Potential Cd Research Articles

CADMIUM ACCUMULATION IN THE ROOTLESS MACROPHYTE WOLFFIA GLOBOSA AND ITS POTENTIAL FOR PHYTOREMEDIATION

Cadmium (Cd) pollution around the world is a serious issue demanding acceptable solutions, one of which is phytoremediation that is both cost-effective and eco-friendly. Removal of Cd from contaminated water using plants with high growth rates and sufficient Cd accumulation abilities could be an appropriate choice. Here, we investigated a potential Cd accumulator, Wolffia, a rootless duckweed with high growth rate. Cd uptake, accumulation, tolerance, and phytofiltration ability by Wolffia globosa were examined. Furthermore, the effects of arsenic (As) on Cd uptake and phytofiltration by W. globosa were also studied. Cd uptake kinetics showed a linear pattern and a hyperbolic pattern without a plateau in lower (0–2 μM) and higher (0–200 μM) Cd concentration ranges, respectively, suggesting rapid Cd uptake by W. globosa. Cd accumulation ability by W. globosa was higher at Cd concentrations < 10 μM than at >10 μM. All the five species of Wolffia exposed to 1 μM Cd for 5 days accumulated > 500 mg Cd kg−1 DW. Ten gram fresh W. globosa could diminish almost all the Cd (2 μM) in a 200 mL solution. This enormous accumulation ability was mostly due to passive adsorption of Cd by the apoplast. Arsenic had no significant effect on Cd uptake and phytofiltration. The fresh fronds also showed a great As extracting ability. The results indicated that Wolffia is a strong Cd accumulator and has great Cd phytoremediation potential. Therefore, this plant can be used in fresh aquatic environments co-contaminated by low-levels of Cd and As. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.

Effect of Fertilizers on Cd Uptake of Amaranthus hypochondriacus, a High Biomass, Fast Growing and Easily Cultivated Potential Cd Hyperaccumulator

In a greenhouse pot experiment, we assessed the phytoextraction potential for Cd of three amaranth cultivars (Amaranthus hypochondriacus L. Cvs. K112, R104, and K472) and the effect of application of N, NP, and NPK fertilizer on Cd uptake of the three cultivars from soil contaminated with 5 mg kg−1 Cd. All three amaranth cultivars had high levels of Cd concentration in their tissues, which ranged from 95.1 to 179.1 mg kg−1 in leaves, 58.9 to 95.4 mg kg−1 in stems, and 62.4 to 107.2 mg kg−1 in roots, resulting in average bioaccumulation factors ranging from 17.7 to 29.7. Application of N, NP, or NPK fertilizers usually increased Cd content in leaves but decreased Cd content in stem and root. Fertilizers of N or NP combined did not substantially increase dry biomass of the 3 cultivars, leading to a limited increment of Cd accumulation. NPK fertilizer greatly increased dry biomass, by a factor of 2.7–3.8, resulting in a large increment of Cd accumulation. Amaranth cultivars (K112, R104, and K472) have great potential in phytoextraction of Cd contaminated soil. They have the merits of high Cd content in tissues, high biomass, easy cultivation and little effect on Cd uptake by fertilization.

