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The transcription factor p300 is reportedly involved in age-associated human diseases, including intervertebral disc degeneration (IDD). In this study, we investigate the potential role and pathophysiological mechanism of p300 in IDD. Clinical tissue samples were collected from patients with lumbar disc herniation (LDH), in which the expression of p300, forkhead box O3 (FOXO3), and sirtuin 1 (Sirt1) was determined. Nucleus pulposus cells (NPCs) isolated from clinical degenerative intervertebral disc (IVD) tissues were introduced with oe-p300, oe-FOXO3, Wnt/β-catenin agonist 1, C646 (p300/CBP inhibitor), or si-p300 to explore the functional role of p300 in IDD and to characterize the relationship between p300 and the FOXO3/Sirt1/Wnt/β-catenin pathway. Also, we established a rat IDD model by inducing needle puncture injuries in the caudal IVDs for further verification of p300 functional role. We found that p300 was downregulated in the clinical tissues and NPCs of IDD. Overexpression of p300 promoted the proliferation and autophagy of NPCs while inhibiting cell apoptosis, which was associated with FOXO3 upregulation. p300 could increase the expression of FOXO3 by binding to the Sirt1 promoter, and thus, contributed to inactivation of the Wnt/β-catenin pathway. In vivo results further displayed that p300 slowed down the progression of IDD by disrupting the Wnt/β-catenin pathway through the FOXO3/Sirt1 axis. Taken together, we suggest that p300 can act to suppress IDD via a FOXO3-dependent mechanism, highlighting a potential novel target for treatment of IDD.

OBJECTIVE: To compare the effectiveness of percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) and Wiltse-approach TLIF (W-TLIF) in the treatment of lumbar spondylolisthesis. METHODS: The clinical data of 47 patients with lumbar spondylolisthesis who met the selection criteria between July 2018 and June 2019 were retrospectively analyzed, in which 21 patients were treated with PE-TLIF (PE-TLIF group) and 26 patients were treated with W-TLIF (W-TLIF group). There was no significant difference between the two groups in age, gender, disease duration, level of spondylolisthesis vertebrae, spondylolisthesis degree, spondylolisthesis type, and preoperative visual analogue scale (VAS) score of low back pain and leg pain, lumbar Japanese Orthopaedic Association (JOA) score, and the disc height (DH), segmental lordosis (SL), and Taillard index (TI) of the operated vertebrae (P>0.05). The operation time, intraoperative blood loss, postoperative drainage, postoperative bedridden time, and complications were compared between the two groups. The VAS score and JOA score were used to evaluate the improvement of pain and function. At last follow-up, DH, SL, and TI of operated vertebrae were measured by X-ray films, and lumbar CT was performed to evaluate the interbody fusion. RESULTS: Compared with W-TLIF group, the operation time in PE-TLIF group was significantly longer, but the intraoperative blood loss and postoperative drainage were significantly less, and the postoperative bedridden time was significantly shorter (P0.05). At last follow-up, the DH, SL, and TI of operated vertebrae of the two groups significantly improved when compared with those before operation (P0.05). According to Suk’s standard, the fusion rates of PE-TLIF group and W-TLIF group were 90.5% (19/21) and 92.3% (24/26), respectively, with no significant difference (χ(2)=0.000, P=1.000). At last follow-up, there was no case of Cage sunk into the adjacent vertebral body, or dislodgement of Cage anteriorly or posteriorly in both groups. CONCLUSION: PE-TLIF and W-TLIF are both effective in the treatment of grade Ⅰ and Ⅱ lumbar spondylolisthesis. Although the operation time is prolonged, PE-TLIF has less intraoperative blood loss and postoperative drainage, shorter postoperative bedridden time, and can get more obvious short-term improvement of low back pain and function.

Environmental problems in China have attracted global attention. Grafting returnee executives' green resources to Chinese manufacturing enterprises is an effective way to solve China's sustainable development problems. This paper focuses on the impact of returnee executives and the heterogeneity of returnee and local executives on green innovation performance and the moderating effects of environmental regulation and managerial ties. The paper builds on data from 276 Chinese manufacturing enterprises. The results show that returnee executives tend to achieve sustainable development through green innovation. However, not all kinds of heterogeneity between returnee and local executives can promote green innovation performance. In addition, environmental regulation and managerial ties, as two important external moderation variables, have different impacts and different extents of impact on the relationship between returnee executives and four aspects (R&D, manufacturing, marketing, and management) of green innovation performance, that is, environmental regulation positively moderates the relationship between returnee executives and green manufacturing and management innovation performance but negatively moderates the relationship between returnee executives and green R&D and marketing innovation performance. These findings have clear management implications for Chinese manufacturing enterprises.

