Terahertz and Infrared Plasmon Polaritons in PtTe Type-II Dirac Topological Semimetal.

Surface plasmon polaritons (SPPs) are electromagnetic excitations existing at the interface between a metal and a dielectric. SPPs provide a promising path in nanophotonic devices for light manipulation at the micro and nanoscale with applications in optoelectronics, biomedicine, and energy harvesting. Recently, SPPs are extended to unconventional materials like graphene, transparent oxides, superconductors, and topological systems characterized by linearly dispersive electronic bands.

Synthesis and controlled drug delivery studies of a novel Ubiquinol-Polyethylene glycol-Vitamin E adduct.

CoQ10 and Vitamin E are used in medicinal applications, but they are both lipophilic molecules and the poor solubility in aqueous media results in an inefficient administration, poor bioavailability and potential toxicity. A mixed conjugate Ubiquinol-Polyethylene glycol-Vitamin E was synthesized and characterized to improve the bioavailability of CoQ10 and Vitamin E. The synthesized mixed PEG conjugate was characterized by H NMR spectroscopy and MALDI spectrometry.

Characterization of Arabica and Robusta volatile coffees composition by reverse carrier gas headspace gas chromatography-mass spectrometry based on a statistical approach.

Nineteen samples of Arabica and 14 of Robusta coming from various plantation were analysed by dynamic headspace capillary gas chromatography-mass spectrometry to characterize the volatile fraction of green and roasted samples and the relationships of the same species with geographical origin. As concerns green beans, Arabica species appear characterized by high content of -hexanol, furfural and amylformate, while Robusta species by greater content of ethylpyrazine, dimethylsulfone and 2-heptanone. Four variables, 4-methyl-2,3-dihydrofuran, -hexanol, limonene and nonanal, appear involved in the characterization of the geographical origin of the analysed samples.

Polysaccharides from Pleurotus eryngii var. elaeoselini (Agaricomycetes), a New Potential Culinary-Medicinal Oyster Mushroom from Italy.

Three water-soluble glucans (PELPS-A1, PELPS-A2, and PELPS-A3) purified from the hot water extract of the basidiomata of an edible mushroom Pleurotus eryngii var. elaeoselini by chromatography on DEAE-cellulose 32 and Sephadex G-100 column were found to consist of only D-glucose as monosaccharide constituent. Structural investigation was carried out by acid hydrolysis, periodate oxidation, and NMR experiments (1H-NMR, 13C-NMR, DQF-COSY, TOCSY, ROESY, HMQC, and HMBC).

Imidazole and 1,2,4-Triazole-based Derivatives Gifted with Antitubercular Activity: Cytotoxicity and Computational Assessment.

Background: Mycobacterium Tuberculosis (Mtb) is the causative pathogen of Tuberculosis (TB) and outbreaks are more common among immunosuppressed persons infected with HIV. The current treatment regimens are lengthy and toxic, yet the therapy has remained unchanged for many decades, so there is a need to find new structures with selective mechanism of action. Moreover, the increased incidence of severe disseminated infections produced by undiagnosed Multidrug-resistant (MDR), worsen clinical treatment and contribute the spread of the disease.

PEGylation of coenzyme Q and release studies.

Methoxy polyethylene glycol conjugated with coenzyme Q10 (mPEG)-CoQ10 and analog adducts with amino acids as spacers were synthesized as a new drug delivery systems for CoQ10. Alanine and branched chain amino acids (valine, leucine and isoleucine) were conjugated to mPEG by an amide linkage and to CoQ10 by an ester bond. Recently, branched chain amino acids (BCAAs), which are released along with CoQ10, have received increasing attention as 'anti-fatigue' elements.

Improvement of Chemical and Physical Properties and Antioxidant Evaluation of Eugenol - PEG adduct.

Eugenol (EU) - PEG adduct was synthesized to improve the chemical and physical properties of eugenol. The phenolic group was covalently bound to the carboxyl group of PEG and the release kinetics were studied in vitro in buffer solution at pH 7.4, in simulated gastric fluid and in mouse plasma.

Evidence for a Strong Topological Insulator Phase in ZrTe_{5}.