중금속 오염 농경지에서 축분퇴비와 인산비료의 혼용시용에 의한 카드뮴 식물이용성 저감효과

인산에 의한 카드뮴의 식물저감 효과를 증진시키기 위해 서로 다른 특성의 두 인산제재인 용과린과 <TEX>$K_2HPO_4$</TEX>를 선정하여 축분퇴비와 혼용하여 처리한 후 알타리무 내 카드뮴 흡수특성과 토양 내 카드뮴의 특성을 조사하였다. <TEX>$K_2HPO_4$</TEX>는 토양의 pH와 음하전도를 증대시켜 토양 내 유효태 카드뮴 함량과 알타리무내 카드뮴 흡수농도를 저감시키는 효과를 나타내었다. 반면 용과린은 토양의 pH와 음하전도를 감소시켜 유효태 카드뮴 함량과 알타리무 내 카드뮴 함량을 증가시키는 효과를 나타내었다. 축분퇴비와 인산비료와의 혼용은 인산 제재의 특성에 관계없이 인산비료를 단독으로 시용하였을 때 보다 알타리무 내 카드뮴 흡수농도와 토양 내 유효태 카드뮴 함량을 감소시키는 효과가 훨씬 우수한 것으로 나타났다. 인산비료나 축분퇴비의 시용에 의해 토양 내 인산과 카드뮴의 침전반응에 의한 난용성의 카드뮴 화합물의 형성은 나타나지 않았다. 토양의 pH와 음하전도는 토양 내 유효태 카드뮴의 함량과 알타리무 내 카드뮴의 함량과 고도로 유의한 부의 상관관계를 나타내었다. 본 연구의 결과를 통하여 인산비료와 축분퇴비에 의한 카드뮴의 부동화는 인산과 카드뮴의 직접적인 침전반응에 의한 것이라기보다는 토양의 pH와 음하전도의 증대에 기인된 카드뮴의 흡착증대에 의한 것으로 판단되어진다. ACKGROUND: Cadmium (Cd) has long been recognized as one of most toxic elements. Application of organic amendments and phosphate fertilizers can decrease the bioavailability of heavy metals in contaminated soil. METHODS AND RESULTS: This study was conducted to evaluate effect of combined application of phosphate fertilizer and manure in reducing cadmium phytoavailability in heavy metal contaminated soil. Phosphate fertilizers [Fused and super phosphate (FSP) and <TEX>$K_2HPO_4$</TEX> (DPP)] and manure (M) were applied as single application (FSP, DPP, and M) to combined application (FSP+M and DPP+M) before radish seeding. <TEX>$K_2HPO_4$</TEX> decreased <TEX>$NH_4OAc$</TEX> extractable Cd and plant Cd concentration, mainly due to increases in soil pH and negative charge. However, FSP increased <TEX>$NH_4OAc$</TEX> extractable Cd and plant Cd concentration. Manure significantly increased soil pH and negative charge. Combined application of phosphate fertilizer and manure were much more effective in reducing Cd phytoavailability than a simple application of each component. Calculated solubility diagram indicated that Cd concentrations in the solution of soils amended with phosphate fertilizers and manure were undersaturated with respect to all potential Cd minerals [<TEX>$Cd_3(PO_4)_2$</TEX>, <TEX>$CdCO_3$</TEX>, <TEX>$Cd(OH)_2$</TEX>, and <TEX>$CdHPO_4$</TEX>]. Plant Cd concentration and <TEX>$NH_4OAc$</TEX> extractable Cd were negatively related to soil pH and negative charge. CONCLUSION: Alleviation of Cd phytoavailability with phosphate fertilizer and manure can be attributed primarily to Cd immobilization due to the increase in soil pH and negative charge rather than Cd and phosphate precipitation. Therefore, combined application of alkaline phosphate materials and manure is effective for reducing Cd phytoavailability.

Racemization as a stereochemical measure of dynamics and robustness in shape-shifting organic molecules

Bullvalene is a structurally unique dynamic molecule thought to interconvert among 1.2 million degenerate isomers. The incorporation of different chemical substituents onto the bullvalene core should lead to a "shape-shifting" molecule that can interconvert among thousands of discrete structural isomers. Previous NMR spectroscopy and HPLC studies on substituted bullvalenes ascertained the fact that these compounds are dynamic, but they could not attest to whether the molecules are only interconverting among only a few isomers or if a multitude of structures are being accessed. Here we confirm the remarkable shape-shifting property of a tetrasubstituted bullvalene by means of a racemization experiment. We show that a single, though fleeting, chiral, enantioenriched tetrasubstituted bullvalene isomer can spontaneously equilibrate to a racemic population of dynamic compounds. Despite the fact that conversion from one enantiomer of a bullvalene isomer to the other may require dozens or even hundreds of rearrangements and involve many potential pathways, CD spectroscopy and HPLC analysis of different bullvalene populations showed that multiple pathways exist and result in the complete racemization of an initial enantioenriched chiral bullvalene. These oligosubstituted bullvalenes represent a very rare example of an entity that can spontaneously transform itself into different discrete structures using ambient thermal energy. The confirmation that these shape-shifting organic molecules are chemically robust yet structurally dynamic is an important step toward their further use as materials, sensors, and biologically active compounds.

