Dr. Dominik Brühwiler

Dr. Dominik Brühwiler
ZHAW
School of Life Sciences and Facility Management
Fachgruppe Polymerchemie
Einsiedlerstrasse 31
8820 Wädenswil
Personal profile
Management role
Head, Section of Polymer Chemistry
Position at the ZHAW
Educational background
• MSc in Chemistry (1997, University of Bern)
• PhD in Chemistry (2001, University of Bern)
• Postdoc (Lawrence Berkeley National Laboratory)
• Habilitation (2011, University of Zurich)
Professional milestones
• Head of the Section of Polymer Chemistry at ZHAW (since 2017)
• Member of the Swiss National Research Council (since 2020)
– Review Panel NCCR Catalysis, Chair
– Review Panel NCCR TransCure, Chair
– Review Panel NCCR Chemical Biology, Co-Chair
– Review Panel NCCR Kidney.CH, Co-Chair
– Evaluation Commission Practice-to-Science
• Member of the Sounding Board for Open Research Data (since 2022)
Membership of networks
- National Research Council
- Swiss Chemical Society
- American Chemical Society
- Editorial Board of Materials
- Graduate School of Chemical and Molecular Sciences Zurich
Projects
- Aroma beladene mesoporöse Silicapartikel (MSP) für Dropz / Deputy project leader / Project ongoing
- NanoPAT – Process Analytical Technologies for Industrial Nanoparticle Production / Deputy project leader / Project ongoing
- Umweltverträgliches Hochleistungsgleitmittel für Wintersportgeräte / Project leader / Project completed
- Preventing capsular contracture by coating of silicone implants with bioglass / Project co-leader / Project completed
- newTracer / Project leader / Project completed
- Local bioColours / Deputy project leader / Project completed
- Optimizing Synthesis of Zeolites by means of Photon Density Wave Spectroscopy (PDWS) / Deputy project leader / Project completed
- Multimodal Porous Particles / Project leader / Project completed
- TCP4tex / Project leader / Project completed
- novoSUN / Project leader / Project completed
- True Color Pigments / Project leader / Project completed
- Elucidating Ice Nucleation Mechanisms Relevant to the Atmosphere / Project co-leader / Project completed
- Nanoporous Hybrid Optical Fiber Platform / Project leader / Project completed
- Long-term stability of embedded ZeoFRET composites / Project leader / Project completed
- Molecular Alignment Chips (MACs) / Project leader / Project completed
Publications
-
Calzaferri, Gion; Gallagher, Samuel H.; Lustenberger, Simon; Walther, Fabian; Brühwiler, Dominik,
2023.
Materials Chemistry and Physics.
296(127121).
Available from: https://doi.org/10.1016/j.matchemphys.2022.127121
-
Bützer, Peter; Brühwiler, Dominik; Bützer, Marcel Roland; Al-Godari, Nassim; Cadalbert, Michelle; Giger, Mathias; Schär, Sandro,
2022.
Materials.
15(3), pp. 883.
Available from: https://doi.org/10.3390/ma15030883
-
Calzaferri, Gion; Gallagher, Samuel H.; Brühwiler, Dominik,
2022.
Microporous and Mesoporous Materials.
330(111563).
Available from: https://doi.org/10.1016/j.micromeso.2021.111563
-
Calzaferri, Gion; Gallagher, Samuel; Brühwiler, Dominik,
2021.
Microporous and Mesoporous Materials.
312(110744).
Available from: https://doi.org/10.1016/j.micromeso.2020.110744
-
Gallagher, Samuel H.; Schlauri, Paul; Cesari, Emanuele; Durrer, Julian; Brühwiler, Dominik,
2021.
Nanoscale Advances.
3(22), pp. 6459-6467.
Available from: https://doi.org/10.1039/D1NA00599E
-
David, Robert O.; Fahrni, Jonas; Marcolli, Claudia; Mahrt, Fabian; Brühwiler, Dominik; Kanji, Zamin A.,
2020.
The role of contact angle and pore width on pore condensation and freezing.
Atmospheric Chemistry and Physics.
20(15), pp. 9419-9440.
Available from: https://doi.org/10.5194/acp-20-9419-2020
-
Gallagher, Samuel; Trussardi, Olivier; Lipp, Oliver; Brühwiler, Dominik,
2020.