The complex electronic properties of ZrTe_{5} have recently stimulated in-depth investigations that assigned this material to either a topological insulator or a 3D Dirac semimetal phase. Here we report a comprehensive experimental and theoretical study of both electronic and structural properties of ZrTe_{5}, revealing that the bulk material is a strong topological insulator (STI). By means of angle-resolved photoelectron spectroscopy, we identify at the top of the valence band both a surface and a bulk state.

Lipid Metabolites from the Mushroom Meripilus giganteus.

The phytochemical investigation of the methanolic extract of the white rot fungus Meripilus giganteus resulted in the isolation and identification of complex mixtures of free fatty acids (1), monoacylglycerols (2), cerebrosides (3), ergosterol (4) and ergosterol peroxide (5). The structures of the isolated lipid metabolites (1-5) were determined by chemical and spectroscopic methods. The antioxidant activity of the whole MeOH extract of the fungus was evaluated through in vitro model systems, such as 2,2-diphenyl-l-picrylhydrazyl (DPPH) and superoxide anion.

Ultrafast Optical Control of the Electronic Properties of ZrTe₅.

We report on the temperature dependence of the ZrTe(5) electronic properties, studied at equilibrium and out of equilibrium, by means of time and angle resolved photoelectron spectroscopy. Our results unveil the dependence of the electronic band structure across the Fermi energy on the sample temperature. This finding is regarded as the dominant mechanism responsible for the anomalous resistivity observed at T*∼160  K along with the change of the charge carrier character from holelike to electronlike.

Antioxidant Properties of Oak Bracket Mushroom, Pseudoinonotus dryadeus (Higher Basidiomycetes): A Mycochemical Study.

A complex mixture of free fatty acids (1), cerevisterol (2), a sphingosine (3), and a complex mixture of diacylglycerophospholipids (4) were isolated from the fruiting body of the basidiomycete mushroom Pseudoinonotus dryadeus and subjected to spectroscopic analyses. The antioxidant activities of the whole extract of the fungus, of the isolated fractions, and of compounds 1-4 were evaluated in two in vitro model systems: 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide anion. In each systems, the extract of fungus and compound 2 showed the same free radical scavenging activity (with SC50 data of 18.

Ultrafast electron dynamics in epitaxial graphene investigated with time- and angle-resolved photoemission spectroscopy.

In order to exploit the intriguing optical properties of graphene it is essential to gain a better understanding of the light-matter interaction in the material on ultrashort timescales. Exciting the Dirac fermions with intense ultrafast laser pulses triggers a series of processes involving interactions between electrons, phonons and impurities. Here we study these interactions in epitaxial graphene supported on silicon carbide (semiconducting) and iridium (metallic) substrates using ultrafast time- and angle-resolved photoemission spectroscopy (TR-ARPES) based on high harmonic generation.

Momentum-resolved spin dynamics of bulk and surface excited States in the topological insulator Bi(2)Se(3).

The prospect of optically inducing and controlling a spin-polarized current in spintronic devices has generated wide interest in the out-of-equilibrium electronic and spin structure of topological insulators. In this Letter we show that only measuring the spin intensity signal over several orders of magnitude by spin-, time-, and angle-resolved photoemission spectroscopy can provide a comprehensive description of the optically excited electronic states in Bi_{2}Se_{3}. Our experiments reveal the existence of a surface resonance state in the second bulk band gap that is benchmarked by fully relativistic ab initio spin-resolved photoemission calculations.

Tunable carrier multiplication and cooling in graphene.

Time- and angle-resolved photoemission measurements on two doped graphene samples displaying different doping levels reveal remarkable differences in the ultrafast dynamics of the hot carriers in the Dirac cone. In the more strongly (n-)doped graphene, we observe larger carrier multiplication factors (>3) and a significantly faster phonon-mediated cooling of the carriers back to equilibrium compared to in the less (p-)doped graphene. These results suggest that a careful tuning of the doping level allows for an effective manipulation of graphene's dynamical response to a photoexcitation.

Ultrafast dynamics of massive dirac fermions in bilayer graphene.

