[The effect of Helicobacter pylori infection on duodenal bulbar microbiota in children with duodenal ulcer].

Objective: To investigate the characteristics of duodenal bulbar microbiota in children with duodenal ulcer and Helicobacter pylori (Hp) infection. Methods: This prospective cohort study enrolled 23 children with duodenal ulcers diagnosed by gastroscopy who were admitted to the Children's Hospital of Zhejiang University School of Medicine due to abdominal pain, abdominal distension, and vomiting from January 2018 to August 2018. They were divided into Hp-positive and Hp-negative groups according to the presence or absence of Hp infection. Duodenal bulbar mucosa was sampled to detect the bacterial DNA by high-throughput sequencing. The statistical difference in α diversity and ß diversity, and the relative abundance in taxonomic level between the two groups were compared. Microbial functions were predicted using the software PICRUSt. T-test, Rank sum test or χ2 test were used for comparison between the two groups. Results: A total of 23 children diagnosed with duodenal ulcer were enrolled in this study, including 15 cases with Hp infection ((11.2±3.3) years of age, 11 males and 4 females) and 8 cases without Hp infection ((10.1±4.4) years of age, 6 males and 2 females). Compared with Hp-negative group, the Hp-positive group had higher Helicobacter abundance (0.551% (0.258%, 5.368%) vs. 0.143% (0.039%, 0.762%), Z=2.00, P=0.045) and lower abundance of Fusobacterium, Streptococcus and unclassified- Comamonadaceae (0.010% (0.001%, 0.031%) vs. 0.049% (0.011%, 0.310%), Z=-2.24, P=0.025; 0.031% (0.015%, 0.092%) vs. 0.118% (0.046%, 0.410%), Z=-2.10, P=0.036; 0.046% (0.036%, 0.062%) vs. 0.110% (0.045%, 0.176%), Z=-2.01, P=0.045). Linear discriminant analysis (LDA) effect sized showed that at the genus level, only Helicobacter was significantly enriched in Hp-positive group (LDA=4.89, P=0.045), while Streptococcus and Fusobacterium significantly enriched in Hp-negative group (LDA=3.28, 3.11;P=0.036,0.025, respectively). PICRUSt microbial function prediction showed that the expression of oxidative phosphorylation and disease-related pathways (pathways in cancer, renal cell carcinoma, amoebiasis, type 1 diabetes mellitus) in Hp-positive group were significantly higher than that in Hp-negative group (all P<0.05), while the expression of pathways such as energy metabolism and phosphotransferase system pathways were significantly lower than that in Hp-negative group (all P<0.05). Conclusion: In children with Hp-infected duodenal ulcers, the mucosal microbiota of the duodenal bulb is altered, characterized by an increased abundance of Helicobacter and a decreased abundance of Clostridium and Streptococcus, and possibly alters the biological function of the commensal microbiota through specific metabolic pathways.

[Characteristics of gastric mucosa microbiota in children with chronic gastritis and duodenal ulcer].

