#CGS2015: An Evaluation of Twitter Use at the Canadian Geriatrics Society Annual Scientific Meeting.

BACKGROUND: Twitter is a microblogging platform increasingly used in medicine to overcome geographic barriers and promote international connections. Tweets, the 280-character microblogs, are catalogued by hashtags (#). This study evaluates and describes the participation, content, and impact of Twitter at the 2015 Canadian Geriatrics Society (CGS) Annual Scientific Meeting, during which #CGS2015 was the official conference hashtag. METHODS: Twitter transcripts of #CGS2015 were obtained from Symplur to prospectively analyze tweets for content and quantitative metrics. TweetReach was used to retrospectively analyze tweets with the hashtag #CGS2014 from the 2014 meeting for growth analysis. The impact of Twitter on the conference experience was derived from questionnaires. RESULTS: There were 1,491 #CGS2015 tweets, 40% of which were original. Tweet content was categorized into conference sessions (38.8%), networking (29.2%), resource sharing (17.6%), and conference promotion (14.3%). Of the 279 participants, 60% were non-Canadian. The questionnaire data from 86 respondents demonstrated generally positive experiences with Twitter, particularly with facilitating collegial interactions, resource sharing, and insight into sessions not attended live. The most cited drawback was divided attention when using personal devices. Analysis comparing #CGS2014 to #CGS2015 demonstrated increases in total participants (50 to 279), number of tweets (434 to 1,491) and impressions (155,600 to 943,825). CONCLUSIONS: Twitter engagement at the CGS 2015 annual meeting enabled international participation in networking, resource sharing, and online discussions of sessions. Future conferences may benefit from a workshop on Twitter basics for attendees and presenters.

#GeriMedJC: The Twitter Complement to the Traditional-Format Geriatric Medicine Journal Club.

Twitter is a public microblogging platform that overcomes physical limitations and allows unrestricted participation beyond academic silos, enabling interactive discussions. Twitter-based journal clubs have demonstrated growth, sustainability, and worldwide communication, using a hashtag (#) to follow participation. This article describes the first year of #GeriMedJC, a monthly 1-hour live, 23-hour asynchronous Twitter-based complement to the traditional-format geriatric medicine journal club. The Twitter moderator tweets from the handle @GeriMedJC; encourages use of #GeriMedJC; and invites content experts, study authors, and followers to participate in critical appraisal of medical literature. Using the hashtag #GeriMedJC, tweets were categorized according to thematic content, relevance to the journal club, and authorship. Third-party analytical tools Symplur and Twitter Analytics were used for growth and effect metrics (number of followers, participants, tweets, retweets, replies, impressions). Qualitative analysis of follower and participant profiles was used to establish country of origin and occupation. A semistructured interview of postgraduate trainees was conducted to ascertain qualitative aspects of the experience. In the first year, @GeriMedJC has grown to 541 followers on six continents. Most followers were physicians (43%), two-thirds of which were geriatricians. Growth metrics increased over 12 months, with a mean of 121 tweets, 25 participants, and 105,831 impressions per journal club. Tweets were most often related to the article being appraised (87.5%) and ranged in thematic content from clinical practice (29%) to critical appraisal (24%) to medical education (20%). #GeriMedJC is a feasible example of using social media platforms such as Twitter to encourage international and interprofessional appraisal of medical literature.

The effect of temperature and pressure on the crystal structure of piperidine.

BACKGROUND: The response of molecular crystal structures to changes in externally applied conditions such as temperature and pressure are the result of a complex balance between strong intramolecular bonding, medium strength intermolecular interactions such as hydrogen bonds, and weaker intermolecular van der Waals contacts. At high pressure the additional thermodynamic requirement to fill space efficiently becomes increasingly important. RESULTS: The crystal structure of piperidine-d11 has been determined at 2 K and at room temperature at pressures between 0.22 and 1.09 GPa. Unit cell dimensions have been determined between 2 and 255 K, and at pressures up to 2.77 GPa at room temperature. All measurements were made using neutron powder diffraction. The crystal structure features chains of molecules formed by NH…N H-bonds with van der Waals interactions between the chains. Although the H-bonds are the strongest intermolecular contacts, the majority of the sublimation enthalpy may be ascribed to weaker but more numerous van der Waals interactions. CONCLUSIONS: Analysis of the thermal expansion data in the light of phonon frequencies determined in periodic DFT calculations indicates that the expansion at very low temperature is governed by external lattice modes, but above 100 K the influence of intramolecular ring-flexing modes also becomes significant. The principal directions of thermal expansion are determined by the sensitivity of different van der Waals interactions to changes in distance. The principal values of the strain developed on application of pressure are similarly oriented to those determined in the variable-temperature study, but more isotropic because of the need to minimise volume by filling interstitial voids at elevated pressure. Graphical AbstractThough H-bonds are important interactions in the crystal structure of piperidine, the response to externally-applied conditions are determined by van der Waals interactions.

