Methylene blue adsorption by chemically activated waste pork bones

Bone is an inorganic template containing organic material inside which can be converted into hydroxyapatite‐rich material by pyrolysis. Nowadays, there is a growing research interest in the use of hydroxyapatite, the chemical formula of which is Ca₁₀(PO₄)₆(OH)₂. In the present work, pork bone, an abundant biomass source and food waste, has been converted into structured porous hydroxyapatite by a three‐step process including precharring under mild conditions, chemical activation, and thermal activation. The investigated activating agents were NaOH, KOH, K₂CO₃, H₂SO₄, and H₃PO₄. A thorough investigation of the influence of different activating protocols on the chemical and textural properties of the produced material was carried out by nitrogen adsorption–desorption at 77 K, potentiometric titrations, Fourier transform infrared, and X‐ray diffraction techniques. Chemical activation with NaOH, K₂CO₃, and H₂SO₄ increased the specific surface area up to 53%. H₃PO₄ reduced both surface area and pore volume, and KOH showed little influence on the pore structure. The produced materials were evaluated by methylene blue adsorption tests and showed significant improvement as a result of chemical activation. As a main effect, acid treatment increased methylene blue adsorption kinetics, probably owing to an increase in micropororosity, whereas alkali activation enhanced the adsorption capacity of the resultant biochar.     

MoO3/MgO as a catalyst in the oxidative dehydrogenation of n-butane in a two-zone fluidized bed reactor

Butadiene has been produced from butane by oxidative dehydrogenation on a MoO₃/MgO catalyst using a two-zone fluidized bed reactor (TZFBR). The effect of the main TZFBR operating variables was studied, and its performance was compared with that of conventional fluidized beds and fixed bed reactors loaded with the same catalyst. These results have been compared with those obtained on a selective V₂O₅/MgO catalyst.     

Novel poly(vinyl alcohol)-g-poly(hydroxy acid) copolymers: Synthesis and characterization

Poly(vinyl alcohol) (PVA) was reacted with three hydroxy acids (HA), namely D,L-lactic acid (LA), glycolic acid (GA) and D,L-3-hydroxybutyric acid (HB). The graft copolymers obtained were thoroughly characterized by ¹H and ¹³C NMR, FTIR, and DSC. Copolymer compositions were in the range 14–45 mol% HA with average lateral chain lengths in the range 1.1–1.3. The CO stretching band, arising from the lateral polyester chains, presents significant differences from that of pure polyesters. In case of the VALA and VAGA copolymers, carbonyl groups are almost completely interassociated with hydroxyl groups and as a result the carbonyl band presents a single contribution; however, splitting appears in VAHB. The band at about 1735 cm^?1 already observed for Poly(3-hydroxybutyrate) P3HB was reexamined in the light of molecular models for VAHB and the splitting observed was attributed to C–H???OC and to O–H???OC hydrogen bonding. The thermal analysis of copolymers demonstrates that esterification suppresses crystallinity and increases free volume, both accounting for a Tg reduction with regard to PVA. The stronger intermolecular hydrogen bonding interactions found in PVA with the chemically modified PVAs opens an interesting way towards miscibility with polyesters and other polymer systems containing carbonyl groups.     

Assessment of a Cylindrical and a Rectangular Plate Differential Mobility Analyzer for Size Fractionation of Nanoparticles at High-Aerosol Flow Rates

An existing differential mobility analyzer (DMA) of cylindrical electrodes and a novel DMA of rectangular plate electrodes are demonstrated for size fractionation of nanoparticles at high-aerosol flow rates in this work. The two DMAs are capable of delivering monodisperse size selected nanoparticles (SMPS σ_g < 1.1) at gas flow rates ranging from 200 slm to 500 slm. At an aerosol flow rate of 200 slm, the maximum attainable particle mean size is of about 20 nm for the cylindrical DMA and of nearly 50 nm for the rectangular plate DMA. The number concentration of the monodisperse nanoparticles delivered by the high-flow DMAs spans from 10⁴ cm^?3 to 10⁶ cm^?3 depending upon the particle mean size and particle size dispersion.

Copyright 2014 American Association for Aerosol Research     

Discriminating power of the hydrocarbon content from virgin olive oil of extremadura cultivars

Samples of virgin olive oils (105) from seven Extremaduran olive varieties (Cacereña, Carrasqueña, Cornezuelo, Corniche, Morisca, Picual, and Verdial de Badajoz) in three stage of maturity (green, semi-ripe, and ripe) were collected and the alkane, alkene, and sesquiterpene contents determined. There were significant differences at the 0.01 probability level in most of the hydrocarbons, both by variety and by state of maturity. Discriminant analysis applied to 70 samples explained 72.3% of the variance between the different groups of varieties and allowed 90% of the samples to be classified according to their variety. The acceptability of the model was verified against the remaining 35 samples, giving a mean level of correct classification of 94%.     

