Successful endovascular management for spontaneous hemothorax in a patient with neurofibromatosis Type1: A case report and review

INTRODUCTION AND IMPORTANCE

Neurofibromatosis Type 1 (NF1) is a rare autosomal dominant genetic disorder that affects multiple organs and systems, including the nervous system, integumentary system, and connective tissues. Spontaneous hemothorax occurs infrequently in patients with NF1 and is associated with high fatality rates. However, it is commonly overlooked or misdiagnosed.

CASE PRESENTATION

We present the case of a 29-year-old woman with NF1 who complained of chest pain and was detected with hemothorax on radiographic examination. No bleeding sites were identified following thrombectomy. The patient's condition deteriorated with conservative treatment over nine days, posing a potentially life-threatening risk. After a diagnostic evaluation using computerized tomography angiography (CTA) and digital subtraction angiography (DSA) of the neck vasculature, the patient was diagnosed with spontaneous rupture of the vertebral artery (VA) and subclavian artery (SuA) aneurysm. Following a multidisciplinary discussion and extensive investigations, the patient underwent successful endovascular treatment. A VIABAHN covered stent was implanted in the left SuA to overlay the emergent orifice. The endovascular treatment challenge due to the inaccessible of the proximal of left VA. To prevent retrograde flow into the VA aneurysm, the coils were used to embolize the left VA via the right vertebral artery-basilar artery (VA-BA) passage. The patient was alive at the 5-year follow-up without further complications.

CLINICAL DISCUSSION

The CTA examination led to the diagnosis of vascular rupture due to NF1, and endovascular treatment was performed to occlude the vascular lumen. There have been no recurrences during the five-year follow-up period.

CONCLUSION

Vasculopathy is the second leading cause of death in patients with NF1 after malignancy. Early diagnosis of spontaneous hemothorax in patients with NF1 is crucial, as misdiagnosis can result in missed treatment opportunities. CTA plays a vital role in preliminarily diagnosing the cause of spontaneous hemothorax, while endovascular treatment offers a new therapeutic option for such patients.

Observation of the effect of angiojet to treat acute lower extremity arterial embolization

BACKGROUND

Through significant advances in the treatment of peripheral arterial occlusive disease, acute ischemia of the lower extremity is still associated with significant morbidity, limb threat and mortality. The two main causes of acute ischemia in lower extremities are arterial embolism and atherosclerotic arteries. Timely recognition and treatment of acute limb ischemia in emergency situations is essential in order to minimize the duration of ischemia.

AIM

To investigate the application effect of angiojet thrombolysis in the treatment of acute lower extremity arterial embolization.

METHODS

Sixty-two patients with acute lower extremity arterial embolization admitted to our hospital from May 2018 to May 2020 were selected. Among them, the observation group (twenty-eight cases) had received angiojet thrombolysis, and the control group (thirty-four cases) had received femoral artery incision and thrombectomy. After thrombus clearance, significant residual stenosis of the lumen was combined with balloon dilation and/or stent implantation. When the thrombus removal was not satisfactory, catheter-directed thrombolysis was performed. The incidence of postoperative complications, recurrence rate and recovery of the two groups were compared.

RESULTS

There were no significant differences in postoperative recurrence (target vessel reconstruction rate), anklebrachial index and the incidence of postoperative complications between the two groups (P > 0.05); there were statistically significant differences in postoperative pain score and postoperative rehabilitation between the two groups (P < 0.05).

CONCLUSION

The application of angiojet in the treatment of acute lower limb artery thromboembolism disease is safe and effective, minimally invasive, quicker recovery after operation, less postoperative complications, which is more suitable for the treatment of femoral popliteal arterial thromboembolism lesions. If the thrombus removal is not satisfactory, the combination of coronary artery aspiration catheter and catheterized directed thrombolysis can be used. Balloon dilation and stent implantation can be considered for obvious lumen stenosis.

[Determination of methylmercury in urine by direct mercury analyzer]

Objective: To develop asolvent extraction-direct mercury analyzer method for determination of methylmercury in urine. Methods: After the urinehydrolyzesd by hydrobromic acid, methylmercury was extracted by tolueneand reverse-extracted from L-cysteine solution, it was then detectedbydirect mercuryanalyzer. Results: The linear range was 0.2-50.0 μg/L, and the related coefficient was 0.9999. The relative standard deviations (RSD) within the group were 5.04%-6.64%, and the RSD between the group were 5.65%-8.11 %. The average recovery efficiencies were 85.4%-95.5%. The detection limitation was 0.0482 μg/L and the quantification concentrations was 0.1607 μg/L. Conclusion: The method, which has low detection limit, high sensitivity, easy to operate, is stability for the determination of methylmercury in urine.

Cardiac myxoma shedding leads to lower extremity arterial embolism: A case report

BACKGROUND

Left cardiac myxoma (CM) is the most common benign tumor of primary cardiac tumors, but because of its special position caused by pathological physiology change, caused by the complications of the heavier, the surface is often accompanied by blood clots, once fall out, it causes peripheral vascular embolization, such as acute lower limb artery embolization, harmfulness is large, high morbidity, and easy to occur repeatedly.

CASE SUMMARY

A 67-year-old male patient suddenly appeared numbness and weakness of the left lower limb and could not walk without obvious incentive. The patient was finally diagnosed as left CM complicated with acute lower limb arterial embolism after completing cardiac ultrasound, computer tomography angiography, and histopathological analysis, such as hematoxylin-eosin stain staining, immunohistochemistry and special staining including alcian blue staining and periodic acid schiff staining. Arterial thrombosis was removed successfully by femoral artery thrombectomy, postoperative numbness and weakness of the patient's left lower limb disappeared, skin temperature became warm, and dorsal foot artery pulsation was accessible. The patient was readmitted to the hospital 8 mo after discharge for left atrial mass resection, and was diagnosed as CM by postoperative histopathological examination.

CONCLUSION

Although CM is rare, it may be considered as the source of embolism in patients with acute limb ischemia. Repeated loss of thrombus on the tumor and its surface may lead to repeated embolism of peripheral vessels. Cardiac ultrasound is helpful for early diagnosis. Here, we use this case report to highlight left CM as an important cause of acute limb ischemia and to report our experience in the diagnosis and treatment of lower limb arterial embolism caused by CM detachment.

Adsorption of lead(II) onto PE microplastics as a function of particle size: Influencing factors and adsorption mechanism

The adsorption of Pb ions, on high-density polyethylene (PE) microplastics (MPs) with the diameter of 48-500 μm, was examined in this study. According to the Langmuir isotherm, MP of the smallest size, 48 μm, had the greatest adsorption capacity of 0.38 μmol g^-1. The mechanism of Pb ions adsorption onto PE MPs was chemical adsorption, in particular, hydrogen bonding and surface complexation. Pb adsorption onto PE particles was proceeded at a rapid rate, as predicted by the pseudo-second-order rate model (R² > 0.99). The PE 48 μm had the maximum adsorption capacity of 0.44 μmol g-1 (or 0.2 mol m^-2) at pH 5. While humic acid can operate as a bridging agent, boosting heavy metal adsorption on the surface of PE MPs, fulvic acid has the reverse effect. The findings indicated that PE particles may serve as a carrier of heavy metals in the aquatic environment, posing perceived risks to the environment and public health.

