Characterisation of organic matter associated with groundwater arsenic in reducing aquifers of southwestern Taiwan

Arsenic (As) in groundwaters extensively used by people across the world constitutes a serious public health threat. The importance of organic matter (OM) as an electron donor in microbially-mediated reduction of As(V) or Fe(III)-bearing As-host minerals leading to mobilisation of solid-phase arsenic is widely recognised. Notwithstanding this, there are few studies characterising OM in such aquifers and, in particular, there is a dearth of data from the classic arsenic bearing aquifers in southwestern Taiwan. Organic geochemical analyses of sediments from a known groundwater arsenic hot-spot in southwestern Taiwan revealed contributions of thermally mature and plant derived origin, consistent with OM sources in all other Asian groundwater aquifer sediments analysed to date, indicating comparable sources and routes of OM transfer. The combined results of amended As(V) reduction assays with the organic geochemical analysis revealed that the microbiological process of dissimilatory As(V) reduction is active in this aquifer, but it is not controlled by a specific source of analysed OM. These indicate that (i) part of the OM that was considered to be less bio-available could still be used as an electron donor or (ii) other electron donors, not analysed in present study, could be controlling the rate of As release.

Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter

The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ(18)O-rich fluids may be associated with silicate and carbonate mineral released through water-rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of organic matter among the mud volcanoes being examined. Because arsenate concentration in the mud fluids was found to be independent from geochemical factors, it was considered that organic matter may induce arsenic mobilization through an adsorption/desorption mechanism with humic substances under reducing conditions. Organic matter therefore plays a significant role in the mobility of arsenic in mud volcanoes.

Thalamic post-inhibitory bursting occurs in patients with organic dystonia more often than controls

We now test the hypothesis that post-inhibitory bursting in the human pallidal receiving nucleus of the thalamus (ventral oral) mediates inhibitory pallido-thalamic transmission during dystonia. We have compared thalamic single neuron activity in nine patients with organic dystonia to that in a patient with psychogenic dystonia (Psyd) and in healthy waking monkeys. In organic dystonia, EMG power is commonly concentrated at the lowest frequency of the smoothed autopower spectrum (0.39Hz). Therefore, segments of spike trains with a signal-to-noise ratio ≥2 at 0.39Hz were termed dystonia frequency (DF) segments, which occurred more commonly during dystonia related to movement. Those with a SNR<2 were termed non-dystonia frequency (nDF) segments, which were associated with spontaneous dystonia. We concentrated on nDF activity since neuronal activity in our controls was measured at rest. Neuronal spike trains were categorized into those with post-inhibitory bursts (G, grouped), with single spikes (NG, non-grouped), or with both single spikes and bursts (I, intermediate). nDF spike trains in ventral oral had more G category firing in dystonia than in controls. The burst rate and the pre-burst silent period in nDF firing of organic dystonia were consistently greater than those of both the monkeys and the patient with Psyd. The distribution of the pre-burst silent period was bimodal with a longer mode of approximately GABAb (gamma amino butyric acid receptor-type b) duration. These results demonstrate distinct differences of post-inhibitory bursting in organic dystonia versus controls. The presence of inhibitory events consistent with GABAb duration suggests interventions for treatment of dystonia.

The prognostic value of circumferential resection margin in esophageal squamous cell carcinoma after concurrent chemoradiation therapy and surgery

BACKGROUND

Despite the significant advances in surgical techniques and multimodality treatments for esophageal cancer, the overall survival remains unsatisfactory. During the past years, efforts were made to determine the prognostic factors that would help in identifying patients suitable for surgery or guiding adjuvant therapy. Positive circumferential resection margins (CRMs) in esophageal cancer have been previously linked with poor prognosis, but their impact on survival remains controversial in patients treated by a multimodality protocol. The aim of our study was to examine the significance of tumor involvement of CRM in patients with esophageal squamous cell carcinoma after concurrent chemoradiation therapy followed by esophagectomy.