The present study aimed to develop nomograms to predict survival in patients with chondroblastic osteosarcoma (COS). An analysis was conducted of 320 cases of COS collected from the surveillance, epidemiology, and end results (SEER) database between 2004 and 2015. Independent prognostic factors were screened using univariate and multivariate Cox analyses. Subsequently, nomograms were established to predict the patients’ cancer-specific survival (CSS) and overall survival (OS) rates. The prediction accuracy and discriminative ability of the nomograms were examined using calibration curves and the concordance index (C-index). As revealed in the univariate and multivariate Cox regression analysis, age, tumor size, the primary site, the presence of metastasis, a history of having undergone surgery, and a history of having received radiotherapy were found to be independent prognostic factors associated with survival in patients with COS (all P 39 years, the presence of distant metastasis, no history of having undergone any surgery, and tumor size >103 mm were found to be associated with poor prognosis in patients, while the primary site of the mandible and no history of having undergone radiotherapy showed associations with a more favorable prognosis in patients. Next, nomograms were constructed to predict the OS and CSS in patients with COS. We constructed nomograms that can provide accurate survival predictions in patients with chondroblastic osteosarcoma. These nomograms can help surgeons customize the treatment strategies for patients with chondroblastic osteosarcoma.

OBJECTIVE: To compare the clinical and radiological effectiveness of oblique lumbar interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) in the treatment of Cage dislodgement after lumbar surgery. METHODS: The clinical data of 40 patients who underwent revision surgery due to Cage dislodgement after lumbar surgery betweem April 2013 and March 2017 were retrospectively analyzed. Among them, 18 patients underwent OLIF (OLIF group) and 22 patients underwent PLIF (PLIF group) for revision. There was no significant difference between the two groups in age, gender, body mass index, intervals between primary surgery and revision surgery, number of primary fused levels, disc spaces of Cage dislodgement, and visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), the segmental lordosis (SL) and disc height (DH) of the disc space of Cage dislodgement, and the lumbar lordosis (LL) before revision (P>0.05). The operation time, intraoperative blood loss, hospital stay, and complications of the two groups were recorded and compared. The VAS scores of low back pain and leg pain were evaluated at 3 days, 3, 6, and 12 months after operation, and the ODI scores were evaluated at 3, 6, and 12 months after operation. The SL and DH of the disc space of Cage dislodgement and LL were measured at 12 months after operation and compared with those before operation. CT examination was performed at 12 months after operation, and the fusion of the disc space implanted with new Cage was judged by Bridwell grading standard. RESULTS: The intraoperative blood loss in the OLIF group was significantly less than that in the PLIF group (t=−12.425,P=0.000); there was no significant difference between the two groups in the operation time and hospital stay (P>0.05). Both groups were followed up 12-30 months, with an average of 18 months. In the OLIF group, 2 patients (11.1%) had thigh numbness and 1 patient (5.6%) had hip flexor weakness after operation; 2 patients (9.1%) in the PLIF group had intraoperative dural sac tear. The other patients’ incisions healed by first intention without early postoperative complications. There was no significant difference in the incidence of complications between the two groups (χ(2)=0.519, P=0.642). The VAS scores of low back pain and leg pain, and the ODI score of the two groups at each time point after operation were significantly improved when compared with those before operation (P0.05). At 12 months after operation, SL, LL, and DH in the two groups were significantly increased when compared with preoperative ones (P0.05). CT examination at 12 months after operation showed that all the operated disc spaces achieved bony fusion. According to the Bridwell grading standard, 12 cases were grade Ⅰ and 6 cases were grade Ⅱ in the OLIF group, and 13 cases were grade Ⅰ and 9 cases were grade Ⅱ in the PLIF group; there was no significant difference between the two groups (Z=–0.486,P=0.627). During follow-up, neither re-displacement or sinking of Cage, nor loosening or fracture of internal fixation occurred. CONCLUSION: OLIF and PLIF can achieve similar effectiveness in the treatment of Cage dislodgement after lumbar surgery. OLIF can further reduce intraoperative blood loss and restore the SL and DH of the disc space of Cage dislodgement better.

