ORCID Profile
0000-0001-9496-4174
Current Organisation
Universidade de São Paulo
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Publisher: Springer Science and Business Media LLC
Date: 23-12-2014
Publisher: International Union of Crystallography (IUCr)
Date: 28-09-2002
DOI: 10.1107/S0907444902011022
Abstract: Bucain is a three-finger toxin, structurally homologous to snake-venom muscarinic toxins, from the venom of the Malayan krait Bungarus candidus. These proteins have molecular masses of approximately 6000-8000 Da and encompass the potent curaremimetic neurotoxins which confer lethality to Elapidae and Hydrophidae venoms. Bucain was crystallized in two crystal forms by the hanging-drop vapour-diffusion technique in 0.1 M sodium citrate pH 5.6, 15% PEG 4000 and 0.15 M ammonium acetate. Form I crystals belong to the monoclinic system space group C2, with unit-cell parameters a = 93.73, b = 49.02, c = 74.09 A, beta = 111.32 degrees, and diffract to a nominal resolution of 1.61 A. Form II crystals also belong to the space group C2, with unit-cell parameters a = 165.04, b = 49.44, c = 127.60 A, beta = 125.55 degrees, and diffract to a nominal resolution of 2.78 A. The self-rotation function indicates the presence of four and eight molecules in the crystallographic asymmetric unit of the form I and form II crystals, respectively. Attempts to solve these structures by molecular-replacement methods have not been successful and a heavy-atom derivative search has been initiated.
Publisher: Cambridge University Press (CUP)
Date: 30-08-2016
DOI: 10.1017/S0021859616000666
Abstract: Experiments were conducted to determine the effect of lime pre-treatment on the chemical composition and in vitro rumen degradability of date palm leaves (DPL). Lime pre-treatments, with or without oxygen supply, were applied for 1, 2 and 3 weeks at 25 and 40 °C. Lime was neutralized by the Calcium-Capturing-by-Carbonation process. Delignification and in vitro rumen gas production were significantly influenced by duration, temperature and oxygen. At 40 °C, oxygen presence stimulated more delignification and subsequently increased in vitro rumen degradability. Lime pre-treatment with 0·2 g calcium hydroxide (Ca(OH) 2 )/g dry biomass for 3 weeks at 40 °C in the presence of oxygen resulted in a 3-fold increase in gas production after 24 h of incubation, compared with untreated biomass. Lime treatment of DPL with aeration resulted in higher lignin removal and subsequent rumen degradability than without aeration. A techno-economic analysis is needed to select the most efficient and economically feasible pre-treatment procedure.
Publisher: Informa UK Limited
Date: 24-04-2015
Publisher: Public Library of Science (PLoS)
Date: 14-10-2021
DOI: 10.1371/JOURNAL.PONE.0255658
Abstract: This paper explores the evolution of research collaboration networks in the ‘stakeholder theory and management’ (STM) discipline and identifies the longitudinal effect of co-authorship networks on research performance, i.e., research productivity and citation counts. Research articles totaling 6,127 records from 1989 to 2020 were harvested from the Web of Science Database and transformed into bibliometric data using Bibexcel, followed by applying social network analysis to compare and analyze scientific collaboration networks at the author, institution and country levels. This work maps the structure of these networks across three consecutive sub-periods ( t 1 : 1989–1999 t 2 : 2000–2010 t 3 : 2011–2020) and explores the association between authors’ social network properties and their research performance. The results show that authors collaboration network was fragmented all through the periods, however, with an increase in the number and size of cliques. Similar results were observed in the institutional collaboration network but with less fragmentation between institutions reflected by the increase in network density as time passed. The international collaboration had evolved from an uncondensed, fragmented and highly centralized network, to a highly dense and less fragmented network in t 3 . Moreover, a positive association was reported between authors’ research performance and centrality and structural hole measures in t 3 as opposed to ego-density, constraint and tie strength in t 1 . The findings can be used by policy makers to improve collaboration and develop research programs that can enhance several scientific fields. Central authors identified in the networks are better positioned to receive government funding, maximize research outputs and improve research community reputation. Viewed from a network’s perspective, scientists can understand how collaborative relationships influence research performance and consider where to invest their decision and choices.
No related grants have been discovered for Igor Polikarpov.