Download Molecular Genetics of Bacteria, 4th book pdf free read online here in ... Online PDF Ebook Epub Library snyder molecular genetics of bacteria 3rd .... Manoharudu Movie Download Telugu Torrent · [BETTER] Kal Ho Naa Ho ... Pdf 13 nilspapah · Molecular Genetics Of Bacteria Snyder Pdf Free Download 2020 ...
of bacterial meningitis pathogens include culture, Gram stain, and latex agglutination. ... molecular methods (see below) that can be applied on DNA extracted from clinical ... This assay targets the Cu, Zn superoxide dismutase gene, sodC, which is not ... 1.5 ml microcentrifuge tubes (sterile, DNAase free, or PCR grade).. 5.1.1 Not all species of bacteria are equally efficient at DNA uptake 74 ... standing of the molecular nature of the gene until the 1940s. Indeed ... linear, with two free ends, and represents the DNA present in the phage head struc- ture. ... Phizicky, E., Bastiaens, P.I.H., Zhu, H., Snyder, M. & Fields, S. (2003) Protein analysis on.
snyder and champness molecular genetics of bacteria
snyder and champness molecular genetics of bacteria, molecular genetics of bacteria larry snyder free download, molecular genetics of bacteria snyder pdf, molecular genetics of bacteria snyder, snyder and champness molecular genetics of bacteria 5th edition, molecular genetics of bacteria snyder pdf free download, snyder and champness molecular genetics of bacteria pdf, molecular genetics of bacteria snyder 3rd edition pdf, molecular genetics of bacteria snyder 4th
Apr 14, 2019 — Molecular genetics of bacteria 4th edition download pdf. April 6th, 2019 - Free Download Human Molecular Genetics 3rd Edition 2018 03.. Sign in to download full-size image. Figure 3. ... Adapted with permission from Snyder L and Chapman W (1997) Molecular Genetics of Bacteria, 3rd edn.
molecular genetics of bacteria snyder pdf
. 9. Wehr and Frank (ed.). 2004. ... have benefited from free amino acids and other low molecular ... studies and bacterial molecular genetics applications.6,7. Grade A Agar ... Snyder and Lichstein. 1940.. Molecular Genetics of Bacteria, 4th Edition PDF Download Molecular Genetics ... Snyder and Champness Molecular Genetics of Bacteria, 5th Edition. ... we'll send you a link to download the free Kindle App. Then you can start reading Kindle .... exposure to potentially mutagenic impurities, the bacterial mutagenicity assay is used to assess the mutagenic ... appropriate acceptable limit, it is recommended that the impurity be tested in an in vivo gene ... http://www.who.int/ipcs/publications/cicad/en/cicad40.pdf. 10. ... via free radical formation and tissue injury (Ref. 32).. Oct 10, 2015 -- FUNDAMENTALS OF MOLECULAR BIOLOGY 100. MIC 203 ... Unit 4: Thermodynamics endergonic and exergonic processes, enthalpy, entropy, free energy ... Snyder L and Champness W. Molecular genetics of bacteria.. You could quickly download this molecular genetics bacteria 4th edition dale after getting deal. So, ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, ... Molecular cell biology : Lodish, Harvey F : Free Download .. by LDB Evans · 2014 · Cited by 72 -- The N terminus (blue) of the subunit docked at the export gate is captured by the free C terminus (red) of an exiting subunit in the flagellar channel, linking subunits .... by Y Hong · 2019 · Cited by 74 -- Article · Figures & SI · Info & Metrics · PDF ... The finding that ROS levels continue to surge and kill bacteria even after ... can occur after plating on drug-free agar due to poststress ROS-mediated toxicity. ... data have been deposited in the Gene Expression Omnibus (GEO) database, ... Snyder M,; Drlica K.. ... Third Edition ( Snyder , Molecular Genetics of Bacteria )Fast way of spotting multidrug resistant bacteria could help stop . Download free pdf . . Free books on .... have led to the molecular and genetic characterization of the transmissible ... walls are perforated and allow free passage of nuclei and cyto- plasm. The entire ... Snyder L, Champness W: Molecular Genetics of Bacteria. ASM. Press, 1997.. Read Free Modern Chemistry Chapter 7 Quiz Answers Derutaore ... Solomons′s ORGANIC CHEMISTRY Solomons, Fryhle & Snyder′s tradition of ... Pathways Molecular Genetics DNA: The Basic Substance of Genes CHAPTER 2 ... Multiple Choice Questions and Answers" PDF book to download covers solved quiz .... Mar 4, 2020 -- Molecular Genetics Of Bacteria Snyder Pdf Free Download > http://tinurll.com/15xyfc 733888b65d Molecular Genetics of Bacteria , 3rd Edition .... by A Zaprasis · 2014 · Cited by 19 -- Microbiology and Genetics, Georg-August University. Göttingen ... additional level of adaptation that allows bacteria to rapidly conquer ... dependence on SigL to promote growth in a proline-free minimal ... molecular mechanism(s) underlying the different effects of ... Snyder, M., and Gerstein, M.B. (2011) Measuring the evo-.. Molecular biotechnology : principles and applications of recombinant DNA / ... Decoding Genetic information: rNa ... Vaccines Directed against Bacteria 492 ... Will the quest for patents inhibit the free exchange of ideas among ... itive, and the download times were interminable. ... Hall, D. A., J. Ptacek, and M. Snyder. 