Backgroud Few studies compared radiographic and clinical outcomes between oblique lumbar interbody fusion and posterior lumbar interbody fusion in degenerative lumbar scoliosis. Methods This study retrospectively analyzed the case data of 40 patients with degenerative lumbar scoliosis in our hospital from July 2016 to October 2018. Among which,19 cases underwent oblique lumbar Interbody fusion(OLIF group) and 21 cases underwent posterior lumbar interbody fusion(PLIF group). The duration of the operation, volume of intraoperative hemorrhage, incision length, bed rest time, length of hospital stay, and complications were recorded for all patients. The clinical effects of 40 patients were evaluated by VAS for back pain and Oswestry Disability Index (ODI) and The radiographic parameters were evaluated using the lumbar scoliosis Cobb angle, sagittal vertical axis(SVA), coronal vertical axis(CVA), lumbar lordosis(LL), pelvic tilt(PT), sacral slope(SS), and Disc height(DH). Results The duration of the operation, the volume of intraoperative hemorrhage, incision length, bed rest time, length of hospital stay of the OLIF group were shorter than the PLIF group( P ＜ 0.05 ). The VAS scores for back pain, the ODI of the two groups were significantly decreased, which compared with the preoperative( P ＜ 0.05 )，which in OLIF group was significantly more decreased than in PLIF( P ＜ 0.05 ) at 7 days and 3 months postoperatively, but at the last follow-up there were no significant difference between the two groups( P ＞ 0.05 ); The lumbar scoliosis Cobb angle, SVA, CVA, PT, LL, SS were significantly improved postoperatively( P ＜ 0.05 ). The OLIF group showed higher DH, smaller Cobb angle, and greater LL than the PLIF group at any time point( P ＜ 0.05 ). but there were no significant difference in SVA, CVA, PT and SS between the two groups at any follow-up points( P ＞ 0.05 ). The overall complication rate was slightly higher in the PLIF group（47.62%）than in the OLIF group（26.32%）without significant difference(x 2 =1.931, P =0.165). But the incidence of major complications in the PLIF group was significantly higher than that in the OLIF group (Fisher, P =0.026). Conclusion OLIF provides an alternative minimally invasive treatment for DLS, which compared with PLIF. It has the characteristics of a small incision, rapid recovery, fewer complications related to the surgical approach, and satisfactory orthopedics. Keywords : Minimally invasive, Oblique lumbar interbody fusion, Degenerative adult lumbar scoliosis , Posterior lumbar interbody fusion

Long noncoding RNAs (LncRNAs) may serve as miRNA sponges to regulate the expressions of miRNA target genes. LncRNA LINC00969 has been indicated to be upregulated in intervertebral disk degeneration. However, the regulatory mechanism of LINC00969 in intervertebral disk degeneration progression remains unclear. Differently expressed LINC00969, miR-335-3p, and thioredoxin-interacting protein (TXNIP) were determined in nucleus pulposus (NP) tissues and cells isolated from patients with intervertebral disk degeneration. The interaction between LINC00969, miR-335-3p, and TXNIP was also assessed. In this study, we demonstrated that LINC00969 was highly expressed, whereas miR-335-3p was aberrantly downregulated in NP tissues and cells of intervertebral disk degeneration patients. In addition, our results suggested that LINC00969 enhanced NP cell apoptosis. More importantly, LINC00969 was identified to function as a competitive endogenous RNA (ceRNA) for miR-335-3p to positively regulate TXNIP expression in vitro. Our study provided evidence for the cross-talk between LINC00969, miR-335-3p, and TXNIP, shedding light on the therapy for intervertebral disk degeneration. © 2018 IUBMB Life, 71(5):611-618, 2019.

Optimal power flow (OPF) refers to the problem of optimizing the operating decisions such as electric power generation in power systems, which are always subjected to dynamic factors like bus loads. Conventionally, OPF in dynamic environments has been solved by static-oriented optimization methods based on the prediction of the dynamic factors. However, as the dynamics of modern power systems become more and more complex and difficult to predict, research interest of intelligent methods that track the optimal decisions of OPF has been grown recently. Devoted to this objective, a learning enhanced differential evolution (LEDE) is proposed in this paper. LEDE incorporates the idea of nearest-neighbor rule from the field of machine learning, with which decisions of the previous environments are retrieved continually to replace the newly generated individuals of differential evolution. A so-called elitism stochastic ranking strategy is also proposed, used in LEDE to handle constraints of OPF. Experiments are conducted on the dynamic IEEE 30-bus system and IEEE 118-bus system, and the results show the efficiency of LEDE in comparison with other algorithms.

