The pH dependent reactions of graphene oxide with small molecule thiols

Graphene oxide (GO) is a heterogenous 2D carbon-based material composed of sp² and sp³ hybridized carbon atoms and oxygen containing functionalities, i.e., alcohols and epoxides. Thus, the chemical reactivity of GO is complex and both complimentary and contrasting to the reactivity of corresponding small molecules (e.g., tertiary alcohols, epoxides, and alkenes). Understanding the reactivity of GO under different conditions and with different reagents will ensure the chemical composition can be controlled and thus electronic and optical properties dictated, and solubility tuned for desired applications. Reaction of GO nanosheets towards a variety of reagents has been reported, however controlling the reaction pathway of GO nanosheets with a single nucleophile by simple alternation of the reaction medium has not been realized. This ability to tune the reaction by modification of solution pH, for example, would aid in understanding the reactivity of GO. Herein, we report that GO undergoes two distinct reaction pathways with ethane thiol depending on the pH of the reaction media: under aprotic basic conditions GO nanosheets undergo functionalization with minimal reduction, and under superacidic conditions GO nanosheets are reduced with no functionalization.

Graphene oxide (GO), a heterogenous 2D carbon-based material, is functionalized or reduced with ethane thiol depending on solution pH.     

Genetic Variation of Echinococcus canadensis (G7) in Mexico

We evaluated the genetic variation of Echinococcus G7 strain in larval and adult stages using a fragment of the mitochondrial cox1 gen. Viscera of pigs, bovines, and sheep and fecal samples of dogs were inspected for cystic and canine echinococcosis, respectively; only pigs had hydatid cysts. Bayesian inferences grouped the sequences in an E. canadensis G7 cluster, suggesting that, in Mexico, this strain might be mainly present. Additionally, the population genetic and network analysis showed that E. canadensis in Mexico is very diverse and has probably been introduced several times from different sources. Finally, a scarce genetic differentiation between G6 (camel strain) and G7 (pig strain) populations was identified.Echinococcus granulosus sensu lato (s.l.) includes species that cause cystic echinococcosis (CE), one of the most important and widespread parasitic zoonoses. Recent phylogenetic studies based on both mitochondrial and nuclear DNA genes show that E. granulosus s.l. consists of at least four valid species: E. granulosus sensu stricto (s.s.; genotypes G1–G3), E. equinus (G4), E. ortleppi (G5), and E. canadensis (G6–G10). Genotypes G6/G7 are closely related and referred to as camel and pig strains, respectively.^1–3 The pig–dog cycle is mainly present in Mexico and maintains the G7 strain.^4,5 Although there are isolated reports of E. oligarthrus in a wild cat,⁶ E. ortleppi (E. granulosus s.l.; G5) in a patient,⁷ and E. granulosus s.s. (G1) in a rural pig, there is no evidence that these species are maintained in Mexico.⁸ No data of CE caused by G7 have been documented in Mexican patients, although there is a high number of E. canadensis G7-infected patients in central Europe, pointing to the importance of this strain as a cause of human CE.^9,10 There are only two genetic studies performed in samples from Mexico. Cruz-Reyes and others⁵ documented that G7 parasites of Mexican and Polish pig isolates showed similar patterns by restriction fragment length polymorphism (RFLP) of ribosomal DNA (rDNA) internal transcribed spacer 1 (ITS1) and random amplified polymorphic DNA (RAPD) techniques, and although polymerase chain reaction (PCR) -sequencing analysis of mitochondrial cox1 gen fragment was performed, no polymorphism data were reported. Sharma and others¹¹ identified two variants (A and B) inside of the G6/G7 group consisting of samples from Mexico and Argentina using five nuclear markers (elongation factor 1α, transforming growth factor-β receptor kinase, thioredoxin peroxidase, calreticulin, and ezrin-radixin-moesin-like protein). Because some local slaughter records from northern Mexico indicate the presence of Echinococcus spp. in livestock animals,⁵ the objective of this study was to investigate if parasites in pigs and dogs correspond to G7 and