METHODS

Between 2000 and 2010, 94 esophageal squamous cell carcinoma patients who received preoperative concurrent chemoradiation therapy followed by surgery were enrolled in our study. We focused on the CRM, which was defined microscopically as clear (negative) or involved (positive). Univariate and multivariate survival analyses were performed with overall survival as the endpoint.

RESULTS

Our cohort was predominantly male (94.7%) with a median age of 57 years. All of them received concurrent chemoradiation therapy followed by esophagectomy. Overall, 17 patients (18.1%) had positive CRM. Kaplan-Meier survival analysis demonstrated that the 5-year overall survival of patients with clear and involved CRM is 60.1% and 11.8%, respectively (log rank p < 0.001). Multivariate analysis with the Cox proportional hazard model demonstrated that CRM involvement is a significant prognostic factor for overall survival (p < 0.001).

CONCLUSION

In patients with esophageal squamous cell carcinoma who underwent trimodality treatment, CRM involvement is a significant risk factor predicting survival. Additional effort is required to achieve a clear CRM in esophageal cancer treatment.

An odorant receptor from the common cutworm (Spodoptera litura) exclusively tuned to the important plant volatile cis-3-hexenyl acetate

Olfaction plays an important role in insect behaviours. The odorant receptor (OR) repertoire, housed within the dendritic membrane of sensory neurons, is one of the primary determinants of odour recognition. ORs in moths could be classified into pheromone receptors (PRs) and non-pheromone receptors (non-PR ORs). Much research in the field of insect olfaction recently has been focused on PRs of the male moth, but few Lepidoptera studies have been done on the functional study of non-PR ORs. In the present study, we identified and characterized four non-PR ORs from Spodoptera litura (Lepidoptera: Noctuidae) antennae. The tissue expression pattern showed that the four ORs were mainly expressed in adult antennae and further in situ hybridization revealed SlituOR12 was expressed in both long and short sensilla trichodea and sensilla basiconica. A functional analysis of the four SlituORs was conducted in the heterologous expression system Xenopus oocytes. SlituOR12 was exclusively and sensitively tuned to cis-3-Hexenyl acetate and SlituOR19 slightly responded to 4'-Ethylacetophenone; however, SlituOR44 and SlituOR51 did not respond to any chemicals tested in this study. It is proposed that SlituOR12 might partially account for some key behaviours of the female, such as detection of host location and oviposition site.

Thalamic physiology of intentional essential tremor is more like cerebellar tremor than postural essential tremor

The neuronal physiological correlates of clinical heterogeneity in human essential tremor are unknown. We now test the hypothesis that thalamic neuronal and EMG activities during intention essential tremor are similar to those of the intention tremor which is characteristic of cerebellar lesions. Thalamic neuronal firing was studied in a cerebellar relay nucleus (ventral intermediate, Vim) and in a pallidal relay nucleus (ventral oral posterior, Vop) during stereotactic surgery for the treatment of tremor. Nine patients with essential tremor were divided clinically into two categories: one with a substantial component of tremor with intention (termed intention ET) and the other without (postural ET). These types of essential tremor were compared with patients having intention tremor plus other clinical signs of cerebellar disease (cerebellar tremor). Neurons in patients with either intention ET or cerebellar tremor had lower firing rates and lower spike×EMG coherence than those in patients with postural ET. Patients with intention ET had a lower spike×EMG phase lead than those with postural ET. Overall, thalamic activity measures of intention ET were different from postural ET but not apparently different from those of cerebellar tremor. One patient with the intention ET (number 4) had a good response to a left thalamotomy and then suffered a right cerebellar hemispheric infarct five years later. After the stroke the intention ET recurred, which is consistent with our hypothesis that intention ET is similar to that of the intention tremor which is characteristic of cerebellar lesions.