Objective: To investigate the differences of gastric mucosa microbiota between children with chronic gastritis and duodenal ulcer under the condition of Helicobacter pylori (Hp) infection. Methods: This prospective cohort study involved 57 children with Hp infection diagnosed by gastric endoscopy who were admitted to the Children's Hospital of Zhejiang University School of Medicine due to "abdominal pain, abdominal distension and vomiting" between January 2018 to August 2018. According to gastroscopy and pathological examination, the children were divided into chronic gastritis group and duodenal ulcer group. Gastric mucosa from Hp infected patients were sampled, and the flora DNA was analyzed by high-throughput sequencing. The statistical difference of α diversity, ß diversity between two groups were analyzed. The relative abundance of the two groups in each taxonomic level was analyzed statistically. T test, Rank sum test or χ2 test was used for comparison between the two groups. Results: A total of 57 children diagnosed with Hp infection were enrolled in this study, including 42 cases of chronic gastritis (the age was (9.3±2.8) years, 22 males and 20 females) and 15 cases of duodenal ulcer (the age was (11.1±3.3) years, 9 males and 6 females). Alpha diversity index Chao and ACE in Hp infected chronic gastritis group were significantly higher than those in Hp infected duodenal ulcer group (217±50 vs. 183±64, t=2.088, P=0.009;218±47 vs. 192±76, t=1.566, P=0.016, respectively). The Beta-diversity index such as nonmetric multidimensional scaling (NMDS) analysis were significantly different in the two groups (analysis of similarity R=0.304, P=0.028). Among the main bacteria genera, there were 6 genera with significant differences between the two groups, which were Prevotella (0.190% (0.008%-1.983%) vs. 0.021% (0.005%-2.398%), Z=-2.537, P=0.011), Alloprevotella (0.097% (0.010%-0.813%) vs. 0.015% (0.003%-0.576%), Z=-2.492, P=0.013), Haemophilus (0.109% (0.004%-0.985%) vs. 0.014% (0.004%-0.356%), Z=-2.900, P=0.004), Neisseria (0.074% (0.004%-0.999%) vs. 0.024% (0.003%-0.255%), Z=-2.718, P=0.007), Streptococcus (0.166% (0.008%-1.869%) vs. 0.045% (0.006%-0.879%), Z=-2.537, P=0.010), and an unclassified-Microbacteriaceae (0.214% (0.060%-1.762%) vs. 0.117% (0.010%-0.954%), Z=-2.120, P=0.034). Linear discriminant analysis (LDA) effect sized analysis showed that at the genus level, only Prevotella was significantly enriched in the duodenal ulcer group (LDA=2.90, P=0.010), while Streptococcus, Neisseria and Haemophilus were significantly enriched in the chronic gastritis group (LDA=2.83, 2.82, 2.69, P=0.011, 0.007, 0.004, respectively). Conclusions: The gastric mucosal microbiota in duodenal ulcer associated with Hp is significantly different from that in chronic gastritis. Hp may promote the occurrence of peptic ulcer together with gastric microbiota.

Understanding colossal barocaloric effects in plastic crystals.

Plastic crystal neopentylglycol (NPG) exhibits colossal barocaloric effects (BCEs) with record-high entropy changes, offering exciting prospects for the field of solid-state cooling through the application of moderate pressures. Here, we show that the intermolecular hydrogen bond plays a key role in the orientational order of NPG molecules, while its broken due to thermal perturbation prominently weakens the activation barrier of orientational disorder. The analysis of hydrogen bond strength, rotational entropy free energy and entropy changes provides insightful understanding of BCEs in order-disorder transition. External pressure reduce the hydsrogen bond length and enhance the activation barrier of orientational disorder, which serves as a route of varying intermolecular interaction to tune the order-disorder transition. Our work provides atomic-scale insights on the orientational order-disorder transition of NPG as the prototypical plastic crystal with BCEs, which is helpful to achieve superior caloric materials by molecular designing in the near future.

Super-resolution imaging for infrared micro-scanning optical system.

The image super-resolution (SR) reconstruction technology based on the micro-scanning system is one of the best methods for realizing high-resolution infrared imaging. Thus, in this work, we first present a frequency domain phase-based projection onto convex sets SR reconstruction algorithm. This method takes advantage of the texture details and contrast-independent feature of the phase information in the frequency domain and can be used to realize image denoising and SR reconstruction for the infrared image simultaneously. We also propose the use of an image quality assessment metric based on the frequency domain phase spectrum. Second, we design and realize an infrared micro-scanning optical system to obtain sub-pixel low-resolution images for SR reconstruction. The infrared micro-scanning optical system we constructed can realize controllable sub-pixel micro-scanning of an arbitrary step size. Furthermore, we can realize sub-pixel low-resolution image collection by moving two light and compact pieces instead of moving the entire lens, sensor array, or sample-as in the traditional method. Thus, the precision of the sub-pixel movements can be greatly improved. Using our proposed algorithm and infrared micro-scanning optical system, we realize infrared SR imaging in both simulations and experiments.