Direct comparison of circulating tumor DNA sequencing assays with targeted large gene panels

Next generation sequencing (NGS) assays with large targeted gene panels can comprehensively profile cancer somatic mutations in a tumor sample. Given the rapid adoption of such assays for circulating tumor DNA (ctDNA) analysis in clinical oncology, it is essential for the community to understand their analytical performance in liquid biopsy settings. Here, we directly compared five ctDNA NGS assays, most of which having a panel of 400 or more genes, with simulated samples harboring mutations relevant to solid tumors or myeloid malignancy. Our results indicate that the detection sensitivity and reproducibility of all five assays was 90% or higher when the mutations were at 0.5% or 1.0% allele frequency, and with optimal DNA input of 30 ng or 50 ng per vendor’s protocol. The performances decreased and varied dramatically, when mutations were at a 0.1% allele frequency and/or when a lower genomic input of 10 ng DNA was used. Interestingly, one of the assays repeatedly showed higher rate of false positivity than the others across two different sample sets. Multiple intrinsic technical factors pertaining to the NGS assays were further investigated. Notable differences among the assays were seen for depth of coverage and background noise, which profoundly impacted assay performance. The results derived from this study are highly informative and provide a framework to assess and select suitable assays for specific application in cancer monitoring and potential clinical use.

In Vivo Cellular Expansion of Lisocabtagene Maraleucel and Association With Efficacy and Safety in Relapsed/Refractory Large B-Cell Lymphoma

Lisocabtagene maraleucel (liso‐cel) is an autologous, CD19‐directed, chimeric antigen receptor T‐cell product for the treatment of adult patients with relapsed or refractory large B‐cell lymphoma (LBCL) after 2 or more lines of systemic therapy. In vivo cellular expansion after single‐dose administration of liso‐cel has been characterized. In this article, in vivo liso‐cel expansion in the pivotal study TRANSCEND NHL 001 (ClinicalTrials.gov identifier, NCT02631044) was further characterized to assess the relationship between in vivo cellular expansion after single‐dose administration of liso‐cel and efficacy or safety after adjusting for key baseline characteristics. Two bioanalytical methods, quantitative polymerase chain reaction and flow cytometry, were used for the assessment of cellular kinetics of liso‐cel, which showed high concordance for in vivo cellular expansion. Multivariable logistic regression analyses demonstrated that higher in vivo cellular expansion of liso‐cel was associated with a higher overall response and complete response rate, and a higher incidence of cytokine release syndrome and neurological events in patients with relapsed or refractory LBCL. Age and tumor burden (by sum of the product of perpendicular diameters) were likely to confound the relationship between in vivo cellular expansion and efficacy, where the association became stronger after controlling for these factors. Repeat dosing of liso‐cel was tested in the study; however, in vivo cellular expansion of liso‐cel was lower after repeat dosing than after the initial dose. These findings should enable a comprehensive understanding of the in vivo cellular kinetics of liso‐cel and the association with outcomes in relapsed/refractory LBCL.

Intravascular fasciitis involving the external jugular vein and subclavian vein: A case report

BACKGROUND

Intravascular fasciitis (IVF) is a rare nodular fasciitis that often involves the layers and lumens of blood vessels; therefore, it is easily misdiagnosed as a malignant tumor with invasion into blood vessels.

CASE SUMMARY

A 13-year-old boy was admitted due to a mass on the left side of his neck. Duplex ultrasonography revealed a circular solid hypoechoic mass in the external jugular vein, and magnetic resonance imaging revealed an enhanced longitudinal mass-like lesion in the left supraclavicular fossa. Surgical treatment was arranged and completed, histopathological analysis showed a large amount of spindle cell proliferation, and immunohistochemistry showed that the spindle cells were positive for the expression of vimentin, caldesmon, and smooth muscle actin and negative for the expression of S-100 protein, desmin, CD34, and c-kit; Ki-67 staining revealed a low proliferative index (5%-10%), which confirmed the differentiation characteristics of myofibroblasts. Fluorescence in situ hybridization detected the rearrangement of USP6. IVF was subsequently diagnosed.

CONCLUSION

IVF is characterized by intraluminal, intramural and extramural involvement of small to large arteries or veins. Unless the doctor has a deep understanding of the disease or suspects that there is an initial indicator, IVF may be confused with other intravascular malignancies, leading to unnecessary radical surgery. Imaging examination combined with histopathological examination can improve the diagnostic accuracy of this disease.

Transformation of copper oxide nanoparticles as affected by ionic strength and its effects on the toxicity and bioaccumulation of copper in zebrafish embryo

This study aimed to investigate the transformation of copper oxide nanoparticles (CuO NPs) in aquatic environments under different ionic strength and further examine its effects on copper toxicity and bioaccumulation by monitoring the responses and uptake behaviours of zebrafish embryo. Ionic strength (IS) was simulated according to surface water (1.5 mM), groundwater (15 mM), and wastewater (54 mM), representing low-, mid-, and high-IS water, respectively. At the highest exposure of 10 mg CuO/L, zebrafish larvae mortality was increased from 21.3% to 33.3%, when IS decreased from 54 to 1.5 mM. Low-IS solution also caused the highest numbers of delayed hatching embryo (81.3%) and opaque yolk deformation (36.3%). Copper bioaccumulation markedly increased when larvae were exposed to low-IS water (35%) relative to high-IS water (15%). Exposing to low-IS particularly enhanced copper uptake (~15 ng Cu/g inside embryo), facilitating the copper accumulation in the heart of larvae, whereas aggregated CuO NPs (>500 nm) in mid- and high-IS water were blocked from the embryo and found abundantly in the body axis and tail. Results indicate that CuO NPs in low-IS solutions rapidly form the relatively small CuO NP aggregates with a high copper dissolution, which would pose great concern for aquatic organisms.

[Chlamydia psittaci pneumonia complicated with rhabdomyolysis: a case report and literature review]

Objective: To analyze the clinical characteristics and the diagnosis and treatment of Chlamydia psittaci pneumonia complicated with rhabdomyolysis. Methods: We reported a case of Chlamydia psittaci pneumonia complicated with rhabdomyolysis. We did a literature review on the published reports between January 1978 and May 2020 by searching with the key words of "psittacosis" or "Chlamydia psittaci" and "rhabdomyolysis" in the PubMed database (time frame: January 1, 1967 to May 30, 2020). Results: Our patient was a 64-year-old male presenting with high-grade fever, fatigue, myalgia and dyspnea. A computed tomographic scan of the chest revealed bilateral pneumonia, which was further complicated with rhabdomyolysis during disease progression. This prompted the metagenomic next-generation sequencing, revealing the sequences of Chlamydia psittaci in both the bronchoalveolar lavage fluid and blood. Of the 11 cases in the 3 literature reports that we retrieved, 5 had concomitant rhabdomyolysis (two of which did not have complete clinical information), and the other 6 cases had myositis complicated with an elevated level of creatine phosphokinase. This yielded 3 cases with complete clinical information for our analysis. We had further incorporated their information with the single case managed within our study site. Two were males and the other 2 were females. The patients were aged 66, 46, 44 and 64 years, respectively. All cases had fever and 3 had a contact history with live poultry. Two cases had myalgia and progressed rapidly into having respiratory failure, and the other 2 cases did not develop myalgia and improved significantly after a timely treatment. All 4 cases were cured and discharged after treatment with appropriate antibiotics. No adverse outcomes were observed. Conclusions: The prognosis of Chlamydia psittaci pneumonia complicated with rhabdomyolysis was poor in case of a delayed treatment. Early diagnosis would help reduce the mortality.

