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Early‐career investigator special issue
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science
Yazar(lar) :
Nathaniel A. Lynd , Jian Qin
Yıl :
2021
Nathaniel A. Lynd
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DOI : 10.1002/pol.20210769
ISSN: 2642-4150
Sayı: 21
Cilt: 59
Sayfa: 2364-2364
2
Optimization of the Gal4-UAS system in an Anopheles gambiae cell line
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Insect Molecular Biology
Yazar(lar) :
A. Lynd , G. J. Lycett
Konu :
Insect Science, Genetics, Molecular Biology
Yıl :
2011
A. Lynd
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The development of the bipartite Gal4‐UAS system in Anopheles gambiae would improve the functional characterization of genes in this important malaria vector. Towards this aim, we used Gal4 driver plasmids to successfully activate expression of the reporter gene, luciferase, from UAS responder plasmids when cotransfected into an An. gambiae cell line. To optimize Gal4‐regulated gene expression in mosquitoes, we compared the efficiency of a series of alternative Gal4 transactivators to drive reporter gene expression from responder plasmids incorporating different numbers of tandemly arrayed Gal4 binding sites or upstream activation sequences (UAS). The results indicated that the native Gal4 is only weakly active in these cells. Modified forms of Gal4, including those carrying minimal VP16 activation domains, as well as a deleted form of Gal4, give up to 20‐fold greater activity than the native protein, when used in conjunction with a responder plasmid having 14 UAS repeats. The identification of Gal4‐UAS vectors that are efficiently expressed in a mosquito cell line should facilitate the transfer of this versatile expression system to An. gambiae, and potentially to other insects of medical importance.
DOI : 10.1111/j.1365-2583.2011.01090.x
ISSN: 0962-1075
Sayı: 5
Cilt: 20
Sayfa: 599-608
3
ChemInform Abstract: A STEREOSELECTIVE SYNTHESIS OF TRANS-α,β-UNSATURATED ESTERS VIA HYDROALUMINATION OF 1-ALKYNES
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Chemischer Informationsdienst
Yazar(lar) :
G. ZWEIFEL , R. A. LYND
Yıl :
1976
A. LYND
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DOI : 10.1002/chin.197651131
ISSN: 0009-2975
Sayı: 51
Cilt: 7
Sayfa: no-no
4
ChemInform Abstract: ALLYLATION OF VINYLALANES, A CONVENIENT SYNTHESIS OF ISOMERICALLY PURE TRANS-1,4-DIENES
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Chemischer Informationsdienst
Yazar(lar) :
R. A. LYND , G. ZWEIFEL
Yıl :
1975
A. LYND
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DOI : 10.1002/chin.197502205
ISSN: 0009-2975
Sayı: 2
Cilt: 6
Sayfa: no-no
5
ChemInform Abstract: A STEREOSELECTIVE SYNTHESIS OF TRANS-ALLYL ETHYL ETHERS FROM 1-ALKYNES
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Chemischer Informationsdienst
Yazar(lar) :
G. ZWEIFEL , R. A. LYND
Yıl :
1977
A. LYND
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Kaydet Alıntıla
DOI : 10.1002/chin.197711140
ISSN: 0009-2975
Sayı: 11
Cilt: 8
Sayfa: no-no
6
Polydispersity and block copolymer self-assembly
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Progress in Polymer Science
Yayıncı:
Elsevier
Yazar(lar) :
Nathaniel A. Lynd , Adam J. Meuler , Marc A. Hillmyer
Yıl :
2008
Nathaniel A. Lynd
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Block copolymers consist of two or more chemically distinct polymers that are covalently bound. These materials self-assemble into fascinating mesostructures with features on the nanometer length scale and have been the subject of intense research interest for about four decades. These efforts have generally focused on model block copolymer systems where the molecular weight distributions of all blocks are very narrow. Traditionally, many block copolymer systems have been prepared by living anionic polymerization and thus usually exhibit narrow molecular weight distributions in all blocks. Therefore, the assumption of monodisperse blocks that greatly simplifies theoretical work is on solid experimental ground. Preparation of block copolymers with relatively broad molecular weight distributions in one or more block has become increasingly common, however, as use of synthetic techniques such as controlled radical polymerization has proliferated. Advances in these techniques have increased the number of monomers readily incorporated into block copolymers and potentially will drive commercial costs down. These polymerization strategies often, however, result in broader molecular weight distributions than are typically obtained using living anionic, cationic, or metal-catalyzed techniques; understanding polydispersity effects should aid deployment of these block copolymers in advanced materials applications. This review describes both theoretical and experimental investigations of the effects of polydispersity on the melt-phase morphological behavior of block copolymers. The summary includes research efforts focused on both continuous molecular weight distributions and multicomponent blends. The review concludes with a summary and outlook on the potential utility of polydispersity as a tool to tune the morphological behavior of block copolymers.
