1,199 research outputs found
Voltammetric Investigation on Uranyl Sorption by Alginate Based Material. Influence of Hydrolysis and pH Dependence
The removal of U(VI) as uranyl (UO22+) from aqueous solutions was investigated by sorption onto alginate based material. The hydrolysis of uranyl ion was always taken into account in the calculations of free (22UO) ion in aqueous solution, in the experimental pH range considered, as well as the acid-base properties of alginate polymer. The sorption process follows a pseudo-second order kinetic model and the sorption rate decreases when the pH value increases. In addition to the classical Langmuir and Freundlich models, the equilibrium data were fitted by using a modified multi-component equilibrium model, never tested before. Differential Pulse Voltammetry (DPV) and
Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) measurements were carried out in NaNO3 aqueous solutions for the kinetic and equilibrium studies, respectively. Direct measurements of uranyl by DPV
were carried out without using complexing agent, as usually reported in the literature; this allowed us to know the free
UO22+ concentration and the hydrolyzed species formed in the ~ 2.0 to 5.0 pH range investigated. The physical structure and morphology of biomaterials was investigated by Scanning Electron Microscopy (SEM) analysis and Energy Dispersive X-ray spectroscopy (EDX) measurements
Work-related allergic rhinitis: a contemporary review of the literature
Adverse health effects have been reported in workers exposed to inhaled allergens. Allergic rhinitis is a heterogeneous disorder that significantly affects daily activity, work productivity, sleep, learning, and quality of life in all generations. Occupational-ly-related hazards which contribute to the development of allergic rhinitis represent an important avoidable cause of morbidity. The occupational exposure to chemicals or biological agents is the cause of high incidences of allergic rhinitis and this risk is high when the organization and preparation are inadequate and there is a lacking or insufficient information, education and communication. The prevalence of work-related rhinitis, which encompasses both occupational rhinitis and work-exacerbated rhinitis, is estimated to be 31-61%. Data on occupational rhinitis itself are scarce. Although work-related asthma and allergies are a huge burden for society, investigation of oc-cupational exposures in early work life using an unexposed reference group is rare. Occupational allergic diseases are likely to worsen or become intractable as a result of continuous exposure to high concentrations of causative antigens, and are socioeco-nomically important diseases with which the patients might sometimes lose jobs due to work interruptions. It is important to adequately assess, communicate and manage risks in occupational chemical exposure settings with the aim to protect workers and the necessity to introduce periodic health examinations programs focusing on workers to monitor health and well-being and improve working conditions and the working environment
speciation of chitosan with low and high molecular weight carboxylates in aqueous solution
Quantitative data on the speciation of chitosan (310kDa) with low and high molecular weight carboxylates in aqueous solution are reported. The following carboxylic ligands were considered: monocarboxylate (butyrate); dicarboxylates (malonate, succinate, azelate); tricarboxylate (1,2,3-propanetricarboxylate); tetracarboxylate (1,2,3,4-butanetetracarboxylate); polyacrylates (2.0 and 20kDa); polymethacrylate (5.4kDa). The investigation was performed by potentiometry at t Ā¼ 25 ļæ½ C, at low ionic strength (without addition of supporting electrolyte) and at I Ā¼ 0:15mol L ļæ½ 1 (NaCl). For all the systems the formation of (chitosan)LHi species was found (L Ā¼carboxylic ligand; i Ā¼1 to 4 depending on the carboxylic ligand considered). The stability of protonāchitosanācarboxylate species depends on the number of carboxylic groups involved in the complexation, and it was possible to calculate a rough free energy value per bond DGn Ā¼ļæ½ 15 ļæ½ 2kJ mol ļæ½ 1 . By using the stability data, the quantitative sequestering capacity of chitosan towards the carboxylates here considered [expressed as theālog(total chitosan concentration) necessary to bind 50% of carboxylate, i.e., pL50] was calculated for different pH values, at low ionic strength and at I Ā¼ 0:15mol L ļæ½ 1 . The pL50 values, ranging from 3 to 7, show that chitosan is quite a strong sequestering agent towards carboxylates. Evidences were also obtained for the different behaviour between low and high molecular weight carboxylates
A tomographic approach to assessing the possibility of ring shake presence in standing chestnut trees
AbstractRing shake is a widespread phenomenon affecting a great number of species of both softwood and hardwood and is found in trees grown in temperate and tropical climates. Chestnut (Castanea sativaMill.) represents one of the most important hardwood timbers that is very often affected by ring shake. This defect seems to be the only real limit to the spread and use of chestnut wood worldwide on a scale closer to the availability of this wood. The aim of this study was to examine the potential of tomographic measurement as a non-destructive method for predicting the possibility of the presence of ring shake in standing chestnut trees. For this reason, the experiments were carried out in a chestnut coppice stand where one hundred chestnut standards were monitored using an acoustic tomographic device, and subsequently harvested by a local company and cross-sectioned corresponding to the acoustic tests. This work proposed an applied approach to predicting and determining wood quality (sound wood vs. defective wood) from tomographic data. The model, based on a non-linear approach, showed that sonic tomography can identify ring shake in a tree trunk without affecting its biological activity, overcoming the difficulties of predicting ring shake using only visual inspection
Optimization of coupled advanced oxidation processes and activated carbons for purification of salt water
Photocatalysis, ozonation and activated carbons were investigated separately and in combination as tools for the purification of polluted salt water. Coupling different processes enables to overcome many drawbacks related to the use of the single technologies and at the same time to exploit possible synergistic effects. In this work a kinetic analysis was
performed for modelling the degradation of 4-nitrophenol (4NP) as a probe pollutant molecule in synthetic seawater.