CoO-3D ordered mesoporous carbon nitride (CoO@mpgCN) composite as peroxymonosulfate activator for the degradation of sulfamethoxazole in water

A facile impregnation method was used to fabricate a hybrid CoO-3D ordered mesoporous carbon nitride (CoO@mpgCN) catalyst that effectively activated peroxymonosulfate (PMS) for the degradation of pharmaceutical chemical, exemplified by antibiotic sulfamethoxazole (SMX) in aqueous solutions. The CoO@mpgCN/PMS system exhibited high catalytic reactivity and SMX removal efficiency over a wide pH range with an observed rate constant (k_obs) of 0.314 min^-1. Furthermore, CoO@mpgCN was stable with consistently high degree of SMX degradation without having cobalt dissolution and loss of catalytic activity for at least five consecutive cycles. The significant catalysis performance of CoO@mpgCN was due to its uniformly distributed mesopores, large specific surface area, and high electron transfer ability at the active CoO sites. Both quenching experiments and electron paramagnetic resonance (EPR) analysis verified the yield, in abundance, of highly active species, specifically SO₄^- and OH from the CoO@mpgCN activation of PMS, primarily. Hence, SMX degradation followed a radical chain reaction mechanism. The result of this study revealed a novel prospective of CoO@mpgCN composite as PMS activator for the remediation of recalcitrant pollutants in water.

[Analysis of 2-level logistic model on influencing factors of suspected occupational diseases]

Objective: To investigate the detection of suspected occupational diseases in the occupational health examination population in Hangzhou, and to establish a two-level logistic model of influencing factors. Methods: In October 2018, the information of physical examinees was collected through the 2015-2017 occupational health examination and reexamination database of Hangzhou Hospital for the Prevention and Treatment of Occupational Disease. MlwiN 2.02 software was used to establish a 2-level logistic model of suspected occupational diseases, with the occupational hazard factors as the level 2 unit and the employees as the level 1 unit. χ(2) test was used to compare the detection rates of suspected occupational diseases with different characteristics. The trend of detection rates of suspected occupational diseases with age and working age were tested by Cochran-Armitage trend test. Results: The morbidity rate of suspected occupational diseases in 2965 workers was 59.6% (1767/2965) , and the rates caused by different occupational hazardous factors were significantly difference (χ(2)=1615.27, P<0.01) , that caused by noises was the highest (98.0%, 1206/1231) , and the next was the dust (87.5%, 70/80) . The rate in male was 61.5% (1532/2492) , and that in female was 49.7% (235/473) , they were significantly difference (χ(2)=22.96, P<0.01) . The rates of suspected occupational diseases increased with the ages (Z=8.77, P<0.01) and working years (Z=3.62, P<0.01) . The multivariate analysis by 2-level logistic model indicated that gender, age and working year were all no significant, instead the level 2 unit random effect was significant (χ(2)=4.77, P<0.05) . Conclusion: Suspected occupational diseases will occur in clusters in occupational hazardous factors. The influence of occupational hazardous factors on suspected occupational diseases was more than that of personal characteristics.

Biochar derived from red algae for efficient remediation of 4-nonylphenol from marine sediments

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO₂ atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H₂O₂, which increased the generation of reactive radicals under alkaline pH condition. Ca²⁺ ion was the active species responsible for 4-NP degradation. CaO/CaCO₃ on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.

Electrochemical analysis of naproxen in water using poly(l-serine)-modified glassy carbon electrode

A poly(l-serine)-modified glassy carbon electrode (PLS/GCE) was fabricated by electropolymerization and used to study the detection of naproxen (NPX), a representative non-steroidal anti-inflammatory drug, in phosphate buffer supporting electrolyte at pH 5.0. Results indicated that the PLS/GCE was capable of determination of NPX at a working potential of 0.92 (vs. Ag/AgCl) in voltammetry mode. Experimental factors such as scan rate, accumulation time, solution pH, initial NPX concentration, and interferences were optimized for NPX determination efficiency. The morphology and elemental distribution of the electrode surface were characterized by ESEM, TEM, PSD, XRD, FTIR, TGA, XPS, and zeta potential. NPX oxidation current increased with increasing analyte concentration and scan rate but decreased with increasing pH. Linear sweep voltammetry calibration curve was established in the NPX concentration range of 4.3-65 μM, with detection limit and average recovery of 0.69 μM (n = 3) and 104 ± 2.5%, respectively. PLS/GCE is simple, accurate, reproducible, and easy for operation, therefore would be cost-effective for the determination of NPX.

Loofah-derived activated carbon supported on nickel foam (AC/Ni) electrodes for the electro-sorption of ammonium ion from aqueous solutions

Activated carbon (AC), prepared from dried loofah sponge, was supported on nickel foam to fabricate AC/Ni electrodes. The characteristics of ammonium electrosorption on AC/Ni electrodes was studied. Results showed that AC prepared in one-step activation (without pre-pyrolysis), i.e., OAC, had relatively low crystallinity, high mesoporosity, and high specific capacitance compared to those made in two-step carbonation followed by activation. Adsorption and desorption density of NH₄⁺ were measured at constant potential of -1.0 V (vs. Hg/HgO) and +0.1 V (vs. Hg/HgO), respectively. Non-faradaic charging contributed to the electrochemical storage and adsorption of ammonium ions on the AC surface with a maximal charge efficiency of 80%, at an applied potential of -1.0 V (vs. Hg/HgO). Multiple-layer adsorption isotherm better described the electrosorption of ammonium ion on OAC/Ni electrodes yielding a maximum adsorption capacity of 6 mg-N g^-1, which was comparable with other similar systems. Overall, results clearly demonstrated the effect of synthesis strategy on the capacitive charging behaviors of AC/Ni electrodes and its relationship to NH₄⁺ electrosorption.

[First bite syndrome: clinical study of six cases and review of the literature]

Objective:The aim of this study is to explore the etiology, diagnosis and treatment of first bite syndrome（FBS）. Method:Clinical data of six patients with FBS were analyzed retrospectively. There were 4 cases of parapharyngeal space tumor resection complicated with FBS, 1 case of parotidectomy of deep lobe parotid gland tumor complicated with FBS, and 1 case of no definite cause. Analgesic treatments such as ibuprofen and tramadol capsules were given, in combination with carbamazepine （200 mg, 3 times a day） for four weeks. Result:The severity of symptoms decreased in five cases, 2-16 months after treatment. While another one had no amelioration during 10 months' follow-up. Conclusion:FBS is one of the possible complications of surgery of the upper cervical region, especially parotid deep lobe tumor resection, which should be distinguished from the usual postoperative pain. The cause of the disease may be related to intraoperative injury to the sympathetic plexus of the parotid gland. Currently, there is no standard treatment method, but the symptoms are usually relieved within a few months.

