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1.  Crystal structure determination as part of an undergraduate laboratory experiment: 1′,3′,3′-tri­methyl­spiro­[chromene-2,2′-indoline] and 1′,3′,3′-trimethyl-4-[(E)-(1,3,3-tri­methyl­indolin-2-yl­idene)meth­yl]spiro­[chroman-2,2′-indoline] 
The crystal structures of the title compounds were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between mol­ecular structure and function. 1′,3′,3′-Tri­methyl­spiro­[chromene-2,2′-indoline] is both a photoswitch and thermochromic mol­ecule. Students synthesized it and a bis-indoline adduct and compared the crystallographically determined structures to computed gas-phase models.
The crystal structures of the title compounds, C19H19NO and C31H34N2O, were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between mol­ecular structure and function. 1′,3′,3′-Tri­methyl­spiro­[chromene-2,2′-indoline] is both a photoswitch and thermochromic mol­ecule. Students synthesized it and a bis-indoline adduct and compared the crystallographically determined structures to computed gas-phase models.
PMCID: PMC5095856  PMID: 27840731
crystal structure; spiro­pyran; undergraduate teaching laboratory
2.  Crystal structure of poly[di­chlorido­(μ-2,5-di­carb­oxy­benzene-1,4-di­carboxyl­ato-κ2 O 1:O 4)bis­[μ-4′-(pyridin-3-yl)-4,2′:6′,4′′-terpyridine-κ2 N 1:N 4′]dizinc] 
Both the 2,5-di­carb­oxy­benzene-1,4-di­carboxyl­ate dianions and pyridyl-terpyridine ligands bridge the ZnII atoms, forming a ladder-like polymeric complex.
In the title polymeric ZnII complex, [Zn2(C10H4O8)Cl2(C20H14N4)2]n, the ZnII cations are bridged by both 2,5-di­carb­oxy­benzene-1,4-di­carboxyl­ate dianions and 4′-(pyridin-3-yl)-4,2′:6′,4′′-terpyridine ligands, forming ladder-like polymeric chains propagating along [1-10]. The Cl− anion further coordinates the ZnII cation to complete a distorted tetra­hedral environment. In the 4′-(pyridin-3-yl)-4,2′:6′,4′′-terpyridine ligand, the three sideward pyridine rings are twisted with respect to the central pyridine ring by 39.27 (12), 14.89 (13) and 3.36 (13)°, respectively. In the crystal, classical O—H⋯N hydrogen bonds and weak C—H⋯O and C—H⋯Cl hydrogen bonds link the chains into a three-dimensional supra­molecular architecture. π–π stacking is observed between the pyridine and benzene rings of neighbouring polymeric chains, with a centroid-to-centroid distance of 3.7280 (14) Å.
PMCID: PMC5095857  PMID: 27840732
crystal structure; 4′-(pyridin-3-yl)-4,2′:6′,4′′-terpyridine; zinc(II) complex; coord­ination polymer
3.  Crystal structures of four co-crystals of (E)-1,2-di(pyridin-4-yl)ethene with 4-alk­oxy­benzoic acids: 4-meth­oxy­benzoic acid–(E)-1,2-di(pyridin-4-yl)ethene (2/1), 4-eth­oxy­benzoic acid–(E)-1,2-di(pyridin-4-yl)ethene (2/1), 4-n-propoxybenzoic acid–(E)-1,2-di(pyridin-4-yl)ethene (2/1) and 4-n-but­oxy­benzoic acid–(E)-1,2-di(pyridin-4-yl)ethene (2/1) 
Crystal structures of four co-crystals of (E)-1,2-di(pyridin-4-yl)ethene with 4-alk­oxy­benzoic acids have been determined. Each compound comprises two acid mol­ecules and one base mol­ecule, which are held together by O—H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1 unit.