Hollow silica cubes with customizable porosity.
Materials.
13(11), pp. 2474.
Available from: https://doi.org/10.3390/ma13112474
-
David, Robert O.; Marcolli, Claudia; Fahrni, Jonas; Qiu, Yuqing; Perez Sirkin, Yamila A.; Molinero, Valeria; Mahrt, Fabian; Brühwiler, Dominik; Lohmann, Ulrike; Kanji, Zamin A.,
2019.
Proceedings of the National Academy of Sciences of the United States of America.
116(17), pp. 8184-8189.
Available from: https://doi.org/10.1073/pnas.1813647116
-
Häne, Janick; Brühwiler, Dominik; Ecker, Achim; Hass, Roland,
2019.
Real-time inline monitoring of zeolite synthesis by Photon Density Wave spectroscopy.
Microporous and Mesoporous Materials.
288(109580).
Available from: https://doi.org/10.1016/j.micromeso.2019.109580
-
Wuillemin, Michel A.; Reber, Michael; Fox, Thomas; Spingler, Bernhard; Brühwiler, Dominik; Alberto, Roger; Braband, Henrik,
2019.
Towards 99mTc- and Re-based multifunctional silica platforms for theranostic applications.
Inorganics.
7(11), pp. 134.
Available from: https://doi.org/10.3390/inorganics7110134
-
Woodtli, Pascal; Giger, Sandro; Müller, Patrick; Sägesser, Lucie; Zucchetto, Nicola; Reber, Michael; Ecker, Achim; Brühwiler, Dominik,
2018.
Indigo in the nanochannels of zeolite L : towards a new type of colorant.
Dyes and Pigments.
2018(149), pp. 456-461.
Available from: https://doi.org/10.1016/j.dyepig.2017.10.029
-
Zucchetto, Nicola; Brühwiler, Dominik,
2018.
Chemistry of Materials.
30(20), pp. 7280-7286.
Available from: https://doi.org/10.1021/acs.chemmater.8b03603
-
Reber, Michael; Zucchetto, Nicola; Brühwiler, Dominik,
2018.
Synthesis of advanced mesoporous materials by partial pseudomorphic transformation.
Chimia.
72(3), pp. 158-159.
Available from: https://doi.org/10.2533/chimia.2017.158
-
Zucchetto, Nicola; Reber, Michael; Pestalozzi, Lias; Schmid, Ramon; Neels, Antonia; Brühwiler, Dominik,
2018.
The structure of mesoporous silica obtained by pseudomorphic transformation of SBA-15 and SBA-16.
Microporous and Mesoporous Materials.
257, pp. 232-240.
Available from: https://doi.org/10.1016/j.micromeso.2017.08.046
-
Zucchetto, Nicola; Brühwiler, Dominik,
2016.
Functionalization of arrays of silica nanochannels by post-condensation.
Dalton Transactions.
45(36), pp. 14363-14369.
Available from: https://doi.org/10.1039/C6DT02033J
-
Cao, Pengpeng; Khorev, Oleg; Devaux, André; Sägesser, Lucie; Kunzmann, Andreas; Ecker, Achim; Häner, Robert; Brühwiler, Dominik; Calzaferri, Gion; Belser, Peter,
2016.
Chemistry - A European Journal.
22(12), pp. 4046-4060.
Available from: https://doi.org/10.1002/chem.201504404
-
Reber, Michael; Brühwiler, Dominik,
2015.
Particle & Particle Systems Characterization.
32(2), pp. 243-250.
Available from: https://doi.org/10.1002/ppsc.201400150
-
Reber, Michael; Brühwiler, Dominik,
2015.
Bimodal mesoporous silica with bottleneck pores.
Dalton Transactions.
44(41), pp. 17960-17967.
Available from: https://doi.org/10.1039/C5DT03082J
-
Widmer, Susanne; Reber, Michael J.; Müller, Patrick; Housecroft, Catherine E.; Constable, Edwin C.; Rossi, René M.; Brühwiler, Dominik; Scherer, Lukas J.; Boesel, Luciano F.,
2015.
The Analyst.
140(15), pp. 5324-5334.
Available from: https://doi.org/10.1039/C5AN00850F
-
Zucchetto, Nicola; Brühwiler, Dominik,
2015.
Tuning the aspect ratio of arrays of silica nanochannels.