Heavy Metals in Water, Sediments, and Aquatic Macrophytes: River Hindon, India

AbstractConcentrations of heavy metals (Cd, Cu, Cr, Mn, Zn, Pb, and Ni) were investigated in water, sediments, and aquatic macrophytes (Eichhornia crassipes and Nelumbo nucifera) collected from the River Hindon, India. Quantitative analysis of data and evaluation of potential ecological risk index (RI) indicated that the river Hindon is suffering from serious metal contamination. Statistical analyses (cluster analysis and correlation analysis) suggested that heavy metal pollution in the river originates from anthropogenic sources, especially industrial and urban discharges. The study also revealed that the heavy metals were selectively accumulated in different parts of the aquatic macrophytes. Metal translocation factor (MTF) estimation of Eichhornia and Nelumbo sp. highlighted their phyto-remediation potential (Cd, Mn, Pb, and Ni), the latter being an unexplored plant species for such studies.

Accumulation and tolerance characteristics of cadmium in Chlorophytum comosum: a popular ornamental plant and potential Cd hyperaccumulator

The effects on the growth, physiological indexes and the cadmium (Cd) accumulation in Chlorophytum comosum under Cd stress were examined by pot-planting. The results showed that the tolerance index (TI) of C. comosum were all above 100 in soil Cd concentration of 100 mg kg(-1). The O(2˙)⁻ production rate and electrical conductivity of C. comosum were significantly positively correlated to Cd adding-concentration while the MDA content increased and had significant differences with the control. The activities of SOD, CAT, and POD all rose significantly in lower Cd concentration and the Cd threshold of them were around 10, 50 and 20 mg kg(-1), respectively. The Cd in C. comosum root and aboveground part reached 1,522 and 865·5 mg kg(-1), respectively, in Cd concentration of soil up to 200 mg kg(-1). For the advantages of high tolerance, high accumulation, and high ornamental value, C. comosum may have tremendous application value in the treatment of Cd-contaminated soils.

Potential coeliac disease in type 1 diabetes mellitus: does a positive antibody lead to increased complications?

IntroductionCoeliac disease (CD) is more common in people with type 1 diabetes than in the general population. We have previously shown that patients with type 1 diabetes and newly identified...

Cadmium accumulation in and tolerance of rice ( Oryza sativa L.) varieties with different rates of radial oxygen loss

Cadmium (Cd) uptake and tolerance were investigated among 20 rice cultivars based on a field experiment (1.2 mg Cd kg −1 in soil) and a soil pot trial (control, 100 mg Cd kg −1), and rates of radial oxygen loss (ROL) were measured under a deoxygenated solution. Significant differences were found among the cultivars in: (1) brown rice Cd concentrations (0.11–0.29 mg kg −1) in a field soil, (2) grain Cd tolerance (34–113%) and concentrations (2.1–6.5 mg kg −1) in a pot trial, and (3) rates of ROL (15–31 mmol O 2 kg −1 root d.w. h −1). Target hazard quotients were calculated for the field experiment to assess potential Cd risk. Significant negative relationships were found between rates of ROL and concentrations of Cd in brown rice or straw under field and greenhouse conditions, indicating that rice cultivars with higher rates of ROL had higher capacities for limiting the transfer of Cd to rice and straw.