[Endoscopic management of ingested foreign bodies in the upper gastrointestinal tract in childhood: a retrospective study of 1 334 cases].

Objective: To explore the clinical features and complications of foreign bodies in the upper gastrointestinal tract in children and to investigate the effectiveness of endoscopic management. Methods: Data of patients with foreign bodies in upper gastrointestinal tract were collected retrospectively at Endoscopy Center, the Children's Hospital, Zhejiang University School of Medicine, from January 2011 to December 2016. Clinical characteristics, the types of foreign bodies, the location and duration of foreign body impaction were summarized. The risk factors of complications and endoscopic removal failure were analyzed by using Logistic regression analysis. Results: A total of 1 334 patients (825 males and 509 females) were enrolled. The median age was 2.5 years, with a range from 0.25 to 15 years and peak age 1-3 years. Twenty patients had esophageal diseases. The most common foreign body ingested was coin (n=964, 72.3%). Foreign bodies were most commonly located in the esophagus (n=1 002, 75.1%), especially in the upper esophagus (n=857, 85.5%). The duration of foreign body impaction ranged from 3 hours to 5 years. Among 1 334 patients, 252 patients (18.9%) developed complications, including ulcers (n=101, 40.0%) and perforations(n=13, 5.2%). The success rate of endoscopic removal was 96.6% (n=1 288). By Logistic regression analysis, sharp foreign body ingestion (OR=6.893, 95%CI: 4.421-10.746) , esophageal impaction (OR=5.253, 95%CI:3.352-8.233) and foreign body impaction longer than 24 hours (OR=4.336, 95%CI:3.091-6.082) were risk factors of complications. Sharp foreign body ingestion was the risk factor of endoscopic failure (OR=5.372, 95%CI:2.773-10.406) . Conclusions: Coin is the most common foreign body in upper gastrointestinal tract. Sharp foreign bodies impacted in the esophagus over 24 hours increase the risk of complications. Endoscopic removal of foreign bodies from the upper gastrointestinal tract in children has a high success rate. Sharp foreign body ingestion increases the risk of failure in endoscopic removing.

In situ preservation of the inferior parathyroid gland during central neck dissection for papillary thyroid carcinoma.

BACKGROUND: Postoperative hypocalcaemia due to dysfunction of the parathyroid glands is the most common complication after total thyroidectomy plus central neck dissection (CND). There is a lack of surgical techniques described to help preserve the inferior parathyroid gland in situ during CND. The objective of this study was to introduce the 'TBP layer' (layer of thymus-blood vessel-inferior parathyroid gland) concept for preserving the inferior parathyroid gland in situ during CND, and to evaluate its effectiveness. METHODS: The study group included patients with primary papillary thyroid cancer who underwent total thyroidectomy with CND using the new surgical concept between January and December 2014. The control group included sex- and age-matched patients who underwent conventional total thyroidectomy with CND between January 2012 and December 2013. The proportion of inferior parathyroid glands preserved in situ and postoperative hypoparathyroidism rates in the two groups were compared. RESULTS: There were 181 patients in the study group and 306 in the control group. There were no significant differences between the groups in tumour size, multifocality, extrathyroidal extension, and number of harvested and metastatic central lymph nodes. The rate of inferior parathyroid gland preservation in situ was significantly improved from 37·9 to 76·3 per cent on the left side (P < 0·001), and from 52·0 to 77·9 per cent on the right side (P < 0·001), in the study group compared with the control group. The incidence of transient hypoparathyroidism decreased significantly from 35·0 to 7·2 per cent (P < 0·001). CONCLUSION: Applying the proposed surgical concept improved the rate of inferior parathyroid gland preservation in situ and decreased the incidence of transient postoperative hypoparathyroidism.

