Detonation and Blast Wave Characteristics of Nitromethane Mixed with Particles of an Aluminium–Magnesium Alloy

Investigation of detonation parameters, blast wave characteristics and quasi‐static pressures (QSPs) for the mixtures of nitromethane and particles of an aluminium and magnesium (Al₃Mg₄) alloy was carried out. The mixtures of gelled nitromethane containing 15–60 wt.‐% Al Mg alloy were tested. Detonation velocity and Gurney energy were determined. Parameters of blast waves produced by charges of the investigated explosives were measured. QSP measurements were conducted in a steel chamber of 0.15 m³ volume filled with air. Thermochemical and gasdynamical calculations were also performed. The degree of combustion of the metallic addition with the gaseous products during detonation and expansion is discussed.     

Analysis of glycerophosphonolipids in egg yolk

Glycerophosphonolipids are a relatively unknown class of polar lipids. Little information is available on any special biological function of these substances or specific technological use for them. Since glycerophosphonolipids have been reported to occur in egg yolk, further studies are needed in order to determine their relevancy. However, analysis of these lipids is rather difficult, due both to their chemical similarity to phospholipids and the lack of commercially available reference substances. Therefore, a reference substance for phosphono analogues of phosphatidylethanolamine (PnE)—1,2-dioctadecanoyl-glycero-3-aminoethylphosphonate—has been synthesized and an HPLC/ELSD method to separate PnE from its phosphonoanalog was developed. Although the present results showed no evidence of glycerophosphonolipids in egg yolk (limit of detection <0.02% for PnE), the spectroscopic data gathered here do point to an approach for further analysis of glycerophosphonolipids. Furthermore, a characteristic ESI–MS² fragmentation pattern for PnE was established, which can be used as a “fingerprint” for the identification of this substance in other biological systems. It was found to be characteristic for a fatty acid fragment to be split off as an internal anhydride (ketene) [M–H–RCH=C=O]⁻ along with the whole fatty acid fragment [M–H–RCH₂COOH]⁻ in the negative ion mode. In the positive mode, there was a selective loss of only the head group of the phosphonolipid [PO₃H₂–C₂H₄–NH₃]⁺, resulting in the so-called “diacylglycerol-like fragment ion” [DAG]⁺.     

Bimetallic Au–Cu, Ag–Cu/CrAl3O6 Catalysts for Methanol Synthesis

The influence of silver and gold addition on the activity and physicochemical properties of supported Cu/CrAl₃O₆ catalysts was the aim of this work. The reduction of CrAl₃O₆ support shows only one reduction stage attributed to Cr (VI) species reduction originating from previously oxidized binary oxide. Supported copper catalysts reduce in one or two stages depending on copper concentration representing the reduction of copper oxide—CuO, copper oxide chemically combined with Cr(III) oxide as copper chromite—CuCr₂O₄ and Cr(VI) species originating from surface chromate ions CrO₄ ^2?. Additionally, the introduction of silver into supported copper catalysts Cu/CrAl₃O₆ can led to the appearance of silver chromate phase. XRD investigations of support CrAl₃O₆ alone, supported copper and gold and silver promoted copper supported catalysts calcined at 400, 700 and 900 °C indicated the presence of highly amorphous alumina γ-Al₂O₃ like structure network in which some of cationic locations of aluminum were occupied by chromium atoms and small quantities of α-Cr₂O₃ phase. Additionally, for copper, silver–copper, and gold–copper supported catalysts the following oxide phases were distinguished: monometallic oxides CuO, Ag₂O, binary oxides CuAl₂O₄, Ag₂CrO₄, CuCr₂O₄ and even ternary oxide CuAlCrO₄. In the case of gold promoted copper supported catalysts metallic gold phase was detected. Activity tests carried out for these catalysts show that the most active was 20 wt.% Cu/CrAl₃O₆ catalyst. Promotion of copper catalysts by silver improves the activity in methanol synthesis, what can be assigned to silver chromate formation. The analogical gold chromate like formation was not confirmed.     

Thermal stability of expanded perlite modified by mullite

Results of the thermal stability of expanded perlite modified by mullite are presented. Mullite was formed from alumino-silicate gel by sol–gel method. This method allowed us to obtain very homogenous and reactive gel and phase formation of mullite took place at relatively low temperatures. Expanded perlite modified with alumino-silicate gel after firing above the temperature of mullite formation had better thermal stability and durability during heating. The thermal stability of this material was examined up to 1400 °C.     