Thus, the optimum synergistic conditions of the three processes acting together were determined and discussed
Hydrocarbons removal from wastewater by adsorption onto biochar from Posidonia oceanica
Environmental pollution by petroleum derivatives is a very current topic. In particular, low concentration of this kind of pollutants can seriously compromise the life of animals and plants of aquatic ecosystems [1]. For this reason, recent environmental legislation imposes severe restriction to oil-in-water content for overboard discharge with concentration limits from 15 to 5 ppm [2]. The shipping industry is trying to adapt to these directives by equipping ships with cleaning treatment devices in which there are several oil removal steps. Usually, the last step of bilge water treatment is based on adsorption onto suitable adsorbent materials that must be able to remove the last and most dispersed oil fraction reducing its concentration within legal limits. In this work, a biochar obtained from pyrolysis of Posidonia oceanica, a Mediterranean sea plant, has been tested as adsorbent material of a synthetic bilge water. The pristine biochar (BCP) was tested as it was and after two chemical activation treatments with sulfuric acid (BCA) and potassium hydroxide (BCB). The adsorbent materials have been characterized by using different techniques (TGA, SEM-EDAX, FT-IR, etc) and their adsorption capacity was studied by batch and column experiments. Oil concentration measurements were performed by using: HPLC-FLD and TOC techniques
Adoption of Machine Learning Techniques to Enhance Classification Performance in Reactive Brain-Computer Interfaces
This paper proposes the adoption of an innovative algorithm to enhance the performance of highly wearable, reactive Brain-Computer Interfaces (BCIs), which exploit the Steady-State Visually Evoked Potential (SSVEP) paradigm. In particular, a combined time-domain/frequency-domain processing is performed in order to reduce the number of features of the brain signals acquired. Successively, these features are classified by means of an Artificial Neural Network (ANN) with a learnable activation function. In this way, the user intention can be translated into commands for external devices. The proposed algorithm was initially tested on a benchmark data set, composed by 35 subjects and 40 simultaneous flickering stimuli, obtaining performance comparable with the state of the art. Successively, the algorithm was also applied to a data set realized with highly wearable BCI equipment. In particular, (i) Augmented Reality (AR) smart glasses were used to generate the flickering stimuli necessary to the SSVEPs elicitation, and (ii) a single-channel EEG acquisition was conducted for each volunteer. The obtained results showed that the proposed strategy provides a significant enhancement in SSVEPs classification with respect to other state-of-the-art algorithms. This can contribute to improve reliability and usability of brain computer interfaces, thus favoring the adoption of this technology also in daily-life applications
A Wnt1 regulated Frizzled-1/Ī²-Catenin signaling pathway as a candidate regulatory circuit controlling mesencephalic dopaminergic neuron-astrocyte crosstalk: Therapeutical relevance for neuron survival and neuroprotection.