Experiences with a simple laparoscopic gastric tube construction

Background

Minimally invasive esophagectomy (MIE) is a complex operation, and the detailed optimal surgical procedure has not been well described. Our aim was to evaluate use of a simple method of laparoscopic gastric tube construction as minimally invasive surgery for patients with esophageal cancer.

Methods

We performed a retrospective review of 26 consecutive patients who underwent MIE for esophageal cancer in the Koo Foundation Sun Yat-Sen Cancer Center between September 2009 and August 2011. Perioperative data and postoperative complications were statistically analyzed.

Results

The patient group consisted of 22 men and 4 women. MIE was performed successfully in all patients. The mean operative time was 430.4 ± 60.6 minutes, and the mean estimated operative blood loss was 135.0 ± 97.8 mL. There were no cases of conversion to open surgery during the procedure. The postoperative complication rate was 53.8%, and there was no surgical mortality.

Conclusions

We recommend this novel method of total laparoscopic staplized formation of gastric tube to facilitate gastric pull-up.

Multimodality treatment and long-term follow-up of the primary pulmonary lymphoepithelioma-like carcinoma

INTRODUCTION

Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a very rare subtype of non-small-cell lung cancer. Most cases are reported in Southeast Asia and are associated with Epstein-Barr virus infections. Because of its rare incidence, the optimal treatment and the results of long-term follow-up are not well understood. This study is an attempt to discover the multimodality treatment results of the primary pulmonary LELC.

METHODS

This retrospective study enrolled 21 patients with primary pulmonary LELC treated at 2 hospitals with a multimodality approach, including surgery, chemotherapy, radiotherapy, and targeted therapy.

RESULTS

The median follow-up time is 5.9 years and the median survival is 6.4 years. The median overall survival for patients with stage III and with stage IV disease is 3.4 years. In early-stage primary pulmonary LELC, surgery and adjuvant chemotherapy provided good treatment outcome. Advanced primary pulmonary LELC is relatively more chemosensitive and radiosensitive.

CONCLUSION

Patients with primary pulmonary LELC showed better prognosis than those with other types of non-small-cell lung cancer and achieved longer survival under multimodality treatment. This disease character is similar to that of nasopharyngeal carcinoma. Accurate pathologic diagnosis is recommended before the treatment. For advanced diseases, platinum-based doublet chemotherapy can be considered the first-line treatment. Radiation dose should consider tumor location, and 5000 to 7000 cGy is frequently applied for pulmonary LELC.

Urbanization and prevalence of depression in diabetes

OBJECTIVES

To depict recent secular trend (2001-2005) in prevalence of depression among diabetic population in Taiwan, and to explore the influences of urbanization on the prevalence of depression.

STUDY DESIGN

A descriptive correlation study design relating urbanization and prevalence of depression.

METHODS

Annual prevalence of depression was calculated as the ratio of number of individuals with depression (ICD-9-CM: 296, 309, or 311) to the size of diabetic population (ICD-9-CM: 250), which were ascertained from ambulatory care claim data of Taiwan's National Health Insurance between 2001 and 2005. Multivariate Poisson regression analysis was used to assess the secular trend in the prevalence of comorbid depression, and to appraise the influence of urbanization on prevalence of depression in diabetic patients.

RESULTS

The prevalence of depression among diabetic population increased annually from 22.6/10(3) in 2001 to 27.0/10(3) in 2005 with a significantly and linearly rising trend (β = 0.0461, p < 0.0001). Diabetic population living in urban areas showed the largest increase in prevalence (6.3/10(3)), followed by those from rural areas (5.6/10(3)). Compared to the diabetic patients residing in rural areas, those living in urban areas (RR = 1.28, 95% CI = 1.25-1.31) and those from satellite towns (RR = 1.22, 95% CI = 1.19-1.25) both had significantly increased adjusted RR.

CONCLUSIONS

There is a significant increasing trend in prevalence of depression among diabetic population in recent years in Taiwan. Diabetic patients from urban areas not only had the greatest prevalence of depression but also showed the largest increase in prevalence during the study period, which highlights a need for managing depression in urban diabetes.

