Life Cycle Assessment of a system for the extraction and transformation of Waste Water Treatment Sludge (WWTS)-derived lipids into biodiesel.

In recent years, the demand for biofuels has been growing exponentially, as has the interest in biodiesel produced from organic matrices. Particularly interesting, due to its economic and environmental advantages, is the use of the lipids present in sewage sludge as a raw material for the synthesis of biodiesel. The possible processes of this biodiesel synthesis, starting from lipid matter, are represented by the conventional process with sulfuric acid, by the process with aluminium chloride hexahydrate and by processes that use solid catalysts such as those consisting of mixed metal oxides, functionalized halloysites, mesoporous perovskite and functionalized silicas. In literature there are numerous Life Cycle Assessment (LCA) studies concerning biodiesel production systems, but not many studies consider processes that start from sewage sludge and that use solid catalysts. In addition, no LCA studies were reported on solid acid catalysts nor on those based on mixed metal oxides which present some precious advantages, over the homogeneous analogous ones, such as higher recyclability, prevention of foams and corrosion phenomena, and an easier separation and purification of biodiesel product. This research work reports the results of a comparative LCA study applied to a system that uses a solvent free pilot plant for the extraction and transformation of lipids from sewage sludge via seven different scenarios that differ in the type of catalyst used. The biodiesel synthesis scenario using aluminium chloride hexahydrate as catalyst has the best environmental profile. Biodiesel synthesis scenarios using solid catalysts are worse due to higher methanol consumption which requires higher electricity consumption. The worst scenario is the one using functionalized halloysites. Further future developments of the research require the passage from the pilot scale to the industrial scale in order to obtain environmental results to be used for a more reliable comparison with the literature data.

Hybrid supramolecular gels of Fmoc-F/halloysite nanotubes: systems for sustained release of camptothecin.

Supramolecular gel hybrids obtained by self-assembly of Fmoc-l-phenylalanine (Fmoc-F) in the presence of functionalized halloysite nanotubes (f-HNT) were obtained in biocompatible solvents and employed as carriers for the delivery of camptothecin (CPT) molecules. The synthesis of the new f-HNT material as well as its characterization are described. The properties of the hybrid hydrogels and organogels were analyzed by several techniques. The presence of small amounts of f-HNT allows good dispersion of the tubes and the subsequent formation of homogeneous gels. The experimental results show that f-HNT functions only as an additive in the hybrid gels and does not demonstrate gelator behavior. The in vitro kinetic release from both f-HNT/CPT and Fmoc-F/f-HNT/CPT was studied in media that imitates physiological conditions, and the factors controlling the release process were determined and discussed. Furthermore, the antiproliferative in vitro activities of the gels were evaluated towards human cervical cancer HeLa cells. A comparison of data collected in both systems shows the synergistic action of f-HNT and the gel matrix in controlling the release of CPT in the media and maintaining the drug in its active form. Finally, a comparison with pristine HNT is also reported. This study suggests a suitable strategy to obtain two-component gel hybrids based on nanocarriers with controlled drug carrier capacity for biomedical applications.

Covalently modified halloysite clay nanotubes: synthesis, properties, biological and medical applications.

Halloysite (HNT) is a promising natural nanosized tubular clay mineral that has many important uses in different industrial fields. It is naturally occurring, biocompatible, and available in thousands of tons at low cost. As a consequence of a hollow cavity, HNT is mainly used as nanocontainer for the controlled release of several chemicals. Chemical modification of both surfaces (inner lumen and outer surface) is a strategy to tune the nanotube's properties. Specifically, chemical modification of HNT surfaces generates a nanoarchitecture with targeted affinity through outer surface functionalization and drug transport ability from functionalization of the nanotube lumen. The primary focus of this review is the research of modified halloysite nanotubes and their applications in biological and medical fields.

Correction: Covalently modified halloysite clay nanotubes: synthesis, properties, biological and medical applications.

Correction for 'Covalently modified halloysite clay nanotubes: synthesis, properties, biological and medical applications' by M. Massaro et al., J. Mater. Chem. B, 2017, 5, 2867-2882.

Halloysite nanotubes loaded with peppermint essential oil as filler for functional biopolymer film.