Expression of transforming growth factor-ß1 and connective tissue growth factor in congenital biliary atresia and neonatal hepatitis liver tissue.

We investigated the expression of transforming growth factor-ß1 (TGF-ß1) and connective tissue growth factor (CTGF) in the liver tissue of infants with congenital biliary atresia and neonatal hepatitis, as well as the relationship between the expression of the two factors and liver fibrosis. Thirty-six infants who met the cholestasis criteria were classified into congenital biliary atresia and neonatal hepatitis groups. All specimens were stained with hematoxylin and eosin and Masson's trichrome, and the degree of liver fibrosis was assessed. The scope and level of CTGF and TGF-ß1 expression in the different specimens was evaluated by immunohistochemistry and observation. Liver fibrosis in the congenital biliary atresia group was more advanced than that in the neonatal hepatitis group, and the difference was significant (P < 0.01). In the neonatal hepatitis patients, CTGF and TGF-ß1 were mainly expressed in the hepatocytes, while they were expressed in both hepatocytes and biliary epithelial cells in the congenital biliary atresia patients, and in these patients the expression was significantly stronger than in the neonatal hepatitis patients (P < 0.01). With the aggravation of hepatic fibrosis, CTGF and TGF-ß1 expression levels in liver tissue gradually increased, and their expression levels were significantly correlated (P < 0.01). Liver fibrosis is present in both congenital biliary atresia and neonatal hepatitis patients. The gradual increase of CTGF and TGF-ß1 expression levels in liver tissue is associated with liver fibrosis. Early expression of CTGF and TGF-ß1 in biliary epithelial cells may be involved in the pathogenesis of congenital biliary atresia.

Varicocele and male infertility in Northeast China: Y chromosome microdeletion as an underlying cause.

The prevalence of Y chromosome microdeletions among azoospermic, severe oligozoospermic, moderate oligozoospermic, and mild oligozoospermic patients with varicocele-related and idiopathic infertility shows conflicting data in Asian countries. We aimed to detect this frequency in Northeast China, and investigated spermatogenic defects whether associated with varicocele or Y chromosome microdeletions. All samples underwent a thorough physical examination, semen analysis, and PCR analyses for Y chromosome microdeletions. We randomly selected 150 infertile non-obstructive azoospermic patients with left varicocele (Group 1), 150 idiopathic non-obstructive azoospermic infertility patients (Group 2), 150 infertile severe oligozoospermic patients with left varicocele (Group 3), 150 idiopathic severe oligozoospermic infertility patients (Group 4), 150 infertile moderate oligozoospermic patients with left varicocele (Group 5), 150 idiopathic moderate oligozoospermic infertility patients (Group 6), 150 infertile mild oligozoospermic patients with left varicocele (Group 7), 150 idiopathic mild oligozoospermic infertility patients (Group 8), and 60 healthy unrelated men with proven fertility were recruited as control subjects (Group 9). We observed that our samples from Northeastern China had a higher frequency of microdeletions among the non-obstructive azoospermic individuals with varicocele, as compared with other Asian countries. Furthermore, the spermatogenic defect is due to the underlying Y chromosome microdeletion, and not the varicocele itself. Although varicocele is not the cause of male infertility, it may be associated with male infertility in the Northeastern Chinese population.

Protective effect of ischaemic preconditioning in total knee arthroplasty.