Evaluation of porous membrane core elasticity and porous morphology for polypyrrole trilayer actuators

Multilayer electroactive polymer actuators consisting of polypyrrole films electropolymerized on a passive polymer membrane core have been harnessed as a source of simple actuation. As an integral component of the actuator, the membrane plays a vital role in the transport of ionic species and largely dictates the stiffness of the layered configuration, yet in past studies the specification of the membrane has remained largely arbitrary. In this investigation, we use quasi-static and dynamic mechanical analysis to investigate the impact of the mechanical properties of the membrane on the actuation response of polypyrrole-based trilayer bending actuators. Candidate materials with distinctly varied microcellular morphologies are identified and include polyvinylidene difluoride, nylon, and nitrocellulose. The quasi-static stress-strain response and the frequency-dependent viscoelastic nature of the candidates are then evaluated. On the basis of mechanical properties these results indicate that polyvinylidene difluoride membranes are superior to the other candidates for application as trilayer actuator cores. Bis(trifluoromethane)sulfonimide doped polypyrrole actuators with polyvinylidene difluoride cores and nylon cores are then fabricated under various synthesis conditions and their electromechanical actuation behavior is reported.

Smart sensor systems for human health breath monitoring applications

Breath analysis techniques offer a potential revolution in health care diagnostics, especially if these techniques can be brought into standard use in the clinic and at home. The advent of microsensors combined with smart sensor system technology enables a new generation of sensor systems with significantly enhanced capabilities and minimal size, weight and power consumption. This paper discusses the microsensor/smart sensor system approach and provides a summary of efforts to migrate this technology into human health breath monitoring applications. First, the basic capability of this approach to measure exhaled breath associated with exercise physiology is demonstrated. Building from this foundation, the development of a system for a portable asthma home health care system is described. A solid-state nitric oxide (NO) sensor for asthma monitoring has been identified, and efforts are underway to miniaturize this NO sensor technology and integrate it into a smart sensor system. It is concluded that base platform microsensor technology combined with smart sensor systems can address the needs of a range of breath monitoring applications and enable new capabilities for healthcare.

A comparative study on arsenic and humic substances in alluvial aquifers of Bengal delta plain (NW Bangladesh), Chianan plain (SW Taiwan) and Lanyang plain (NE Taiwan): implication of arsenic mobilization mechanisms

Humic substances in groundwater and aquifer sediments from the arsenicosis and Blackfoot disease (BFD) affected areas in Bangladesh (Bengal delta plain) and Taiwan (Lanyang plain and Chianan plain) were characterized using fluorescence spectrophotometry and Fourier transform infrared (FT-IR) spectroscopy. The results demonstrate that the mean concentration of As and relative intensity of fluorescent humic substances are higher in the Chianan plain groundwater than those in the Lanyang plain and Bengal delta plain groundwater. The mean As concentrations in Bengal delta plain, Chianan plain, and Lanyang plain are 50.65 μg/l (2.8-170.8 μg/l, n=20), 393 μg/l (9-704 μg/l, n=5), and 104.5 μg/l (2.51-543 μg/l, n = 6), respectively. Average concentrations and relative fluorescent intensity of humic substances in groundwater are 25.381 QSU (quinine standard unit) and 17.78 in the Bengal delta plain, 184.032 QSU and 128.41 in the Chianan plain, and 77.56 QSU and 53.43 in the Lanyang plain. Moreover, FT-IR analysis shows that the humic substances extracted from the Chianan plain groundwater contain phenolic, alkanes, aromatic ring and amine groups, which tend to form metal carbon bonds with As and other trace elements. By contrast, the spectra show that humic substances are largely absent from sediments and groundwater in the Bengal delta plain and Lanyang plain. The data suggest that the reductive dissolution of As-adsorbed Mn oxyhydroxides is the most probable mechanism for mobilization of As in the Bengal delta plain. However, in the Chianan plain and Lanyang plain, microbially mediated reductive dissolution of As-adsorbed amorphous/crystalline Fe oxyhydroxides in organic-rich sediments is the primary mechanism for releasing As to groundwater. High levels of As and humic substances possibly play a critical role in causing the unique BFD in the Chianan plain of SW Taiwan.