if so, describe its genetic variation.Infected animals were identified in the municipal slaughterhouse of Calera, Zacatecas (north central Mexico), where farm and backyard livestock animals coming from the whole state and other surrounding states were included. For this purpose, viscera from 387 pigs, 243 bovines, and 32 sheep were inspected for the larval stage of Echinococcus. Nine pigs (six pigs from Zacatecas, two pigs from Aguascalientes, and one pig from Morelos) were found infected, and hydatid cysts were obtained under aseptic conditions. After cyst contents were aspirated and centrifuged, aliquots were examined under microscopy to confirm the presence of protoscolices, and pellets were kept in 70% ethanol at −20°C until DNA extraction. Each cyst from each animal was considered as an isolate.Based on the presence of the parasites previously identified in Calera''s slaughterhouse, a rural community located in the central area of Zacatecas at 22°55′ N, 102°48′ W was selected to look for the adult stage of this parasite. For this search, all dogs (60) present in the community were sampled one time for feces after obtaining verbal consent from the owner; samples were used to identify taeniid eggs by the Faust technique, antigens in stool samples (copro-antigens) by enzyme-linked immunosorbent assay (ELISA; CpAg ELISA), and DNA by Copro-PCR. The CpAg ELISA was performed as described by Allan and others¹² and Moro and others.¹³ For Copro-PCR, only positive samples by CpAg ELISA were analyzed using JB3 and JB4 primers to amplify a cox1 gen fragment.¹⁴ Coprological analysis of dogs showed that 11 samples were positive by CpAg ELISA (18.3%); only 2 of these samples had taeniid tapeworms (3.4%), and 3 of 11 samples yielded products of approximately 450 bp. All amplicons obtained of hydatid cysts and fecal samples were purified, sequenced on both strands, submitted to GenBank (accession numbers {"type":"entrez-nucleotide-range","attrs":{"text":"KF734649-KF734660","start_term":"KF734649","end_term":"KF734660","start_term_id":"570963772","end_term_id":"570963794"}}KF734649-KF734660), and compared with several mitochondrial DNA sequences of cox1. Dogs positive for taeniid eggs or antigens were purged and treated with praziquantel at 30 mg/kg and arecoline bromide at 2 mg/kg. The protocol was previously approved by the Ethics and Research Committees of the General Hospital “Dr. Manuel Gea Gonzalez”; government and health authorities of the municipality and community also authorized our study.All sequences were subjected to the Basic Local Alignment Search Tool (BLAST) search in the GenBank database; multiple alignments were performed with the CLUSTAL W and MUSCLE programs,^15,16 with manual adjusted in MEGA program v5¹⁷ to determine the appropriate model of molecular evolution in the Modeltest 3.7 program.¹⁸ The phylogenetic reconstruction using Bayesian inference was performed with Mr Bayes 3.2.1 program.¹⁹ Unrooted haplotype networks were created using NETWORK 4.611 software and nested according to the rules in median-joining networks.²⁰ An analysis of genetic diversity within and between populations was performed using DnaSPv4²¹ and included nucleotide diversity (π), haplotype polymorphism (θ), genetic differentiation index (F_ST), and Tajima''s D test. Analysis of molecular variance (AMOVA) was used to examine the population genetic structure between populations by Φ_ST as the genetic fixation index (analogous to F_ST) obtained by ARLEQUIN software.²²After multiple alignments, all sequences of larval and adult stages showed 98% or higher identity with E. canadensis, whereas the Bayesian phylogenetic tree and the haplotype network inference grouped these sequences in the E. canadensis G7 cluster. Sequences for cox1 of E. canadensis from Africa, Asia, Europe, Latin America, and North America deposited in the GenBank databases (N = 58) as well as our sequences (accession numbers {"type":"entrez-nucleotide-range","attrs":{"text":"KF734649-KF734660","start_term":"KF734649","end_term":"KF734660","start_term_id":"570963772","end_term_id":"570963794"}}KF734649-KF734660) were analyzed. The results for π and θ were 0.0118 and 0.718, and the result of Tajima''s D test was −2.1885 (P < 0.01). Genetic differentiation indexes between different paired sequences of E. canadensis genotypes are shown in