For both developed and developing countries, manufacturing plays a crucial role in international competition. There is a growing consensus that 3D printing (3DP) technologies will revolutionise the development of global manufacturing. Although considerable research has previously been conducted to define the technological and economic benefits of 3DP on global manufacturing, minimal research has linked 3DP with Chinese manufacturing (CM). Therefore, to address this research gap and to investigate 3DP’s potential impact on alleviating CM’s development issues, this paper explores the definition, characteristics and mainstream technologies of 3DP, presents the current situation and the main problems of CM, and analyses the potential impact of 3DP on the development of CM. Then, this study introduces the current 3DP promotion and industrialisation situation in China as well as the issues with promoting 3DP in CM.

Objective To explore the effect of ginsenoside Rg1 on intervertebral disc degeneration (IVDD) in vivo and in vitro and its mechanism. Methods 60 rats were underwent surgery to construct rat models of IVDD and divided in the sham group, model group and gradient G-Rg1 groups (10 mg/kg/d, 20 mg/kg/d and 40 mg/kg/d).The change of histology was observed by HE staining, the water content and the expression of β-catenin in IVD were detected. Rat nucleus pulposus cells(NPCs) were isolated from IVDD rats and divided in D-NPCs group, and gradient G-Rg1 groups(20 μg/ml, 50 μg/ml and 100 μg/ml).The cell proliferation activity, cell apoptosis rate,the expression of proteins related to ECM and Wnt/β-catenin were detected respectively, Finally the agonist of Wnt/β-catenin pathway LiCl was used for reversed experiments. Results In vivo, G-Rg1 treatment could improve the structural disorganization, low water content, NPCs number and aggrecan and collagenⅡ expression in IVD and down-regulate the expression of β-catenin. In vitro NPCs, G-Rg1 treatment could improve the low cell proliferation, high apoptosis rate and low expression of aggrecan and collagenⅡ in degenerative NPCs in a dose-dependent manner.G-Rg1 treatment could down-regulate the expression of proteins related to β-catenin signal and LiCl could reverse the increase of cell proliferation and ECM synthesis, decrease of apoptosis of degenerative NPCs induced by G-Rg1. Conclusion G-Rg1 could promote ECM synthesis of degenerative NPCs and inhibiting its apoptosis, improve the IVDD via inhibiting the Wnt/β-catenin pathway.

The transplantation of bone marrow mesenchymal stem cells (BMSCs) has been found to be used as an effective therapy of intervertebral disc degeneration (IDD). However, the underlying mechanisms of BMSCs in the progress of IDD are not fully explained. In this study, we found that exosomes derived from BMSCs (BMSCs-Exos) inhibited the apoptotic rate, extracellular matrix (ECM) degradation, and fibrosis deposition in TNF-α-induced nucleus pulposus cells (NPCs). Importantly, the level of miR-532-5p was observed to be decreased in apoptotic NPCs, but abundant in BMSCs-Exos with TNF-α treatment. The results showed that BMSCs-Exos under TNF-α stimuli exerted better effects on NPCs than BMSCs-Exos, which might be mitigated by the inhibition of miR-532-5p in BMSCs-Exos. The gain-of-function results suggested that the direct overexpression of miR-532-5p in NPCs could inhibit TNF-α-induced increase of apoptotic process, activation of apoptotic proteins, imbalance of anabolism/catabolism levels, and accumulation of collagen I. In addition, RASSF5 was demonstrated to be a target of miR-532-5p. Knockdown of RASSF5 could decrease the apoptotic cells and reduce the activated apoptotic protein levels in TNF-α-induced NPCs. Overall, these data indicate that exosomes from BMSCs may suppress TNF-α-induced apoptosis, ECM degradation, and fibrosis deposition in NPCs through the delivery of miR-532-5p via targeting RASSF5. This work provides a promising therapeutic strategy for the progress of IDD.