Respiration rate and swimming activity of larvae of two sub-tidal nassariid gastropods under reduced oxygen levels: implications for their distributions in Hong Kong waters

The effects of hypoxia on the larvae of two sub-tidal nassariid gastropods, Nassarius siquijorensis and N. conoidalis were compared so as to understand how the species-specific tolerance to hypoxia might have resulted in changes in the abundance and distribution of these two species in the hypoxic Tolo Harbour, Hong Kong, since the 1980s. Respiration rates of N. siquijorensis and N. conoidalis larvae were reduced at 4.5 mg O2 l(-1), or below, as compared with the normoxic control. Significant reduction in swimming velocity was also observed for 10-day old larvae which were exposed to <2.0 mg O2 l(-1) for N. siquijorensis and <1.0 mg O2 l(-1) for N. conoidalis. The 48 h LC50 values of N. siquijorensis and N. conoidalis larvae were 0.7 and 1.7 mg O2 l(-1), respectively. The results suggested that N. siquijorensis are more tolerant to hypoxia than N. conoidalis.

Kinetics and mechanism of arsenate removal by nanosized iron oxide-coated perlite

This study discussed the adsorption kinetics of As(V) onto nanosized iron oxide-coated perlite. The effects of pH, initial concentration of As(V) and common anions on the adsorption efficiency were also investigated. It was observed that a 100% As(V) adsorption was achieved at pH value of 4-8 from the initial concentration containing 1.0 mg-As(V)L(-1) and the adsorption percentage depended on the initial concentration; the phosphate and silicate ions would not interfere with the adsorption efficiency. Furthermore, nanosized iron oxide-coated perlite (IOCP) has been shown to be an effective adsorbent for the removal of arsenate from water. The adsorption kinetics were studied using pseudo-first- and pseudo-second-order models, and the experimental data fitted well with the pseudo-second-order model. Moreover, it suggests that the Langmuir isotherm is more adequate than the Freundlich isotherm in simulating the adsorption isotherm of As(V). The adsorption rate constant is 44.84 L mg(-1) and the maximum adsorption capacity is 0.39 mg g(-1). These findings indicate that the adsorption property of IOCP gives the compound a great potential for applications in environmental remediation.

Painful laser stimuli induce directed functional interactions within and between the human amygdala and hippocampus

The pathways by which painful stimuli are signaled within the human medial temporal lobe are unknown. Rodent studies have shown that nociceptive inputs are transmitted from the brainstem or thalamus through one of two pathways to the central nucleus of the amygdala. The indirect pathway projects from the basal and lateral nuclei of the amygdala to the central nucleus, while the direct pathway projects directly to the central nucleus. We now test the hypothesis that the human ventral amygdala (putative basal and lateral nuclei) exerts a causal influence upon the dorsal amygdala (putative central nucleus), during the application of a painful laser stimulus. Local field potentials (LFPs) were recorded from depth electrode contacts implanted in the medial temporal lobe for the treatment of epilepsy, and causal influences were analyzed by Granger causality (GRC). This analysis indicates that the dorsal amygdala exerts a pre-stimulus causal influence upon the hippocampus, consistent with an attention-related response to the painful laser. Within the amygdala, the analysis indicates that the ventral contacts exert a causal influence upon dorsal contacts, consistent with the human (putative) indirect pathway. Potentials evoked by the laser (LEPs) were not recorded in the ventral nuclei, but were recorded at dorsal amygdala contacts which were not preferentially those receiving causal influences from the ventral contacts. Therefore, it seems likely that the putative indirect pathway is associated with causal influences from the ventral to the dorsal amygdala, and is distinct from the human (putative) indirect pathway which mediates LEPs in the dorsal amygdala.