The crystal structures of four hydrogen-bonded co-crystals of 4-alk­oxy­benzoic acid–(E)-1,2-di(pyridin-4-yl)ethene (2/1), namely, 2C8H8O3·C12H10N2, (I), 2C9H10O3·C12H10N2, (II), 2C10H12O3·C12H10N2, (III) and 2C11H14O3·C12H10N2, (IV), have been determined at 93 K. In compounds (I) and (IV), the asymmetric units are each composed of one 4-alk­oxy­benzoic acid mol­ecule and one half-mol­ecule of (E)-1,2-di(pyridin-4-yl)ethene, which lies on an inversion centre. The asymmetric unit of (II) consists of two crystallographically independent 4-eth­oxy­benzoic acid mol­ecules and one 1,2-di(pyridin-4-yl)ethene mol­ecule. Compound (III) crystallizes in a non-centrosymmetric space group (Pc) and the asymmetric unit comprises four 4-n-propoxybenzoic acid mol­ecules and two (E)-1,2-di(pyridin-4-yl)ethane mol­ecules. In each crystal, the acid and base components are linked by O—H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1 unit of the acid and the base. In (I), (II) and (III), inter­molecular C—H⋯O inter­actions are observed. The 2:1 units of (I) and (II) are linked via C—H⋯O hydrogen bonds, forming tape structures. In (III), the C—H⋯O hydrogen bonds, except for those formed in the units, link the two crystallographically independent 2:1 units. In (IV), no C—H⋯O inter­actions are observed, but π–π and C—H⋯π inter­actions link the units into a column structure.
PMCID: PMC5095858  PMID: 27840733
crystal structure; (E)-1,2-di(pyridin-4-yl)ethene; 4-alk­oxy­benzoic acid; hydrogen-bonded liquid crystal
4.  Crystal structure of 5-butyl­amino-3-methyl-1-(pyridin-2-yl)-1H-pyrazole-4-carbaldehyde obtained from a microwave-assisted reaction using caesium carbonate as catalyst 
The new compound 5-butyl­amino-3-methyl-1-(pyridin-2-yl)-1H-pyrazole-4-carbaldehyde has been synthesized using a microwave-assisted reaction.
The title compound, C14H18N4O, synthesized from an unconventional microwave-assisted method using caesium carbonate as catalyst, has an approximately planar conformation with the pyridyl and pyrazole rings inclined by a dihedral angle of 7.94 (3)°, allowing the formation of an intra­molecular N—H⋯N hydrogen bond. The supra­molecular assembly has a three-dimensional arrangement controlled mainly by weak C—H⋯O and C—H⋯π inter­actions.
PMCID: PMC5095859  PMID: 27840734
crystal structure; pharmaceutical compound; 5-amino­pyrazoles; nucleophilic substitution; hydrogen bonding
5.  Bis(2-amino­pyridine)dibenzoatocobalt(II). Erratum 
Erratum to Acta Cryst. (2006), E62, m1012—m1013.
In the paper by Ju et al. [Acta Cryst. (2006), E62, m1012–m1013], the metal atom was reported incorrectly.
PMCID: PMC5095860
6.  N′-[Bis(benzyl­sulfan­yl)methyl­idene]benzo­hydrazide. Corrigendum 
Erratum to Acta Cryst. (2012), E68, o1640–o1641.
In the paper by Tayamon et al. [Acta Cryst. (2012), E68, o1640–o1641], the chemical name in the title is incorrect.
PMCID: PMC5095861  PMID: 27840735
7.  Crystal structure of 2,4-di-tert-butyl-6-(hy­droxy­methyl)­phenol 
The crystal structure of 2,4-di-tert-butyl-6-hy­droxy­methyl­phenol is presented.
The title compound, C15H24O2, is an example of a phenol-based pendant-arm precursor. In the mol­ecule, the phenol hy­droxy group participates in an intra­molecular O—H⋯O hydrogen bond with the pendant alcohol group, forming an S(6) ring. This ring adopts a half-chair conformation. In the crystal, O—H⋯O hydrogen bonds connect mol­ecules related by the 31 screw axes, forming chains along the c axis. The C—C—O angles for the hy­droxy groups are different as a result of the type of hybridization for the C atoms that are involved in these angles. The C—C—O angle for the phenol hy­droxy group is 119.21 (13)°, while the angle within the pendant alcohol is 111.99 (13)°. The bond length involving the phenolic oxygen is 1.3820 (19) Å, which contrasts with that of the alcoholic oxygen which is 1.447 (2) Å. The former is conjugated with the aromatic ring and so leads to the observed shorter bond length.