OBJECTIVE: To investigate the genomic response induced by ischaemic preconditioning (IPC) in muscle biopsies taken from the operative leg of total knee arthroplasty patients. MATERIALS AND METHODS: The gene expression profile GSE21164 was extracted from Gene Expression Omnibus (GEO) database. Patients undergoing primary knee arthroplasty were randomized to control and treatment (IPC) groups. Muscle biopsies were taken from the quadriceps muscle of the operative knee at the immediate onset of surgery (T0) and at 1 hour into surgery (T1). Limma package of R language was used to identify the differentially expressed genes (DEGs) between control and treatment group. To find out specific genes, DEGs at T0 were compared with DEGs at T1. Scansite was used to find out the binding domain for specific DEGs. Functional enrichment analysis was done by DAVID. RESULTS: Of the genes queried on the Affymetrix Human Genome U133 Plus 2.0 microarray, we identified 263 (T0) and 266 (T1) DEGs compared to the control group. Down-regulation of DEGs related with regulation neuron apoptosis was observed at T1. The most significant function of DEGs at T0 was related with neurological system process. The most specific DEG was FAM125B at T0 and T1 time points. Its common binding domain was SH3. CONCLUSIONS: The protective effect of IPC was associated with altered expression of genes involved in neurological system process and regulation of neuron apoptosis. The dynamic expression of FAM125B can be a supervised marker during the surgery. IPC may be of potential benefit in this and other musculoskeletal conditions.

Accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the Pearl River Delta, South China.

This study investigated the extent of heavy metal accumulation in leaf vegetables and associated potential health risks in agricultural areas of the Pearl River Delta (PRD), South China. Total concentrations of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and arsenic (As) were determined in 92 pairs of soil and leaf vegetable (flowering Chinese cabbage, lettuce, pakchoi, Chinese cabbage, loose-leaf lettuce, and Chinese leaf mustard) samples collected from seven agricultural areas (cities). The bioconcentration factors (BCF) of heavy metals from soil to vegetables were estimated, and the potential health risks of heavy metal exposure to the PRD residents through consumption of local leaf vegetables were assessed. Results showed that among the six leaf vegetables, pakchoi had the lowest capacity for heavy metal enrichment, whereas among the five heavy metals, Cd had the highest capacity for transferring from soil into vegetables, with BCF values 30-fold those of Hg and 50-fold those of Cr, Pb and As. Sewage irrigation and fertilization were likely the main sources of heavy metals accumulated in leaf vegetables grown in agricultural areas of the PRD region. Different from previous findings, soil pH had no clear effect on metal accumulation in leaf vegetables. Despite a certain degree of metal enrichment from soil to leaf vegetables, the PRD residents were not exposed to significant health risks associated with consumption of local leaf vegetables. Nevertheless, more attention should be paid to children due to their sensitivity to metal pollutants.

Kinetics and mechanism of propachlor reductive transformation through nucleophilic substitution by dithionite.

Chloroacetanilide herbicides are extensively used in the control of weeds and have widely resulted in nonpoint contamination of groundwater and soil resources. In the attempt to achieve better remediation for herbicide-contaminated resources, we investigated the reductive transformation of propachlor through nucleophilic substitution by dithionite (S(2)O(4)(2-)). Results showed that propachlor underwent rapid dechlorination in the presence of dithionite. The reaction was of second-order kinetics and strongly influenced by pH and temperature. At pH 7.0 and temperature 308K, the rate constant of propachlor dechlorination was estimated at 123.4±0.7M(-1)h(-1). Within the pH range tested (3.0-9.5), higher pH promoted the ionization of dithionite, resulting in a more active nucleophilic reagent of S(2)O(4)(2-) to enhance the propachlor transformation rate. Similarly, higher reaction temperature overcame the activation barrier of steric hindrance in propachlor structure and accelerated the excitation of dithionite, in which higher rate constants of propachlor reductive dechlorination were obtained. Dechlorination was found to be the first and necessary step of propachlor nucleophilic substitution by dithionite. Sulfur nucleophile substituted compounds, including propachlor dithionite, propachlor ethanesulfonic acid (ESA), and hydroxyl propachlor, were identified as the dechlorination products of propachlor, indicating bimolecular nucleophilic substitution (S(N)2) as the mechanism for propachlor transformation initiated by dithionite.

Comparison of the effects of alendronate sodium and calcitonin on bone-prosthesis osseointegration in osteoporotic rats.