RSC Advances.
5(91), pp. 74638-74644.
Available from: https://doi.org/10.1039/C5RA16913E
-
Wuillemin, Michel A.; Stuber, Wanda T.; Fox, Thomas; Reber, Michael J.; Brühwiler, Dominik; Alberto, Roger; Braband, Henrik,
2014.
Dalton Transactions.
43(11), pp. 4260-4263.
Available from: https://doi.org/10.1039/C3DT53019A
-
Devaux, André; Calzaferri, Gion; Belser, Peter; Cao, Pengpeng; Brühwiler, Dominik; Kunzmann, Andreas,
2014.
Efficient and robust host-guest antenna composite for light harvesting.
Chemistry of Materials.
26(23), pp. 6878-6885.
Available from: https://doi.org/10.1021/cm503761q
-
Riedl, Wolfgang; Fischer, Fabian; Marti, Roger; Brühwiler, Dominik,
2013.
Energy-related chemical research at the universities of applied sciences.
Chimia.
67(7-8), pp. 611-613.
Available from: https://doi.org/10.2533/chimia.2013.611
-
Fois, Ettore; Tabacchi, Gloria; Devaux, André; Belser, Peter; Brühwiler, Dominik; Calzaferri, Gion,
2013.
Host-guest interactions and orientation of dyes in the one-dimensional channels of zeolite L.
Langmuir.
29(29), pp. 9188-9198.
Available from: https://doi.org/10.1021/la400579w
-
Devaux, André; Calzaferri, Gion; Miletto, Ivana; Cao, Pengpeng; Belser, Peter; Brühwiler, Dominik; Khorev, Oleg; Häner, Robert; Kunzmann, Andreas,
2013.
Self-absorption and luminescence quantum yields of dye-zeolite L composites.
The Journal of Physical Chemistry C.
117(44), pp. 23034-23047.
Available from: https://doi.org/10.1021/jp408556g
-
Ma, Yujie; Rajendran, Prayanka; Blum, Christian; Cesa, Yanina; Gartmann, Nando; Brühwiler, Dominik; Subramaniam, Vinod,
2011.
Journal of Colloid and Interface Science.
356(1), pp. 123-130.
Available from: https://doi.org/10.1016/j.jcis.2010.12.082
-
Bauer, Christophe; Gartmann, Nando; Dieu, Le-Quyenh; Zuber, Nora; Dolamic, Igor; Ramm, Jan Hinrich; Brühwiler, Dominik,
2011.
Self-organized patterns of microparticles in polymer films.
Thin Solid Films.
519(11), pp. 3674-3678.
Available from: https://doi.org/10.5167/uzh-47902
-
Gartmann, Nando; Brühwiler, Dominik,
2011.
Materials.
4(6), pp. 1096-1103.
Available from: https://doi.org/10.5167/uzh-48368
-
Calzaferri, Gion; Méallet-Renault, Rachel; Brühwiler, Dominik; Pansu, Robert; Dolamic, Igor; Dienel, Thomas; Adler, Pauline; Li, Huanrong; Kunzmann, Andreas,
2011.
Designing dye-nanochannel antenna hybrid materials for light harvesting, transport and trapping.
ChemPhysChem.
12(3), pp. 580-594.
Available from: https://doi.org/10.1002/cphc.201000947
-
Gartmann, Nando; Brühwiler, Dominik,
2011.
Functional group distributions on mesoporous silica.
Chimia.
65(4), pp. 250-252.
Available from: https://doi.org/10.5167/uzh-48006
-
López-Duarte, Ismael; Dieu, Le-Quyenh; Dolamic, Igor; Martínez-Díaz, M. Victoria; Torres, Tomás; Calzaferri, Gion; Brühwiler, Dominik,
2011.
Chemistry - A European Journal.
17(6), pp. 1855-1862.
Available from: https://doi.org/10.1002/chem.201002210
-
Ince, Mine; Gartmann, Nando; Claessens, Christian G.; Brühwiler, Dominik,
2011.
Synthesis of subphthalocyanines as probes for the accessibility of silica nanochannels.
Organic Letters.
13(18), pp. 4918-4921.
Available from: https://doi.org/10.1021/ol2019983
-
Dienel, Thomas; Bauer, Christophe; Dolamic, Igor; Brühwiler, Dominik,
2010.