BACKGROUND: Dopamine-synthesizing (dopaminergic, DA) neurons in the ventral midbrain (VM) constitute a pivotal neuronal population controlling motor behaviors, cognitive and affective brain functions, which generation critically relies on the activation of Wingless-type MMTV integration site (Wnt)/Ī²-catenin pathway in their progenitors. In Parkinson's disease, DA cell bodies within the substantia nigra pars compacta (SNpc) progressively degenerate, with causes and mechanisms poorly understood. Emerging evidence suggests that Wnt signaling via Frizzled (Fzd) receptors may play a role in different degenerative states, but little is known about Wnt signaling in the adult midbrain. Using in vitro and in vivo model systems of DA degeneration, along with functional studies in both intact and SN lesioned mice, we herein highlight an intrinsic Wnt1/Fzd-1/Ī²-catenin tone critically contributing to the survival and protection of adult midbrain DA neurons. RESULTS: In vitro experiments identifie Fzd-1 receptor expression at a mRNA and protein levels in dopamine transporter (DAT) expressing neurons, and demonstrate the ability of exogenous Wnt1 to exert robust neuroprotective effects against Caspase-3 activation, the loss of tyrosine hydroxylase-positive (TH+) neurons and [3H] dopamine uptake induced by different DA-specific insults, including serum and growth factor deprivation, 6-hydroxydopamine and MPTP/MPP+. Co-culture of DA neurons with midbrain astrocytes phenocopies Wnt1 neuroprotective effects, whereas RNA interference-mediated knockdown of Wnt1 in midbrain astrocytes markedly reduces astrocyte-induced TH+ neuroprotection. Likewise, silencing Ī²-catenin mRNA or knocking down Fzd-1 receptor expression in mesencephalic neurons counteract astrocyte-induced TH+ neuroprotection. In vivo experiments document Fzd-1 co-localization with TH+ neurons within the intact SNpc and blockade of Fzd/Ī²-catenin signaling by unilateral infusion of a Fzd/Ī²-catenin antagonist within the SN induces reactive astrocytosis and acutely inhibits TH+ neuron survival in ipsilateral SNpc, an effect efficiently prevented by pharmacological activation of Ī²-catenin signaling within the SNpc. CONCLUSION: These results defining a novel Wnt1/Fzd-1/Ī²-catenin astrocyte-DA autoprotective loop provide a new mechanistic inside into the regulation of pro-survival processes, with potentially relevant consequences for drug design or drug action in Parkinson's disease.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Type III pleuropulmonary blastoma in a 7-month-old female baby with impending respiratory failure: a case report
INTRODUCTION: Pleuropulmonary blastoma is a very rare, aggressive, embryonal pulmonary neoplasm which mostly affects children under the age of 5. According to the histopathological features, three subtypes of pleuropulmonary blastoma have been recognized: type I (purely cystic), type II (grossly visible cystic and solid elements) and type III (purely solid). Characteristics of type I and type II blastoma allow an earlier diagnosis compared with type III. Here we present a case report of an unusual presentation of type III pleuropulmonary blastoma. CASE PRESENTATION: We describe the case of a 7-month-old female baby of Italian mother and Kurdish father who was diagnosed with type III pleuropulmonary blastoma, which entirely occupied her right hemithorax. CONCLUSIONS: The reported case is an unusual presentation because type III pleuropulmonary blastoma typically occurs in older children. The complete re-expansion of her residual, previously totally compressed, right lung observed immediately after the resection of the lesion suggests an atypical rapid growth of this embryonal tumor in the late phase of gestation or after delivery. This case report suggests that, in addition to other childhood tumors, type III pleuropulmonary blastoma should be included in the differential diagnosis of solid nonhomogeneous thoracic large masses, compressing the mediastinal and chest wall structures in infants. This is an original case report of interest for several specialities such us pediatrics, radiology, surgery and oncology
Dietary habits in children of immigrant families from developing countries: an Italian multicentre study
Objectives. The aim of this study was to investigate the dietary habits of immigrant children
who come to Italy from developing countries, and of their families.
Methods. A multicentre cross-sectional study was carried out from Jan. 1st 2003 to Dec.
31st 2004. The study population comprised 1284 immigrant mothers, 629 infants, and 767
children with more than 2 years of age. A structured questionnaire was employed to inquire
retrospectively on dietary habits and, on breastfeeding, complementary breastfeeding,
bottle-feeding and weaning.
Results. Exclusive and complementary breastfeeding was more frequent and of longer duration
among immigrant infants than Italian infants, but not compared to infants living in
the immigrantsā native countries, compared to whom breastfeeding was lower and of
shorter duration. Age and manner of weaning among immigrant infants were similar to
Italian ones. Immigrant children older than 2 years preferred foods from their native countries
only in a few cases, and the rates of their morning and afternoon snacks were higher
in Italy than in their native countries. In Italy, immigrant children consume eggs, fish, vegetables,
legumes, and tea less often, and bread, pasta and oat flakes more often than in their
native countries. These dietary habits might likely be related to both being born and having
migrated to Italy since more than 4 years. Immigrant families are also inclined to adopt
Italian dietary habits.
Conclusions. Our investigation suggests that immigrant children and their families are
adopting Italian eating habits. Considering the association between diet in infancy and
childhood, and the development of some diseases later on in life, paediatricians must pay
great attention to dietary habits among immigrant children
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