Mass and composition matrix-assisted laser desorption ionization time of flight analysis enabling inference of the sequence of most peptides where the protein of origin is known

Mass spectrometers combining matrix-assisted laser-desorption ionization (MALDI) and time-of-flight analysis are among the most widely used in peptide analysis. They excel at accurate mass determinations on complex samples but, compared with tandem instruments, have very limited capacity to determine amino acid sequence through daughter ion analysis. Here we have investigated the sequence information that can be inferred from the masses of peptides in the special circumstance in which the peptides are known to be sub-sequences of known parent sequences. We show how sequence can be inferred from the measured m/z of a peptide (mass analysis) and examine the parameters that influence the level of confidence that can be placed in "inferred sequences". We further describe how specific amino acid modifications can be used with MALDI-TOF analysis to obtain partial composition information and demonstrate that combined mass and composition (MAC) analysis enables the sequences of most peptide ions to be inferred with very high confidence.     

Web and database software for identification of intact proteins using "top down" mass spectrometry

For the identification and characterization of proteins harboring posttranslational modifications (PTMs), a "top down" strategy using mass spectrometry has been forwarded recently but languishes without tailored software widely available. We describe a Web-based software and database suite called ProSight PTM constructed for large-scale proteome projects involving direct fragmentation of intact protein ions. Four main components of ProSight PTM are a database retrieval algorithm (Retriever), MySQL protein databases, a file/data manager, and a project tracker. Retriever performs probability-based identifications from absolute fragment ion masses, automatically compiled sequence tags, or a combination of the two, with graphical rendering and browsing of the results. The database structure allows known and putative protein forms to be searched, with prior or predicted PTM knowledge used during each search. Initial functionality is illustrated with a 36-kDa yeast protein identified from a processed cell extract after automated data acquisition using a quadrupole-FT hybrid mass spectrometer. A +142-Da delta(m) on glyceraldehyde-3-phosphate dehydrogenase was automatically localized between Asp90 and Asp192, consistent with its two cystine residues (149 and 153) alkylated by acrylamide (+71 Da each) during the gel-based sample preparation. ProSight PTM is the first search engine and Web environment for identification of intact proteins (https://prosightptm.scs.uiuc.edu/).     

Ring-opening Metathesis Co-polymerization of a C60-cyclopentadiene Cycloadduct and Norbornene with the Grubbs Second-generation Catalyst

A series of C₆₀-containing polymers were synthesized by the co-polymerization of a C₆₀-cyclopentadiene cycloadduct and norbornene in varying ratios. The polymerization was facilitated by a catalytic amount of Grubbs second generation catalyst and the co-polymers formed were investigated by spectroscopic and thermal techniques.     

Processing of observed pupil size modulates perception of sadness and predicts empathy.

Facial autonomic responses may contribute to emotional communication and reveal individual affective style. In this study, the authors examined how observed pupillary size modulates processing of facial expression, extending the finding that incidentally perceived pupils influence ratings of sadness but not those of happy, angry, or neutral facial expressions. Healthy subjects rated the valence and arousal of photographs depicting facial muscular expressions of sadness, surprise, fear, and disgust. Pupil sizes within the stimuli were experimentally manipulated. Subjects themselves were scored with an empathy questionnaire. Diminishing pupil size linearly enhanced intensity and valence judgments of sad expressions (but not fear, surprise, or disgust). At debriefing, subjects were unaware of differences in pupil size across stimuli. These observations complement an earlier study showing that pupil size directly influences processing of sadness but not other basic emotional facial expressions. Furthermore, across subjects, the degree to which pupil size influenced sadness processing correlated with individual differences in empathy score. Together, these data demonstrate a central role of sadness processing in empathetic emotion and highlight the salience of implicit autonomic signals in affective communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Highly aluminium doped barium and strontium ferrite nanoparticles prepared by citrate auto-combustion synthesis

Aluminium doped barium and strontium hexaferrite nanoparticles BaAl_xFe_(12−x)O₁₉ and SrAl_xFe_(12−x)O₁₉ were synthesised via a sol-gel route using citric acid to complex the ions followed by an auto-combustion reaction. This method shows promise for the synthesis of complex ferrite powders with small particle size. It was found that around half of the iron could be substituted for aluminium in the barium ferrite with structure retention, whereas strontium aluminium ferrites could be produced with any aluminium content including total substitution of the iron. All synthesised materials consisted of particles smaller than 1 μm, which is the size of a single magnetic domain, and various doping levels were achieved with the final elemental composition being within the bounds of experimental error. The materials show structural and morphological changes as they move from iron to aluminium ferrites. Such materials may be promising for imaging applications.     

Laser melting functionally graded composition of Waspaloy<Superscript>®</Superscript> and Zirconia powders

An approach for fabricating functionally graded specimens of supernickel alloy and ceramic compositions via Selective Laser Melting (SLM) is presented. The focus aimed at using the functionally graded material (FGM) concept to gradually grade powdered compositions of Zirconia within a base material of Waspaloy^®. A high power Nd:YAG laser was used to process the material compositions to a high density with gradual but discrete changes between layered compositions. The graded specimens initially consisted of 100% Waspaloy^® with subsequent layers containing increased volume compositions of Zirconia (0–10%). Specimens were examined for porosity and microstructure. It was found that specimens contained an average porosity of 0.34% with a gradual change between layers without any major interface defects.     

A Far Infrared Super Radiant FEL

The basic physics, results of 3–D simulations, and relevant parameters for the design of a far infrared FEL, which operates in the SASE superradiant short bunch regime, are presented. It is shown that a quite interesting device can be easily developed, with rather new features, producing coherent laser pulses with ～10 psec duration and around 7 MW peak power.     

Nurturing health-related online support groups: Exploring the experiences of patient moderators

The aim of this study was to examine the views of moderators across a diverse and geographically broad range of online support groups about their moderator experiences and to explore both the personal benefits as well as challenges involved. Thirty-three patient moderators completed an online questionnaire which included a series of open-ended questions. Thematic analysis identified three themes: emergence, empowerment, nurturing. Several moderators declared their own diagnosis and for some, being able to share personal insights motivated them to establish the group and in turn offered validation. They felt empowered by helping others and learned more about the condition through accessing the “communal brain”. Some felt the group aided patients’ access to health services and their ability to communicate with health professionals while others worried about them becoming over-dependent. Moderators described needing to nurture their group to ensure it offered a safe space for members. Clear rules of engagement, trust, organisation skills, compassion and kindness were considered essential. Patient moderated online support groups can be successfully developed and facilitated and can be empowering for both the group member and moderator alike.