Mechanisms of cadmium toxicity and tolerance in Populus

Abstract Background and Methods: Cadmium (Cd), ranked the 7th most hazardous substance, is one of the most widespread pollutants of soil and water in industrialized nations. Its increased movement in soil-plant systems is posing a serious threat to human health. Cd, without any known functions in plants, was found to be toxic even at minute concentrations, leading to the development of symptoms such as leaf roll, chlorosis and root and shoot growth reduction. Phytoremediation is an emerging cost-effective and environment friendly technology that utilizes high biomass producing plants including Populus plants to remove, transform or stabilize contaminants in soils. The objectives of our study were to record phenotypic variation in a Populus pedigree to Cd exposure, to identify Cd tolerant and susceptible genotypes of Populus, to map QTLs (Quantitative Trait Loci - genomic regions responsible) for Cd tolerance and accumulation in Populus and to predict a mechanism for Cd toxicity and tolerance in susceptible and tolerant Populus genotypes.QTL mapping was accomplished by conducting a greenhouse hydroponic study in which 252 genotypes of a Populus pseudo-backcross progeny were grown for 40 days and treated with 25 µM Cd. Phenotypic variation in total dry weight was recorded on these genotypes and was used for identifying QTL for Cd tolerance. We identified genotypes with contrasting responses to the Cd treatment and conducted a microarray study to identify potential Cd tolerance mechanisms based on gene expression patterns. Results/Conclusions: Significant variation was observed among genotypes in response to Cd treatment based on changes in total dry weight. Cd tolerant and susceptible genotypes were identified based on the least square mean differences (Control-Cd treated for each genotype) among all the genotypes. Three QTLs were identified for Cd tolerance and they accounted for approximately 25% of the phenotypic variation in Cd tolerance measured as total dry weights.In the microarray study, the Cd-susceptible genotype had higher expression of Fe-transporters compared to the tolerant genotypes, and Cd and Fe levels were significantly different in foliage. Even the susceptible genotype controls had higher, though not significant, Fe levels than tolerant genotype controls. We therefore hypothesize that part of the mechanism for Cd tolerance is determined by the differences in the activity of Fe transporters in genotypes with differential Fe homeostasis.

Mechanisms of cadmium toxicity and tolerance in Populus

Cadmium (Cd), ranked the 7th most hazardous substance, is one of the most widespread pollutants of soil and water in industrialized nations. Its increased movement in soil-plant systems is posing a serious threat to human health. Cd, without any known functions in plants, was found to be toxic even at minute concentrations, leading to the development of symptoms such as leaf roll, chlorosis and root and shoot growth reduction. Phytoremediation is an emerging cost-effective and environment friendly technology that utilizes high biomass producing plants including Populus plants to remove, transform or stabilize contaminants in soils. The objectives of our study were to record phenotypic variation in a Populus pedigree to Cd exposure, to identify Cd tolerant and susceptible genotypes of Populus, to map QTLs (Quantitative Trait Loci - genomic regions responsible) for Cd tolerance and accumulation in Populus and to predict a mechanism for Cd toxicity and tolerance in susceptible and tolerant Populus genotypes.QTL mapping was accomplished by conducting a greenhouse hydroponic study in which 252 genotypes of a Populus pseudo-backcross progeny were grown for 40 days and treated with 25 µM Cd. Phenotypic variation in total dry weight was recorded on these genotypes and was used for identifying QTL for Cd tolerance. We identified genotypes with contrasting responses to the Cd treatment and conducted a microarray study to identify potential Cd tolerance mechanisms based on gene expression patterns. Significant variation was observed among genotypes in response to Cd treatment based on changes in total dry weight. Cd tolerant and susceptible genotypes were identified based on the least square mean differences (Control-Cd treated for each genotype) among all the genotypes. Three QTLs were identified for Cd tolerance and they accounted for approximately 25% of the phenotypic variation in Cd tolerance measured as total dry weights.In the microarray study, the Cd-susceptible genotype had higher expression of Fe-transporters compared to the tolerant genotypes, and Cd and Fe levels were significantly different in foliage. Even the susceptible genotype controls had higher, though not significant, Fe levels than tolerant genotype controls. We therefore hypothesize that part of the mechanism for Cd tolerance is determined by the differences in the activity of Fe transporters in genotypes with differential Fe homeostasis.

Few-Nucleon Calculations With Δ Degrees of Freedom

Three- and four-nucleon bound states and hadronic and electromagnetic reactions are described using the realistic coupled-channel potential CD Bonn +Δ which allows the excitation of a single nucleon to a Δ isobar. It yields effective two-, three- and four-nucleon forces and currents, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. Δ-isobar effects are more pronounced at higher energies where they often improve the description of the experimental data. In addition the effect of relativistic one-nucleon current corrections on low-energy observables is studied.

