Performance of Xanthate-Modified Multi-Walled Carbon Nanotubes on Adsorption of Lead Ions

Abstract

A novel adsorbent was prepared by introducing xanthate group onto pristine multi-walled carbon nanotubes (MWCNTs) for removing Pb (II) from aqueous solution. The structure and property of xanthate-modified MWCNT (MWCNT-X) were detected by the technologies of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET). The investigation of various parameters, such as initial metal concentration, pH, contact time, and temperature, was taken to illustrate the adsorption behaviors of Pb (II) on MWCNT-X. Based on experimental data, Langmuir isotherm and pseudo-second-order kinetic provided a better correspondence to the adsorption process. The negative values of ΔG ^θ and ΔH ^θ indicated that the adsorption process is exothermic and spontaneous. Besides, the maximum uptake of MWCNT-X reached to 83.01 mg/g, which was much higher than that of pristine MWCNT and hydroxylated MWCNT (MWCNT-OH). Thus, the MWCNT-X can be potentially applied in heavy metal treatment.

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The role of interleukin-1β and extracellular signal-regulated kinase 1/2 in glucose-stimulated insulin secretion

Publication date: Available online 7 April 2017
Source:The Kaohsiung Journal of Medical Sciences
Author(s): Ben Niu, Heng Su, Xue-Shan Xia, Qiu He, Yuan-Ming Xue, Xin-Ming Yan
Glucose-stimulated insulin secretion (GSIS) is one of the important physiological characteristics of islet β cells, and extracellular-regulated protein kinase 1/2 (ERK1/2) is an important member of the mitogen-activated protein kinase family that regulates this process. The inflammatory cytokine interleukin (IL)-1β can inhibit the insulin secretion of pancreatic β cells, but the exact mechanism is unclear. This study was designed to investigate the inhibitory effect of IL-1β on GSIS in βTC-6 cells and its relation with the ERK1/2 signal transduction pathway. β-TC6 cells were cultured and stimulated with 0mM, 1.38mM, or 5.5mM glucose. In addition, GSIS in β-TC6 cells was blocked by IL-1β at concentrations of 0.15 ng/mL, 1.5 ng/mL, and 15 ng/mL. After glucose stimulation and IL-1β intervention, the insulin level in the cell supernatant was detected by radioimmunoassay, and the phosphorylation level of ERK1/2 was detected by western blotting assay. The insulin level in the 1.38mM glucose group was 108.52 ± 5.94 uIU/mL, which was significantly higher than the 0mM and 5.5mM glucose groups (p < 0.05). Compared with the 0mM glucose group, the level of ERK1/2 phosphorylation was increased in the 1.38mM and 5.5mM glucose groups. After intervention by 0.15 ng/mL, 1.5 ng/mL, and 15 ng/mL IL-1β, the level of ERK1/2 phosphorylation induced by 1.38mM glucose stimulation decreased in a dose-dependent manner, and the insulin level correspondingly decreased. IL-1β can inhibit GSIS in βTC-6 cells, which is related to its inhibition of the phosphorylation of ERK1/2.



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Response to Letter to the Editor Regarding “Abiraterone Acetate for the Treatment of Chemotherapy-Naïve Metastatic Castration-Resistant Prostate Cancer: An Evidence Review Group Perspective of a NICE Single Technology Appraisal”

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Friedreich Ataxia: current status and future prospects

Abstract

Friedreich ataxia (FA) represents the most frequent type of inherited ataxia. Most patients carry homozygous GAA expansions in the first intron of the frataxin gene on chromosome 9. Due to epigenetic alterations, frataxin expression is significantly reduced. Frataxin is a mitochondrial protein. Its deficiency leads to mitochondrial iron overload, defective energy supply and generation of reactive oxygen species. This review gives an overview over clinical and genetic aspects of FA and discusses current concepts of frataxin biogenesis and function as well as new therapeutic strategies.

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High Rate of Deformed Larvae among Gynogenetic Brown Trout (Salmo trutta m. fario) Doubled Haploids

Mitotic gynogenesis results in the production of fully homozygous individuals in a single generation. Since inbred fish were found to exhibit an increased frequency of body deformations that may affect their survival, the main focus of this research was to evaluate the ratio of individuals with spinal deformities among gynogenetic doubled haploids (DHs) brown trout as compared to nonmanipulated heterozygous individuals. Gynogenetic development was induced by the activation of brown trout eggs by UV-irradiated homologous and heterologous (rainbow trout) spermatozoa. The subsequent exposure of the activated eggs to the high hydrostatic pressure disturbed the first cleavage in gynogenetic zygotes and enabled duplication of the maternal haploid set of chromosomes. The survival rate was significantly higher among gynogenetic brown trout hatched from eggs activated with the homologous UV-irradiated spermatozoa when compared to DHs hatched from eggs activated by the heterologous spermatozoa. More than 35% of the gynogenetic larvae exhibited body deformities, mostly lordosis and scoliosis. The percentage of malformed brown trout from the control group did not exceed 15%. The increased number of deformed larvae among DHs brown trout suggested rather a genetic background of the disease related to the fish spine deformities; however, both genetic and environmental factors were discussed as a cause of such conditions in fish.