Functionalized-radiolabeled hydroxyapatite/tenorite nanoparticles as theranostic agents for osteosarcoma

Hydroxyapatite (HA) nanoparticles (NPs) doped with different radioisotopes for use as theranostic systems play an important role in scientific research nowadays due to their ability to simultaneously act in the treatment and diagnosis of various types of cancers. In this work, we describe the synthesis and characterization of a hydroxyapatite/tenorite nanocomposite functionalized with folic acid, representing a nanotheranostic material with potential for application as an agent in positron emission tomography imaging systems and to act specifically in the treatment and diagnosis of osteosarcoma. ⁶⁴Cu and ³²P were produced by nuclear activation in the TRIGA reactor at CDTN. The obtained samples were characterized by XRD with Rietveld refinement, XAFS, SEM, BET, TGA, FTIR, CHN, ICP-AES, XPS and gamma spectroscopy. We investigated how CuO grows in HA NPs, the stability of the interactions between CuO and HA constituents and the interactions between folic acid and the surface of the HA NPs. The results indicate the formation of a second phase (tenorite) besides hydroxyapatite, and that the interactions between the two phases are stable, resulting in a nanocomposite. Furthermore, the activation of ⁶⁴Cu and ³²P inside the HA matrix, through the exposition to a neutron flux, produces a theranostic material of interest for biological tests.     

Single‐lumen tunneled catheter: An old but useful option

We report a case of long‐term uneventful catheter use in a patient with previous recurrent vascular access dysfunction and infection. A single‐lumen tunneled catheter was inserted into the left internal jugular vein after a failed attempt of dual‐lumen permanent catheter placement. The follow‐up since device implantation has exceeded 5 years without any complications related to vascular access.     

Protection of normal cells from irradiation bystander effects by silica-flufenamic acid nanoparticles

The development of a myriad of nanoparticles types has opened new possibilities for the diagnostics and treatment of many diseases, especially for cancer. However, most of the researches done so far do not focus on the protection of normal cells surrounding a tumor from irradiation bystander effects that might lead to cancer recurrence. Gap-junctions are known to be involved in this process, which leads to genomic instability of neighboring normal cells, and flufenamic acid (FFA) is included in a new group of gap-junction blockers recently discovered. The present work explores the use of mesoporous silica nanoparticles MCM-41 functionalized with 3-Aminopropyltriethoxysilane (APTES) for anchoring the flufenamic acid for its prolonged and controlled release and protection from radiation bystander effects. MCM-41 and functionalized samples were structurally and chemically characterized with multiple techniques. The biocompatibility of all samples was tested in a live/dead assay performed in cultured MRC-5 and HeLa cells. HeLa cells cultured were exposed to 50?Gy of gamma-rays and the media transferred to fibroblast cells cultured separately. Our results show that MCM-41 and functionalized samples have high biocompatibility with MCR-5 and HeLa cells, and most importantly, the FFA delivered by these NPs was able to halt apoptosis, one of main bystander effects.     

Molecular Design of Solid‐State Nanopores: Fundamental Concepts and Applications

Solid‐state nanopores are fascinating objects that enable the development of specific and efficient chemical and biological sensors, as well as the investigation of the physicochemical principles ruling the behavior of biological channels. The great variety of biological nanopores that nature provides regulates not only the most critical processes in the human body, including neuronal communication and sensory perception, but also the most important bioenergetic process on earth: photosynthesis. This makes them an exhaustless source of inspiration toward the development of more efficient, selective, and sophisticated nanopore‐based nanofluidic devices. The key point responsible for the vibrant and exciting advance of solid nanopore research in the last decade has been the simultaneous combination of advanced fabrication nanotechnologies to tailor the size, geometry, and application of novel and creative approaches to confer the nanopore surface specific functionalities and responsiveness. Here, the state of the art is described in the following critical areas: i) theory, ii) nanofabrication techniques, iii) (bio)chemical functionalization, iv) construction of nanofluidic actuators, v) nanopore (bio)sensors, and vi) commercial aspects. The plethora of potential applications once envisioned for solid‐state nanochannels is progressively and quickly materializing into new technologies that hold promise to revolutionize the everyday life.     

Synthesis and Characterization of Pyridine Compounds for Amperometric Measurements of Leukocyte Esterase

We introduce a new class of substrates (compounds I – III ) for leukocyte esterase (LE) that react with LE yielding anodic current in direct proportion to LE activity. The kinetic constants K_m and k_cat for the enzymatic reactions were determined by amperometry at a glassy carbon electrode. The binding affinity of I – III for LE was two orders of magnitude better than that of existing optical LE substrates. The specificity constant k_cat/K_m was equal to 2.7, 3.8, and 5.8×10⁵ m ^?1 s^?1 for compounds containing the pyridine ( I ), methoxypyridine ( II ), and (methoxycarbonyl)pyridine ( III ), respectively, thus showing an increase in catalytic efficiency in this order. Compound III had the lowest octanol/water partition coefficient (log p=0.33) along with the highest topological surface area (tPSA=222 Ų) and the best aqueous solubility (4.0 mg mL^?1). The average enzymatic activity of LE released from a single leukocyte was equal to 4.5 nU when measured with compound III .