2007.. Before download book BRS Biochemistry, Molecular Biology, and Genetics, see ... content * All the illustrations will be available free for downloading (from ... Download pdf file Snyder and Champness Molecular Genetics of BacteriaHuman.. Free Printer Technician for Life when you use Us!. ... While coconut oil is mostly lauric acid, which feeds acne and dandruff-causing bacteria, MCT oil ( if you buy the right kind) ... Search Torrents: wii monopoly streets pal iso - Download Game Torrent! ... The rapid advances in molecular genetics and reproductive technology .... by MA Jabbar · 1984 · Cited by 23 -- M. ABDUL JABBARt AND LARRY SNYDER*. Department ... The restrictive locus seems to be a gene, or genes, unique to CTr5X ... Bacteriophage and bacterial strains. Source or ... Carrier-free 32p (1 mCi) was added to 100 ml of induced culture ... molecular weight, but is being ignored by the transcription.. by AD Baxevanis · Cited by 985 -- I am writing these words on a watershed day in molecular biology. This morning, a ... for data download directly to a satellite dish with a southern exposure, with uploads occuring ... In this example, the Bacterial genetic code (code 11) is ... dates are error-free; they are included as guides to users and should not be submitted.. Molecular Genetic Medicine-Theodore Friedmann 2013-10-22 Molecular ... molecular genetics Snyder & Champness Molecular Genetics of Bacteria is a ... Thank you very much for downloading Genes in Medicine: Molecular Biology ... Free Pdf Books Genes In Medicine: Molecular Biology And Human Genetic Disorders.. Anello turned the questionnaire into a user-friendly dynamic PDF that was distributed to ... Bacteria that are used in aquaculture ... Molecular genetics in fisheries. Chapman & Hall. Chambers, P.A., Lacoul, P., ... Downloaded from http://193.206.192.138/gisd/ ... in situ in vivo, e.g. free-living, wild and feral ... Snyder et al.. Current findings: molecular genetics . ... The lack of replicated findings in molecular genetics . ... expressed in the concepts of free will and moral responsibility. Chapter 13 then ... November 2001. http://www.sirc.org/publik/revised_guidelines.pdf (9 Aug 2002). ... bacterial artificial chromosome-mediated transgenesis. Hum.. by JA Jenkins · 2014 · Cited by 41 -- Printed in the United States of America on acid-free paper. ... http://history.nih.gov/research/downloads/PL99-158.pdf). ... target species, and genetic consequences for ecosystems (Tiersch and Jenkins 2003). ... Studies of molecular ... techniques that minimize potential for electrofishing injury to fishes (Snyder 2003; Dean .... chapters concerning post-genomics and molecular evolution were so ... describes virus genomes and mobile genetic elements, these being grouped together because ... of known or predictable sequence in cell-free systems, and partly by deter- ... pieces of cloned genomic DNA, or simply by downloading sequences that.. by CY LI · Cited by 14 -- Nitrogen-fixing bacteria associated with mycorrhizal fungi and mycorrhizas can be dem- ... Department of Microbiology, Institute of General and Molecular Biology, ... were aseptically removed and placed in a N-free liquid medium in a serum ... systems with.a genetic diversity of tree species can reduce impacts of insects and.. Oct 22, 2017 -- Translation and Its Role in Cancer - Free ebook download as PDF File (. ... Graduate student in the Department of Molecular Genetics, The Ohio State University. ... level (2) genetics and nucleic acids/protein synthesis (3) viruses, bacteria, protists, and fungi (4) organisms and the body. ... Rosemary Snyder.. You could speedily download this molecular genetics bacteria 4th edition dale after getting deal. ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, ... Molecular cell biology : Lodish, Harvey F : Free Download .. by Y Hasin · 2017 · Cited by 752 -- 2Department of Microbiology, Immunology and Molecular Genetics, 10833 ... Many studies have implicated perturbations in gut bacteria in a variety of disorders, ... 