The purpose of this paper is to show how a functional bionanocomposite film with both antioxidant and antimicrobial activities was successfully prepared by the filling of a pectin matrix with modified Halloysite nanotubes (HNT) containing the essential peppermint oil (PO). Firstly, HNT surfaces were functionalized with cucurbit[6]uril (CB[6]) molecules with the aim to enhance the affinity of the nanofiller towards PO, which was estimated by means of HPLC experiments. The HNT/CB[6] hybrid was characterized by several methods (thermogravimetry, FT-IR spectroscopy and scanning electron microscopy) highlighting the influence of the supramolecular interactions on the composition, thermal behavior and morphology of the filler. Then, a pectin+HNT/CB[6] biofilm was prepared by the use of the casting method under specific experimental conditions in order to favor the entrapment of the volatile PO into the nanocomposite structure. Water contact angle measurements, thermogravimetry and tensile tests evidenced the effects of the modified filler on the thermo-mechanical and wettability properties of pectin, which were correlated to the microscopic structure of the biocomposite film. In addition, PO release in food simulant solvent was investigated at different temperatures (4 and 25°C), whereas the antioxidant activity of the nanocomposite film was estimated using the DPPH method. Finally, we studied the in vitro antibacterial activity of the biofilm against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), which were isolated by beef and cow milk, respectively. These experiments were carried out at specific temperatures (4, 37 and 65°C) that can be useful for a multi-step food conservation. This paper puts forwards an easy strategy to prepare a functional sustainable edible film with thermo-sensitive antioxidant/antimicrobial activity.

Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications.

Covalently functionalized halloysite nanotubes (HNTs) were successfully employed as dual-responsive nanocarriers for curcumin (Cur). Particularly, we synthesized HNT-Cur prodrug with a controlled curcumin release on dependence of both intracellular glutathione (GSH) and pH conditions. In order to obtain HNT-Cur produgs, halloysite was firstly functionalized with cysteamine through disulphide linkage. Afterwards, curcumin molecules were chemically conjugated to the amino end groups of halloysite via Schiff's base formation. The successful functionalization of halloysite was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and scanning electron microscopy. Experimental data confirmed the presence of curcumin on HNT external surface. Moreover, we investigated the kinetics of curcumin release by UV-vis spectroscopy, which highlighted that HNT-Cur prodrug possesses dual stimuli-responsive ability upon exposure to GSH-rich or acidic environment. In vitro antiproliferative and antioxidant properties of HNT-Cur prodrug were studied with the aim to explore their potential applications in pharmaceutics. This work puts forward an efficient strategy to prepare halloysite based nanocarriers with controlled drug delivery capacity through direct chemical grafting with stimuli-responsive linkage.

Multicavity halloysite-amphiphilic cyclodextrin hybrids for co-delivery of natural drugs into thyroid cancer cells.

Multicavity halloysite nanotube materials were employed as simultaneous carriers for two different natural drugs, silibinin and quercetin, at 6.1% and 2.2% drug loadings, respectively. The materials were obtained by grafting functionalized amphiphilic cyclodextrin onto the HNT external surface. The new materials were characterized by FT-IR spectroscopy, SEM, thermogravimetry, turbidimetry, dynamic light scattering and ζ-potential techniques. The interaction of the two molecules with the carrier was studied by HPLC measurements and fluorescence spectroscopy, respectively. The release of the drugs from HNT-amphiphilic cyclodextrin, at two different pH values, was also investigated by means of UV-vis spectroscopy. Biological assays showed that the new complex exhibits anti-proliferative activity against human anaplastic thyroid cancer cell lines 8505C. Furthermore, fluorescence microscopy was used to evaluate whether the carrier was uptaken into 8505C thyroid cancer cell lines. The successful results revealed that the synthesized multicavity system is a material of suitable size to transport drugs into living cells.

Functionalized halloysite multivalent glycocluster as a new drug delivery system.

A new design for halloysite nanotube materials was obtained by grafting chemically modified cyclodextrin units onto the nanotube surface. In particular, grafted cyclodextrins were decorated with thiosaccharide pendants, in order to mimic the well-known binding of sugars to proteins and the glyco-cluster effect occurring during cellular recognition events. The obtained materials were characterized by using a combination of varied techniques (FT-IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, dynamic light scattering, turbidimetry), and their potential drug-delivery abilities were tested by studying their interactions with the common naturally occurring anticancer agent curcumin. A suitable model describing the interaction between our materials and curcumin is proposed.

Isolation of Gram-positive n-alkane degraders from a hydrocarbon-contaminated Mediterranean shoreline.