The degradation of phthalate esters in marine sediments by persulfate over iron-cerium oxide catalyst

This study investigated the degradation of phthalate esters (PAEs) in marine sediments by sodium persulfate (Na₂S₂O₈, PS) activated by a series of iron-cerium (Fe-Ce) bimetallic catalysts (FCBCs). The surface structure and chemistry of the FCBCs were characterized by TEM, HRTEM, XRD, FTIR, BET and XPS. Results show successful synthesis of FCBC catalysts. Factors such as PS concentration, Fe to Ce molar ratio, catalyst dosage, and initial pH that might affect PAEs degradation were investigated. Results revealed that PAEs was degraded more effectively over FCBC with a Fe-Ce molar ratio of 1.5:1. Increase in Ce improved the catalytic activity of FCBC due to increase in oxygen storage capacity (OSC). Acidic conditions enhanced PAEs degradation with a maximum degradation of 86% at pH 2 and rate constant (k_obs) of 1.5 × 10^-1 h^-1 when the PS and FCBC concentrations were to 1.0 × 10^-5 M and 1.67 g/L, respectively. Di-(2-ethylhexyl) phthalate (DEHP) was a salient marker of PAE contamination in sediments. Dimethyl phthalate (DMP) and diethyl phthalate (DEP) were easier to degrade than DEHP, diisononyl phthalate (DINP), dioctyl phthalate (DnOP) and diisononyl phthalate (DIDP). The synergistic catalytic effect of Fe³⁺/Fe²⁺ and Ce⁴⁺/Ce³⁺ redox couples, in addition to electron transfer of oxygen vacancies, activated S₂O₈^2- to generate SO₄^- and HO radicals, which played the major role of PAEs degradation. 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trapping EPR studies verified the crucial role of SO₄^- and HO in the oxidative degradation process. FCBC/PS oxidation exhibited high-performance for the remediation of PAEs-contaminated marine sediments.

The adsorption characteristics of fluoride on commercial activated carbon treated with quaternary ammonium salts (Quats)

Commercial activated carbon was treated with six quaternary ammonium salts (Quats), namely, hexyltrimethylammonium (HTMA), octyltrimethylammonium (OTMA), decyltrimethylammonium (DCTMA), dodecyltrimethylammonium (DDTMA), Tetradecyltrimethylammonium (TDTMA), and hexadecyltrimethylammoium (HDTMA) as to enhance the fluoride adsorption capacity. In batch mode experiments, fluoride adsorption onto the Quats-treated activated carbon decreased dramatically with increase in solution pH. Fluoride removal by the Quats-treated activated carbons was closely related to the Quats chain length at less-than critical micelle concentration (CMC). Multi-site adsorption isotherm described fluoride adsorption characteristics well. Results showed that activated carbon treated with DDTMA exhibited the best fluoride adsorption density among all Quats investigated. DDTMA-treated activated carbons exhibited two-fold increase in the fluoride adsorption capacity compared to the untreated activated carbon. Results of regeneration, by alkaline desorption and/or Quats re-loading, showed fluoride-laden activated carbons have high reusability. DDTMA increased the positive surface charge of the activated carbon that enhanced fluoride adsorption. DDTMA-treated activated carbon was promising for fluoride removal from water with much enhanced removal capacity.

Cobalt-impregnated biochar (Co-SCG) for heterogeneous activation of peroxymonosulfate for removal of tetracycline in water

Cobalt-impregnated spent coffee ground biochar (Co-SCG) was synthesized and applied for tetracycline (TC) removal from water. The results showed that Co-SCG biochar exhibited marked adsorption capacity and catalyst activity. The maximum adsorption capacity of Co-SCG biochar toward TC was 370.37 mg g^-1. TC was almost completely degraded in 25 min with a rate constant of 17.78 × 10^-2 min^-1 under the following optimal condition: TC concentration of 0.2 mM, PMS concentration of 0.6 mM, Co-SCG dosage of 100 mg L^-1, and pH of 7.0. Co-SCG was characterized for surface properties by SEM, TEM, HRTEM, and BET. The concentration of 16 PAHs in Co-SCG biochar was studied also. Results demonstrated that Co-SCG was an effective eco-friendly material for the removal of tetracycline from water.

Activation of persulfate by CoO nanoparticles loaded on 3D mesoporous carbon nitride (CoO@meso-CN) for the degradation of methylene blue (MB)

A simple and facile synthesis method is developed for the fabrication of CoO loaded ordered mesoporous carbon nitride (CoO@meso-CN) composites, at various CoO loadings, and used, for the first time, to activate persulfate (PS) for methylene blue (MB) degradation. The interfacial interaction between the ultrafine CoO nanoparticles, immobilized by high surface area, regular mesopores, and graphitic nature of the meso-CN support can further enhance the catalytic activation of PS for methylene blue (MB) degradation. Among all catalysts studied, the 5-wt% CoO@meso-CN exhibits the best catalytic performance with a k_obs of 0.264 min^-1. High initial pH, especially at pH-11, is more beneficial for PS activation. Furthermore, the CoO@meso-CN nanocatalyst is highly stable with a consistently high degree of MB degradation and negligible cobalt leaching for at least 5 consecutive catalytic cycles. Both SO₄^- and OH are the major reactive species based on results of EPR and quenching experiments. The degradation intermediates of MB are also identified by HPLC/MS/MS and the possible degradation pathway is proposed. Results clearly demonstrate that CoO@meso-CN is a promising green catalyst with enormous potential for the remediation of hazardous chemicals using PS.

The effect of crystal phase of manganese oxide on the capacitive deionization of simple electrolytes

MnO₂ is a common material for the fabrication and design of capacitive deionization (CDI) devices but there is little information on the role of MnO₂ crystal phase on CDI performance. A series of MnO₂ (α, β, γ, and δ phase) were synthesized and fabricated as cathodes for studying the CDI performance as affected by pH in simple batch mode experiments. Our results revealed that the deionization efficiency decreased with increased negative surface charge as a result of the deprotonated surface. Importantly, this correlation was pH independent and the surface heterogeneity due to different MnO₂ phase was likely responsible for the different degree of surface ionization and consequently the CDI efficiency. Results of electrochemical impedance spectroscopy analyses further implicated that a highly ionized surface would result in a diffusion layer with a great resistance that conversely inhibited the access of co-ions in the CDI process. This indicated the applied potential was mainly responsible for driving ions transporting through the double layer resistance instead of accommodating them (electrosorption). Based on our results, the surface heterogeneity as a result of different spatially distributed MnO₆ octahedral would be accounted for the varying degree of surface ionization and consequently the discrepancy in CDI efficiency among different MnO₂ phases.

