Combination of ESI and MALDI-MS Imaging Enhances Analysis on Brain Gangliosides

Recent advances in matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) have led to the direct analysis of tissue slices. The major advantage of MSI is its capability of simultaneously localizing and identifying a parent molecule and its metabolites without any labeling or any prior knowledge. MSI has been extensively employed to detect the differentiated pattern of lipids in various organs in different diseases, such as brains in Alzheimer’s disease. Poor reproducibility of MALDIMSI analysis due to the heterogeneity of the matrix-analyte crystals, hindersits use on quantitative analysis. In addition, discontinuous ion flow due to quickly consumption of the samples under laser irradiation on specific site affects its ability in qualitative analysis. Although electrospray ionization mass spectrometry (ESI-MS) cannot directly be used for imaging, ESI tandem mass spectrometry (LC/ESI-MS/MS) can separate and distinguish gangliosides.

Zhang et al. have presented a promising workflow for qualitative, semi-quantitative and in situ analysis of gangliosides by combiningthe MALDI MSI and ESI-MS. Following obtaining the brain from the mice, fresh-frozen murine brain sections were prepared and coated with matrix for subsequent MALDI MSI analysis.

Potentiometric and pHmetric Studies of Paracetamol

Paracetamol (acetaminophen) is one of the most popular analgesic and antipyretic drugs. Paracetamol is available in different dosage forms: tablet, capsules, drops, elixirs, suspensions and suppositories. Dosage forms of paracetamol and its combinations with other drugs have been listed in various pharmacopoeias. The combination of paracetamol with dipyrone is used asan antipyretic, analgesic and anti-inflammatory drug. Numerous methods have been reported for the analysis of paracetamol and its combinations in pharmaceuticals or in biological fluids. Paracetamol has been determined in combination with other drugs using titrimetry, voltammetry, fluorimetry, colorimetry, UV-spectrophotometry, quantitative thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and gas chromatography (GC) in pharmaceutical preparations. 

Effect of electrophilic and electrodotic groups on the potentiometric titration of amides and other weak bases was studied. Electrodotic groups enhance the potentiometric end point and electrophilicgroups depress it, sometimes to the extent that the compound is not titratable. A combination of chloroform and acetic anhydride is a useful alternative medium for the titration of weak bases. A potentiometric method for determination of p-acetamidophenol was reported.

Excitonic Quasimolecules in Nano Systems of Semiconductor and Dielectric Quantum Dots

The idea of superatom was fruitful for the development of nanophysics Superatom (quasiatomic nanoheterostructures) consists of a spherical quantum dot (QD) with radius a, the volume of that contains the semiconductor (or dielectric) material. QD is surrounded by dielectric(semiconductor) matrix. A hole is localized in the volume of QD, and the electron is localized over a spherical interface (QD-matrix). In this nanosystem the lowest electronic level is in matrix, and the lowest hole level is within volume of QD. A large shift of the valence band (700 meV) generates the localization of holes in the volume of QD. A significant shift of the conduction band (about 400 meV) is a potential barrier for electrons. 

The electrons moving in the matrix and do not penetrate in the volume of QD. Theenergy of the Coulomb interaction of electron with hole and the energy of thepolarization interaction of electron with interface (QDmatrix) form a potential well, in which the electron is localized over the surface of quantum dot. The certain orbitals, localized surrounding quantum dot correspond to electrons in superatom . During investigation of the optical characteristics of nanosystems with CdS, ZnSe, Al2O3 and Ge quantum dots in experimental papersit was found that the electron can be localized above the surface of the QD while the hole here moves in the volume of the QD. In Ref.

Effect of Climate Changes on Surviving of Nitzschia inconspicua Grunow

The climate is changing at a rate never seen before. Aquatic organisms are endangered throughout the world for various reasons, including global climate change. Changes in precipitation and temperature will dramatically affect the survival of many species. Plants play a key role in moderating climate change becausethey take up carbon dioxide (CO2). If plants are lost, the carbon (as CO2) will continue accumulating in our atmosphere and causes air temperature to rise, leading to ocean acidification. With climate changes, aquatic environments face increases in oceans salinity and sea level rise due to melting of the ice in the poles. These combined factors result in drastic world destruction. 

Organisms need specific conditions in order to survive. Scientists predict that these conditions will be altered when the global climate changes. A change insalinity and temperature could lead to death, migration, or poor health of the living organisms. The loss of aquatic environments will be a major disasterthat will take place because of previous changes

Synthesis and Characterization of Deshydroxy Posaconazole

A general scheme is set for the estimation of the impurities in bulk drug substances by the rational use of chromatographic, spectroscopic and analytical techniques. The various parameters to be fulfilled in an impurity profiling of drug substances are discussed. Impurity is definedas any substance coexisting with the original drug, such as starting materialor intermediates or these formed, due to any side reactions. The presence of these unwanted chemicals, even in small amounts, may influence the efficacy and safety of the pharmaceutical products. Impurity profiling (i.e., the identity as well as the quantity of impurity in the pharmaceuticals), is now gaining critical attention from regulatory authorities. 

The different Pharmacopoeias, such as the British Pharmacopoeia (BP), United States Pharmacopeia (USP), and Indian Pharmacopoeia (IP) are slowly incorporating limits for allowable levels of impurities present in the APIs or formulations. The process-relatedimpurities in an active pharmaceutical ingredient (API) can have a significantimpact on the quality and safety of the drug products. The impurity levels in any drug substance are described as per its biological or toxicological data. It is quite important for “regulatory” aspect of drug approval to provide limitation of “related impurities.” Therefore, it is necessary to study the impurity profile of any API and control it during the manufacturing of a drug product.