A new synthesis of charge-neutral tris-pyrazolyl and -methimazolyl borate ligands.

The dimethylamine in the adducts [(HNMe(2))B(azolyl)(3)] (azolyl=methimazolyl, pyrazolyl), obtained by reaction of the azole with B(NMe(2))(3), can readily be substituted with a range of nitrogen donors to provide new charge-neutral, tripodal ligands in high yield. This observation has led to a revision of an earlier interpretation of the mechanism of the formation of these species. The donor properties of the ligands [(nmi)B(azolyl)(3)] (nmi=N-methylimidazole) have been compared with their anionic analogues [HB(azolyl)(3)](-) by synthesis of their manganese(I)-tricarbonyl complexes and comparison of their infrared nu(CO) energies. This comparison indicates that the new neutral ligands are only marginally weaker donors than the corresponding anionic hydrotris(azolyl)borate ligands. This may be explained by the ability of the attached nmi ring to stabilize a positive charge remotely from the coordinated metal, which may also account for the fact that the [(nmi)B(pyrazolyl)(3)] ligand is a substantially stronger donor than the similarly neutral tris(pyrazolyl)methane ligand.

Oxovanadium(IV) cyclam and bicyclam complexes: potential CXCR4 receptor antagonists.

Metal complexation can have a major influence on the antiviral and coreceptor binding properties of cyclam and bicyclam macrocycles. We report the synthesis of the vanadyl cyclam complexes [V((IV))O(cyclam)SO(4)] (1) and [V((IV))O(cyclam)Cl]Cl (2) and the analogous xylylbicyclam sulfato (3) and chlorido (4) complexes. The X-ray crystal structures of 1.1.33CH(3)OH and 2.CH(3)OH.1.5H(2)O show short V=O bonds (1.6093(19) and 1.599(3) A, respectively) with monodentate sulfate H-bonded to ring NH groups for 1, but a long V-Cl bond (2.650(12) A) for 2. The solid-state structures of 3 and 4 were compared to those of 1 and 2 using vanadium K-edge extended X-ray absorption fine structure (EXAFS) data. These suggested that complex 4 was oligomeric and contained bridging chlorido ligands. Electron paramagnetic resonance (EPR) studies suggested that the SO(4)(2-) (from 1) and Cl(-) (from 2) ligands are readily substituted by water in solution, whereas these remain partially bound for the V(IV) xylylbicyclam complexes 3 and 4. The vanadyl xylylbicyclam complexes were highly active against HIV-1 (III(B)) and HIV-2 (ROD) strains with IC(50) values in the range 1-5 microM for 3 and 0.1-0.3 microM for 4; in contrast the vanadyl cyclam complexes 1 and 2 were inactive. The factors that contribute to the activity of these complexes are discussed. Studies of vanadyl cyclam docked into a model of the human CXCR4 coreceptor revealed that the coordination of vanadium to the carboxylate of Asp171 may be accompanied by H-bonding to the macrocycle and an attractive V=O...H interaction involving the backbone Trp195 alpha-carbon proton of CXCR4. In addition, hydrophobic interactions with Trp195 are present. Both ring configuration and the xylyl linker may play roles in determining the higher activity of the bicyclam complexes.

Polymetallic clusters of iron(III) with derivatised salicylaldoximes.