UNLABELLED: Alendronate (ALO) and calcitonin (CT), as commonly used antiosteoporosis drugs in current clinical practice, have been experimentally confirmed to produce the effectiveness of promoting osseointegration at the interface between prosthesis and host bone and enhancing the long-term stability of the prosthesis. Our current study compared these two drugs' effects on the osseointegration of prosthesis and found that both of them could promote bone attachment between prosthesis and host bone; moreover, ALO produced more pronounced effectiveness. INTRODUCTION: A series of findings confirmed that ALO and CT improved bone attachment of implant in animals. However, which one shows stronger effectiveness has not yet been reported by previous researches. Our study compared the effects of the two commonly used antiosteoporosis drugs on the bone-prosthesis osseointegration so as to provide valuable reference for current clinical options of medication. METHODS: Forty female SD rats aged 5 months were randomly set into A, B, C, and D groups. Except for group A, the others were ovariectomized to establish osteoporosis model (lumbar bone mineral density (BMD) decreased by 20% 4 weeks after ovariectomy). All the rats received prosthesis implantation at their tibial plateau. Then, the rats in groups C and D were given ALO (7 mg/kg/w) orally and CT (5 IU/kg/day) subcutaneously for 12 weeks, respectively. Prior to the execution, application of tetracycline hydrochloride for staining in vivo was done. After harvesting and embedding, the tibia with implants were cut into thin slides, then the bone histomorphometry was measured to observe the new bone around prosthesis and to calculate the osseointegration rate of the implants. By comparison, the effect of the two drugs on osseointegration was evaluated. RESULTS: (1) Both ALO and CT can effectively enhance the volume of bone mass surrounding the hydroxyapatite (HA) prosthesis and also significantly lever up osseointegration rate to 63.7% and 45.7%, respectively (p < 0.05). However, ALO produced more periprosthesis osseointegration rate than CT, with difference of 18% (p < 0.05). (2) The rats' lumber BMD increased in both ALO and CT groups, from 0.081 ± 0.009 and 0.078 ± 0.009 to 0.116 ± 0.008 and 0.109 ± 0.010 g/cm(2), respectively. Moreover, the effect of ALO was observed more pronounced than that of CT. CONCLUSIONS: In osteoporotic conditions, both administration of ALO orally and CT subcutaneously can enhance periprosthesis bone mass and the effects on osseointegration between host bone and prosthesis. Compared with CT, the effect of ALO is more pronounced.

Effect of Aeromonas hydrophila on reductive dechlorination of DDTs by zero-valent iron.

This study presents a reductive transformation method that combines zerovalent iron (ZVI) and Aeromonas hydrophila HS01 with iron oxide reduction property to degrade DDT (1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) under anoxic conditions. The results suggest that HS01 has weak capability in terms of reducing DDT to DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) and nearly failed to reduce DDD or its transformed intermediates. The coexistence of ZVI and HS01 results in a slight enhancement of DDT degradation compared with the ZVI system alone. The reduction of intermediates by ZVI, however, can be obviously accelerated in the presence of HS01, and the addition of anthraquinone-2,6-disulfonic disodium salt (AQDS) can accelerate the transformation rates further, especially for intermediate reduction. The analysis of the amount and electrochemical properties of Fe(III)/Fe(II) indicates that the presence of HS01 with or without AQDS is beneficial to the reduction of Fe(III) to Fe(II), resulting in the removal of passivating ferric precipitates on the ZVI surface. A mechanism and pathway that clarify the roles of ZVI, HS01, and AQDS in the ZVI + HS01 + AQDS system for DDT transformation are proposed. The quick removal of surface ferric precipitates is thought to be the reason for the enhancement of the transformation of DDT and its intermediates.

Enhanced reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide.