PMCID: PMC5095846  PMID: 27840721
crystal structure; O—H⋯O hydrogen bonding; intra- and inter­molecular hydrogen bonding; pendent arm
8.  Crystal structure and Hirshfeld surface analysis of 2-{[2,8-bis­(tri­fluoro­meth­yl)quinolin-4-yl](hy­droxy)meth­yl}piperidin-1-ium 2-hy­droxy-2-phenyl­acetate hemihydrate 
The l-shaped cations in the centrosymmetric title salt are related across a non-crystallographic centre of inversion. In the crystal, hydrogen-bonded layers are linked by π–π and C—H⋯F⋯π inter­actions.
The asymmetric unit of the title salt, C17H17F6N2O+·C8H7O3 −·0.5H2O, comprises a pair of pseudo-enanti­omeric (i.e. related by a non-crystallographic centre of symmetry) piperidin-1-ium cations, two carboxyl­ate anions and a water mol­ecule of crystallization. The cations have similar conformations approximating to a letter, L: one of them shows disorder of its –CF3 group over two sets of sites in a 0.775 (3):0.225 (3) ratio. Distinctive conformations are found for the anions, one with the carboxyl­ate group lying to one side of the plane through the phenyl ring and the other where the oxygen atoms lie to either side of the plane. In the latter, an intra­molecular hy­droxy-O—H⋯O(carboxyl­ate) charge-assisted hydrogen bond is found. The packing features extensive O—H⋯O,N hydrogen bonding, often charge-assisted; C—H⋯π inter­actions are also formed. The hydrogen bonding results in the formation of five distinctive supra­molecular synthons and assembles mol­ecules in the ac plane. The quinolinyl rings lie to either side of the layer and inter-digitate with layers on either side, are approximately parallel to the b axis and are connected by π–π [inter-centroid separation = 3.6904 (18) Å] as well as C—F⋯π(quinolin­yl) inter­actions to consolidate the three-dimensional crystal. The dominance of the conventional hydrogen bonding in the mol­ecular packing is confirmed by an analysis of the Hirshfeld surface.
PMCID: PMC5095847  PMID: 27840722
crystal structure; salt; hydrogen bonding; mefloquine
9.  Crystal structure and Hirshfeld surface analysis of 1-carb­oxy-2-(3,4-di­hydroxy­phen­yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di­hydroxy­phen­yl)propano­ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart 
The crystal structure of new monoclininc polymorph of l-dopa HCl is reported, and hydrogen-bonding inter­actions are discussed.
The title mol­ecular salt, C9H12NO4 +·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841–845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa mol­ecules has a positive charge with a protonated α-amino group and the α-carb­oxy­lic acid group uncharged, while the second dopa mol­ecule has a neutral charge, the α-amino group is protonated and the α-carb­oxy­lic acid is deprotonated. In the previously reported form, a single dopa mol­ecule is observed in which the α-amino group is protonated and the α-carb­oxy­lic acid group is uncharged. The invariant and variations of various types of inter­molecular inter­actions present in these two forms of dopa HCl structures are discussed with the aid of two-dimensional fingerprint plots.
PMCID: PMC5095848  PMID: 27840723
crystal structure; l-dopa; cyclic N—H⋯Cl hydrogen bonds; Hirshfeld surfaces
10.  Crystal structure of di-μ-chlorido-bis­[chlorido­bis­(1,2-dimethyl-5-nitro-1H-imidazole-κN 3)copper(II)] acetonitrile disolvate 
1,2-Dimethyl-5-nitro­imidazole (dimetridazole, dimet) reacts with copper(II) chloride to give dinuclear [Cu(dimet)2(μ-Cl)Cl]2, in which each copper moiety is coordinated to two dimet ligands in a trans arrangement.