AIMS: To investigate the petroleum hydrocarbon (HC)-degrading potential of indigenous micro-organisms in a sandy Mediterranean coast, accidentally contaminated with petroleum-derived HCs. METHODS AND RESULTS: Using culturable methods, a population of Gram-positive n-alkane degraders was detected in the contaminated soil. Five isolates, identified as one Nocardia, two Rhodococcus and two Gordonia strains, were able to degrade medium- and long-chain n-alkanes up to C(36) as assessed by growth assays and gas chromatography-mass spectrometry analysis. Diverging alkane hydroxylase-encoding genes (alkB) were detected by PCR, using degenerated primers, in all the strains; multiple sequences were obtained from the Nocardia strain, while only one alkB gene was detected in the Rhodococcus and Gordonia strains. The majority of the alkB sequences were related to Rhodococcus alkB2, but none was identical to it. CONCLUSIONS: Actinomycetes might have a key role in bioremediation of n-alkane-contaminated sites under dry, resource-limited conditions, such as those found in the Mediterranean shorelines. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first study on the bioremediation potential in Mediterranean contaminated beaches.

Cutaneous antihistaminic action of cetirizine and dose-related EEG concomitants of sedation in man.

The cutaneous antihistaminic action (prick test; 1:100, 1:200 and 1:1000) and neuropsychological and electroencephalographic (EEG) concomitants of sedation following the histamine H1 receptor antagonist cetirizine (10- and 20-mg acute oral doses) and chlorpheniramine, 4 mg, were investigated in a cross-over, placebo-controlled study in healthy male volunteers (age 23-29 years). With an average Cmax of cetirizine of 697.0 ng/ml (10 mg) and 1000.2 ng/ml (20 mg), the diameter of histamine-induced skin weals was reduced by 24.0-74.9% depending on histamine concentration and with no dose dependence for cetirizine. Placebo and chlorpheniramine were ineffective. Behavioral or neuropsychological signs of sedation were never observed. An increase of the 6.5-14.5 Hz EEG power, with anterior scalp preponderance, was observed after chlorpheniramine or cetirizine 20 mg. This effect of cetirizine was accounted for by a substantial increase of power in the 6.5-8.0 Hz frequency subsegment and is regarded, for these experimental conditions, as an established early EEG indication of mild sedation (vigilance 'state A'). No EEG effects were observed after placebo or cetirizine at the 10 mg dose. The existence of some histaminergic (H1) specificity of the mechanisms modulating vigilance and of a threshold dose of cetirizine for sedative action is suggested.

Effects of physiological changes of serum glucose on the pattern-VEP of healthy volunteers.

The correlation between amplitude and latencies of the pattern-reversal VEP (1.7-3.6 50% contrast) and the serum glucose was studied in six healthy, male volunteers (21-26 yr.; mean: 23.2 +/- 1.6 yr.). Pattern-VEP and serum glucose were obtained at 2-h intervals during a 8-h experimental session. The effect of spatial frequency on VEP (increased latencies and amplitude with increasing spatial frequency) was removed statistically by computing the residuals from the nonlinear regression function vs. the spatial frequency. The residuals were then processed as stimulus-independent variables. At glucose serum concentrations within the physiological range of variability (55-103 mg/dl), the P100 latency increased (p < 0.04) with increasing serum glucose, with a 6.9% estimated latency difference between lower and higher glucose concentrations. This correlation depends mostly on the association of shorter and longer P100 latencies with glucose concentration values in the lower and upper portions of the normal concentration range respectively, but accounts for about 4% of the overall variance and may be accidental (therefore a potential bias in otherwise controlled VEP studies) or suggest functional relationships between glucose availability and vision.

Pharmacokinetics and electroencephalographic effects of darodipine 50-200 mg modified release (MR) acute oral administration: dose-finding study in healthy volunteers.

Pharmacokinetics and electroencephalographic [EEG; power spectral analysis] effects of the acute oral Ca-antagonist darodipine (50 mg MR, 100 mg MR, and 200 mg MR) were investigated in a cross-over, placebo-controlled study on healthy male volunteers (age 23-28 yrs). No effects on heart rate, blood pressure or behaviour were observed with these doses at average Cmax levels ranging between 4.74 and 33.53 ng/ml and with a Tmax ranging from 2 to 6 h depending on the dose. No significant differences in drug kinetics were observed between the 100-mg and the 200-mg dose. A significant increase of EEG total power and a decrease of relative power in the 14.5-32.0 Hz frequency interval were observed at the 100-mg and 200-mg doses. These effects were greater and more consistent across subjects at 100 mg than at 200 mg, and were correlated with darodipine plasma concentrations, with indications of an active concentration threshold at approximately 4-5 ng/ml. The 50-mg dose proved ineffective on the EEG signal.