2011_May.pdf). ... Massively parallel single-cell RNA-seq for marker-free decomposition of ... Wang Z, Gerstein M, Snyder M. RNA-Seq: a revolutionary tool for.. EbookNetworking.net : Allows you online search for PDF Books - ebooks for Free downloads In one place.Current search Molecular Genetics Of Bacteria .... Jun 8, 2021 -- Molecular Genetics of Bacteria, 4th edition (PDF) is the classic comprehensive and ... Show more Download books for free. ... COUPON: RENT Snyder and Champness Molecular Genetics of Bacteria 5th edition by Henkin .... As this molecular genetics bacteria 4th edition, it ends up visceral one of the favored book ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, Joseph E. ... Molecular cell biology : Lodish, Harvey F : Free Download .. Download Free Molecular Genetics Of Bacteria 4th Edition ... Molecular Genetics of Bacteria, Third Edition Snyder, Molecular Genetics of BacteriaTransformation, ... Reviews (0) Molecular Genetics of Bacteria, 4th edition (PDF) is the classic .... by GCL Wong · 2021 · Cited by 1 -- This content was downloaded from IP address 66.249.70.116 on ... Department of Molecular Biology & Biochemistry, University of ... physics to engage fundamental concepts in bacterial biofilm ... tions in the gene regulatory networks that regulate the ... in such devices using the label-free imaging method.. Knowledge on DNA lead to advances in Molecular Biology• Central dogma of Life – Deoxyribonucleic acid• DNA carries the Genetic information• DNA is .... by HM Bohle · 2012 · Cited by 12 -- Molecular markers serve to assign individual samples to specific ... Sign in here to access free tools such as favourites and alerts, or to ... Download PDF [PDF] ... Ten years of bacterial genome sequencing: Comparative-genomics-based ... The dnaJ gene as a novel phylogenetic marker for identification of .... File Type PDF Chapter 15 Water Aqueous Systems Worksheet Answers ... to make labels for bottles, jars, packages, products, boxes or classroom activities for free. ... of an Prentice hall Biology Worksheets Classical and Modern Genetics - Follow ... Snyder, St. Science is real answer key macromolecules webquest rating .... Access Free Marine Fishes 500 Essential To. Know Aquarium Species called “occasional visitors.” David B. Snyder and George H. Burgess intertwine personal.. Microbiology and Molecular Biology Reviews (MMBR) keeps researchers current with the ... as well as related fields such as immunology and molecular and cellular biology. ... Annual HTML+PDF Usage ... signal affecting bacterial gene expression, physiology, and pathogenesis. ... Free Radic Biol Med 50:1591–1598.. Molecular Genetics Of Bacteria Snyder Pdf Free Download molecular genetics of bacteria larry snyder free download, molecular genetics of bacteria 4th edition .... Sep 29, 2012 -- THIRD EDITION molecular genetics of bacteria &*' *M Larry Snyder and Wendy C dampness. 0.25x, 0.5x, 0.75x, 1.0x, 1.25x, 1.5x, 1.75x, 2x.. The single most comprehensive and authoritative textbook on bacterial molecular genetics Snyder Champness Molecular Genetics of Bacteria is a new edition .... Snyder, L., Peters, L., Henkin, T.M. and Champness, W. 2013. Molecular ... A Short Course in Bacterial Genetics: Lab Manual, Cold Spring Harbor. Laboratory Press. ... ExPASy Molecular Biology Server: http://www.expasy.ch/. (A very ... Net Primer (a site that allows downloaded or on-line design of PCR primers. They also .... Buy Molecular Genetics of Bacteria, 4th Edition (ASM Books) on Amazon.com ✓ FREE SHIPPING on ... Snyder and Champness Molecular Genetics of Bacteria (ASM Books) ... Get your Kindle here, or download a FREE Kindle Reading App.. Molecular Genetics of Bacteria, 4th Edition (ASM Books) $195.95 ... Larry Snyder,. 4.3 out of 5 ... Get your Kindle here, or download a FREE Kindle Reading App.. by K Śliżewska · 2021 · Cited by 6 -- Institute of Molecular and Industrial Biotechnology, Faculty of ... The risk of developing cancer depends on genetic factors, as well ... The presence of such a large count of intestinal bacteria means that the human ... involved in the cellular detoxification process, preventing the activity of free radicals and.. Free PDF By Larry Snyder Molecular Genetics Of Bacteria 3rd Third Edition download or read online. 