effects of protic solvent, and (1)H NMR titration confirmed the formation of hydrogen-bonding complexes between the new N-benzamidothiourea receptors and anions. The binding constants with AcO(-), for example, are at 10(5)-10(7) mol(-1) L order of magnitude, which are 13 to 590 times those of the corresponding classic N-phenylthioureas in the same solvent. It was found that, whereas the absorption of the N-benzamidothiourea receptors showed essentially no dependence on the substituent, the substantially red-shifted new absorption band of the N-benzamidothiourea-anion binding complex was sensitively subject to the substituent. A linear relationship was found between the absorption energies of the N-benzamidothiourea-acetate binding complexes and the Hammett constants of the substituents with a negative slope of -0.34 eV. This led to the assignment that the substantially red-shifted absorption band was the ground-state intramolecular charge-transfer absorption with the substituent locating in the electron acceptor moiety. It was concluded that anion binding to the thiourea moiety of the N-benzamidothiourea receptors switched on their ground-state charge transfer. An anion-binding induced structural change was suggested to occur around the N-N bond in N-benzamidothioureas, which resulted in a substantially increased electron donating ability of the electron donor in the receptor molecules. As a consequence, the ground-state charge transfer takes place in the N-benzamidothiourea-anion binding complexes, leading to unprecedented red shifts in the absorption spectra and substantially enhanced anion binding affinities than those of the corresponding N-phenylthiourea receptors. N-Benzamido-N'-phenylthioureas represent a new generation of neutral thiourea-based anion receptors that show substantially improved anion binding performance important for anion sensing and recognition.

[The test of metal-ceramic bonding strength among three ceramic alloies]

PURPOSE

To compare the metal-ceramic bonding strength of different ceramic alloies.

METHODS

30 wax sheets were divided into 6 groups at random. Each group included 5 sheets. After being invested conventionally with Bellaves SH,the samples were casted and fused with porcelain.The metal-ceramic bonding strength was evaluated.

RESULTS

The highest bonding strength was found in Bio Herador N alloy, and then in TILITE alloy and Heraenium S alloy respectively. Bio Herador N alloy and TILITE alloy all had significant differences of the bonding strength before and after treatment (P<0.05). There was no significant differences in the bonding strength of the Heraenium S alloy after treatment (P>0.05).

CONCLUSION

The bonding strength of precious metal-ceramic was higher than that of non-precious metal-ceramic.Pre-oxygen treatment can improve the metal-ceramic bonding strength of Bio Herador N alloy and TILITE alloy,but it had no effect on the metal-ceramic bonding strength of the Heraenium S alloy.

Evaluation of factors influencing root-induced changes of copper fractionation in rhizosphere of a calcareous soil

Major factors influencing the root-induced copper fractionation changes within the rhizosphere of maize, wheat, pea, and soybean seedlings were evaluated using a contaminated calcareous soil. The effects of acidification, alkalization, and introduction of root exudates were investigated by addition of acid, alkaline and root exudates from solution cultures, prior to incubation and copper fractionation. Raw and sterilized soils were compared for changes of copper fractionation in the rhizosphere using rhizoboxes with maize, wheat, pea and soybean seedlings. The results indicated that the general trend in considerable changes was similar among the plant species studied. The rhizosphere experienced a depletion of carbonate associated and organic bound copper along with an accumulation of exchangeable and Fe-Mn oxide bound copper. The resulting significant influence of root exudates on copper fractionation appears to have been produced through complexation rather than acidification or alkalization. The increase in exchangeable copper in rhizosphere was strengthened by microorganisms.

Residues of hexachlorocyclohexane isomers and their distribution characteristics in soils in the Tianjin area, China

Hexachlorocyclohexane (HCH) has a history of use in China. This paper presents the results of an investigation of HCH residue isomers and their distribution characteristics in soils near Tianjin, China. One hundred eighty-eight soil samples were collected from the Tianjin area. Four HCH isomers-alpha-HCH, beta-HCH, gamma-HCH, and delta-HCH-were detected using gas chromatography for all samples. Concentrations of the sum HCH ranged from 1.3 to 1095 ng g(-1), among which beta-HCH accounted for 52.5%. In addition, residues of HCH within Tianjin's urban areas were found to be higher. No significant differences were found between the residues of HCH in soils from waste irrigation areas and those in other areas. Total organic carbon content was determined to impact the residue levels of HCH in soils, while pH value and clay content were not related to concentrations of HCH. In general, all HCH isomers in soil samples had abnormally high residue levels, possibly the result of continuous use of HCH in this area.

Sample purification for analysis of organochlorine pesticides in sediment and fish muscle

The methods of sample purification for determinations of organochlorine pesticides (OCPs) in sediment and fish muscle were investigated in this study. A two-step procedure with preliminary cleanup and florisil column fraction was adopted. The working conditions of florisil column were firstly optimized. As to preliminary cleanup, liquid-liquid extraction by mixture of dimethyl formamide (DMF) and hexane and sulphonation by concentrated sulfuric acid were applied respectively and compared for the studied samples. The results indicated that liquid-liquid distribution could effectively separate lipids from fish muscle extracts, while failed in elimination of chlorophyll extracted from the relicts of hydrophytes in the sediment sample. In view of the sample appearance and clarity of gas chromatogram, sulphonation was more suitable to purify the sediment sample, however, the recoveries of the spiked standards were poor. The use of eluting solvent with stronger polarity could improve the corresponding recoveries significantly. Due to complete loss of Dieldrin, Endrin, and Endrin aldehyde after sulphonation, this pretreatment was improper to the three components. Sulfur, as the particular disturbing element in sediment, could be removed sufficiently by addition of activated copper powder. The relevant detection limits of the selected methods for OCPs in the studied substrates were also provided.

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.

Use of sequential ASE extraction to evaluate the bioavailability of DDT and its metabolites to wheat roots in soils with various organic carbon contents

An accelerated solvent extraction (ASE) procedure using water, n-hexane and a mixture of n-hexane and acetone as solvents in sequence was developed and tested to evaluate the bioavailability of DDT and its metabolites including p,p'-DDT, o,p'-DDT, p,p'-DDE, and p,p'-DDD (SigmaDDTs) to wheat uptake from soils characterized by varied organic carbon contents. Results indicated that the extractability of SigmaDDTs with water was enhanced considerably in the presence of water soluble organic carbon (WSOC), while the amount of SigmaDDTs extracted with n-hexane was negatively correlated to the content of water insoluble organic carbon (WIOC). The interaction between SigmaDDTs and WIOC also reduced the bioavailability of the pesticides to wheat roots during uptake. There was a good positive correlation between the amount of SigmaDDTs extracted by n-hexane and the amount of SigmaDDTs accumulated in wheat roots, suggesting some potential for the use of the n-hexane ASE-extracted fraction as an indicator of SigmaDDTs' bioavailability to plant uptake. As such, the three sequentially extracted fractions may be viewed as representing the mobile, bioavailable, and fixed pools of SigmaDDTs in the soil.