Constrained Markov control processes with randomized discounted cost criteria: infinite linear programming approach

In this paper, we study constrained Markov control processes on Borel spaces with possibly unbounded one‐stage cost, under a discounted optimality criterion with random discount factor and restrictions of the same kind. We prove that the corresponding optimal control problem is equivalent to an infinite‐dimensional linear programming problem. In addition, considering the dual program, we show that there is no duality gap, and moreover, the strong duality condition holds. Hence, both programs are solvable, and their optimal values coincide. Copyright © 2013 John Wiley & Sons, Ltd.     

On the Formation and Electropolymerization of a Star Copolymer With Peripheral Carbazoles

Utilizing a hyperbranched cored ring‐opening polymerization of caprolactone, carbazole peripheral groups are extended to afford electropolymerizable star‐like copolymers. Different arm lengths are obtained on the basis of different degrees of polymerization from the polyethyleneimine core. This is confirmed by NMR and Fourier transform IR (FTIR) spectroscopy, size‐exclusion chromatography (SEC), and quantitative spectral characterization. Atomic force microscopy (AFM) imaging shows two distinct particle aggregation characteristics, before and after functionalization with carbazole groups. Cyclic voltammetry verifies the electrochemical cross‐linking properties. The results indicate that the conformational freedom of the electroactive peripheral functional groups can be controlled. Moreover, an interesting “loop effect” together with solid‐state polymerization is observed.     

Ultrasound anthropometric reliability

Method errors and reliabilities were estimated for seven sonographic measurements in pregnancies of 106 women examined between January and July 1989. Teams of two experienced sonographers replicated the following measurements: biparietal diameter (BPD), occipital-frontal diameter (OFD), anterior-posterior diameter (APD), transabdominal distance (TAD), and femur diaphysis length (FDL). Multilevel modeling procedures were used to estimate the variance components. Significant (p < 0.01) covariates in the fixed part of the model included an increase in error with greater parity, estimated menstrual age (EMA), and maternal abdominal wall thickness (taken at the umbilicus). Intraobserver reliability ranged from 85.2% (AC) to 99.3% (FDL); interobserver reliability ranged from 80.8% (TAD) to 92.4% (FDL). Method errors, describing the expected error for 68% of the measurements taken, ranged from 0.8 mm to 7.7 mm (intraobserver) and from 1.2 mm to 7.8 mm (interobserver). These results suggest that large error components should be considered in the interpretation of the reliability of ultrasonographically obtained measurements. © 1994 John Wiley & Sons, Inc.     

A retrospective analysis of patients with gallbladder cancer treated with radical resection versus cholecystectomy plus external radiotherapy

BACKGROUND/AIMS: To compare patients with gallbladder cancer treated with radical resection and regional lymphadenectomy (RR-RL) versus simple cholecystectomy and adjuvant external radiotherapy (SC-ERT) and determine outcome. METHODOLOGY: Presentation, operative data, complications and survival were examined in 137 patients. In particular, the 45 patients treated with RR-RL or SC-ERT. RESULTS: Twenty-five had SC-ERT and 20 had a RR-RL. There were no epidemiological differences between groups. Resection of segments IV-b and V and en bloc dissection of regional lymph nodes was the most frequently used procedure (75%). The morbidity and mortality of the radical procedure were 25% and 10%. The morbidity of SC-ERT was 16%. All patients with Nevin I are alive. For lesions Nevin II and Nevin III RR-RL offered a 100% 5-year survival rate and SC-ERT had a 62% and 39% 5-year survival rate respectively. For lesions Nevin IV and V there was no difference in long-term survival. CONCLUSIONS: RR-RL is better than SC-ERT in patients with Nevin II and III lesions because it improves survival rate. SC-ERT can be recommended as an alternative treatment. For more advanced lesions further trials are needed.     