The transformation of DDT was studied in an anaerobic system of dissimilatory iron-reducing bacteria (Shewanella decolorationis S12) and iron oxide (alpha-FeOOH). The results showed that S. decolorationis could reduce DDT into DDD, and DDT transformation rate was accelerated by the presence of alpha-FeOOH. DDD was observed as the primary transformation product, which was demonstrated to be transformed in the abiotic system of Fe(2+)+alpha-FeOOH and the system of DIRB+alpha-FeOOH. The intermediates of DDMS and DBP were detected after 9 months, likely suggesting that reductive dechlorination was the main dechlorination pathway of DDT in the iron-reducing system. The enhanced reductive dechlorination of DDT was mainly due to biogenic Fe(II) sorbed on the surface of alpha-FeOOH, which can serve as a mediator for the transformation of DDT. This study demonstrated the important role of DIRB and iron oxide on DDT and DDD transformation under anaerobic iron-reducing environments.

Fe(III) oxide reduction and carbon tetrachloride dechlorination by a newly isolated Klebsiella pneumoniae strain L17.

AIMS: To isolate an iron-reducing bacterium and examine its ability of Fe(III) oxide reduction and dechlorination. METHODS AND RESULTS: A fermentative facultative anaerobe, strain L17 isolated from subterranean sediment, can reduce Fe(III) oxides and carbon tetrachloride (CT). It was identified as Klebsiella pneumoniae by 16S rRNA sequence analysis. Strain L17 can metabolize fermentable substrates such as citrate, glycerol, glucose and sucrose coupled with the reduction of hydrous ferric oxide, goethite, lepidocrocite and hematite. Fe(III) reduction was influenced by crystal structure of Fe(III) oxide, type of fermentable substrate, metabolic status of the strain, and significantly enhanced by addition of anthraquinone-2,6-disulfonate (AQDS). Strain L17 could dechlorinate CT to chloroform, and the rate was accelerated in the presence of Fe(III) oxide and AQDS. Biotic dechlorination by strain L17 and abiotic dechlorination by sorbed Fe(II) were proposed as the two main mechanisms. AQDS might accelerate the dechlorination by transferring electrons from strain L17 to Fe(III) oxide and CT. CONCLUSIONS: K. pneumoniae L17 can reduce Fe(III) oxides and CT. The two reductions can occur simultaneously, and be significantly promoted by AQDS. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of a strain of K. pneumoniae capable of reducing Fe(III) oxides and CT. As a strain of environmental origin, strain L17 may have the potential for bioremediation of chlorinated compound-contaminated sites.

Photodegradation of polycyclic aromatic hydrocarbon pyrene by iron oxide in solid phase.

To better understand the photodegradation of polycyclic aromatic hydrocarbons (PAH) in solid phase in natural environment, laboratory experiments were conducted to study the influencing factors, kinetics and intermediate compound of pyrene photodegradation by iron oxides. The results showed that the pyrene photodegradation rate followed the order of alpha-FeOOH>alpha-Fe(2)O(3)>gamma-Fe(2)O(3)>gamma-FeOOH at the same reaction conditions. Lower dosage of alpha-FeOOH and higher light intensity increased the photodegradation rate of pyrene. Iron oxides and oxalic acid can set up a photo-Fenton-like system without additional H(2)O(2) in solid phase to enhance the photodegradation of pyrene under UV irradiation. All reaction followed the first-order reaction kinetics. The half-life (t(1/2)) of pyrene in the system showed the higher efficiencies of using iron oxide as photocatalyst to degrade pyrene. Intermediate compound pyreno was found during photodegradation reactions by gas chromatography-mass spectrometry (GC-MS). The photodegradation efficiency for PAHs in this photo-Fenton-like system was also confirmed by using the contaminated soil samples. This work provides some useful information to understand the remediation of PAHs contaminated soils by photochemical techniques under practical condition.

Baseline concentrations and spatial distribution of trace metals in surface soils of Guangdong province, China.