Spectral-based analysis of thin film luminescent solar concentrators.
Solar Energy.
84(8), pp. 1366-1369.
Available from: https://doi.org/10.5167/uzh-34993
-
Ramm, Jan Hinrich; Gartmann, Nando; Brühwiler, Dominik,
2010.
Direct synthesis and fluorescent imaging of bifunctionalized mesoporous iodopropyl-silica.
Journal of Colloid and Interface Science.
345(2), pp. 200-205.
Available from: https://doi.org/10.5167/uzh-33745
-
Ritter, Hanna; Ramm, Jan Hinrich; Brühwiler, Dominik,
2010.
Influence of the structural properties of mesoporous silica on the adsorption of guest molecules.
Materials.
3(8), pp. 4500-4509.
Available from: https://doi.org/10.5167/uzh-44804
-
Brühwiler, Dominik,
2010.
Postsynthetic functionalization of mesoporous silica.
Nanoscale.
2(6), pp. 887-892.
Available from: https://doi.org/10.5167/uzh-34994
-
Gasecka, Alicja; Dieu, Le-Quyenh; Brühwiler, Dominik; Brasselet, Sophie,
2010.
The Journal of Physical Chemistry B.
114(12), pp. 4192-4198.
Available from: https://doi.org/10.1021/jp9116529
-
Calzaferri, Gion; Brühwiler, Dominik; Meng, Tao; Dieu, Le-Quyenh; Malinovskii, Vladimir L.; Häner, Robert,
2010.
Surprising properties of a furo-furanone.
Chemistry - A European Journal.
16(37), pp. 11289-11299.
Available from: https://doi.org/10.1002/chem.201000728
-
Gartmann, Nando; Schütze, Christina; Ritter, Hanna; Brühwiler, Dominik,
2010.
The effect of water on the functionalization of mesoporous silica with 3-aminopropyltriethoxysilane.
The Journal of Physical Chemistry Letters.
1(1), pp. 379-382.
Available from: https://doi.org/10.1021/jz9002795
-
Ritter, Hanna; Nieminen, Minna; Karppinen, Maarit; Brühwiler, Dominik,
2009.
Microporous and Mesoporous Materials.
121(1-3), pp. 79-83.
Available from: https://doi.org/10.5167/uzh-17901
-
Ritter, Hanna; Brühwiler, Dominik,
2009.
Accessibility of amino groups in postsynthetically modified mesoporous silica.
The Journal of Physical Chemistry C.
113(24), pp. 10667-10674.
Available from: https://doi.org/10.1021/jp901983j
-
Gartmann, Nando; Brühwiler, Dominik,
2009.
Controlling and imaging the functional-group distribution on mesoporous silica.
Angewandte Chemie: International Edition.
48(34), pp. 6354-6356.
Available from: https://doi.org/10.1002/anie.200902436
-
Brühwiler, Dominik; Ritter, Hanna; Ramm, Jan Hinrich; Dieu, Le-Quyenh; Bauer, Christophe; Dolamic, Igor; Gartmann, Nando,
2009.
Chimia.
63(1-2), pp. 8-13.
Available from: https://doi.org/10.5167/uzh-17902
-
Gartmann, Nando; Brühwiler, Dominik,
2009.
Kontrolle und Visualisierung der Verteilung funktioneller Gruppen auf mesoporösem Siliciumdioxid.
Angewandte Chemie.
121(34), pp. 6472-6475.
Available from: https://doi.org/10.1002/ange.200902436
-
Brühwiler, Dominik; Calzaferri, Gion; Torres, Tomás; Ramm, Jan Hinrich; Gartmann, Nando; Dieu, Le-Quyenh; López-Duarte, Ismael; Martínez-Díaz, M. Victoria,
2009.
Nanochannels for supramolecular organization of luminescent guests.
Journal of Materials Chemistry.
19(43), pp. 8040-8067.
Available from: https://doi.org/10.1039/B907308F
-
Calzaferri, Gion; Li, Huanrong; Brühwiler, Dominik,
2008.
Dye-modified nanochannel materials for photoelectronic and optical devices.
Chemistry - A European Journal.
14(25), pp. 7442-7449.