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Mapping mitochondrial heteroplasmy in a Leydig tumor by laser capture micro-dissection and cycling temperature capillary electrophoresis

Abstract

Background

The growth of tumor cells is accompanied by mutations in nuclear and mitochondrial genomes creating marked genetic heterogeneity. Tumors also contain non-tumor cells of various origins. An observed somatic mitochondrial mutation would have occurred in a founding cell and spread through cell division. Micro-anatomical dissection of a tumor coupled with assays for mitochondrial point mutations permits new insights into this growth process. More generally, the ability to detect and trace, at a histological level, somatic mitochondrial mutations in human tissues and tumors, makes these mutations into markers for lineage tracing.

Method

A tumor was first sampled by a large punch biopsy and scanned for any significant degree of heteroplasmy in a set of sequences containing known mutational hotspots of the mitochondrial genome. A heteroplasmic tumor was sliced at a 12 μm thickness and placed on membranes. Laser capture micro-dissection was used to take 25000 μm² subsamples or spots. After DNA amplification, cycling temperature capillary electrophoresis (CTCE) was used on the laser captured samples to quantify mitochondrial mutant fractions.

Results

Of six testicular tumors studied, one, a Leydig tumor, was discovered to carry a detectable degree of heteroplasmy for two separate point mutations: a C → T mutation at bp 64 and a T → C mutation found at bp 152. From this tumor, 381 spots were sampled with laser capture micro-dissection. The ordered distribution of spots exhibited a wide range of fractions of the mutant sequences from 0 to 100% mutant copies. The two mutations co-distributed in the growing tumor indicating they were present on the same genome copies in the founding cell.

Conclusion

Laser capture microdissection of sliced tumor samples coupled with CTCE-based point mutation assays provides an effective and practical means to obtain maps of mitochondrial mutational heteroplasmy within human tumors.

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Utilizing BD MAX™ Enteric Bacterial Panel to Detect Stool Pathogens from Rectal Swabs

Abstract

Background

The BD MAX™ Enteric Bacterial Panel (BDM-EBP) is designed and FDA-cleared to detect Salmonella, Shigella, Campylobacter, and Shiga toxin genes stx1/2 from stool samples. However, rectal swabs, which are not FDA-cleared for clinical testing with the BDM-EBP, are common specimens received from pediatric patients for enteric pathogen testing. The purpose of this study was to evaluate the ability of the BDM-EBP to detect stool pathogens from rectal swabs.

Methods

Routine cultures, Shiga toxin testing, and molecular testing with BDM-EBP were performed on 272 sequential rectal swabs collected from August 2015 to December 2015. Discrepant test results were resolved using Verigene® Enteric Pathogens Nucleic Acid Test (EP). 36 challenge samples (13 Salmonella spp., 3 Shigella spp., 10 Campylobacter spp., and 10 Shiga toxin positive Escherichia coli) were tested using reference strains (American Type Culture Collection) and previous patient isolates diluted to10³-10⁴ cfu/ml in saline then added to Sample Buffer Tube (SBT) with negative stool matrix delivered via a swab. Limit of detection testing was performed by serial 10 fold dilutions in saline then added to SBT with negative stool matrix provided via a swab.

Results

A total of 272 rectal swab specimens were evaluated and 89 were positive by culture and/or MAX EBP. All discrepant results were BDM-EBP positive and culture negative. 21 of 31 (68%) of the apparent false positive BDM-EBP discrepant results resolved as positive with Nanosphere's Verigene® EP. After resolution of the discordant results, the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) are as follows for each target: Salmonella (n = 4) 100%, PPA and 100%, NPA; Shigella (n = 79) 100%, PPA and 95.3%, NPA; Campylobacter (n = 4) 100%, PPA and 99.6%, NPA; and Shiga toxin producing organisms (n = 2) 100%, PPA and 100%, NPA. 8.8% of the patient samples did not initially yield a result on the BDM-System. Upon repeat, half of the problematic samples resolved, and 4.4% of the total specimen tested did not yield a result. All organisms in the challenge samples were detected. Limits of detection for BDM-EBP testing of rectal swabs were as follows (in cfu/ml in SBT): Salmonella-1.44 × 10²; Shigella-5.10 × 10⁰; Campylobacter-1.51 × 10¹; and Shiga Toxin-1.13 ×10³.

Conclusion

Rectal swabs are acceptable samples for detecting Salmonella, Shigella, Campylobacter, and Shiga toxin using BDM-EBP.

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