Electro-sorption of ammonium ion onto nickel foam supported highly microporous activated carbon prepared from agricultural residues (dried Luffa cylindrica)

An electrode made of loofah sponge derived activated carbon supported on nickel foam (AC/Ni) was successfully fabricated and used to remove ammonium ion (NH₄⁺) from aqueous solution. A multilayer adsorption isotherm was used to describe ammonium electro-sorption on AC/Ni electrodes at different temperature, initial NH₄⁺ concentration, and electrical field. The cyclic voltammetry (CV) results suggested that the electrical capacitance of AC/Ni electrodes, with the AC being prepared without preheating (OAC) or with low temperature heating (i.e., 300 AC), were higher than those prepared at high preheating temperature (i.e., 400 AC and 500 AC). Increasing the electro-sorption temperature from 10 to 50 °C decreased the monolayer NH₄⁺ adsorption capacity from 5 to ca. 2-3 mg-N g^-1, respectively. Background electrolyte, namely, sodium sulfate, exhibited significant competitive effect on the adsorption of ammonium ion at sodium ion concentration > 10^-2 M. The activation energy and heat of adsorption were 9-23.2 kJ mol^-1 and -3.7--10.7 kJ mol^-1, respectively, indicating a physisorption and exothermic adsorption characteristics. Based on the kinetics and thermodynamics analysis, there was slight increase in the activation energy with elevating preheating temperature, which increased the quantity of micro-pores and surface heterogeneity of the AC materials. Overall, results clearly demonstrated that carbon pyrolysis played a role on the capacitive charging behaviors of electrodes and the efficiency of NH₄⁺ electro-sorption on the AC/Ni electrodes.

A dual TiO2/Ti-stainless steel anode for the degradation of orange G in a coupling photoelectrochemical and photo-electro-Fenton system

A dual-anode consists of stainless steel and TiO₂/Ti electrodes is used to study the kinetics of the degradation of hazardous chemicals exemplified by azo dye orange G (OG) using a coupling photoelectrochemical catalytic and photoelectro-Fenton (PEC/PEF) system. Concurrent generation of hydroxyl radicals on the TiO₂/Ti photocatalyst and in-situ generation of Fenton reagents on the stainless steel electrode greatly enhances the performance of the PEC/PEF electrodes over that of the PEC and the PEF alone process. The efficiency of the PEC/PEF process is a function of Fe²⁺ and H₂O₂ concentration OH⋅ in the solution bulk, which promotes the oxidative degradation of OG and its byproducts. The mean carbon oxidation state (COS) is estimated to reflect the degree of mineralization. Based on the pseudo first-order kinetics with respect to OH, OG, Fe²⁺, the corresponding reaction rates is established. UV-Vis spectrometry reveals the presence of four major intermediates, which helps establish the OG degradation pathways.

Adsorption characteristics of ammonium ion onto hydrous biochars in dilute aqueous solutions

This research aims at studying the characteristics of ammonium adsorption onto hydrous bamboo biochar. Results showed that pH played the most important role in ammonium adsorption. High ionic strength enhanced the ammonium adsorption capacity of bamboo biochar. Ammonium adsorption was exothermic and spontaneous. FTIR results showed shift, disappearance, or appearance of specific functional groups on the bamboo biochar surface. Surface precipitation and complex formation contributed to the adsorption of ammonium onto hydrous bamboo biochar. Biochar can be an effective adsorbate for ammonium removal from water. Additionally, the formation of nitrogen containing precipitates on the biochar surface, potentially, leads to the in-situ synthesis of slow-release fertilizer.

Photocatalytic degradation of bisphenol A over a ZnFe2O4/TiO2 nanocomposite under visible light

A ZnFe₂O₄-TiO₂ nanocomposite combining p-type ZnFe₂O₄ and n-type TiO₂ was successfully fabricated. The ZnFe₂O₄-TiO₂ nanocomposite greatly enhanced the bisphenol A (BPA) photodegradation under visible light irradiation at 465 ± 40 nm. Loading TiO₂ with 1 wt% of ZnFe₂O₄ produced high photocurrent and low charge transfer resistance. The photodegradation rate of BPA by ZnFe₂O₄-TiO₂, which was highly dependent on the water chemistry including pH, anions, and humic acid, was 20.8-21.4 times higher than that of commercial TiO₂ photocatalysts. Chloride and sulfate ions enhanced BPA photodegradation mostly due to the production of more radical species; whereas nitrate, dihydrogen phosphate, and bicarbonate ions decreased the photodegradation rate of BPA due to the scavenge of hydroxyl radicals. The photoactivity and recyclability of ZnFe₂O₄-TiO₂ in lake water was also assessed. A near complete BPA removal from lake water was observed under visible light irradiation. Furthermore, >90% of photocatalytic activity toward BPA degradation was achieved in 5 cycles of continuous addition of BPA to the lake water. The BPA degradation intermediates were identified by HPLC/MS/MS and possible reaction pathways were proposed. Results clearly demonstrate the excellent visible-light-sensitive photocatalytic degradation of BPA over ZnFe₂O₄-TiO₂ composite which has a great application potential for the decomposition of emerging contaminants in impaired waters.

Hazardous Wastes Treatment Technologies

A review of the literature published in 2017 on topics relating to hazardous waste management in water, soils and air. This review covers hazardous waste treatment theologies and applying physical, chemical, and biological principles.

Long non-coding RNA CRNDE may be associated with poor prognosis by promoting proliferation and inhibiting apoptosis of cervical cancer cells through targeting PI3K/AKT

Long non-coding RNAs (lncRNAs) are attracting more and more attention from researchers because they are relatively new factors in regulating biological processes in human cancers. The Colorectal Neoplasia Differentially Expressed (CRNDE) lncRNA is transcribed from chromosome 16 on the opposite strand to the neighboring IRX5 gene. It was originally discovered abnormally expressed in colorectal cancer (CRC) and was certified a critical biomarker in many cancers. However, its biological function and mechanism underlying the tumorigenesis of cervical cancer still require exploration. This study confirmed that CRNDE is markedly up-regulated in clinical tissues and cell lines of cervical cancer. The high expression of CRNDE positively correlates with advanced FIGO stage and lymph node metastasis. Furthermore, the overall survival rate in the group with highly expressed CRNDE was worse, and the high level of CRNDE may be regarded a prognostic factor because of its results from proportional hazard analysis. Loss-of-function assays revealed that CRNDE influences proliferation and apoptosis in cervical cancer cells, and Western blot assays revealed that the PI3K/AKT pathway was inactivated in response to CRNDE knockdown. Therefore, we conclude that CRNDE exerts oncogenic function in cervical cancer and should be further explored as a novel prognostic predictor.

Uptake of BDE-209 on zebrafish embryos as affected by SiO2 nanoparticles

It was hypothesized that interactions between emerging contaminants such as decabromodiphenyl ether (BDE-209) and nanoparticles (NPs) such as nano-SiO₂ (nSiO₂), can affect contaminant transport in the aquatic environment and its ecotoxicity. This study assessed the influence of nSiO₂ on the uptake of BDE-209 by zebrafish embryo. The distribution of BDE-209 and nSiO₂ on the external chorion and the internal embryo mass (i.e., dechorionated embryo) was measured. For single exposure of nSiO₂ to zebrafish embryo, separately, results showed that nSiO₂ accumulation on the chorion surface was higher than that in the dechorionated embryo. The nSiO₂ accumulation on the chorion surface was 129-200 mg-nSiO₂/g-chorion at 48 h post fertilization, hpf, of exposure time, whereas the equilibrium adsorption of nSiO₂ on the dechorionated embryo was ca. 0.42-0.54 mg-nSiO₂/g-embryo at 6 hpf. Results showed that the formation of nSiO₂-BDE-209 associates promoted both extracellular and intracellular uptake of BDE-209 by zebrafish embryo, thereby increasing the bioconcentration of BDE-209 on the chorion surface and in embryo. The results also revealed that the accumulation of BDE-209 on the chorion was remarkably greater than that on the dechorionated embryo at 48 hpf. The uptake of BDE-209 was 17.2 ± 0.45 mg/g-chorion (or 86 ng-BDE-209/chorionated embryo) and 0.37 ± 0.01 mg/g-embryo (or 18.6 ng-BDE-209/dechorionated embryo), respectively, when co-exposure of zebrafish embryos to BDE-209 and nSiO₂. Results from the SEM and EDS analysis revealed that nSiO₂ already passed through the chorion and adhered to the embryo surface/mass.

