Single-shot biodiesel analysis: nearly instantaneous typification and quality control solely by ambient mass spectrometry

Using a simple and easily implemented desorption/ionization mass spectrometry technique, a tiny droplet of biodiesel placed on the surface of a sheet of paper is analyzed directly and nearly instantaneously under ambient conditions. No pre-separation or sample preparation is required, and clean mass spectra are obtained with great simplicity. In the positive ion mode, easy ambient sonic-spray ionization mass spectrometry, EASI(+)-MS, provides typical profiles of the major components of biodiesel samples, that is, either methyl esters (FAME) or ethyl esters (FAEE) of the natural fatty acids and triglycerides (TAG) from residual oil or oil from adulteration. Each FAME (FAEE) or TAG molecule is detected as a single sodiated molecule, [M + Na] (+) with relative intensities that correlate well with the known fatty acid profiles of the oil. Using EASI(-)-MS, typical and complementary profiles of free fatty acids (FFA) are obtained, which are detected in their deprotonated forms [FAA - H] (-). A general, single-shot approach for biodiesel analysis is therefore described, and samples from different feedstocks, from blends with petrodiesel, or from either methanol or ethanol trans-esterification are readily typified and major parameters of quality accessed.     

Mass spectrometry imaging under ambient conditions

Mass spectrometry imaging (MSI) has emerged as an important tool in the last decade and it is beginning to show potential to provide new information in many fields owing to its unique ability to acquire molecularly specific images and to provide multiplexed information, without the need for labeling or staining. In MSI, the chemical identity of molecules present on a surface is investigated as a function of spatial distribution. In addition to now standard methods involving MSI in vacuum, recently developed ambient ionization techniques allow MSI to be performed under atmospheric pressure on untreated samples outside the mass spectrometer. Here we review recent developments and applications of MSI emphasizing the ambient ionization techniques of desorption electrospray ionization (DESI), laser ablation electrospray ionization (LAESI), probe electrospray ionization (PESI), desorption atmospheric pressure photoionization (DAPPI), femtosecond laser desorption ionization (fs‐LDI), laser electrospray mass spectrometry (LEMS), infrared laser ablation metastable‐induced chemical ionization (IR‐LAMICI), liquid microjunction surface sampling probe mass spectrometry (LMJ‐SSP MS), nanospray desorption electrospray ionization (nano‐DESI), and plasma sources such as the low temperature plasma (LTP) probe and laser ablation coupled to flowing atmospheric‐pressure afterglow (LA‐FAPA). Included are discussions of some of the features of ambient MSI for example the ability to implement chemical reactions with the goal of providing high abundance ions characteristic of specific compounds of interest and the use of tandem mass spectrometry to either map the distribution of targeted molecules with high specificity or to provide additional MS information on the structural identification of compounds. We also describe the role of bioinformatics in acquiring and interpreting the chemical and spatial information obtained through MSI, especially in biological applications for tissue diagnostic purposes. Finally, we discuss the challenges in ambient MSI and include perspectives on the future of the field. © 2012 Wiley Periodicals, Inc., Mass Spec Rev 32:218–243, 2013     

Neurotrophin Trk receptors in the brain of a teleost fish, Nothobranchius furzeri

Trk neurotrophin receptors are transmembrane tyrosine kinase proteins known as TrkA, TrkB, and TrkC. TrkA is the high affinity receptor for nerve growth factor, TrkB is the one for both brain-derived neurotrophic factor and neurotrophin-4, and TrkC is the preferred receptor for neurotrophin-3. In the adult mammalian brain, neurotrophins are important regulators of neuronal function and plasticity. This study is based on Nothobranchius furzeri, a teleost fish that is becoming an ideal candidate as animal model for aging studies because its life expectancy in captivity is of just 3 months. In adult N. furzeri, all three investigated neurotrophin Trk receptors were immunohistochemically detected in each brain region. TrkA positive neuronal perikarya were localized in the dorsal and ventral areas of the telencephalon and in the cortical nucleus; TrkB immunoreactivity was observed in neuronal perikarya of the dorsal and ventral areas of the telencephalon, the diffuse inferior lobe of the hypothalamus, and Purkinje cells; TrkC positive neuronal perikarya were detected in the most aboral region of the telencephalon, in the magnocellular preoptic nucleus and in few neurons dispersed in the hypothalamus. Numerous positive fibers were widely distributed throughout the brain. Radial glial cells lining the mesencephalic and rhombencephalic ventricles showed immunoreactivity to all three Trks. These findings suggest an involvement of neurotrophins in many aspects of biology of adult N. furzeri.     

Analysis of a number and type of publications that editors publish in their own journals: case study of scholarly journals in Croatia

To assess the publication practices of editors in their own journals, we analysed the number of articles that Croatian editors published in the journals they edit. From 2005 to 2008, 256 decision-making editors of 180 journals published a total of 887 publications in their own journals. Out of these, 332 were relevant for their academic promotion. Only 18 editors published 5 or more articles in their own journals. A single journal had regulations for self-publishing in the instructions for authors. Although the majority of editors did not misuse their own journals for scientific publishing and academic promotion, there is a need for greater transparency of the declaration and management of editorial conflict of interest in academic and scholarly journals.     