Effects of restraint stress on NALT structure and nasal IgA levels

The effects of stress on the mucosal immune responses in inflammatory disorders of the gut, as well as on salivary and intestinal IgA levels are well known. However, its effects on the structure and function of the NALT have not yet been reported, and are examined in the present study. Balb/c mice were submitted to restraint stress for 3h per day during 4 or 8d. The immunohistochemistry and flow cytometric analysis revealed that repeated restraint stress (4 and 8d) decreased the percentage, compared to the control group, of CD3(+) and CD4(+) T cells, without affecting the percentage of CD8(+) T cells or B220(+) cells (B cells). The numbers of IELs (CD4(+) and CD8(+) T cells) were lower at 4d of stress and higher at 8d. IgA(+) cells in NALT and nasal IgA levels showed a similar pattern, being significantly lower at 4d of stress and significantly higher at 8d. In summary, repeated restraint stress altered the distribution and number of lymphocytes and IgA(+) cells in nasal mucosa, probably due to changes in norepinephrine and corticosterone levels.     

Chronic exposure to toluene changes the sleep-wake pattern and brain monoamine content in rats

Toluene, found in glues and cleaners, is among the inhalants most commonly abused by workers and young drug addicts. In this study, we examined the changes in sleep patterns and monoamine content induced by chronic toluene exposure. Rats were chronically exposed to toluene vapors beginning at 30 days of age for a duration of 30 days. Experiment I was performed in a control group (n=10) and a chronic toluene exposure group (n=10). Rats were implanted with bipolar stainless steel electrodes for electroencephalographic recording (EEG). In experiment II, conducted in two other groups (control and exposed to toluene, n=10 each), animals were sacrificed by decapitation prior to chromatographic analysis. We found that chronic toluene administration affected the organization of sleep patterns and monoamine content. Dopamine (DA) and noradrenaline (NA) increased in the midbrain and striatum. 3,4-dihydroxyphenylacetic acid (DOPAC) increased only in the striatum. Midbrain levels of serotonin (5-HT) increased in the pons and decreased in the hypothalamus and striatum. 5-hydroxyindoleacetic acid (5-HIAA) increased in the pons, midbrain and striatum and decreased in the hypothalamus. Chronic toluene exposure induced changes in the serotonergic and dopaminergic systems and increased SWS and PS deficits. We conclude that toluene exposure disrupts the sleep-wake cycle by affecting the monoaminergic response in cerebral areas related to sleep.     

Anionic Synthesis of Epoxy End‐Capped Polymers

The reaction of living anions of polystyrene (PS) or poly(methyl methacrylate) (PMMA) with epibromohydrin for the synthesis of well‐defined epoxy end‐functionalized polymers is reported. Polyanions were reacted with an excess of epibromohydrin in tetrahydrofuran (THF) at ?78 °C. The functionalities of the resulting polymers were analyzed by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS), NMR, and size exclusion chromatography (SEC). The epoxy end groups were reacted with 1,1‐diphenyl‐ hexyllithium, and MALDI‐TOF MS and NMR before and after this chemical modification were used to determine the presence of the epoxy end groups. The presence of the epoxy end group was confirmed by anionically polymerizing ethylene oxide from these epoxy end group. The formation of a block copolymer due to the epoxy end groups was proved by SEC analysis. The combined MALDI‐TOF MS, ¹H NMR, and SEC results indicate that epoxy end‐capped PS was obtained in quantitative yield. The method was extended to the synthesis of epoxy end‐capped PMMA. With this polymer the extent of end‐functionalization was high but not quantitative, with non‐dimeric byproducts detected by MALDI‐TOF MS.