Background Osteosarcoma is one of the most common primary bone tumour in children and young patients, and the third most common among adults. Its main treatment option is currently based on neoadjuvant or adjuvant chemoradiotherapy along with the lesion's surgical resection. The current study's primary aim is to examine the clinical therapeutic impacts of combined methotrexate, along with other chemotherapeutic agents to treat children and young adults suffering from osteosarcoma. Methods We will perform a comprehensive literature search in English database (PubMed, EMBASE, Cochran Library CINAHL, and PsycINFO) and Chinese database (Chinese National Knowledge Infrastructure, VIP information database, Chinese Biomedical Database, and WanFang Database) with no language restriction from their inception to the search date. Additionally, two independent authors will screen the works of literature obtained from these databases, obtain information, and examine the risks of data included for the studies' bias. Furthermore, we intend to employ the Q statistics as well as I2 statistics to calculate heterogeneity among each study's analysis. Accordingly, we will utilize the funnel plots and Egger test to assess the possibility of publication bias where relevant. Results The current study aims to provide significant information regarding the clinical therapeutic impacts of combines methotrexate along with other chemotherapeutic agents to treat children and young adults suffering from osteosarcoma. Conclusions The present study will generate compelling evidence of combined methotrexate as well as other chemotherapeutic agents for osteosarcoma among children and young adults. Also, it will provide clinical practice suggestions. Ethics and dissemination The study is founded upon published data. Therefore, there is no requirement for ethics approval. Osf registration number March 26, 2021.osf.io/a23rc. (https://osf.io/a23rc/).

The low-carbon economy is an economic form which expenses the lowest carbon emissions, environmental and economic cost to get the future development. As the most important microeconomic activity units, manufacturing companies are the pillars to develop a low-carbon economy because of their huge energy consumption and emission. The performance of manufacturing companies' operation and development mainly reflect through the performance evaluation system. However, the traditional performance evaluation system which emphasize on the economic benefits exposed some shortcomings, such as neglecting the environmental and social benefits, etc. For this reasons, this paper established the manufacturing companies' performance evaluation system which based on economic performance aspect, focus on the social responsibility and environment aspects. Through the applied research of this system shows that: the weight of indicator-“three wastes” emissions ranks second place, and the weight of indicator-“rate of environmental protection investment” ranks the fifth. The outcome reflects Chinese manufacturing companies have realized, also would like to use certain amount of profit into the R&D of low-carbon and green technology, the reduction of energy emission, and other environment protection aspects.

In the present study, we sought to explore the mechanism of quercetin-induced apoptosis in rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs). DNA fragmentation assay was used to detect quercetin-induced apoptosis in RAFLSs. The cleavages of caspase-3 and caspase-9 and the accumulation of cytosolic cytochrome C were measured by western blot in quercetin-treated RAFLSs. Mitochondrial membrane potential was tested by flow cytometry. Small interfering RNAs were used to knock down the expression of protein 53 (p53) and analyze the role of p53 in quercetin-induced apoptosis in RAFLSs. DNA fragmentation assay showed that quercetin dose-dependently elevated the apoptosis of RAFLSs, accompanying with enhanced caspase-3 and caspase-9 cleavages. Moreover, quercetin caused a concentration-dependent loss of mitochondrial membrane potential and cytochrome c release to cytosol and also decreased Bcl-2/Bax ratio, indicating that quercetin-induced apoptosis is through mitochondrial pathway. Quercetin also elevated p53 phosphorylation at ser15. Pretreatment with pifithrin-α, a p53 inhibitor, significantly diminished p53 phosphorylation at the concentration of 30 μM and abrogated quercetin-induced apoptosis in a dose-dependent manner. Quercetin-induced apoptosis was also significantly blocked by p53 silencing, further suggesting the involvement of p53 in quercetin-induced apoptosis in RAFLSs. Our study indicated that quercetin-induced apoptosis of RAFLSs is through mitochondrial pathway, in which p53 plays an important role.

Spinal fusion has become a standard treatment for symptomatic intervertebral degenerative disc disease. The present study aimed to compare perioperative parameters, clinical outcomes, and radiographic results of stand-alone oblique lumbar interbody fusion (OLIF) with posterior lumbar interbody fusion (PLIF) for the revision of rostral adjacent segment disease (ASD) following prior posterior lumbar fusion. Thirty-six patients who underwent revision surgeries for rostral ASD were retrospectively reviewed. Among them, 17 patients underwent stand-alone OLIF (OLIF group) and 19 patients underwent PLIF (PLIF group). The length of operation, intraoperative hemorrhage, bed rest duration, and length of hospital stay were compared between the 2 groups. Clinical results were evaluated with the Oswestry Disability Index (ODI) and visual analog scale (VAS). Radiological results were evaluated with disc height (DH), foraminal height (FH), retrolisthesis index (RI), and lumbar lordosis (LL), as well as the fusion rate and cage subsidence. Follow-up results at 1 week, 3 months, and 12 months postoperatively were compared between the 2 groups. The OLIF group had less intraoperative blood loss, shorter operative time, bed rest time, and hospital stay than did the PLIF group (P .05); the OLIF group showed higher DH and FH than the PLIF group at all time points (P