DOI : 10.1016/j.progpolymsci.2008.07.003
Anahtar Kelimeler : Polydispersity, Block copolymers, Self-assembly
ISSN: 0079-6700
Sayı: 9
Cilt: 33
Sayfa: 875-893
Sınıflandırma :
7
The Anopheles gambiae alpha-tubulin-1b promoter directs neuronal, testes and developing imaginal tissue specific expression and is a sensitive enhancer detector
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Insect Molecular Biology
Yazar(lar) :
G. J. Lycett , D. Amenya , A. Lynd
Konu :
Insect Science, Genetics, Molecular Biology
Yıl :
2011
A. Lynd
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A knowledge gap in mosquito functional genetic analysis is the dearth of characterized regulatory regions that can target tissue specific transgene expression. To broaden the tools available, a promoter region of the Anopheles gambiaeα‐tubulin1b gene has been assayed following fusion to the green fluorescent protein (GFP) reporter gene and stable transformation of An. gambiae. In eight transgenic lines, the Angtub α1b regulatory region directed a core profile of tissue specific expression in the head, chordotonal organs, ventral nerve cord and testes. This profile overlaps those seen for α2‐tubulin expression in Drosophila melanogaster and Bombyx mori. In addition, widespread position dependant expression was observed in other specific tissues that were unique to each line. For example, in different lines, expression was observed in larval and adult muscles, fatbody, cuticle and midgut secretory cells. The majority of genomic transgene insertions were mapped to within 10 kb of a gene, suggesting that the Angtub α1b basal promoter is particularly sensitive to enhancers and may be suitable to form the basis of a sensitive enhancer trapping construct, in combination with a binary expression system such as Gal4‐UAS.
DOI : 10.1111/j.1365-2583.2011.01112.x
ISSN: 0962-1075
Sayı: 1
Cilt: 21
Sayfa: 79-88
8
Monitoring multicomponent transport using in situ ATR FTIR spectroscopy
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Journal of Membrane Science
Yayıncı:
Elsevier
Yazar(lar) :
Bryan S. Beckingham , Nathaniel A. Lynd , Daniel J. Miller
Yıl :
2018
Nathaniel A. Lynd
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Membranes are a critical component of many energy generation and storage technologies, including artificial photosynthesis systems that reduce atmospheric CO2 to high-value products. In this study, we used in situ ATR FTIR spectroscopy to monitor the crossover of three commonly-reported CO2 reduction products—methanol, sodium formate, and sodium acetate—through Nafion® 117, a common cation exchange membrane. Measurement errors for the permeation of mixtures of solutes are discussed. Permeabilities from one-, two-, and three-solute mixed aqueous solutions were measured using a standard diffusion cell, and ATR FTIR spectra were used to obtain time-resolved concentration data that were fit to a model describing transport of ions and small molecules through hydrated polymer films. The permeability of Nafion® 117 to methanol measured using this methodology was in agreement with literature reports. The sorption of methanol, sodium formate, and sodium acetate, and mixtures thereof, were measured using a desorption technique. From the measured permeabilities and solubilities, diffusivities of each solute were calculated. Differences in permeability among the solutes were found to be primarily due to differences in their solubility in Nafion® 117.
DOI : 10.1016/j.memsci.2017.12.072
Anahtar Kelimeler : Permeability, Multicomponent transport, Artificial photosynthesis, In situ ATR FTIR spectroscopy
ISSN: 0376-7388
Cilt: 550
Sayfa: 348-356
Sınıflandırma :
9
Sequence-Dependent Peptide Surface Functionalization of Metal-Organic Frameworks.