The synthesis and magnetic properties of the compounds [HNEt(3)][Fe(2)(OMe)(Ph-sao)(2) (Ph-saoH)(2)].5MeOH (1.5MeOH), [Fe(3)O(Et-sao)(O(2)CPh)(5)(MeOH)(2)].3MeOH (2.3MeOH), [Fe(4)(Me-sao)(4)(Me-saoH)(4)] (3), [HNEt(3)](2)[Fe(6)O(2)(Me-sao)(4)(SO(4))(2)(OMe)(4)(MeOH)(2)] (4), [Fe(8)O(3)(Me-sao)(3)(tea)(teaH)(3)(O(2)CMe)(3)] (5), [Fe(8)O(3)(Et-sao)(3)(tea)(teaH)(3)(O(2)CMe)(3)] (6), and [Fe(8)O(3)(Ph-sao)(3)(tea)(teaH)(3)(O(2)CMe)(3)] (7) are reported (Me-saoH(2) is 2'-hydroxyacetophenone oxime, Et-saoH(2) is 2'-hydroxypropiophenone oxime and Ph-saoH(2) is 2-hydroxybenzophenone oxime). 1-7 are the first Fe(III) compounds synthesised using the derivatised salicylaldoxime ligands, R-saoH(2). 1 is prepared by treatment of Fe(2)(SO(4))(3).6H(2)O with Ph-saoH(2) in the presence of NEt(3) in MeOH; 2 prepared by treatment of Fe(ClO(4))(2).6H(2)O with Et-saoH(2) and NaO(2)CPh in the presence of NEt(4)OH in MeOH; 3 prepared by treatment of Fe(ClO(4))(2).6H(2)O with Me-saoH(2) and NaO(2)CCMe(3) in the presence of NEt(4)OH in MeOH; and 4 prepared by treatment of Fe(2)(SO(4))(3).6H(2)O with Me-saoH(2) in the presence of NEt(3) in MeOH. 4 is a rare example of a polynuclear iron complex containing a coordinated SO(4)(2-) ion. Compounds 5-7 are prepared by treatment of Fe(O(2)CMe)(2) with Me-saoH(2) (5), Et-saoH(2) (6), Ph-saoH(2) (7) in the presence of H(3)tea (triethanolamine) in MeOH, and represent the largest nuclearity Fe(III) clusters containing salicyladoxime-based ligands, joining a surprisingly small family of characterised octanuclear Fe complexes. Variable temperature magnetic susceptibilty measurements of 1, 3 and 5-7 reveal all five complexes possess S = 0 spin ground states; 2 possesses an S = 1/2 spin ground state, while 4 has an S = 4 +/- 1 spin ground state.

Two frustrated, bitetrahedral single-molecule magnets.

Two unusual mixed-valent {MnIII6MnII} bitetrahedra display frustrated magnetic exchange, leading to S = 13/2 +/- 1 and 11/2 +/- 1 ground states and slow magnetization relaxation.

A family of [Mn6] complexes featuring tripodal ligands.

The synthesis and magnetic properties of four new Mn complexes containing tripodal alcohol ligands are reported: [Mn6(OAc)6(H2tea)2(tmp)2].2MeCN (1.2MeCN), [Mn6(acac)4(OAc)2(Htmp)2(H2N-ep)2] (2), [Mn6(OAc)8(tmp)2(py)4].2py (3.2py), and [Mn6(OAc)8(thme)2(py)4].2py (4.2py) [H3tea, triethanolamine; H3tmp, 1,1,1-tris(hydroxymethyl)propane; H2N-H2ep, 2-amino-2-ethyl-1,3-propanediol; H3thme, 1,1,1-tris(hydroxymethyl)ethane]. All complexes are mixed-valent with a [Mn(III)2Mn(II)4] oxidation assignment and are constructed from four edge-sharing triangles but differ slightly in that complexes 1 and 2 display a [Mn(III)2Mn(II)4(mu2-OR)6(mu3-OR)4]4+ core, while complexes 3 and 4 feature [Mn(III)2Mn(II)4(mu2-OR)2(mu3-OR)4]8+ and [Mn(III)2Mn(II)4(mu2-OR)4(mu3-OR)4]6+ cores, respectively. dc and ac magnetic susceptibility studies in the 2-300 K range for complexes 1-4 reveal the presence of dominant antiferromagnetic exchange interactions, leading to ground states of S = 0 for 1 and 2, while complexes 3 and 4 display S = 4 ground states with D = -0.44 and -0.58 cm(-1), respectively. Single-molecule magnetism behavior was confirmed for 3 and 4 by the presence of sweep-rate and temperature-dependent hysteresis loops in single-crystal M vs H studies at temperatures down to 40 mK. Theoretical density functional calculations were used to evaluate the individual pairwise exchange interactions present, confirming the diamagnetic ground states for 1 and 2 and the S = 4 ground states for 3 and 4.