To screen and identify the proteins related with tumor metastasis of gastric cancer in a nude mouse model bearing orthotopic transplanted tumor.Zinc finger protein 139 (ZNF139)-specific siRNA was synthesized and transfected into gastric cancer cell line SGC7901, which was then screened by G418. ZNF139-siRNA-transfected cells, negative plasmid-transfected cells and untreated SGC7901 cells were orthotopically transplanted separately on the stomach wall of BALB/c nude mice. The primary tumors and metastatic lymph nodes were harvested to separate the proteins by 2-D fluorescence difference gel electrophoresis (2-D DIGE); after gel digestion, the differential proteins were subjected to liquid chromatography-mass spectrometry (LC-MS) for identification and their functions were analyzed. Western blotting was performed to verify the identified proteins.ZNF139 expression was effectively inhibited in siRNA-transfected SGC7901 cells. ZNF139-siRNA-transfected cells showed obviously suppressed tumor growth with a lowered lymph node metastasis rate in nude mice compared with untreated cells and the negative control cells (P0.05). Proteomic study with 2-D DIGE showed that fascin and hnRNPA2/B1 were down-regulated while ANXA1 was up-regulated in the primary tumors, and ANXA5 was down-regulated in the metastatic lymph nodes in ZNF139-siRNA-transfected group. Western blotting confirmed the results of proteomic analysis.ZNF139 gene may promote lymph node metastasis of gastric cancer by regulating fascin, hnRNPA2/B1, ANXA1, and ANXA5.

In this study, a diffusion-type device for generating gaseous mercuric chloride (HgCl(2)) was systematically evaluated and applied to validate the annular denuder method for sampling gaseous HgCl(2) species in a synthetic gas stream. The results show that it takes at least 48 h for the system to reach a steady-state condition after the diffusion cell reaches the temperature set-point and the carrier gas is activated. The primary Hg species from the source was proven to be HgCl(2). In the temperature range from -5.00 to 11.80 degrees C, the Hg emission rates from the source vary from 1.8 to 14.2 pg min(-1). It is shown that, under the experimental conditions examined, KCl-coated annular quartz denuders designed for ambient reactive gaseous mercury (RGM) collection could quantitatively collect HgCl(2). It is also demonstrated that the impactors used to remove coarse airborne particulate matter could lead to a loss of up to one third of the HgCl(2) in the gas stream.

The study with compartment model on the phosphorus (P) and sulphur (S) bio-cycling in alpine tundra ecosystem of Changbai Mountains showed that the total storage of P and S was 16 088.6 t and 26 079.4 t, of which, 46.14 t and 64.82 t was in vegetation pool, 89.63 t and 53.16 t in litterfall pool, and 15952.8 t and 26014.6 t in soil pool, respectively. The above- and below-ground vegetation pool stored 21.88 t and 44.21 t, and 24.28 t and 20.61 t of P and S, respectively, and the above-ground vegetation pool had 47.4% of P and 68.2% of S in the vegetation subsystem. The transferable P amount was 24.25 t x yr(-1) through plant absorption and 31.59 t x yr(-1) through litterfall return, while the transferable S amount was 31.18 t x yr(-1), 10.12 t x yr(-1) and 21.06 t x yr(-1) in the aboveground plant, belowground root system, and litterfall return, respectively. The natural return ratio of S was 67.5%.

This paper describes a method for speciation of Hg associated with airborne particulate matter. This method uses a mini-sampler for sample collection and analysis, thermal desorption for separating Hg species, and inductively coupled plasma mass spectrometry (ICP-MS) for identification and quantification of Hg. Coal fly ash spiked with different Hg compounds (e.g. Hg0, HgCl2, HgO, and HgS) was used for qualitative calibration. A standard reference material with a certified value for Hg concentration was used to evaluate the method. When the temperature of the furnace was programmed at a linear rate of increase of 50 degrees min(-1), different Hg compounds could clearly be separated. Three airborne particulate matter samples were collected in parallel in Toronto, ON, Canada and analyzed using this method. Reproducible results were obtained and Hg0, HgCl2, HgO, and HgS species from these samples were detected.