1,2-Dimethyl-5-nitro­imidazole (dimetridazole, dimet) is a compound that belongs to a class of nitro­imidazole drugs that are effective at inhibiting the activity of certain parasites and bacteria. However, there are few reports that describe structures of compounds that feature metals complexed by dimet. Therefore, we report here that dimet reacts with CuCl2·H2O to yield a chloride-bridged copper(II) dimer, [Cu2Cl4(C5H7N3O2)4] or [Cu(μ-Cl)Cl(dimet)2]2. In this mol­ecule, the CuII ions are coordinated in an approximately trigonal–bipyramidal manner, and the mol­ecule lies across an inversion center. The dihedral angle between the imidazole rings in the asymmetric unit is 4.28 (7)°. Compared to metronidazole, dimetridazole lacks the hy­droxy­ethyl group, and thus cannot form inter­molecular O⋯H hydrogen-bonding inter­actions. Instead, [Cu(μ-Cl)Cl(dimet)2]2 exhibits weak inter­molecular inter­actions between the hydrogen atoms of C—H groups and (i) oxygen in the nitro groups, and (ii) the terminal and bridging chloride ligands. The unit cell contains four disordered aceto­nitrile mol­ecules. These were modeled as providing a diffuse contribution to the overall scattering by SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18], which identified two voids, each with a volume of 163 Å3 and a count of 46 electrons, indicative of a total of four aceto­nitrile mol­ecules. These aceto­nitrile mol­ecules are included in the chemical formula to give the expected calculated density and F(000).
PMCID: PMC5095849  PMID: 27840724
crystal structure; copper(II); chloride-bridged dimer; dimetridazole; dimet
11.  Crystal structures of 2′-benzoyl-1′-(4-methyl­phenyl)-1,1′,2,2′,5′,6′,7′,7a′-octa­hydro­spiro­[indole-3,3′-pyrrolizin]-2-one and 2′-(4-bromo­benzoyl)-1′-(2-chloro­phen­yl)-1,1′,2,2′,5′,6′,7′,7a′-octa­hydro­spiro­[indole-3,3′-pyrrolizin]-2-one 
The chemical modifications in terms of changes in substituents in the title compounds have not affected the type nor strength of two defining inter­molecular inter­actions present in both crystal structures.
The two title compounds, C28H26N2O2, (I), and C27H22BrClN2O2, (II), differ in their substituents, viz.4-methyl­phenyl and benzoyl rings in (I) replaced by 2-chloro­phenyl and 4- bromo­benzoyl, respectively, in (II). A significant difference between the two mol­ecules is found in the deviation of the benzoyl O atom from the least-squares plane of the ring to which it is attached [0.593 (4) and 0.131 (3) Å, respectively], a fact which may be attributed to the different participation of the benzoyl O atoms as acceptors in their inter­molecular C—H⋯O inter­actions. The chemical modifications in (I) and (II) do not seem to affect the type nor strength of the inter­molecular N—H⋯N and C—H⋯O hydrogen bonds responsible for the two crystal structures, such that the aggregation of mol­ecules appears similar in spite of the mol­ecular changes.
PMCID: PMC5095850  PMID: 27840725
crystal structure; indoline-3,3′-pyrrolizin derivatives; hydrogen bonding
12.  Crystal structure of 9-(di­bromo­meth­yl)-1,1-di­fluoro-3,7-dimethyl-1H-[1,3,5,2]oxadi­aza­borinino[3,4-a][1,8]naphthyridin-11-ium-1-uide 
The mol­ecule in the title compound, C12H10BBr2F2N3O, exhibits point group symmetry m.
The mol­ecule of the title 1,8-naphthyridine-BF2 derivative, C12H10BBr2F2N3O, is located on a mirror plane running parallel to the entire ring system and the attached methyl C atoms. Individual mol­ecules are stacked along the b-axis direction. The cohesion in the crystal structure is accomplished by C—H⋯F hydrogen bonds and additional off-set π–π inter­actions [centroid-to-centroid distance = 3.6392 (9) Å, slippage 0.472 Å], leading to the formation of a three-dimensional supra­molecular network.
PMCID: PMC5095851  PMID: 27840726
crystal structure; 1,8-naphthyridine BF2 complex; hydrogen bonding
13.  Crystal structure of 1,2-bis­(6-bromo-3,4-dihydro-2H-benz[e][1,3]oxazin-3-yl)ethane: a bromine-containing bis-benzoxazine 
The solid-state structure of a 4-bromo­benzoxazine has been determined. The whole mol­ecule of the title compound is generated by inversion symmetry. This is a potential benzoxazine monomer for the preparation of phenolic materials.