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
PubMed
Dergi:
ACS Appl Mater Interfaces
Yazar(lar) :
Gang Fan , Christopher M Dundas , Cheng Zhang , Nathaniel A Lynd , Benjamin K Keitz
Yıl :
2018
Nathaniel A Lynd
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 Piri Tam Metin Bulucu
Kaydet Alıntıla
We report a noncovalent surface functionalization technique for water-stable metal-organic frameworks using short peptide sequences identified via phage display. Specific frameworks-binding peptides were identified for crystalline Zn(MeIM)2 (MeIM: 2-methylimidazole, ZIF-8), semiamorphous Fe-BTC (BTC: 1,3,5-benzene-tricarboxylate), and Al(OH)(C4H2O4) (MIL-53(Al)-FA, FA: fumaric acid), and their thermodynamic binding affinities and specificities were measured. Electron microscopy, powder X-ray diffraction, and gas adsorption analysis confirmed that the peptide-functionalized frameworks retained similar characteristics compared to their as-synthesized counterparts. Confocal laser-scanning microscopy demonstrated that peptide was localized on the surface of the frameworks, whereas surface area measurements showed no evidence of pore blockage. Finally, we measured the pH-dependent release of fluorescein from peptide-functionalized frameworks and discovered that peptide binding can attenuate fluorescein release by improving framework stability under low pH conditions. Our results demonstrate that phage display can be used as a general method to identify specific peptide sequences with strong binding affinity to water-stable metal-organic frameworks and that these peptides can alter drug release kinetics by affecting framework stability in aqueous environments.
DOI : 10.1021/acsami.8b05148
Anahtar Kelimeler : metal−organic frameworks, peptides, phage display and drug delivery, surface functionalization
Sınıflandırma :
Kimya %97
10
ChemInform Abstract: A STEREOSELECTIVE SYNTHESIS OF SYMMETRICALLY SUBSTITUTED TRANS-ENYNES FROM CONJUGATED DIYNES
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Chemischer Informationsdienst
Yazar(lar) :
G. ZWEIFEL , R. A. LYND , R. E. MURRAY
Yıl :
1977
A. LYND
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Kaydet Alıntıla
DOI : 10.1002/chin.197718156
ISSN: 0009-2975
Sayı: 18
Cilt: 8
Sayfa: no-no
11
A Stereoselective Synthesis of trans-α,β-Unsaturated Esters via Hydroalumination of 1-Alkynes
Dergi Makalesi

Dergi Makalesi
Kaynak :
JSTOR
Dergi:
Synthesis
Yayıncı:
Thieme Publishing Group
Yazar(lar) :
George ZWEIFEL* , Richard A. LYND
Yıl :
1976
Richard A. LYND
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
DOI : 10.1055/s-1976-24148
Cilt: 1976
Sayı: 9
Sayfa: 625-626
Yayın Tarihi: 1976-01-01
12
Shewanella oneidensis as a living electrode for controlled radical polymerization.
Dergi Makalesi

Dergi Makalesi
Open Access
Kaynak :
PubMed
Dergi:
Proc. Natl. Acad. Sci. U.S.A.
Yazar(lar) :
Gang Fan , Christopher M Dundas , Austin J Graham , Nathaniel A Lynd , Benjamin K Keitz
Konu :
Bacterial Proteins, Catalysis, Electrodes, Electron Transport, Electrons, Gene Expression Regulation, Bacterial, Metabolic Engineering, Metabolic Networks and Pathways, Oxidation-Reduction, Polymerization, Shewanella
Yıl :
2018
Nathaniel A Lynd
Piri Tam Metin Bulucu
Kaydet Alıntıla
Metabolic engineering has facilitated the production of pharmaceuticals, fuels, and soft materials but is generally limited to optimizing well-defined metabolic pathways. We hypothesized that the reaction space available to metabolic engineering could be expanded by coupling extracellular electron transfer to the performance of an exogenous redox-active metal catalyst. Here we demonstrate that the electroactive bacterium Shewanella oneidensis can control the activity of a copper catalyst in atom-transfer radical polymerization (ATRP) via extracellular electron transfer. Using S. oneidensis, we achieved precise control over the molecular weight and polydispersity of a bioorthogonal polymer while similar organisms, such as Escherichia coli, showed no significant activity. We found that catalyst performance was a strong function of bacterial metabolism and specific electron transport proteins, both of which offer potential biological targets for future applications. Overall, our results suggest that manipulating extracellular electron transport pathways may be a general strategy for incorporating organometallic catalysis into the repertoire of metabolically controlled transformations.