Available from: https://doi.org/10.1002/chem.200800811
-
Dieu, Le-Quyenh; Devaux, André; Lopez-Duarte, Ismael; Martínez-Díaz, M. Victoria; Brühwiler, Dominik; Calzaferri, Gion; Torres, Tomás,
2008.
Novel phthalocyanine based stopcock for zeolite L.
Chemical Communications.
2008(10), pp. 1187-1189.
Available from: https://doi.org/10.1039/B714995F
-
Salmio, Hanna; Brühwiler, Dominik,
2007.
Journal of Physical Chemistry C.
111(2), pp. 923-929.
Available from: https://doi.org/10.1021/jp0651440
-
Brühwiler, Dominik; Dieu, Le-Quyenh; Calzaferri, Gion,
2007.
Nanochannel materials for quantum solar energy conversion devices.
Chimia.
61(12), pp. 820-822.
Available from: https://doi.org/10.5167/uzh-2618
-
Devaux, André; Lutkouskaya, Katsiaryna; Calzaferri, Gion; Dieu, Le-Quyenh; Brühwiler, Dominik; De Cola, Luisa; Torres, Tomas,
2007.
Nanochannels for supramolecular organisation of dyes.
Chimia.
61(10), pp. 626-630.
Available from: https://doi.org/10.2533/chimia.2007.626
-
Yunus, Sami; Spano, Fabrizio; Patrinoiu, Greta; Bolognesi, Alberto; Botta, Chiara; Brühwiler, Dominik; Zabala Ruiz, Arantzazu; Calzaferri, Gion,
2006.
Advanced Functional Materials.
16(17), pp. 2213-2217.
Available from: https://doi.org/10.1002/adfm.200600255
-
Calzaferri, Gion; Bossart, Olivia; Brühwiler, Dominik; Huber, Stefan; Leiggener, Claudia; Van Veen, Marieke K.; Ruiz, Arantzazu Zabala,
2006.
Light-harvesting host–guest antenna materials for quantum solar energy conversion devices.
Comptes Rendus Chimie.
9(2), pp. 214-225.
Available from: https://doi.org/10.1016/j.crci.2005.03.026
-
Brühwiler, Dominik; Calzaferri, Gion,
2005.
Selective functionalization of the external surface of zeolite L.
Comptes Rendus Chimie.
8(3-4), pp. 391-398.
Available from: https://doi.org/10.1016/j.crci.2004.11.008
-
Brühwiler, Dominik; Calzaferri, Gion,
2004.
Molecular sieves as host materials for supramolecular organization.
Microporous and Mesoporous Materials.
72(1-3), pp. 1-23.
Available from: https://doi.org/10.1016/j.micromeso.2004.03.027
-
Ban, Takayuki; Brühwiler, Dominik; Calzaferri, Gion,
2004.
Selective modification of the channel entrances of zeolite L with triethoxysilylated coumarin.
The Journal of Physical Chemistry B.
108(42), pp. 16348-16352.
Available from: https://doi.org/10.1021/jp048516i
-
Zabala Ruiz, Arantzazu; Brühwiler, Dominik; Ban, Takayuki; Calzaferri, Gion,
2004.
Synthesis of zeolite L : tuning size and morphology.
Monatshefte für Chemie - Chemical Monthly.
136(1), pp. 77-89.
Available from: https://doi.org/10.1007/s00706-004-0253-z
-
Leiggener, Claudia; Brühwiler, Dominik; Calzaferri, Gion,
2003.
Luminescence properties of Ag2S and Ag4S2 in zeolite A.
Journal of Materials Chemistry.
13(8), pp. 1969-1977.
Available from: https://doi.org/10.1039/B303937B
-
Brühwiler, Dominik; Frei, Heinz,
2003.
Structure of Ni(II) and Ru(III) ammine complexes grafted onto mesoporous silicate sieve.
The Journal of Physical Chemistry B.
107(33), pp. 8547-8556.
Available from: https://doi.org/10.1021/jp0300795
-
Brühwiler, Dominik; Leiggener, Claudia; Glaus, Stephan; Calzaferri, Gion,
2002.
Luminescent silver sulfide clusters.
The Journal of Physical Chemistry B.
106(15), pp. 3770-3777.
Available from: https://doi.org/10.1021/jp012453b
-
Calzaferri, Gion; Brühwiler, Dominik; Glaus, Stephan; Schürch, David; Currao, Antonio; Leiggener, Claudia,
2001.