The title benzoxazine molecule, C18H18Br2N2O2, was prepared by a Mannich-type reaction of 4-bromo­phenol with ethane-1,2-di­amine and formaldehyde. The title compound crystallizes in the monoclinic space group C2/c with a centre of inversion located at the mid-point of the C—C bond of the central CH2CH2 spacer. The oxazinic ring adopts a half-chair conformation. The structure is compared to those of other functionalized benzoxazines synthesized in our laboratory. In the crystal, weak C—H⋯Br and C—H⋯O hydrogen bonds stack the mol­ecules along the b-axis direction.
PMCID: PMC5095852  PMID: 27840727
crystal structure; benzoxazines; phenolic resins; C—H⋯Br and C—H⋯O hydrogen bonds
14.  Crystal structure of the 1:2 co-crystal of 1,3,6,8-tetra­aza­tri­cyclo­[,8]undecane (TATU) and 4-chloro­phenol (1/2) 
The components of the ternary co-crystalline adduct are linked by inter­molecular O–H⋯N hydrogen bonds.
In the title compound, C7H14N4·2C6H5ClO, which crystallized with two crystallographically independent 4-chloro­phenol mol­ecules and one 1,3,6,8-tetra­aza­tri­cyclo­[,8]undecane (TATU) mol­ecule in the asymmetric unit, the independent components are linked by two O—H⋯N hydrogen bonds. The hydrogen-bond acceptor sites are two non-equivalent N atoms from the aminal cage structure, and the tricyclic system distorts by changing the C—N bond lengths. In the crystal, these hydrogen-bonded aggregates are linked into chains along the c axis by C—H⋯N hydrogen bonds. The crystal structure also features C—H⋯π contacts.
PMCID: PMC5095853  PMID: 27840728
crystal structure; co-crystalline adducts; hydrogen bonding; TATU
15.  Mechanochemical synthesis and crystal structure of a 1:2 co-crystal of 1,3,6,8-tetra­aza­tri­cyclo[,8]undecane (TATU) and 4-chloro-3,5-dimethyl­phenol 
In the crystal, the 1:2 co-crystalline adducts are linked by π–π stacking inter­actions.
Solvent-free treatment of 1,3,6,8-tetra­aza­tri­cyclo­[,8]undecano (TATU) with 4-chloro-3,5-di­methyl­phenol led to the formation of the title co-crystal, C7H14N4·2C8H9ClO. The asymmetric unit contains one aminal cage mol­ecule and two phenol mol­ecules linked via two O—H⋯N hydrogen bonds. In the aminal cage, the N–CH2–CH2–N unit is slightly distorted from a syn periplanar geometry. Aromatic π–π stacking between the benzene rings from two different neighbouring phenol mol­ecules [centroid–centroid distance = 4.0570 (11) Å] consolidates the crystal packing.
PMCID: PMC5095854  PMID: 27840729
crystal structure; mol­ecular co-crystal; mechanochemical synthesis; π–π stacking
16.  Channels with ordered water and bipyridine mol­ecules in the porous coordination polymer {[Cu(SiF6)(C10H8N2)2]·2C10N2H8·5H2O}n  
The structure of a [Cu(SiF6)(C10H8N2)2]n coordination polymer with ordered 4,4′-bi­pyridine and water mol­ecule channels is described.
The coordination polymer {[Cu(SiF6)(C10H8N2)2]·2C10H8N2·5H2O}n, systematic name: poly[[bis­(μ2-4,4′-bi­pyridine)(μ2-hexa­fluorido­silicato)copper(II)] 4,4′-bi­pyridine disolvate penta­hydrate], contains pores which are filled with water and 4,4′-bi­pyridine mol­ecules. As a result of the presence of these ordered species, the framework changes its symmetry from P4/mmm to P21/c. The 4,4′-bi­pyridine guest mol­ecules form chains inside the 6.5 × 6.9 Å pores parallel to [100] in which the mol­ecules inter­act through π–π stacking. Ordered water mol­ecules form infinite hydrogen-bonded chains inside a second pore system (1.6 × 5.3 Å free aperture) perpendicular to the 4,4′-bi­pyridine channels.