Cadmium Accumulation and Tolerance of Two Safflower Cultivars in Relation to Photosynthesis and Antioxidantive Enzymes

To investigate the effects of cadmium (Cd) on photosynthetic and antioxidant activities of safflower (Carthamus tinctorius L.) plants, two cultivars (Yuming and New safflower No. 4) were used for long-term pot experiment, under 0, 25, 50 or 100 mg Cd kg(-1) (DW) soil conditions. The results showed that there is a large amount of Cd (148.6-277.2 mg kg(-1)) accumulated in the shoot of safflower, indicating this species might be a potential Cd accumulator. Exposure to 25-100 mg Cd kg(-1) soil decreased the net photosynthetic rate by 25.6%-48.9% for New safflower No. 4, and 16.7%-57.3% for Yuming, respectively. The inhibition of photosynthesis might result from the limitation of stomatal conductance, reduction in photosynthetic pigment, and destruction of photosynthetic apparatus caused by Cd stress. Cd caused an enhancement of malondialdehyde (MDA), an increase in activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX), and a decrease in catalase (CAT) activity for both cultivars. It seems that SOD and APX accounted for the scavenging of oxidant stress in safflower cultivars. The physiological response of safflower plants to Cd stress was cultivar- and dose-dependent. New safflower No. 4 exhibited high photosynthetic performance at high Cd stress, which may be contributed by high intercellular CO(2) concentration, APX activity and Car/Chl ratio. In contrast, Yuming is more tolerant to Cd toxicity at low Cd level, in which an efficient antioxidant system is involved.

Microscopic enteritis and pathomechanism of malabsorption.

Microscopic enteritis (ME) is the stage of microscopic and sub-microscopic changes (microenteropathy) associated with the symptoms of gluten sensitive enteropathy leading to micronutrient deficiencies. It is characterized by subtle mucosal abnormalities without prominent inflammation, villous effacement, erosions or ulcerations on conventional light microscopy. The intraepithelial lymphocytes are usually in normal range <25/100 enterocytes (microenteropathy) or increased (lymphocytic enteritis). ME is the entity behind atypical forms of CD previously known as potential and latent CD. Systemic inflammation predominantly is found to be engaged in pathophysiology of micro-nutrient deficiency even in absence of macroscopic mucosal changes.

Contamination levels assessment of potential toxic metals in road dust deposited in different types of urban environment

A total of 42 samples of road dust were collected along ring road, city centre, city side, and freeway in Urumqi, China. Total concentrations of Cd, Cr, Cu, Ni, Pb, Mn, Be, Co, Zn, and U were determined by using the inductively coupled plasma-mass spectrometry in order to assess and to compare road dust contamination levels of metals among the four roads. The results show that, among the four categories of roads, mean concentrations of Co and U vary little. City centre locations show strong enrichments of Cd, Cu, Pb, and Be. Along the ring road, the highest mean concentrations were found for Cr, Ni, Mn, and Co. However, the highest concentrations of Zn and U were found along the freeway. The cluster analysis shows that three main groups can be distinguished. Every group may be associated with different main sources and concentrations of the metals. The results of contamination assessment reveal that, among all of the potential toxic metals, Cd, Cu, and Zn pollution were obviously heavier with moderate or high contamination indices for most road dust samples, while Cr, Ni, and Pb contamination were lower along the four categories of roads. Compared with the city side, Cd, Cu, Pb, Ni, and Zn contamination were heavier along the ring road, the city centre, and the freeway with high traffic density. Low Pb contamination or no contamination in all the road dust samples may be related to the increasing usage of lead-free petrol.

Modeling transfer of heavy metals in soil–rice system and their risk assessment in paddy fields

Many studies have been conducted on model transfer in soil–plant systems. However, relatively little information is available on modeling metal transfer in soil–rice system and associated risk assessment in real paddy fields. Based on a random sampling method from Nanxun, Shengzhou and Wenling in Zhejiang province, China, 15 pairs of rice and the corresponding soil samples were respectively collected for analysis of heavy metals and soil pH. The results showed that the accumulation ability of rice for different heavy metals was significantly different (p Zn > Cu > Ni > Cr > Pb. The relationships of heavy metals in rice with those in soil, along with soil pH, were well described by linear regression models. Except for Pb, the contents of most metals in rice were positively correlated with those of the soil. Soil pH was negatively correlated with the contents of Cd, Zn and Ni in rice, and positively correlated with Pb in rice; however, it had less effect on Cr and Cu. Based on risk reference dose (RfD), the risk assessment data indicated that the rice grown in Zhejiang paddy fields does pose some potential Cd and Cr contamination risk to food safety; rice in Shengzhou posed light Ni risk.