Quantum-sized silver, silver chloride and silver sulfide clusters.
Journal of Imaging Science & Technology.
45(4), pp. 331-339.
Available from: http://www.ingentaconnect.com/content/ist/jist/2001/00000045/00000004/art00004
-
Calzaferri, Gion; Brühwiler, Dominik; Megelski, Silke; Pfenniger, Michel; Pauchard, Marc; Hennessy, Brian; Maas, Huub; Devaux, André; Graf, Urs,
2000.
Playing with dye molecules at the inner and outer surface of zeolite L.
Solid State Sciences.
2(4), pp. 421-447.
Available from: https://doi.org/10.1016/S1293-2558(00)00129-1
-
Brühwiler, Dominik; Seifert, Roland; Calzaferri, Gion,
1999.
Quantum-sized silver sulfide clusters in zeolite A.
The Journal of Physical Chemistry B.
103(31), pp. 6397-6399.
Available from: https://doi.org/10.1021/jp990498v
-
Brühwiler, Dominik; Gfeller, Niklaus; Calzaferri, Gion,
1998.
Resorufin in the channels of zeolite L.
The Journal of Physical Chemistry B.
102(16), pp. 2923-2929.
Available from: https://doi.org/10.1021/jp980019c
-
Brühwiler, Dominik,
2010.
Luminescent molecules in nanoporous silicates.
Zürich:
Universität Zürich.
Available from: https://doi.org/10.21256/zhaw-3512
-
Zabala Ruiz, Arantzazu; Brühwiler, Dominik; Dieu, Le-Quyenh; Calzaferri, Gion,
2008.
Controlling Size and Morphology of Zeolite L
.
In:
Schubert, Ulrich; Hüsing, Nicola; Laine, Richard, eds.,
Materials syntheses.
Wien:
Springer.
pp. 9-19.
Available from: https://doi.org/10.1007/978-3-211-75125-1_1
-
Brühwiler, Dominik; Leiggener, Claudia; Calzaferri, Gion,
2001.
14-O-04-Silver ions and quantum-sized silver sulfide clusters in zeolite A [paper].
In:
Galarneau, Anne; Fajula, François; Di Renzo, Francesco; Védrine, Jacques, eds.,
13th International Zeolite Conference, Montpellier, 8-13 July 2001.
Elsevier.
pp. 177.
Available from: https://doi.org/10.1016/S0167-2991(01)81327-6
-
Brühwiler, Dominik,
2021.
Schnell auf Schnee mit Indigo.
Transfer.
2021(1), pp. 7.
Available from: https://doi.org/10.21256/zhaw-24422
-
Brühwiler, Dominik; Ecker, Achim,
2017.
True Color Pigments : die Suche nach dem perfekten Farbmittel.
Transfer.
2017(1), pp. 8.
Available from: https://doi.org/10.21256/zhaw-5024
-
Brühwiler, Dominik; Reber, Michael; Zucchetto, Nicola,
2015.
Transfer.
2015(3), pp. 6.
Available from: https://doi.org/10.21256/zhaw-5028
-
Brühwiler, Dominik,
2018.
Customized mesoporous silica particles.
In:
Advanced Sorption Materials - Empa, Dübendorf, 8. Mai 2018.
-
David, Robert O.; Fahrni, Jonas; Marcolli, Claudia; Mahrt, Fabian; Brühwiler, Dominik; Lohmann, Ulrike; Kanji, Zamin A.,
2018.
The role of pores on ice nucleation.
In:
Abstract Volume : 16th Swiss Geoscience Meeting.
16th Swiss Geoscience Meeting, Bern, 30 November - 1 December 2018.
Swiss Academy of Science.
Available from: https://geoscience-meeting.ch/sgm2018/wp-content/uploads/SGM_2018_Symposium_17.pdf
-
David, Robert O.; Mahrt, Fabian; Marcolli, Claudia; Fahrni, Jonas; Brühwiler, Dominik; Lohmann, Ulrike; Kanji, Zamin A.,
2017.
Deposition nucleation or pore condensation and freezing?.
In:
Geophysical Research Abstracts.
EGU General Assembly 2017, Vienna, 23-28 April 2017.
pp. 16923.
Available from: http://meetingorganizer.copernicus.org/EGU2017/EGU2017-16923-4.pdf