PMCID: PMC5095855  PMID: 27840730
Porous coordination polymer; adsorption; hydrogen bonding; π–π stacking; copper(II); 4,4′-bi­pyridine; crystal structure
17.  Chronic Restraint Stress after Injury and Shock is Associated with Persistent Anemia despite Prolonged Elevation in Erythropoietin Levels 
Following severe traumatic injury, critically ill patients have a prolonged hypercatacholamine state that is associated with bone marrow (BM) dysfunction and persistent anemia. However, current animal models of injury and shock result in a transient anemia. Daily restraint stress (CS) has been shown to increase catecholamines. We hypothesize that adding CS following injury or injury and shock in rats will prolong the hypercatecholaminemia, and prolong the initial anemia, despite elevated erythropoietin levels.
Male Sprague-Dawley Rats (N=6–8/group) underwent lung contusion (LC) or combined lung contusion/hemorrhagic shock (LCHS) followed by six days of chronic stress (CS). CS consisted of a two hour restraint period interrupted with repositioning and alarms every 30 minutes. At seven days, urine was assessed for norepinephrine (NE) levels, blood for erythropoietin (EPO) and hemoglobin (Hgb), and BM for erythroid progenitor growth.
Animals undergoing LC or combined LCHS predictably recovered by day seven; urine NE, EPO and Hgb levels were normal. The addition of CS to LC and LCHS models was associated with a significant elevation in NE on day six. The addition of CS to LC led to a persistent 20–25% decrease in the growth of BM HPCs. These findings were further exaggerated when CS was added following LCHS, resulting in a 20–40% reduction in BM erythroid progenitor colony growth and a 20% decrease in Hgb when compared to LCHS alone.
Exposing injured animals to CS results in prolonged elevation of norepinephrine and erythropoietin which is associated with worsening BM erythroid function and persistent anemia. Chronic restraint stress following injury and shock provides a clinically relevant model to further evaluate persistent injury-associated anemia seen in critically ill trauma patients. Furthermore, alleviating chronic stress after severe injury is a potential therapeutic target to improve BM dysfunction and anemia.
PMCID: PMC4902106  PMID: 26091320
18.  What do Women Want? Experiences of Low-Income Women with Postpartum Contraception and Contraceptive Counseling 
Contraceptive counseling can increase postpartum contraception use, yet the optimal method and timing for counseling are unknown. The objective was to investigate preferences of underserved pregnant and postpartum women regarding contraception use and counseling.
Surveys regarding contraception experiences and perceptions of contraceptive counseling were conducted with 57 women age 18 and older who were postpartum or antepartum with a previous delivery within 5 years and receiving Medicaid-funded care at an academic medical center. Health literacy was assessed using REALM-7. Responses were analyzed using descriptive statistics.
A majority of women reported unplanned pregnancies (78%). Women using contraception at the time of conception reported “not sure” (30%) and “taken wrong” (30%) as primary reasons for failure. Most subjects had at least a high school level of health literacy (88%), desired to use a postpartum contraceptive method (92%) and had a high self-reported understanding of that method (94%). Most women reported receiving counseling (91%) and stated that the best time for counseling was both before and after childbirth (84%). However, only 60% of subjects intended to use the method they were prescribed at discharge; reasons for changing included side effects (37%), desire for different contraception (23%) and too complicated of a method prescribed (17%).
Women perceived the best timing of contraceptive education to be both antepartum and postpartum. Despite a high frequency of prior contraceptive failure, self-reported understanding of the chosen postpartum contraceptive method was high. Contraception counseling should be tailored to a woman’s perceived needs, with such education occurring frequently and within the context of her health literacy.
PMCID: PMC4902110  PMID: 27294202
Postpartum contraception; Family planning; Contraceptive decision making; Health literacy; Health disparities
19.  Perceptions of patient provider agreements 
Use of patient provider agreements (PPAs) is increasing, yet there is limited evidence on the effectiveness of PPAs to prevent prescription opioid misuse and diversion, and few guidelines for providers. We conducted eight focus groups to understand patient and prescriber perceptions of PPAs.