Biogeochemical characteristics of Kuan-Tzu-Ling, Chung-Lun and Bao-Lai hot springs in southern Taiwan

Hot springs are the important natural sources of geothermally heated groundwater from the Earth's crust. Kuan-Tzu-Ling (KTL), Chung-Lun (CL) and Bao-Lai (BL) are well-known hot springs in southern Taiwan. Fluid and mud (sediments) samples were collected from the eruption points of three hot springs for detailed biogeochemical characterization. The fluid sample displays relatively high concentrations of Na(+) and Cl(-) compared with K(+), Mg(2+), Ca(2+), NO(2) (-), and SO(4) (2-), suggesting a possible marine origin. The concentrations of Fe, Cr, Mn, Ni, V and Zn were significantly higher in the mud sediments compared with fluids, whereas high concentrations of As, Ba, Cu, Se, Sr and Rb were observed in the fluids. This suggests that electronegative elements were released during sediment-water interactions. High As concentration in the fluids was observed to be associated with low redox (Eh) conditions. The FTIR spectra of the humic acid fractions of the sediments showed the presence of possible functional groups of secondary amines, ureas, urethanesm (amide), and silicon. The sulfate-reducing deltaproteobacterium 99% similar to Desulfovibrio psychrotolerans (GU329907) were rich in the CL hot spring while mesophilic, proteolytic, thiosulfate- and sulfur-reducing bacterium that 99% similar to Clostridium sulfidigenes (GU329908) were rich in the BL hot spring.

The potential for reductive mobilization of arsenic [As(V) to As(III)] by OSBH(2) (Pseudomonas stutzeri) and OSBH(5) (Bacillus cereus) in an oil-contaminated site

Microbial reduction of arsenate [As(V)] plays an important role in arsenic (As) mobilization in aqueous environments. In this study, we investigated reduction of arsenate by different bacterial isolates such as OSBH(1) (GU329913), OSBH(2) (GU329914), OSBH(3) (GU329915), OSBH(4) (GU329916) and OSBH(5) (GU329917), isolated from the oil sludge of a sewage treatment plant operated by the China Petroleum Refinery Company in Kaohsiung, southern Taiwan. Bacterial strains of pure culture were identified by 16S rRNA analysis (≥99 % nucleotide similarity). Morphological and 16S rRNA analysis show that the isolate OSBH(1) is similar to E. coli, OSBH(2) is similar to P. stutzeri, OSBH(3) is similar to P. putida, OSBH(4) is similar to P. aeruginosa, and OSBH(5) is similar to B. Cereus. The As(V) was transformed to As(III) in the presence of isolates OSBH(2) and OSBH(5) by a detoxification process. The potential reduction rates of As(V) were higher in the presence of isolate OSBH(5) compared to the isolate OSBH(2). The microbial growth (cell/mL) of isolate OSBH(5) was significantly higher in culture medium compared to OSBH(2). The bacterial isolates such as OSBH(1), OSBH(3) and OSBH(4) were found to be incapable of transforming the As(V). It is concluded that the activity of the oil-degrading bacterial isolates described in this work contributes to the mobilization of As in the more toxic As(III) form that affects biotic life.

Role of organic matter and humic substances in the binding and mobility of arsenic in a Gangetic aquifer