DOI : 10.1073/pnas.1800869115
Anahtar Kelimeler : extracellular electron transport, metabolic engineering, polymerization
Sınıflandırma :
13
Aerobic radical polymerization mediated by microbial metabolism
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Nature
Dergi:
Nature Chemistry
Yayıncı:
Springer Nature
Yazar(lar) :
Gang Fan , Austin J. Graham , Jayaker Kolli , Nathaniel A. Lynd , Benjamin K. Keitz
Konu :
Biochemistry, Biotechnology, Microbiology, Polymer synthesis, Polymerization mechanisms
Yıl :
2020
Nathaniel A. Lynd
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Performing radical polymerizations under ambient conditions is a major challenge because molecular oxygen is an effective radical quencher. Here we show that the facultative electrogen Shewanella oneidensis can control metal-catalysed living radical polymerizations under apparent aerobic conditions by first consuming dissolved oxygen via aerobic respiration, and then directing extracellular electron flux to a metal catalyst. In both open and closed containers, S. oneidensis enabled living radical polymerizations without requiring the preremoval of oxygen. Polymerization activity was closely tied to S. oneidensis anaerobic metabolism through specific extracellular electron transfer proteins and was effective for a variety of monomers using low (parts per million) concentrations of metal catalysts. Finally, polymerizations survived repeated challenges of oxygen exposure and could be initiated using lyophilized or spent (recycled) cells. Overall, our results demonstrate how the unique ability of S. oneidensis to use both oxygen and metals as respiratory electron acceptors can be leveraged to address salient challenges in polymer synthesis.





Oxygen is a potent inhibitor of radical polymerization reactions, but the facultative bacterium Shewanella oneidensis has now been shown to facilitate aerobic radical polymerizations by first consuming dissolved oxygen and then directing extracellular electron flux to a metal catalyst. Aerobic polymerization activity is dependent on the S. oneidensis genotype and can be initiated using lyophilized or spent cells.
DOI : 10.1038/s41557-020-0460-1
ISSN: 1755-4349
Cilt: 12
Sayı: 7
Sayfa: 638-646
Sınıflandırma :
14
The role of polydispersity in the lamellar mesophase of model diblock copolymers
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science Part B: Polymer Physics
Yazar(lar) :
Nathaniel A. Lynd , Benjamin D. Hamilton , Marc A. Hillmyer
Konu :
Physical and Theoretical Chemistry, Materials Chemistry, Polymers and Plastics, Condensed Matter Physics
Yıl :
2007
Nathaniel A. Lynd
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High‐resolution small angle X‐ray scattering (SAXS) measurements were performed on two series of poly(ethylene‐alt‐propylene)‐b‐poly(D,L‐lactide) (PEP‐PLA) diblock copolymer materials exhibiting differences in the widths of the poly(D,L‐lactide) block molecular mass distributions as measured by their polydispersity indices (PDIPLA). At symmetric compositions of PEP‐PLA (fPLA ≈ 0.5), all SAXS data were successfully fit to an established model describing the small angle scattering from lamellar mesostructures. According to this model, the increase in the PDIPLA negligibly affected the amount of lattice disorder. The apparent asymmetry of the poly(ethylene‐alt‐propylene)‐block lamellae (ϕ), also determined by the fitting procedure, were more substantially affected; increasing the PDIPLA resulted in a decrease in ϕ. At asymmetric compositions of PEP‐PLA (fPLA ≈ 0.67), only the data at the highest values of the PDIPLA could be reasonably fit to this model. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3386–3393, 2007
DOI : 10.1002/polb.21321
ISSN: 0887-6266
Sayı: 24
Cilt: 45
Sayfa: 3386-3393
15
Allylation of Vinylalanes. A Convenient Synthesis of Isomerically Pure trans-1,4-Dienes
Dergi Makalesi

Dergi Makalesi
Kaynak :
JSTOR
Dergi:
Synthesis
Yayıncı:
Thieme Publishing Group
Yazar(lar) :
George ZWEIFEL , Richard A. LYND*
Yıl :
1974
Richard A. LYND*
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
DOI : 10.1055/s-1974-23393
Cilt: 1974
Sayı: 9
Sayfa: 658-659
Yayın Tarihi: 1974-01-01
16
A Stereoselective Synthesis of trans-Allyl Ethyl Ethers from 1-Alkynes
Dergi Makalesi

Dergi Makalesi
Kaynak :
JSTOR
Dergi:
Synthesis
Yayıncı:
Thieme Publishing Group
Yazar(lar) :
George ZWEIFEL* , Richard A. LYND
Yıl :
1976
Richard A. LYND
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
DOI : 10.1055/s-1976-24218
Cilt: 1976
Sayı: 12
Sayfa: 816-817
Yayın Tarihi: 1976-01-01
17
Factors affecting the complexity of dental implant restoration – what is the current evidence and guidance?