[Preliminary application of next generation sequencing technique in pathogen identification of foodborne disease]

Objective: To analyze genomic features of pathogens based on next generation sequencing technique in a food-borne disease event. Methods: A total of 11 blood samples, stomach contents before gastric lavage from the death and patients' foods were collected. S. aureus, B. cereus and toxic substances were detected. B. cereus detected in foods were counted. The conserved region of 16 S rDNA gene and ces gene(cereulide) of B. cereus isolates were detected by real-time PCR. Next Generation Sequencing (NGS) technology was applied to acquire genome sequences of isolates. Different plasmids distribution and comparative genomics analysis with reference sequences in public databases were analyzed. Results: Only B. cereus tested positive in all samples. The counts of B. cereus in Egg fried rice, one food samples, were 1.9×10(7) CFU/g, and the counts of B. cereus in dried and fried fish and brine pork head meat samples were 3.0×10(3) CFU/g both. Ten isolates were carrying hlyⅢ, nheA, nheB, inlA and inhA genes, and nine isolates carried the plcR gene and nine isolates carried the nheC gene. The PCR result of 16 S rDNA gene and ces gene of all isolates were positive. All carried the complete ces genes cluster sequence which were identical to the sequence of plasmid pCER270 (NC_01 0924.1) from strain AH187 in United Kingdom and pNCcld (NC_016792.1) from NC7401 in Japan. The alignment of plasmids turned out the sequence of the isolate differed from the pXO1 and pXO2 plasmids of B. anthracis, but carried the pNCcld plasmid containing the ces genes cluster. The phylogenetic tree based on genomic sequences of ten isolates showed high similarity (distances in phylogenetic tree from 2.0×10(-6)-9.0×10(-6)) to each other and to the B. cereus strains AH187 and NC7401 (MLST ST26 type, distances in phylogenetic tree from 3.8×10(-5)-4.5×10(-5)). Conclusion: The foodborne disease event was caused by vomiting type Bacillus cereus without plasmid pXO1 and pXO2 contaminated egg fried rice. The vomiting-type food poisoning caused by B. Cereus globally is probably associated with ST26, ST164 and other strains harboring ces gene.

A seasonal observation on the distribution of engineered nanoparticles in municipal wastewater treatment systems exemplified by TiO2 and ZnO

The present research attempted to assess the seasonal variation of engineered nanoparticles (ENPs) in a major municipal wastewater treatment system. A monthly survey over a 12-month period was conducted to monitor the concentration of TiO₂ and ZnO nanoparticles throughout the treatment process. Results showed inflow concentrations in the range of 21.6±5.0-391.0±43.0μg/L and 20.0±12.0-212.0±53.0μg/L for TiO₂ and ZnO, respectively. Seasonal pattern of the inflow ENPs concentration showed elevated value in the summer and winter periods for both TiO₂ and ZnO. Based on the concentration profile, the hydraulic flow rate, and the concentration of mixed liquid suspended solid (MLSS), the daily mass loading (DML) or mass flow rate of nanoparticles and the mass ratio of engineered nanoparticle to MLSS were calculated. DML provided a real-time estimate of temporal distribution of ENPs in the treatment processes. Results indicated a daily mass loading of 50.1±12.7 and 44.7±14.1kg/day (yearly average) for TiO₂ and ZnO, respectively. The amount of ENPs captured by sludge particulates were, yearly average, of 7.1kg-ZnO/d and 39.8kg-TiO₂/d, and 8.9kg-ZnO/d and 25.1kg-TiO₂/d, by the primary and the secondary sludge particulates, respectively. ENPs to MLSS mass ratio also showed a seasonal patter similar to the inflow ENPs concentration, where summer and winter periods showed elevated values. Additionally, loss of ENPs throughout the treatment plant that was not accounted for, also can be estimated from the daily mass loading rate and the mass ratio of ENPs to MLSS. Based on the seasonal distribution of ENPs in wastewater treatment systems, especially the daily mass loading rate, it is possible to estimate the uses of nanoparticle-related commercial and personal care products in the urban areas and enable decision-making on the strategy of sludge disposal management.

[Field epidemiological investigation on a foodborne outbreak caused by Staphylococcus aureus enterotoxin, in Hangzhou, 2014]

Objective: To identify the cause on a foodborne breakout in a university of Hangzhou in 2014. Methods: Data on cases were gathered from the out-patient logs of the university affiliated or neighboring hospitals to describe the disease distribution and epidemiological curves. Case-control and field studies on hazard factors were conducted simultaneously. Results: The incubation period was 1.5-5.0 hours, of which the median was 3 during the outbreak. All the cases consumed food from a restaurant called Chen's Snacks nearby their university and suffered from the Staphylococcus aureus enterotoxin. Results from the Staphylococcus enterotoxin testing were positive in 3 stool and 6 food samples, out of the total 18 samples. Conclusion: This foodborne outbreak was caused through food poisoning by vermicelli which was contaminated with Staphylococcus aureus.

Hazardous Waste Treatment Technologies

This article reviews the scientific literature published in 2016 on physical, chemical, and biological treatment of hazardous contaminants and environmental bioremediation.

Looking for engineered nanoparticles (ENPs) in wastewater treatment systems: Qualification and quantification aspects

The current study developed a rationalized method for the quantification and identification of engineered nanoparticles (ENPs) in wastewaters. A review of current literature revealed that overall, presently available methods focused on single ENP mostly and were applicable mainly to samples of low organic loadings or under well-controlled laboratory conditions. In the present research, procedures including dialysis for desalting and low-temperature oxidation for organic removal were used to pretreat samples of high organic loadings, specifically, municipal wastewater and sludge. SEM mapping technique identified the presence of nanoparticles, which was followed by ICP-OES quantification of different engineering nanoparticles in wastewater and sludge samples collected from two major regional municipal wastewater treatment plants. Results showed successful identification and quantification of nano-size titanium and zinc oxides from wastewater treatment plants studied. Concentration profile was mapped out for the wastewater treatment plants (WWTPs) using the method developed in this research. Results also showed an overall 80% and 68% removal of titanium and zinc by primary and secondary sludge particulates, respectively. Mass flux of engineered nanoparticles (ENPs) was also calculated to estimate the daily flow of engineered nanoparticles in the system.