Arsenic (As) enrichment in groundwater has led to extensive research, particularly on the factors responsible for its release into groundwater. In the Gangetic plain, organic matter driven microbial reduction of Fe-oxyhydroxides is considered as the most plausible mechanism of As release into groundwater. However, the role of organic matter in the aqueous environment is not well known and particularly that of organometallic complex. In this study, we have characterized bulk sediment and groundwater samples, collected from Barasat, West Bengal, India, to understand the effect of organic matter in the binding and mobility of As in the subsurface environment. The results showed a moderate correlation (R(2) = 0.49, p < 0.05) between dissolved organic carbon (DOC) and As in groundwater, suggesting that DOC has a role in releasing As into groundwater. The relative fluorescent intensity (RFI) of the dissolved humic substances in groundwater showed a maximum value of 65 QSU (mean: 47 ± 8 QSU). FT-IR spectra of the extracted humic acid fractions of the sediment showed COO-, C = O, OH, and C = C (aromatic ring) functional groups, which may act as a chelating agents with the metal(loid)s. FT-IR spectra of the HA-As complex exhibited specific peaks at 1242 and 832 cm(-1) in the fingerprint region. This is similar to the extracted humic acid fractions of the Gangetic sediment, suggesting binding of As with humic substances.

Health risks for human intake of aquacultural fish: Arsenic bioaccumulation and contamination

Aquacultural tilapia (Oreochromis mossambicus L.) and shrimp (Penaeus monodon L.) from groundwater-cultured ponds in southwestern Taiwan were analyzed to estimate arsenic (As) bioaccumulation and the potential health risk to human intake. Most of aquacultural ponds exhibited higher arsenic than maximum allowed concentrations (50 μg L(-1)) in pond water of Taiwan. Arsenic levels in tilapia in Budai, Yichu and Beimen were 0.92 ± 0.52 μg g(-1), 0.93 ± 0.19 μg g(-1) and 0.76 ± 0.03 μg g(-1), respectively and in shrimp was 0.36 ± 0.01 μg g(-1) in Beimen. Total arsenic in tilapia is highly correlated (R(2) = 0.80) with total arsenic concentration of pond water. Total arsenic in fish showed high correlation with that in bone (R(2) = 0.98), head (R(2) = 0.97) and tissue (R(2) = 0.96). Organic arsenic species (DMA) was found higher relative to inorganic species of As(III) and As(V). The average percent contribution of inorganic arsenic to total arsenic in fish samples was 12.5% and ranged between 11.7 to 14.2%. Bioaccumulation factors (BAFs) for total arsenic in fish ranged from 10.3 to 22.1, whereas BAF for inorganic arsenic ranged from 1.33 to 2.82. The mean human health cancer risk associated with the ingestion of inorganic arsenic in the fish was estimated at 2.36 × 10(-4) ± 0.99 × 10(-4), which is over 200 times greater than a de Minimus cancer risk of 1 × 10(-6). The mean human health hazard quotient associated with ingesting inorganic arsenic in the fish was 1.22 ± 0.52, indicating that expected human exposure exceeds the reference dose for non-cancer health effects by 22%. These results suggest that the inhabitants in this region are being subjected to moderately elevated arsenic exposure through the consumption of tilapia and shrimp raised in aquaculture ponds.

Biogeochemical interactions among the arsenic, iron, humic substances, and microbes in mud volcanoes in southern Taiwan

Fluid and mud samples collected from Hsiaokunshui (HKS), Wushanting (WST), Yenshuikeng (YSK), Kunshuiping (KSP), Liyushan (LYS), and Sinyangnyuhu (SYNH) mud volcanoes of southwestern Taiwan were characterized for major ions, humic substances (HS) and trace elements concentrations. The relationship between the release of arsenic (As) and activities of sulfate-reducing bacteria has been assessed to understand relevant geochemical processes in the mud volcanoes. Arsenic (0.02-0.06 mg/L) and humic substances (4.13 × 10(-4) to 1.64 × 10(-3) mM) in the fluids of mud volcanoes showed a positive correlation (r = 0.99, p < 0.05) except in Liyushan mud volcano. Arsenic and iron in mud sediments formed two separate groups i) high As, but low Fe in HKS, WST, and SYNH; and ii) low As, but high Fe in the YSK, KSP, and LYS mud volcanoes. The Eh(S.H.E.) values of the mud volcano liquids were characterized by mild to strongly reducing conditions. The HKS, SYNH, and WST mud volcanoes (near the Chishan Fault) belongs to strong reducing environment (-33 to -116 mV), whereas the LYS, YSK, and KSP mud volcanoes located near the coastal plain are under mild reducing environment (-11 to 172 mV). At low Eh values mud volcanoes, saturation index (SI) values of poorly crystalline phases such as amorphous ferric hydroxide indicate understaturation, whereas saturation is reached in relatively high Eh(S.H.E.) values mud volcanoes. Arsenic contents in sediments are low, presumably due to its release to fluids (As/Fe ratio in YSK, KSP, and LYS sediment: 4.86 × 10(-4)-6.20 × 10(-4)). At low Eh(S.H.E.) values (mild to strong reducing environment), arsenic may co-precipitate with sulfides as a consequence of sulfate reduction (As/Fe ratios in WST, HKS, and SYNH sediments: 0.42-0.69).