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Nature
Dergi:
British Dental Journal
Yayıncı:
Springer Nature
Yazar(lar) :
S. P. Wright , J. Hayden , J. A. Lynd , K. Walker-Finch , J. Willett , C. Ucer , S. D. Speechley
Konu :
Dental implants, Restorative dentistry
Yıl :
2016
A. Lynd
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Kaydet Alıntıla
Objectives The aim of this paper is to identify the factors that affect the complexity of implant restoration and to explore the indices that help us to assess it. With this knowledge the growing number of clinicians restoring dental implants will have a better understanding of the available guidance and evidence base, and the differing levels of competence required. Study design A literature review was conducted. The selection of publications reporting on complexity was based on predetermined criteria and was agreed upon by the authors. After title and abstract screening 17 articles were reviewed. The articles that were utilised to form the ITI SAC tool and Cologne Risk Assessment we also included. Assessing complexity Two key guides are available: International Team for Implantology's Straight-forward Advanced Complex tool4 and the Cologne ABC risk score.5 While these guides help identify treatment complexity they do not provide a strong enough evidence base from which to solely base clinical decisions. The key patient factors are expectation, communication, the oral environment, aesthetic outcome, occlusion, soft tissue profile and the intra-arch distance, whereas the key technical factors are impression taking, type of retention, loading protocol and the need for provisional restorations. Human factors also have a significant effect on complexity, specifically, the experience and training of the clinician, team communication and the work environment. Conclusions There are many interconnecting factors that affect the complexity of dental implant restoration. Furthermore the two widely used indices for the assessment of complexity have been investigated, and although these offer a good guideline as to the level of complexity, there is a lack evidence to support their use. The development of evidence-based treatment and protocols is necessary to develop the current indices further, and these need to be expanded to include other critical areas, such as human factors. A practical guide to aid practitioners in reducing complexity has been proposed.
DOI : 10.1038/sj.bdj.2016.855
ISSN: 1476-5373
Cilt: 221
Sayı: 10
Sayfa: 615-622
Sınıflandırma :
18
Controlled co-solvent vapor annealing and the importance of quenching conditions in thin-film block copolymer self-assembly
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science Part B: Polymer Physics
Yazar(lar) :
Brian C. Stahl , Edward J. Kramer , Craig J. Hawker , Nathaniel A. Lynd
Yıl :
2017
Nathaniel A. Lynd
Yayıncı Web Sitesi
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Kaydet Alıntıla
A controlled co‐solvent vapor annealing system was designed and constructed to investigate the effects of solvent vapor activity during the rapid ambient quenching process on the morphology of a cylinder‐forming poly(styrene)‐b‐poly (ethylene oxide) (PS‐PEO) annealed in toluene and water vapor. A phase transformation from cylinders in the bulk to close‐packed spheres in swollen thin films occurred, which was reversed upon quenching with dry nitrogen. Quenching with humidified nitrogen preserved the spherical morphology but could significantly alter domain spacing and reduce long‐range order in the dried films under some circumstances. Specifically, long‐range order in the quenched films was found to decrease as the quenching humidity decreased from the humidity used during annealing, and the best long‐range order was obtained when the humidity remained consistent throughout both annealing and quenching. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1125–1130
DOI : 10.1002/polb.24366
ISSN: 0887-6266
Sayı: 15
Cilt: 55
Sayfa: 1125-1130
19
Thermally cross-linked diaminophenylindane (DAPI) containing polyimides for membrane based gas separations
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Polymer
Yayıncı:
Elsevier
Yazar(lar) :
Michelle E. Dose , Malgorzata Chwatko , Ivo Hubacek , Nathaniel A. Lynd , Donald R. Paul , Benny D. Freeman
Yıl :
2019
Nathaniel A. Lynd
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Kaydet Alıntıla
This study aims to expand structure-property relationships of diaminophenylindane (DAPI)-containing polyimides and the influence of thermal cross-linking on gas transport properties of such materials. A polyimide synthesized from hexafluoroisopropylidene diphthalic anhydride (6FDA), DAPI, and diaminobenzoic acid (DABA) in a molar ratio of 0.5/0.33/0.17, 6FDA0.5-DAPI0.33/DABA0.17, was crosslinked by thermal decarboxylation. After cross-linking, pure gas permeability of 6FDA0.5-DAPI0.33/DABA0.17 increased with increased cross-linking time; gas permeability increased by about 30% after cross-linking at 353 °C for 40 min. This increase in permeability correlated with an increase in d-spacing measured by wide angle x-ray scattering, suggesting an increase in inter-chain spacing upon cross-linking. Minimal changes in O2/N2 and N2/CH4 selectivities occurred with increased thermal cross-linking time for 6FDA0.5-DAPI0.33/DABA0.17. However, CO2/CH4 and C2H4/C2H6 pure gas selectivities increased with thermal treatment, suggesting a potential narrowing of free volume distribution.