An activated carbon fiber cathode for the degradation of glyphosate in aqueous solutions by the Electro-Fenton mode: Optimal operational conditions and the deposition of iron on cathode on electrode reusability

An activated carbon fiber (ACF) cathode was fabricated and used to treat glyphosate containing wastewater by the Electro-Fenton (EF) process. The results showed that glyphosate was rapidly and efficiently degraded and the BOD₅/COD ratio was increased to >0.3 implying the feasibility of subsequent treatment of the treated wastewater by biological methods. The results of ion chromatography and HPLC measurements indicated that glyphosate was completely decomposed. Effective OH generation and rapid recycling/recovery of the Fe²⁺ ions at the cathode were responsible primarily for the high performance of the ACF-EF process. Factors such as inlet oxygen gas flow rate, Fe²⁺ dosage, initial glyphosate concentration, applied current intensity, and solution pH that may affect the efficiency of the ACF-EF process were further studied and the optimum operation condition was established. Results of SEM/EDX, BET and XPS analysis showed the deposition of highly dispersed fine Fe₂O₃ particles on the ACF surface during the EF reaction. The possibility of using the Fe₂O₃-ACF as iron source in the EF process was assessed. Results showed that the Fe₂O₃-ACF electrode was effective in degrading glyphosate in the EF process. The deposition of Fe₂O₃ particles on the ACF electrode had no adverse effect on the reusability of the ACF cathode.

Hazardous Waste Treatment Technologies

The article reviews the scientific literature published in 2015 on physical, chemical, and biological treatment of hazardous contamination and environmental remediation.

Adsorption characteristics of nano-TiO2 onto zebrafish embryos and its impacts on egg hatching

The characteristics of nanoparticles (NPs) uptake may fundamentally alter physicochemical effects of engineered NPs on aquatic organisms, thereby yielding different ecotoxicology assessment results. The adsorption behavior of nano-TiO2 (P-25) on zebrafish embryos in Holtfreter's medium (pH 7.2, I ∼ 7.2 × 10(-2) M) and the presence of sodium alginate (100 mg/L) as dispersant was investigated. Zebrafish embryos (total 100) were exposed to nano-TiO2 at different concentrations (e.g., 0, 10, 20, 60, 120 mg/L) in batch-mode assay. The adsorption capacity of nano-TiO2 on fish eggs was determined by measuring the Ti concentration on the egg surface using ICP-OES analysis. Results showed that the adsorption capacity increased rapidly in the first hour, and then declined to reach equilibrium in 8 h. The adsorption characteristics was visualized as a three-step process of rapid initial layer formation, followed by break-up of aggregates and finally rearrangement of floc structures; the maximum adsorption capacity was the sum of an inner rigid layers of aggregates of 0.81-0.84 μg-TiO2/#-egg and an outer softly flocculated layers of 1.01 μg-TiO2/#-egg. The Gibbs free energy was 543.29-551.26 and 100.75 kJ/mol, respectively, for the inner-layer and the outer-layer aggregates. Adsorption capacity at 0.5-1.0 μg-TiO2/#-egg promoted egg hatching; but hatching was inhibited at higher adsorption capacity. Results clearly showed that the configuration of TiO2 aggregates could impact the hatching efficiency of zebrafish embryos.

The short-term toxic effects of TiO₂nanoparticles toward bacteria through viability, cellular respiration, and lipid peroxidation

To better understand the potential impacts of metal oxide nanoparticles (NPs) on Gram(+) Bacillus subtilis and Gram(-) Escherichia coli (K12) bacteria, eight different nanosized titanium dioxide (TiO2) suspensions with five different concentrations were used. Water quality parameters (pH, temperature, and ionic strength), light sources, and light intensities were also changed to achieve different environmental conditions. The photosensitive TiO2 NPs were found to be harmful to varying degrees under ambient conditions, with antibacterial activity increasing with primary particle sizes from 16 to 20 nm. The presence of light was a significant factor under most conditions tested, presumably due to its role in promoting generation of reactive oxygen species (ROS). However, bacterial growth inhibition was also observed under dark conditions and different water quality parameters, indicating that undetermined mechanisms additional to photocatalytic ROS production were responsible for toxicity. The results also indicated that nano-TiO2 particles in the absence and the presence of photoactivation induced lipid peroxidation and cellular respiration disruption.

Hazardous Waste Treatment Technologies

The article reviews the scientific literature published in 2014 on physical, chemical, and biological treatment of hazardous contaminants and environmental bioremediation.

Effects of nano-ZnO on the agronomically relevant Rhizobium-legume symbiosis

The impact of nano-ZnO (nZnO) on Rhizobium-legume symbiosis was studied with garden pea and its compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure of peas to nZnO had no impact on germination, but significantly affected root length. Chronic exposure of plant to nZnO impacted its development by decreasing the number of the first- and the second-order lateral roots, stem length, leaf surface area, and transpiration. The effect of nZnO dissolution on phytotoxicity was also examined. Results showed that Zn(2+) had negative impact on plant development. Exposure of R. leguminosarum bv. viciae 3841 to nZnO brought about morphological changes by rendering the microbial cells toward round shape and damaging the bacterial surface. Furthermore, the presence of nZnO in the rhizosphere affected root nodulation, delayed the onset of nitrogen fixation, and caused early senescence of nodules. Attachment of nanoparticles on the root surface and dissolution of Zn(2+) are important factors affecting the phytotocity of nZnO. Hence, the presence of nZnO in the environment is potentially hazardous to the Rhizobium-legume symbiosis system.

Specific chemical interactions between metal ions and biological solids exemplified by sludge particulates

The adsorption of metals onto biological surfaces was studied exemplified by municipal sludge particulates of the primary, the secondary, and the tertiary sludge types from four regional wastewater treatment plants. Major factors affecting the extent of metal adsorption including pH, DOM, total biomass, and total metal loading were studied. The acidity-basicity characteristics of the DOM, the metal ions (Lewis acids), and the surface of the sludge particulates make pH the most important parameter in metal adsorption. Change in pH can modify the speciation of the metal ions, the DOM, and the surface acidity of the sludge particulates and subsequently determines the degree of metal distribution between the aqueous phase and the sludge solids. Information on the acidity-basicity characteristics of the DOM and the sludge particulates are used to calculate the stability constant of metal ion-sludge complexes.

Effects of nano-TiO₂ on the agronomically-relevant Rhizobium-legume symbiosis

The impact of nano-TiO₂ on Rhizobium-legume symbiosis was studied using garden peas and the compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure to nano-TiO₂ did not affect the germination of peas grown aseptically, nor did it impact the gross root structure. However, nano-TiO₂ exposure did impact plant development by decreasing the number of secondary lateral roots. Cultured R. leguminosarum bv. viciae 3841 was also impacted by exposure to nano-TiO₂, resulting in morphological changes to the bacterial cells. Moreover, the interaction between these two organisms was disrupted by nano-TiO₂ exposure, such that root nodule development and the subsequent onset of nitrogen fixation were delayed. Further, the polysaccharide composition of the walls of infected cells of nodules was altered, suggesting that the exposure induced a systemic response in host plants. Therefore, nano-TiO₂ contamination in the environment is potentially hazardous to the Rhizobium-legume symbiosis system.

Combined ultrasound and Fenton (US-Fenton) process for the treatment of ammunition wastewater

A wastewater collected from a regional ammunition process site was treated with combined US-Fenton process. Factors such as pH, temperature, reaction time, US energy intensity, initial TOC concentration, and the molar ratio of iron to hydrogen peroxide that might affect the treatment efficiency were investigated. The removal of TOC, COD, and color increased with decreasing pH and increasing temperature and US intensity. Color was removed rapidly reaching 85% in 10 min; whereas TOC and COD were removed slowly, only about 20% for both in 10 min and approaching 65 and 92% removal in 120 min, respectively. The optimal molar ratio of Fe(II) to H(2)O(2) for TOC and COD removal was 500. The results showed that the change in the average carbon oxidation number (ACON) was parallel to that of the removal efficiency of TOC, COD, and color. The toxicity of treated wastewater was reduced as assessed by the respiration rate of Escherichia coli.