We recruited 40 patients who had been asked to sign a PPA and 40 prescribers who had administered at least one PPA. We developed topic guides for the two groups based on prior literature. Focus groups were audio-recorded and transcribed verbatim. Two investigators independently performed the content analysis of the transcripts and reached consensus on recurring themes.
Key findings
PPA use varied according to physician specialty. General practitioners used PPAs the least but reported increasing pressure from liability insurers to use them. Many patients reported signing a PPA in the emergency room of a hospital. Prescribers and patients reported a lack of understanding among patients concerning the purpose and content of the PPA. Prescribers questioned the legal status of the PPA, while patients believed that the PPA was a legal document intended to protect prescribers. Patients and prescribers valued PPA content items differently, although both groups agreed that signing a PPA would not prevent opioid misuse.
We identified several themes concerning the administration, content, effectiveness and utility of PPAs that highlight areas of research to improve PPAs. We also describe trends requiring further investigation. Understanding content of importance to patients will facilitate the development of a patient-centred PPA.
PMCID: PMC4902116  PMID: 27293486
focus group; opioid contract; opioids; patient provider agreement
20.  Self‐Assembly of Disorazole C1 through a One‐Pot Alkyne Metathesis Homodimerization Strategy†  
Alkyne metathesis is increasingly explored as a reliable method to close macrocyclic rings, but there are no prior examples of an alkyne‐metathesis‐based homodimerization approach to natural products. In this approach to the cytotoxic C2‐symmetric marine‐derived bis(lactone) disorazole C1, a highly convergent, modular strategy is employed featuring cyclization through an ambitious one‐pot alkyne cross‐metathesis/ring‐closing metathesis self‐assembly process.
PMCID: PMC4902119  PMID: 27346897
Alkinmetathese; Naturstoffe; Selbstorganisation; Totalsynthese; Zelltoxizität
21.  Flexible White Light Emitting Diodes Based on Nitride Nanowires and Nanophosphors 
ACS Photonics  2016;3(4):597-603.
We report the first demonstration of flexible white phosphor-converted light emitting diodes (LEDs) based on p–n junction core/shell nitride nanowires. GaN nanowires containing seven radial In0.2Ga0.8N/GaN quantum wells were grown by metal–organic chemical vapor deposition on a sapphire substrate by a catalyst-free approach. To fabricate the flexible LED, the nanowires are embedded into a phosphor-doped polymer matrix, peeled off from the growth substrate, and contacted using a flexible and transparent silver nanowire mesh. The electroluminescence of a flexible device presents a cool-white color with a spectral distribution covering a broad spectral range from 400 to 700 nm. Mechanical bending stress down to a curvature radius of 5 mm does not yield any degradation of the LED performance. The maximal measured external quantum efficiency of the white LED is 9.3%, and the wall plug efficiency is 2.4%.
PMCID: PMC4902128  PMID: 27331079
nanowire; flexible; white LED; nitride
22.  Size and Promoter Effects on Stability of Carbon-Nanofiber-Supported Iron-Based Fischer–Tropsch Catalysts 
ACS Catalysis  2016;6(6):4017-4024.
The Fischer–Tropsch Synthesis converts synthesis gas from alternative carbon resources, including natural gas, coal, and biomass, to hydrocarbons used as fuels or chemicals. In particular, iron-based catalysts at elevated temperatures favor the selective production of C2–C4 olefins, which are important building blocks for the chemical industry. Bulk iron catalysts (with promoters) were conventionally used, but these deactivate due to either phase transformation or carbon deposition resulting in disintegration of the catalyst particles. For supported iron catalysts, iron particle growth may result in loss of catalytic activity over time. In this work, the effects of promoters and particle size on the stability of supported iron nanoparticles (initial sizes of 3–9 nm) were investigated at industrially relevant conditions (340 °C, 20 bar, H2/CO = 1). Upon addition of sodium and sulfur promoters to iron nanoparticles supported on carbon nanofibers, initial catalytic activities were high, but substantial deactivation was observed over a period of 100 h. In situ Mössbauer spectroscopy revealed that after 20 h time-on-stream, promoted catalysts attained 100% carbidization, whereas for unpromoted catalysts, this was around 25%. In situ carbon deposition studies were carried out using a tapered element oscillating microbalance (TEOM). No carbon laydown was detected for the unpromoted catalysts, whereas for promoted catalysts, carbon deposition occurred mainly over the first 4 h and thus did not play a pivotal role in deactivation over 100 h. Instead, the loss of catalytic activity coincided with the increase in Fe particle size to 20–50 nm, thereby supporting the proposal that the loss of active Fe surface area was the main cause of deactivation.