Joint effects of arsenic and cadmium on plant growth and metal bioaccumulation: A potential Cd-hyperaccumulator and As-excluder Bidens pilosa L

Joint effects of arsenic (As) and cadmium (Cd) on the growth of Bidens pilosa L. and its uptake and accumulation of As and Cd were investigated using the field pot-culture experiment. The results showed that single Cd (≤25 mg kg −1) and As (≤50 mg kg −1) treatments could promote the growth of B. pilosa, resulting in 34.5–104.4% and 21.0–43.0%, respectively, increase in the dry biomass of shoots while compared with that under the control conditions. However, under the co-contamination of As and Cd, there was an antagonistic effect on the growth of the plant. The concentrations of As and Cd accumulated in tissues of the plant increased with an increase of As and Cd in soils. In particular, the levels of Cd in stems and leaves reached 103.0 and 110.0 mg kg −1, respectively, when soil Cd was 10 mg kg −1. Furthermore, the BF and TF values of Cd were greater than 1.0. However, the highest content of As in roots of the plant was only 13.5 mg kg −1 when soil As was at a high level, i.e. 125 mg kg −1, and the TF values of As were less than 0.1, indicating that B. pilosa can be considered as a potential Cd hyperaccumulator and As excluder. The presence of As had inhibitory effects on Cd absorption by the plant, in particular, the accumulation of Cd in stems, leaves and shoots decreased significantly, with 42.8–53.1, 49.3–66.4 and 37.6–59.5%, respectively, reduction when the level of soil As was up to 125 mg kg −1 compared with that under no addition of As. Whereas, when Cd was added to soils, it could facilitate As accumulation in tissues of the plants and the As concentrations in shoots increased with increasing Cd spiked in soils. The interactive effects of Cd and As may be potential for phytoremediation of Cd and/or As contamination soils.

Hyperaccumulation of lead, zinc, and cadmium in plants growing on a lead/zinc outcrop in Yunnan Province, China

A field survey was conducted to identify potential hyperaccumulators of Pb, Zn or Cd in the Beichang Pb/Zn mine outcrop in Yunnan Province, China. The average total concentrations of Pb, Zn, and Cd in the soils were up to 28,438, 5,109, and 52 mg kg−1, respectively. A total of 68 plant species belonging to 60 genera of 37 families naturally colonizing the outcrop were recorded. According to metal accumulation in the plants and translocation factor (TF), Silene viscidula was identified as potential hyperaccumulator of Pb, Zn, and Cd with mean shoot concentrations of 3,938 mg kg−1 of Pb (TF = 1.2), 11,155 mg kg−1 of Zn (TF = 1.8) and 236 mg kg−1 of Cd (TF = 1.1), respectively; S. gracilicanlis (Pb 3,617 mg kg−1, TF = 1.2) and Onosma paniculatum (Pb 1,837 mg kg−1, TF = 1.9) were potential Pb hyperaccumulators. Potentilla griffithii (Zn 8,748 mg kg−1, TF = 1.5) and Gentiana sp. (Zn 19,710 mg kg−1, TF = 2.7) were potential Zn hyperaccumulators. Lysimachia deltoides (Cd 212 mg kg−1, TF = 3.2) was a potential Cd hyperaccumulator. These new plant resources could be used to explore the mechanisms of Pb, Zn and/or Cd hyperaccumulation, and the findings could be applied for the phytoremediation of Pb, Zn and/or Cd-contaminated soils.

Nitazoxanide to Treat Community Acquired Clostridium difficile-Associated Disease