Magnetoelectrically coupled polariton excitation in a plasmonic crystal composed of nanorod dimers

In this work, the long wavelength optical properties of a plasmonic crystal, composed of gold nanorod dimers arranged parallel, have been studied. Due to the strong coupling between incident light and the oscillation of free electrons inside nanorod dimers, the magnetically induced and/or magnetoelectrically coupled plasmonic polaritons can be excited. A theoretical demonstration has been proposed and coupled equations that show similar profiles to the Huang-Kun equations for ionic crystals have been deduced, indicating the constitutive abnormalities and polaritonic bandgap effect. The analogy between the magnetoelectrically coupled metamaterials and ionic crystals may shed light on physical explanations, as well as constitutive parameter retrieval, for the magnetoelectric metamaterials.

Responses of Ceriodaphnia dubia to TiO2 and Al2O3 nanoparticles: a dynamic nano-toxicity assessment of energy budget distribution

The in vivo responses of C. dubia to nanoparticles exemplified by a photoactive titanium oxide (TiO(2)) and a non-photocatalytic aluminum oxide (Al(2)O(3)) were studied. Both nanomaterials inhibited the growth of C. dubia at concentrations ca. >100mg/L. The EC50 value was 42 and 45 mg/L in the presence of TiO(2) and Al(2)O(3), respectively, based on 3-brood reproduction assay. Results implied that reactive oxygen species (ROS) may not be totally responsible for the adverse effects exerted on the invertebrate. Aggregation and interaction among nanoparticles, C. dubia, and algal cells, major food source of Daphnia, played a significant role on the responses of C. dubia to nanoparticles. Dynamic energy budget (DEB) analysis was used to assess the impact of nanoparticles on the energy allocation of C. dubia. Results indicated that nanoparticles could disrupt the assimilation and consumption of energy in C. dubia dramatically. The assimilation energy was negatively correlated to the concentration of nanomaterials, a reduction from 11 to near 0 μg-C/animal/day in the presence of TiO(2) or Al(2)O(3) nanoparticles at a nanoparticle concentration of 200mg/L. The energy consumed for life-maintenance increased also with increase in the concentration of nanomaterials. Results clearly demonstrated the importance of energy disruption in determining the toxicity of nanoparticles toward C. dubia.

Electro-photocatalytic degradation of acid orange II using a novel TiO2/ACF photoanode

A novel photoanode was prepared by immobilizing TiO(2) film onto activated carbon fibers (TiO(2)/ACF) using liquid phase deposition (LPD) to study the electro-photocatalytic (EPC) degradation of organic compounds exemplified by an azo-dye, namely, Acid Orange II (AOII). Results demonstrated that by applying a 0.5 V bias (vs. SCE) across the TiO(2)/ACF electrode, the AOII degradation rate was increased significantly compared to that of photocatalytic (PC) oxidation. The application of an electric field promotes the separation of photogenerated electrons and holes as confirmed by electrochemical impedance spectroscopy (EIS) measurements. The structural and surface morphology of the TiO(2)/ACF electrode was characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). SEM images showed that TiO(2) was deposited on almost every carbon fiber with an average thickness of about 200 nm with the inner space between neighboring fibers being maintained unfilled. The morphological features of the photo-anode facilitated the passage of solution as well as UV light through the felt-form electrode and created a three-dimensional environment favorable to EPC oxidation. Both the large outer surface area of the 3D electrode and the good organic adsorption capacity of the ACF support promoted high contact efficiency between AOII and TiO(2) surface. Anatase was the major crystalline TiO(2) deposited. UV-vis spectrophotometry, TOC (total organic carbon) analysis, and HPLC technique were used to monitor the concentration change of AOII and intermediates as to gain insight into the EPC degradation of AOII using the TiO(2)/ACF electrode.

Ozonation of pentachlorophenol in unsaturated soils

A heterogeneous model was developed to describe interactions between ozone and hydrophobic organic compounds, exemplified by pentachlorophenol, in highly gas-saturated vadose zones where water moisture was limited to a thin film on soil particle surfaces. The soil was assumed to be free of soil organic matter. The model included a set of transient equations considering diffusion with simultaneous chemical reaction and hydrophobic partitioning. From dimensionless analysis, it was found that the film concentrations of ozone and the hydrophobic organic component were dependent on the Damköhler numbers. Effects of Damköhler numbers on the film profiles of components were examined. With the interfacial flux of ozone calculated from film profiles, dimensionless governing equations of ozone transport and contaminant removal across an experimental column were established. These equations were dependent on the Stanton number. One-dimensional column experiments were conducted to test the model. The optimal time for flow rate adjustment during the process was approximated. Finally, effects of ozone velocity and ozone gas concentration on the Stanton number were evaluated.

Adsorption of arsenic(V) onto fly ash: a speciation-based approach

Arsenic (As) poses a significant water quality problem and challenge for the environmental engineers and scientists in the world. The large volume of coal fly ash produced around the world is a potentially significant anthropogenic source of arsenic. Currently the leaching behavior of arsenic from fly ash is not well understood. Batch methods were used in this study to investigate arsenic leaching using a raw ash, and arsenic adsorption using a clean, washed ash. Experimental results indicated that pH had a significant effect on arsenic leaching or adsorption. Between pH 3 and 7, less arsenic was in the dissolved phase. When pH was less than 3 or greater than 7, increasing amounts of arsenic were leached or desorbed from fly ash. The leaching and adsorption behavior of arsenic was interpreted with the speciation of surface sites and arsenic. In a new approach, a speciation-based model was developed to quantify the arsenic adsorption as a function of pH and surface acidity parameters. This work is important in offering insight into the leaching mechanism of arsenic from coal fly ash, and providing a robust model based upon specific, measurable parameters to quantify arsenic adsorption by other solid media in addition to fly ash.

Characteristics of membrane fouling in submerged membrane bioreactor under sub-critical flux operation

Recently, the membrane bioreactor (MBR) process has become one of the novel technologies to enhance the performance of biological treatment of wastewater. Membrane bioreactor process uses the membrane unit to replace a sediment tank, and this can greatly enhance treatment performance. However, membrane fouling in MBR restricts its widespread application because it leads to permeate flux decline, making more frequent membrane cleaning and replacement necessary, which then increases operating and maintenance costs. This study investigated the sludge characteristics in membrane fouling under sub-critical flux operation and also assessed the effect of shear stress on membrane fouling. Membrane fouling was slow under sub-critical flux operation. However, as filamentous microbes became dominant in the reactor, membrane fouling increased dramatically due to the increased viscosity and polysaccharides. A close link was found between membrane fouling and the amount of polysaccharides in soluble EPS. The predominant resistance was the cake resistance which could be minimized by increasing the shear stress. However, the resistance of colloids and solutes was not apparently reduced by increasing shear stress. Therefore, smaller particles such as macromolecules (e.g. polysaccharides) may play an important role in membrane fouling under sub-critical flux operation.