PMCID: PMC4902129  PMID: 27330847
Fischer−Tropsch; FTO; iron; lower olefins; synthesis gas; stability; sintering
23.  A step-by-step overview of the dynamic process of epitope selection by major histocompatibility complex class II for presentation to helper T cells 
F1000Research  2016;5:F1000 Faculty Rev-1305.
T cell antigen receptors (TCRs) expressed on cytotoxic or helper T cells can only see their specific target antigen as short sequences of peptides bound to the groove of proteins of major histocompatibility complex (MHC) class I, and class II respectively. In addition to the many steps, several participating proteins, and multiple cellular compartments involved in the processing of antigens, the MHC structure, with its dynamic and flexible groove, has perfectly evolved as the underlying instrument for epitope selection. In this review, I have taken a step-by-step, and rather historical, view to describe antigen processing and determinant selection, as we understand it today, all based on decades of intense research by hundreds of laboratories.
PMCID: PMC4902097  PMID: 27347387
Epitope Mapping; Antigen Processing Machinery; immunodominance
24.  Review of the epidemiology of overactive bladder 
Overactive bladder (OAB) is common in both men and women. It is a symptom complex that causes significant detriment to quality of life in patients. Although the prevalence of OAB is similar in both sexes, there are sex-specific differences in individual symptoms and the impact on quality of life. The coexistence of benign prostatic hyperplasia with OAB can worsen quality of life in men. This review examines the major studies that looked at the epidemiology of OAB as it relates to both sexes. It focuses on both the overall prevalence rates and the incidence of individual symptoms. This paper also addresses the level of bother and quality of life in men and women with OAB. In addition, the relationship between OAB and benign prostatic hyperplasia is reviewed.
PMCID: PMC4902138  PMID: 27350947
overactive bladder; prevalence; sex; LUTS; BPH; quality of life
25.  Stability of tramadol with three 5-HT3 receptor antagonists in polyolefin bags for patient-controlled delivery systems 
Mixing 5-hydroxytryptamine-3 (5-HT3) receptor antagonists with patient-controlled analgesia (PCA) solutions of tramadol has been shown to decrease the incidence of nausea and vomiting associated with the use of tramadol PCA for postoperative pain. However, such mixtures are not commercially available, and the stability of the drug combinations has not been duly studied. The study aimed to evaluate the stability of tramadol with three 5-HT3 receptor antagonists in 0.9% sodium chloride injection for PCA administration.
Materials and methods
Test samples were prepared by adding 1,000 mg tramadol hydrochloride, 8 mg ondansetron hydrochloride, and 6 mg granisetron hydrochloride or 5 mg tropisetron hydrochloride to 100 mL of 0.9% sodium chloride injection in polyolefin bags. The samples were prepared in triplicates, stored at either 25°C or 4°C for 14 days, and assessed using the following compatibility parameters: precipitation, cloudiness, discoloration, and pH. Chemical stability was also determined using a validated high-pressure liquid chromatography method.
All of the mixtures were clear and colorless throughout the initial observation period. No change in the concentration of tramadol hydrochloride occurred with any of the 5-HT3 receptor antagonists during the 14 days. Similarly, little or no loss of the 5-HT3 receptor antagonists occurred over the 14-day period.
Our results suggest that mixtures of tramadol hydrochloride, ondansetron hydrochloride, granisetron hydrochloride, or tropisetron hydrochloride in 0.9% sodium chloride injection were physically and chemically stable for 14 days when stored in polyolefin bags at both 4°C and 25°C.
PMCID: PMC4902139  PMID: 27350741
tramadol; ondansetron; granisetron; tropisetron; postoperative pain; patient-controlled analgesia

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