Senescent CD4+CD28− T Lymphocytes as a Potential Driver of Th17/Treg Imbalance and Alveolar Bone Resorption during Periodontitis

Senescent cells express a senescence-associated secretory phenotype (SASP) with a pro-inflammatory bias, which contributes to the chronicity of inflammation. During chronic inflammatory diseases, infiltrating CD4⁺ T lymphocytes can undergo cellular senescence and arrest the surface expression of CD28, have a response biased towards T-helper type-17 (Th17) of immunity, and show a remarkable ability to induce osteoclastogenesis. As a cellular counterpart, T regulatory lymphocytes (Tregs) can also undergo cellular senescence, and CD28⁻ Tregs are able to express an SASP secretome, thus severely altering their immunosuppressive capacities. During periodontitis, the persistent microbial challenge and chronic inflammation favor the induction of cellular senescence. Therefore, senescence of Th17 and Treg lymphocytes could contribute to Th17/Treg imbalance and favor the tooth-supporting alveolar bone loss characteristic of the disease. In the present review, we describe the concept of cellular senescence; particularly, the one produced during chronic inflammation and persistent microbial antigen challenge. In addition, we detail the different markers used to identify senescent cells, proposing those specific to senescent T lymphocytes that can be used for periodontal research purposes. Finally, we discuss the existing literature that allows us to suggest the potential pathogenic role of senescent CD4⁺CD28⁻ T lymphocytes in periodontitis.     

Putrescine: A Key Metabolite Involved in Plant Development,Tolerance and Resistance Responses to Stress

Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research.     

Identification of Human Adenovirus in Respiratory Samples with Luminex Respiratory Virus Panel Fast V2 Assay and Real-Time Polymerase Chain Reaction

In order to compare the last version of the Respiratory Virus Panel (RVP) Fast assay for human Adenovirus (hAdv) detection with a specific real-time polymerase chain reaction (qPCR), which is considered the gold standard for hAdv detection, nasopharyngeal samples collected from 309 children (age range, four months to eight years) with respiratory tract infection were tested using the RVP Fast v2 assay (Luminex Molecular Diagnostics, Inc., Toronto, ON, Canada) and a specific TaqMan qPCR to identify hAdv DNA. The RVP Fast v2 assay detected 30/61 (49.2%) hAdv infections that had been identified by real-time qPCR, demonstrating a significantly lower detection rate (p < 0.001). The sensitivity of the RVP Fast v2 assay in comparison to qPCR was lower in younger children (42.9% vs. 57.7%; Cohen’s kappa coefficient, 0.53); in samples with co-infections (40.0% vs. 56.7%; Cohen’s kappa coefficient, 0.52); and in samples with hAdv type C (45.9% vs. 57.1%; Cohen’s kappa coefficient, 0.60). Samples with lower viral loads were associated with a significantly lower sensitivity of the RVP Fast v2 assay (35.1% vs. 68.2%, p = 0.01; Cohen’s kappa coefficients, 0.49). The RVP Fast v2 assay has important limitations for the detection of hAdv and cannot be used to evaluate whether hAdvs are the main etiologic agent responsible for an outbreak or when epidemiological studies are performed.     

Improving the training time of support vector regression algorithms through novel hyper-parameters search space reductions

The selection of hyper-parameters in support vector machines (SVM) is a key point in the training process of these models when applied to regression problems. Unfortunately, an exact method to obtain the optimal set of SVM hyper-parameters is unknown, and search algorithms are usually applied to obtain the best possible set of hyper-parameters. In general these search algorithms are implemented as grid searches, which are time consuming, so the computational cost of the SVM training process increases considerably. This paper presents a novel study of the effect of including reductions in the range of SVM hyper-parameters, in order to reduce the SVM training time, but with the minimum possible impact in its performance. The paper presents reduction in parameter C, by considering its relation with the rest of SVM hyper-parameters (γ and ε), through an approximation of the SVM model. On the other hand, we use some characteristics of the Gaussian kernel function and a previous result in the literature to obtain novel bounds for γ and ε hyper-parameters. The search space reductions proposed are evaluated in different regression problems from UCI and StatLib databases. All the experiments carried out applying the popular LIBSVM solver have shown that our approach reduces the SVM training time, maintaining the SVM performance similar to when the complete range in SVM parameters is considered.     

Brain fMRI reactivity to smoking-related images before and during extended smoking abstinence.

[Correction Notice: An erratum for this article was reported in Vol 18(3) of Experimental and Clinical Psychopharmacology (see record 2010-11933-011). In the article the authors find it necessary to redefine the thresholding procedure used for data analyses, due to problems in the Brain Voyager software. This does not affect the main findings of the paper.] Reactivity to smoking-related cues may play a role in the maintenance of smoking behavior and may change depending on smoking status. Whether smoking cue-related functional MRI (fMRI) reactivity differs between active smoking and extended smoking abstinence states currently is unknown. We used fMRI to measure brain reactivity in response to smoking-related versus neutral images in 13 tobacco-dependent subjects before a smoking cessation attempt and again during extended smoking abstinence (52 ± 11 days) aided by nicotine replacement therapy. Prequit smoking cue induced fMRI activity patterns paralleled those reported in prior smoking cue reactivity fMRI studies. Greater fMRI activity was detected during extended smoking abstinence than during the prequit assessment subcortically in the caudate nucleus and cortically in prefrontal (BA 6, 9, 44, 46), primary somatosensory (BA 1, 2, 3), temporal (BA 22, 41, 42), parietal (BA 7, 40) anterior cingulate (BA 24, 32), and posterior cingulate (BA 31) cortex. These data suggest that during extended smoking abstinence, fMRI reactivity to smoking versus neutral stimuli persists in brain areas involved in attention, somatosensory processing, motor planning, and conditioned cue responding. In some brain regions, fMRI smoking cue reactivity is increased during extended smoking abstinence in comparison to the prequit state, which may contribute to persisting relapse vulnerability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)