DOI : 10.1016/j.polymer.2018.11.050
Anahtar Kelimeler : Diaminophenylindane (DAPI), Polyimides, Thermal decarboxylation, Cross-linking, Pure gas permeability
ISSN: 0032-3861
Cilt: 161
Sayfa: 16-26
Sınıflandırma :
20
Boric acid removal with polyol-functionalized polyether membranes
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Journal of Membrane Science
Yayıncı:
Elsevier BV
Yazar(lar) :
Matthew R. Landsman , Frederick Rivers , Benjamin J. Pedretti , Benny D. Freeman , Desmond F. Lawler , Nathaniel A. Lynd , Lynn E. Katz
Yıl :
2021
Nathaniel A. Lynd
Yayıncı Web Sitesi
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Kaydet Alıntıla
Poor selectivity of conventional desalination membranes for boron often necessitates multi-stage treatment trains to achieve desired boron removal for end uses such as irrigation. One approach to membrane design for improved single-pass boric acid removal is via incorporation of chelating ligands that selectively sorb boron. In this study, membranes based on epoxy-amine cross-linked poly(glycidyl glycidyl ether) (PGGE) were synthesized and functionalized with N-methyl-d-glucamine (NMDG), a polyol known to interact selectively with boron. PGGE and PGGE-NMDG membranes exhibited boron sorption isotherms that were well-described by dual mode isotherms. PGGE-NMDG sorbed 2.5 mmol B/g dry polymer from a neutral aqueous solution containing 100 mmol B/L, which was almost three times the adsorption density of a commercial boron selective resin, Amberlite IRA743. The membranes were regenerated in acid without a significant loss of boron sorption capacity over four cycles. Interactions between boron and NMDG and PGGE sites (e.g., epoxides) impacted boron diffusion in both membranes. The use of ligand functionalized membranes to capture target solutes such as boron requires high loading of interacting sites to maximize uptake capacity. Establishing fundamental structure/property rules for boron selectivity could lead to new material designs with improved boron separation properties for water purification.
DOI : 10.1016/j.memsci.2021.119690
Anahtar Kelimeler : Poly(allyl glycidyl ether), N-methyl-d-glucamine, Boron, Water reuse, Selective capture
ISSN: 0376-7388
Cilt: 638
Sayfa: 119690
21
A Stereoselective Synthesis of Symmetrically Substituted trans-Enynes from Conjugated Diynes
Dergi Makalesi

Dergi Makalesi
Kaynak :
JSTOR
Dergi:
Synthesis
Yayıncı:
Thieme Publishing Group
Yazar(lar) :
George ZWEIFEL* , Richard A. LYND , Rex E. MURRAY
Yıl :
1977
Richard A. LYND
Yayıncı Web Sitesi
 Piri Tam Metin Bulucu
Kaydet Alıntıla
DOI : 10.1055/s-1977-24274
Cilt: 1977
Sayı: 1
Sayfa: 52-53
Yayın Tarihi: 1977-01-01
22
Controlling the polysulfide diffusion in lithium-sulfur batteries with a polymer membrane with intrinsic nanoporosity
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Dergi:
Materials Today Energy
Yayıncı:
Elsevier
Yazar(lar) :
Xingwen Yu , Sinan Feng , Mathew J. Boyer , Myungsuk Lee , Robert C. Ferrier , Nathaniel A. Lynd , Gyeong S. Hwang , Guibin Wang , Steve Swinnea , Arumugam Manthiram
Yıl :
2018
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Polysulfide-shuttle has been a critical concern for the advancement of lithium-sulfur (Li-S) batteries. Celgard membranes that are generally used in Li-S batteries exhibit a porous structure with a pore dimension generally on the micrometer scale. During cell operation, soluble lithium polysulfide species can easily migrate from the cathode through the porous separator and react with the lithium-metal anode. Such an unexpected chemical reaction induces a cascade of negative effects on the overall performance of Li-S batteries. Use of ion-selective membranes with reduced pore size provides a promising approach to suppress the migration of polysulfide species. In this study, a membrane based on a polymer with intrinsic nanoporosity (PIN) with a pore size of <1.0 nm is explored as a separator in Li-S batteries to mitigate the polysulfide-shuttle problem. The PIN membrane exhibits a unique structure with pore dimensions of less than 1.0 nm, which allows the transport of Li-ions, but effectively blocks the migration of dissolved polysulfides. As a result, the cycling performance of Li-S batteries is significantly improved. In addition to demonstrating a PIN-membrane Li-S battery, the structural characteristics of the PIN membrane have been characterized by a series of experimental methodologies and molecular dynamics (MD) simulations.