Local surface charges direct the deposition of carbon nanotubes and fullerenes into nanoscale patterns

This article reports on the directed deposition of carbon nanotubes (CNTs) and fullerenes onto solid surfaces using local electrostatic fields. Arbitrary patterns of local surface charges are created by charge writing with an atomic force microscope. During the subsequent development of the sample in an aqueous suspension containing surfactant-stabilized CNTs or fullerenes, Coulomb attraction guides the positioning and alignment of these particles onto the charge patterns. The surface potential of the charge patterns provides a direct control over the particle attachment. CNTs and fullerenes precisely reproduce the charge patterns, yielding structures with a lateral resolution down to the particle diameter.     

Musical Instrument Engineering Program at Tufts University

At Tufts University, we have initiated an engineering minor and concentration certificate program in Musical Instrument Engineering (MIE) as an exciting way to introduce and teach principles of mechanical engineering to undergraduate students. The goal of this program is to teach the fundamentals of engineering through the manufacture of musical instruments. As musical instruments are both familiar and complex, they provide non‐threatening and enjoyable focal points for engineering education. This interdisciplinary curriculum combines a variety of learning experiences, including lecturing, experimental analysis, and project development. In this paper we outline the minor and certificate programs, and assess the initial success of the Musical Instrument Engineering program through the response of faculty, administration, and students.     

Transformation on Infinite Double Series and Applications to Harmonic Number Identities

A general transformation formula between an infinite double series and an infinite single sum is established, which specializes to several infinite double series identities, including a recent one due to Lyons, Paule and Riese (2002).     

S-Acetyl-Glutathione Attenuates Carbon Tetrachloride-Induced Liver Injury by Modulating Oxidative Imbalance and Inflammation

Liver fibrosis, depending on the stage of the disease, could lead to organ dysfunction and cirrhosis, and no effective treatment is actually available. Emergent proof supports a link between oxidative stress, liver fibrogenesis and mitochondrial dysfunction as molecular bases of the pathology. A valid approach to protect against the disease would be to replenish the endogenous antioxidants; thus, we investigated the protective mechanisms of the S-acetyl-glutathione (SAG), a glutathione (GSH) prodrug. Preliminary in vitro analyses were conducted on primary hepatic cells. SAG pre-treatment significantly protected against cytotoxicity induced by CCl4. Additionally, CCl4 induced a marked increase in AST and ALT levels, whereas SAG significantly reduced these levels, reaching values found in the control group. For the in vivo analyses, mice were administered twice a week with eight consecutive intraperitoneal injections of 1 mL/kg CCl4 (diluted at 1:10 in olive oil) to induce oxidative imbalance and liver inflammation. SAG (30 mg/kg) was administered orally for 8 weeks. SAG significantly restored SOD activity, GSH levels and GPx activity, while it strongly reduced GSSG levels, lipid peroxidation and H₂O₂ and ROS levels in the liver. Additionally, CCl4 induced a decrease in anti-oxidants, including Nrf2, HO-1 and NQO-1, which were restored by treatment with SAG. The increased oxidative stress characteristic on liver disfunction causes the impairment of mitophagy and accumulation of dysfunctional and damaged mitochondria. Our results showed the protective effect of SAG administration in restoring mitophagy, as shown by the increased PINK1 and Parkin expressions in livers exposed to CCl4 intoxication. Thus, the SAG administration showed anti-inflammatory effects decreasing pro-inflammatory cytokines TNF-α, IL-6, MCP-1 and IL-1β in both serum and liver, and suppressing the TLR4/NFkB pathway. SAG attenuated reduced fibrosis, collagen deposition, hepatocellular damage and organ dysfunction. In conclusion, our results suggest that SAG administration protects the liver from CCl4 intoxication by restoring the oxidative balance, ameliorating the impairment of mitophagy and leading to reduced inflammation.     

Central and Peripheral NPY Age-Related Regulation: A Comparative Analysis in Fish Translational Models

NPY is among the most abundant neuropeptides in vertebrate brain and is primarily involved in the regulation of food intake. The NPY system is also associated with the aging process showing beneficial effects on neuronal survival via autophagy modulation. Here, we explore the age-related regulation of NPY in the brain and foregut of the shortest- and longest-lived fish species, Nothobranchius furzeri and Danio rerio, respectively. These two research models, despite some similarities, display profound biological differences making them attractive vertebrates to elucidate the mechanisms underlying the regulation of neuropeptide synthesis and function. It is noteworthy that in both fish species only Npya has been identified, while in the other teleosts two classes of NPY (Npya and Npyb) have been annotated. Our findings document that in both species: (i) NPY is centrally regulated; (ii) NPY levels increase in the brain during aging; (iii) NPY is localized in the enteroendocrine cells as well as in the myenteric plexus and drastically decreases in old animals. According to our data, the age-related regulation in the gut resembles that described in other vertebrate species while the increased levels in the brain offer the unique possibility to explore the role of NPY in model organisms to develop future experimental and translatable approaches.