Bilayer graphene is a highly promising material for electronic and optoelectronic applications since it is supporting massive Dirac fermions with a tunable band gap. However, no consistent picture of the gap's effect on the optical and transport behavior has emerged so far, and it has been proposed that the insulating nature of the gap could be compromised by unavoidable structural defects, by topological in-gap states, or that the electronic structure could be altogether changed by many-body effects. Here, we directly follow the excited carriers in bilayer graphene on a femtosecond time scale, using ultrafast time- and angle-resolved photoemission.

PEG-Ursolic Acid Conjugate: Synthesis and In Vitro Release Studies.

A highly water-soluble macromolecular compound of ursolic acid with monomethoxypoly(ethylene glycol) (mPEG) was prepared. The physicochemical properties and stabilities under different conditions were investigated. By PEG conjugation, greatly increased water solubility was obtained, and the results showed that this conjugate was a potential prodrug for the oral delivery of ursolic acid.

Anticancer activity of cationic porphyrins in melanoma tumour-bearing mice and mechanistic in vitro studies.

Background: Porphyrin TMPyP4 (P4) and its C14H28-alkyl derivative (C14) are G-quadruplex binders and singlet oxygen (1O2) generators. In contrast, TMPyP2 (P2) produces 1O2 but it is not a G-quadruplex binder. As their photosensitizing activity is currently undefined, we report in this study their efficacy against a melanoma skin tumour and describe an in vitro mechanistic study which gives insights into their anticancer activity.

Lipid metabolites with free-radical scavenging activity from Euphorbia helioscopia L.

The methanolic extract of the plant Euphorbia helioscopia L. exhibited an interesting free-radical scavenging activity. From the aerial parts of Euphorbia helioscopia L.

Direct view of hot carrier dynamics in graphene.

The ultrafast dynamics of excited carriers in graphene is closely linked to the Dirac spectrum and plays a central role for many electronic and optoelectronic applications. Harvesting energy from excited electron-hole pairs, for instance, is only possible if these pairs can be separated before they lose energy to vibrations, merely heating the lattice. Until now, the hot carrier dynamics in graphene could only be accessed indirectly.

Nitric oxide-mediated activity in anti-cancer photodynamic therapy.

Cell recurrence in cancer photodynamic therapy (PDT) is an important issue that is poorly understood. It is becoming clear that nitric oxide (NO) is a modulator of PDT. By acting on the NF-κB/Snail/RKIP survival/anti-apoptotic loop, NO can either stimulate or inhibit apoptosis.

Bioactive lipids metabolites in Amanita virosa.

Thrombin is the key serine proteinase of the coagulation cascade and, therefore, a suitable target for inhibition of blood coagulation. An extract of Amanita virosa considerably inhibited thrombin (48%), but showed no inhibitory activity on trypsin. On the basis of inhibition selectivity between thrombin and trypsin and potency of thrombin inhibition, A.

Chemical composition and functional characterisation of commercial pumpkin seed oil.

Background: Pumpkin (Cucurbita pepo L.) seed oil is a common product in Slovenia, Hungary and Austria and is considered a preventive agent for various pathologies, particularly prostate diseases. These properties are related to its high content of carotenoids and liposoluble vitamins.

Pharmacokinetic analysis of multi PEG-theophylline conjugates.

In the attempt of prolonging the effect of drugs, a new branched, high-molecular weight multimeric poly(ethylene glycol) (MultiPEG), synthesized with a simple assembling procedure that devised the introduction of functional groups with divergent and selective reactivity, was employed as drug carrier. In particular, the attention was focused on the study of theophylline (THEO) and THEO-MultiPEG conjugates pharmacokinetic after oral administration in rabbit. Pharmacokinetic behavior was studied according to an ad hoc developed mathematical model accounting for THEO-MultiPEG in vivo absorption and decomposition into drug (THEO) and carrier (MultiPEG).

The PDT activity of free and pegylated pheophorbide a against an amelanotic melanoma transplanted in C57/BL6 mice.

Pheophorbide a (Pba) is a chlorophyll catabolite that has been proposed as photosensitizer in photodynamic therapy. In a previous study we conjugated Pba to monomethoxy-polyethylene glycol (mPEG-Pba), to increase its solubility and pharmacokinetics. Here, we compare the photodynamic therapy efficacy of free Pba and mPEG-Pba to cure a subcutaneous amelanotic melanoma transplanted in C57/BL6 mice.