Purpose:Clostridium difficile-associated disease (CDAD) is a significant problem which is increasing in incidence and severity in hospitalized patients. Concern has started to focus on outpatients as well with community acquired (CA)-CDAD. The ACG treatment guidelines for CDAD (AJG 1997;92:739–50) recommend metronidazole (MTZ) as initial therapy for most patients with CDAD, however recent studies document failure rates up to 50% with MTZ (CID 2005;40:1586–90, CID 2006;43:421–7). In the past, the only other antibiotic available to clinicians was vancomycin (VAN), the only FDA indicated antibiotic for CDAD. VAN remains a very effective agent for CDAD, but concerns of cost, frequent dosing (QID), and the potential to promote VAN resistant Enterococcus has left clinicians to look for different therapies. A new thiazolide antibiotic, nitazoxanide (NTZ), has demonstrated efficacy for CDAD in trials versus MTZ and VAN, as well as in patients who have failed MTZ (JAC 2007;59:705–10, DDW 2008: Presentation W1272). Like VAN, NTZ is highly active against CD, concentrates in the GI tract and has no known in vitro resistance. The purpose of this study is to evaluate the effectiveness of NTZ in patients with CA-CDAD. Methods: Outpatients reporting to the clinic with diarrhea and clinical features consistent with CDAD and a positive stool test for CD toxins A or B (Diagnos-Techs, Inc., Kent, WA) were eligible for evaluation. CA-CDAD was defined as eligible patients with no known previous hospitalizations 3 months prior to presentation. All patients were treated with NTZ 1000 mg BID for 14 days and encouraged to take a probiotic. Follow-up evaluations including a repeat stool toxin test was made 1–4 weeks after the cessation of therapy to assess clinical efficacy. Results: Overall, 58 patients met the inclusion criteria, 22 males, 36 females, mean age 44 years (range 8–77). At the follow-up evaluation (mean 10 days, range 7–30) 53 (91%) patients were considered a clinical cure. Of the five treatment failures, four patients and their significant others (SO) were retested for CD stool toxins. In all four cases the SO also had a positive stool toxin assay. These patients and their SO were retreated with a second course of NTZ 1000 mg BID for 14 days. Upon retreatment each patient and SO was considered a clinical cure. No clinically significant adverse reactions to NTZ were identified. Conclusion: NTZ is a safe and effective treatment for CA-CDAD. Clinicians should consider testing significant others as a potential CD carrier when patients fail therapy. Further epidemiologic evaluations and clinical studies with NTZ are needed to determine the incidence and severity of CA-CDAD, the relevance of significant contacts, and the efficacy of NTZ in this population.

Cadmium Phytoextraction Efficiency of Arum (Colocasia antiquorum), Radish (Raphanus sativus L.) and Water Spinach (Ipomoea aquatica) Grown in Hydroponics

Selection of a phytoextraction plant with high Cd accumulation potential based on compatibility with mechanized cultivation practice and local environmental conditions may provide more benefits than selection based mainly on high Cd tolerance plants. In this hydroponics study, the potential of Cd accumulation by three plant species; arum (Colocasia antiquorum), radish (Raphanus sativus L.) and water spinach (Ipomoea aquatica) were investigated. Arum (Colocasia antiquorum L.) plants were grown for 60 days in a nutrient solution with 0, 10 or 50 μM Cd, while radish and water spinach plants grew only 12 days in 0, 1.5, 2.5, 5 or 10 μM Cd. Growth of radish and water spinach plants decreased under all Cd treatments (1.5 to 10 μM), while arum growth decreased only at 50 μM Cd. At 10 μM Cd treatment, the growth of arum was similar to the control treatment indicating higher tolerance of arum for Cd than radish and water spinach. Cadmium concentrations in different plant parts of all plant species increased significantly with Cd application in the nutrient solution. Arum and water spinach retained greater proportions of Cd in their roots, while in radish, Cd concentration in leaves was higher than in other plant parts. Cadmium concentrations in arum increased from 158 to 1,060 in the dead leaves, 37 to 280 in the normal leaves, 108 to 715 in the stems, 42 to 290 in the bulbs and 1,195 to 3,840 mg kg−1 in the roots, when the Cd level in the solution was raised from 10 μM Cd to 50 μM Cd. Arum accumulated (dry weight × concentration) 25 mg plant−1 at 10 μM, while the corresponding values for radish and water spinach were 0.23 and 0.44 mg plant−1, respectively. With no growth retardation at Cd concentrations as high as 166 mg kg−1 measured in entire plant (including root) of arum at 10 μM Cd in the nutrient solution, arum could be a potential Cd accumulator plant species and could be used for phytoremediation.

Four-nucleon system with Δ-isobar excitation

The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupled-channel potential CD Bonn+Δ which allows the excitation of a single nucleon to a Δ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, three- and four-nucleon forces, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. The effect of the four-nucleon force on the studied observables is much smaller than the effect of the three-nucleon force. The inclusion of the Δ isobar is unable to resolve the existing discrepancies with the experimental data.