DOI : 10.1016/j.mtener.2018.01.002
ISSN: 2468-6069
Cilt: 7
Sayfa: 98-104
Sınıflandırma :
23
Morphology re-entry in asymmetric PS-PI-PS' triblock copolymer and PS homopolymer blends
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science Part B: Polymer Physics
Yazar(lar) :
Weichao Shi , Wei Li , Kris T. Delaney , Glenn H. Fredrickson , Edward J. Kramer , Christos Ntaras , Apostolos Avgeropoulos , Nathaniel A. Lynd
Konu :
Physical and Theoretical Chemistry, Materials Chemistry, Polymers and Plastics, Condensed Matter Physics
Yıl :
2015
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Here, we report the morphology variation in a series of PS‐b‐PI‐b‐PS' asymmetric triblock copolymer and PS homopolymer (hPS) blends, where PS' and PS are polystyrene blocks with a molecular weight ratio of approximately 0.11 and PI is poly(isoprene). We find that adding a small amount of hPS results in significant order–order transition (OOT) boundary deflection toward higher PS volume fractions fPS, which is accompanied by morphology re‐entry. For example, the neat triblock copolymer with a PS + PS' volume fraction of fPS = 0.38 exhibits a lamellar microphase; adding a small amount of hPS reverts the morphology into a hexagonal phase with PS cylinders, while further increasing the hPS fraction leads to normal OOTs from PS cylinders to lamellae, to PI cylinders and finally to spheres. The morphology variation reported here is significantly different from that reported in binary blends of diblock or symmetric triblock copolymer with homopolymer. While the domain features of the LAM structure can be correctly reproduced by self‐consistent field theory (SCFT), the observed morphology re‐entry is absent in the theoretical SCFT phase diagram. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 169–179
DOI : 10.1002/polb.23811
ISSN: 0887-6266
Sayı: 2
Cilt: 54
Sayfa: 169-179
24
Co-occurrence of East and West African kdr mutations suggests high levels of resistance to pyrethroid insecticides in Anopheles gambiae from Libreville, Gabon
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Medical and Veterinary Entomology
Yazar(lar) :
J. Pinto , A. Lynd , N. Elissa , M. J. Donnelly , C. Costa , G. Gentile , A. Caccone , V. E. DO Rosario
Konu :
Insect Science, Ecology, Evolution, Behavior and Systematics, General Veterinary, Parasitology
Yıl :
2006
A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Abstract. Point mutations in the voltage‐gated sodium channel gene involved in knockdown resistance to DDT and pyrethroid insecticides have been described in several insect species. In the malaria vector Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) two mutations have been identified. The first, consisting of a leucine–phenylalanine substitution at amino acid position 1014, is widespread in West Africa. The second, a leucine–serine substitution at the same position, has to date only been detected in western Kenya. Analysis of the kdr polymorphism in a sample of 106 An. gambiae s.s. of the rDNA S‐form/Type I collected in Libreville (Gabon) surprisingly revealed the presence of both East and West African kdr mutations with frequencies of 63% and 37%, respectively. No wild‐type alleles were detected and there was an excess of heterozygous genotypes (P = 0.04). In addition, an inconsistency was found during the kdr genotyping procedures by polymerase chain reaction, which could have lead to an underestimation of resistance alleles. The implications of these findings are discussed.