Global DNA methylation, DNMT1, and MBD2 in patients with systemic lupus erythematosus

To investigate the associations of DNA methylation levels and mRNA expressions of DNA cytosine-5-methyltransferase 1 (DNMT1) and methyl CpG-binding domain 2 (MBD2) with systemic lupus erythematosus (SLE), 108 patients with SLE and 97 healthy controls were enrolled in this study. DNA and total RNA were extracted from the peripheral blood mononuclear cells of the SLE patients and the controls. The global methylation levels of DNA were measured in 63 patients with SLE and 68 healthy controls by the ELISA method. DNMT1 and MBD2 mRNA were also detected in 108 SLE patients and 97 controls using the quantitative real-time polymerase chain reaction method. The global methylation level of DNA was significantly decreased in the SLE patients in comparison with that in the controls ( p < 0.001, 95% CI = 0.1573–0.5052). The patients with SLE have higher expressions of DNMT1 and MBD2 mRNA than the controls ( p < 0.001, 95% CI = −0.0049 – −0.0019 and p = 0.001, 95% CI = −0.0119 – −0.0029, respectively). We also found that there were no significant differences in the methylation level and the expression of DNMT1 and MBD2 mRNA between the active and the inactive SLE patients. A positive correlation was also found between DNMT1 and MBD2 mRNA expressions in the SLE patients ( p < 0.001). This study demonstrated that the patients with SLE had a significantly lower level of DNA methylation than the controls. The expression of both DNMT1 and MBD2 mRNA was significantly increased in the SLE patients compared with the controls. This study also showed a positive correlation between DNMT1 and MBD2 mRNA levels in the patients with SLE.

Cation exchange interaction between antibiotic ciprofloxacin and montmorillonite

Exploring the interactions between antibiotics and soils/minerals is of great importance in resolving their fate, transport, and elimination in the environment due to their frequent detection in wastewater, river water, sewage sludge and soils. This study focused on determining the adsorption properties and mechanisms of interaction between antibiotic ciprofloxacin and montmorillonite (SAz-1), a swelling dioctahedral mineral with Ca(2+) as the main interlayer cation. In acidic and neutral aqueous solutions, a stoichiometric exchange between ciprofloxacin and interlayer cations yielded an adsorption capacity as high as 330 mg/g, corresponding to 1.0 mmol/g. When solution pH was above its pK(a2) (8.7), adsorption of ciprofloxacin was greatly reduced due to the net repulsion between the negatively charged clay surfaces and the ciprofloxacin anion. The uptake of ciprofloxacin expanded the basal spacing (d(001)) of montmorillonite from 15.04 to 17.23 A near its adsorption capacity, confirming cation exchange within the interlayers in addition to surface adsorption. Fourier transform infrared results further suggested that the protonated amine group of ciprofloxacin in its cationic form was electrostatically attracted to negatively charged sites of clay surfaces, and that the carboxylic acid group was hydrogen bonded to the basal oxygen atoms of the silicate layers. The results indicate that montmorillonite is an effective sorbent to remove ciprofloxacin from water.