A total of 260 surface soil samples were collected to investigate the spatial distribution of trace metals in Guangdong province, one of the fast developing regions in China. The results show that the upper baseline concentrations of Cu, Pb, Zn, Cd, Ni, Cr, and Hg were 28.7, 57.6, 77.8, 0.13, 23.5, 87.0, and 0.15 mg kg(-1), respectively. Regional parent materials and pedogenesis are the primary factors influencing the concentrations of trace metals, and various anthropogenic activities are the second most important factors. The spatial distribution of trace metals is correlated to the geological characters with high concentrations of trace metals always located in regional fault areas, basins, and the Pearl River Delta alluvial plain and to the low concentrations associated with the other areas in Guangdong province.

Clonal diversity and genealogical relationships of gibel carp in four hatcheries.

To conserve and utilize the genetic pool of gynogenetic gibel carp (Carassius auratus gibelio), the Fangzheng and Qihe stock hatcheries have been established in China. However, little information is available on the amount of genetic variation within and between these populations. In this study, clonal diversity in 101 fish from these two stock hatcheries and 35 fish from two other hatcheries in Wuhan and Pengze respectively was analysed for variation in serum transferrin. Thirteen clones were found in Fangzheng and Qihe, of which 12 were novel. Six clones were specific to Fangzheng and three specific to Qihe, whereas four were shared among the Fangzheng and Qihe fish. To obtain more knowledge on genetic diversity and genealogical relationships within gibel carp, the complete mitochondrial DNA (mtDNA) control region (approximately 920 bp) was sequenced in 64 individuals representing all 14 clones identified in the four hatcheries. Differences in the mtDNA sequences varied remarkably among hatcheries, with the Fangzheng and Qihe lines demonstrating high diversity and Wuhan and Pengze showing no variation. The Fangzheng and Qihe lines might represent two distinct matrilineal sources. One of the Qihe samples carried the haplotype shared by a most widely cultivated Fangzheng clone, indicating that a Fangzheng clone escaped from cultivated ponds and moved into the Qihe hatchery. Four Fangzheng samples clustered within the lineage formed mainly by Qihe samples, most likely reflecting historical gene flow from Qihe to Fangzheng. It is suggested that clones in Wuhan originated from Fangzheng, consistent with their introduction history, supporting the hypothesis that gibel carp in Pengze were domesticated from individuals in the Fangzheng hatchery.

Effect of alumina on photocatalytic activity of iron oxides for bisphenol A degradation.

To study the photodegradation of organic pollutants at the interface of minerals and water in natural environment, three series of alumina-coupled iron oxides (Al(2)O(3)-Fe(2)O(3)-300, Al(2)O(3)-Fe(2)O(3)-420, and Al(2)O(3)-Fe(2)O(3)-550) with different alumina fraction were prepared and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halender (BJH), and Fourier transform infrared spectra (FTIR). The XRD results showed that existence of alumina in iron oxides could hinder the formation of maghemite and hematite, and also the crystal transformation from maghemite to hematite during sintering. It has been confirmed that the BET surface area and micropore surface area of Al(2)O(3)-Fe(2)O(3) catalysts increased with an increased dosage of alumina and with decreased sintering temperature. The pore size distribution also depended on the fraction of alumina. Furthermore, all Al(2)O(3)-Fe(2)O(3) catalysts had a mixed pore structure of micropore, mesopore and macropore. FTIR results showed that FTIR peaks attributable to Fe-O vibrations of maghemite or hematite were also affected by alumina content and sintering temperature. It was confirmed that the crystal structure and crystalline, the surface area and pore size distribution of Al(2)O(3)-Fe(2)O(3) catalysts depend strongly on the content of alumina and also sintering temperature. Bisphenol A (BPA) was selected as a model endocrine disruptor in aquatic environment. The effects of alumina on the photocatalytic activity of iron oxides for BPA degradation were investigated in aqueous suspension. The experimental results showed that the dependence of BPA degradation on the alumina content was attributable to the crystal structure, crystalline and also the properties of their surface structures. It was confirmed that the mixed crystal structure of maghemite and hematite could achieve the higher photocatalytic activity than maghemite or hematite alone.