DOI : 10.1111/j.1365-2915.2006.00611.x
ISSN: 0269-283X
Sayı: 1
Cilt: 20
Sayfa: 27-32
25
A facile synthesis of catechol-functionalized poly(ethylene oxide) block and random copolymers
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science Part A: Polymer Chemistry
Yazar(lar) :
Kaila M. Mattson , Allegra A. Latimer , Alaina J. McGrath , Nathaniel A. Lynd , Pontus Lundberg , Zachary M. Hudson , Craig J. Hawker
Konu :
Organic Chemistry, Materials Chemistry, Polymers and Plastics
Yıl :
2015
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Herein we develop a facile synthetic strategy for the functionalization of well‐defined polyether copolymers with control over the number and location of catechol groups. Previously, the functionalization of polyethylene oxide (PEO)‐based polymers with catechols has been limited to functionalization of the chain ends only, hampering the synthesis of adhesive and antifouling materials based on this platform. To address this challenge, we describe an efficient and high‐yielding route to catechol‐functionalized polyethers, which could allow the effects of polymer architecture, molecular weight, and catechol incorporation on the adhesive properties of surface‐anchored PEO to be studied. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2685–2692
DOI : 10.1002/pola.27749
ISSN: 0887-624X
Sayı: 23
Cilt: 53
Sayfa: 2685-2692
26
Tunable, High Modulus Hydrogels Driven by Ionic Coacervation
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Advanced Materials
Yazar(lar) :
Jasmine N. Hunt , Kathleen E. Feldman , Nathaniel A. Lynd , Joanna Deek , Luis M. Campos , Jason M. Spruell , Blanca M. Hernandez , Edward J. Kramer , Craig J. Hawker
Konu :
Mechanical Engineering, General Materials Science, Mechanics of Materials
Yıl :
2011
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1002/adma.201004230
ISSN: 0935-9648
Sayı: 20
Cilt: 23
Sayfa: 2327-2331
27
Modular Hydrogels: Tunable, High Modulus Hydrogels Driven by Ionic Coacervation (Adv. Mater. 20/2011)
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Advanced Materials
Yazar(lar) :
Jasmine N. Hunt , Kathleen E. Feldman , Nathaniel A. Lynd , Joanna Deek , Luis M. Campos , Jason M. Spruell , Blanca M. Hernandez , Edward J. Kramer , Craig J. Hawker
Konu :
Mechanical Engineering, General Materials Science, Mechanics of Materials
Yıl :
2011
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
DOI : 10.1002/adma.201190075
ISSN: 0935-9648
Sayı: 20
Cilt: 23
Sayfa: 2326-2326
28
Poly(allyl glycidyl ether)-A versatile and functional polyether platform
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Journal of Polymer Science Part A: Polymer Chemistry
Yazar(lar) :
Bongjae F. Lee , Matthew J. Kade , Jerred A. Chute , Nalini Gupta , Luis M. Campos , Glenn H. Fredrickson , Edward J. Kramer , Nathaniel A. Lynd , Craig J. Hawker
Konu :
Organic Chemistry, Materials Chemistry, Polymers and Plastics
Yıl :
2011
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Allyl glycidyl ether, polymerized from potassium alkoxide/naphthalenide initiators under both neat and solution conditions was shown to be a highly controlled process. In both cases, molar masses (10–100 kg/mol) were determined by the reaction stoichiometry, and low polydispersity indices (1.05–1.33) could be obtained with a full understanding of the dominant side reaction, isomerization of the allyl side chain, being developed. The degree of isomerization of allyl to cis‐prop‐1‐enyl ether groups (0–10% mol) was not correlated to the molar mass or polydispersity of the polymer but was dictated by the polymerization temperature. This allows the extent of isomerization to be reduced to essentially zero under either melt or solution conditions at polymerization temperatures of less than 40 °C. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
DOI : 10.1002/pola.24891
ISSN: 0887-624X
Sayı: 20
Cilt: 49
Sayfa: 4498-4504
29
Biocompatible Materials Enabled by Biobased Production of Pyomelanin Isoforms Using an Engineered Yarrowia lipolytica
Dergi Makalesi

Dergi Makalesi
Kaynak :
Wiley Online Library
Dergi:
Advanced Functional Materials
Yazar(lar) :
Kelly K. Miller , Sarah K. Springthorpe , Jennifer Imbrogno , David J. F. Walker , Shruti Gadiyar , Benjamin K. Keitz , Andrew D. Ellington , Nathaniel A. Lynd , Hal S. Alper
Yıl :
2021
Nathaniel A. Lynd
Yayıncı Web Sitesi
Tam Metin
Kaydet Alıntıla
Melanin‐like compounds have been studied in recent years for their electron transport and ultraviolet (UV) light absorbance properties as well as applications as functional, biocompatible catalysts, and material additives. Pyomelanin is a unique form of melanin compounds that has not received significant attention. Here, a strain of Yarrowia lipolytica suitable for the production of nearly 2.8 g L−1 of homogentisic acid (HGA) is metabolically engineered, which can then be oxidized to form pyomelanin either in situ or through altering pH. By using this biosourced material, a series of material traits including spectral analysis/UV–vis absorbance properties, electronic and metal interaction/chelation properties, and effectiveness in polymer dispersions with poly(l‐lactide) are evaluated. In all cases, biosourced pyomelanin performs on par with or better than a chemically sourced analog. In a performance application, it is explored how pyomelanin may be blended at low concentrations to increase the elasticity of a rigid commercial polymer. Collectively, this work establishes biosourced pyomelanin as a versatile compound for unique material applications.
DOI : 10.1002/adfm.202109366
ISSN: 1616-301X
Sayfa: 2109366

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