9781555813994 - Molecular Genetics of Bacteria, Third.. by S Huang · 2003 · Cited by 164 -- assays with larvae of Hydroides elegans and for 16S. rRNA-gene sequence taxonomic analysis. Molecular determination of bacterial identities.. May 27, 2021 -- Learn about health implications of genetic changes. ... Email this page to a friend Facebook Twitter Pinterest Download PDF. To use the .... Introduction Part I Genes: Replication and Expression Introduction to macromolecular synthesis: chromosome structure and replication Introduction to .... PDF. By Larry Snyder, Joseph E. Peters, Tina M. Henkin, Wendy Champness. Molecular Genetics of Bacteria, 4th Edition you can download free book and read .... Read Free Molecular Genetics Of Bacteria 4th Edition 4th Fourth By Snyder Larry Peters Joseph E ... Molecular Genetics of Bacteria, Third Edition Snyder, Molecular Genetics of ... Reviews (0) Molecular Genetics of Bacteria, 4th edition (PDF) is the classic ... Molecular Genetics Of Bacteria 4th Edition : Free Download .. by DL Hartl · 2019 · Cited by 2 -- 8 Genetics of Bacteria and Their Viruses. 279. Unit III Organization and Replication of Chromosomes and DNA. 319. 9 Molecular Organization of Chromosomes .... Downloading. References. 1. ... Microbial degradation, decolorization and adsorption of organic dyes (by free and immobilized cells). 7. ... Molecular Genetics of Bacteria, 1997 by Larry, Snyder and Wendy, Champness, ASM. Publications. 11.. Read Free Molecular Genetics Bacteria 4th Edition ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, Joseph E. Peters, ISBN: .... Sep 11, 2020 -- These editing substrates are introduced in the bacteria using transformation, conjugation or transduction, and we refer to Snyder et al. (2013) for .... by KE Mock · 2013 · Cited by 9 -- Genetic techniques are providing important insights about ... Aspen clones can easily be differentiated using molecular tools ... Most naturally-occu rring bacteria produce enzymes to re- ... In many ways the availabili ty of public data and free analysis ... lm_wfn_seedzone_book.pdf> (accessed 30.09.12.).. Access Free Molecular Genetics Of Bacteria 4th Edition 4th Fourth By Snyder Larry Peters Joseph E Henkin Tina. M Champnes 2013 Hardcover. Molecular .... by RT Horbat · 2008 — doi: 10.1097/01.shk.0000286262.09575.ce. Metrics. MOLECULAR GENETICS OF BACTERIA, 3RD EDITION. Authors: Larry Snyder, PhD; Wendy Champness, .... Jan 23, 2018 — Download PDF. Introduction. The coalescent is a population genetic theory that considers the ... Prokaryotes undergo recombination by integrating free extracellular DNA into ... Transduction involves bacterial DNA integration into another ... Snyder L, Peters JE, Henkin TM, Champness W (2013) Molecular .... Molecular genetics of bacteria snyder pdf free download. This item: Molecular Genetics of Bacteria, 4th Edition (ASM Books) by Larry Snyder Hardcover $ Only 3 .... Jun 30, 2021 — [PDF] Genetic and Molecular Analysis of Utility of sd1 . Genetic and ... Diagnostic Pathology: Molecular Oncology 2nd Edition PDF Free Download. Covering all ... Snyder and Champness Molecular Genetics of Bacteria, 5th .. by MG Smith · 2007 · Cited by 523 — Although there are large number of local gene insertions, deletions, and ... (B) The genomes of six bacteria were compared for the distribution of key catabolic ... E. coli OP50 proliferate equally well on ethanol-containing and ethanol-free media. ... is aminoglycoside (kanamycin) sensitive (M.G. Smith and M. Snyder, unpubl.) .... Start reading Snyder and Champness Molecular Genetics of Bacteria for free online and get access to an unlimited library of academic and non-fiction books on .... By Snyder Larry Peters Joseph E Henkin Tina M Champnes 2013 Hardcover ... Free Download, Borrow Molecular Genetics Of Bacteria 4th ... Bacteria 4th Edition (PDF)hardcover$ library@@ Molecular Genetics of Bacteria 4th Download.. DHA status or FADS2 gene expression in any model system. ... Bovine serum albumin (BSA; fatty acid free), ALA, DHA, EPA, nonadecanoic acid. (19:0) .... Results 1 - 16 of 206 — ... a variety of topics related to genetics and evolutionary theory. ... [Glencoe McGraw-Hill] BSCS Biology A Molecular Approach. ... by McGraw Hill Paperback $9. pdf View Download: 102k: v. ... Bacteria and Protists. ... All texts are available for free reading online, or for downloading in various formats.. molecular genetics of bacteria : Free Download, Borrow ... 23/10/2019 · Molecular Genetics of Bacteria 4th Edition by Larry Snyder, J. E. Peters is a great molecular genetics book ... Molecular Genetics of Bacteria 5th Edition PDF Download.. About Us. We believe everything in the internet must be free. So this tool was designed for free download documents from the internet.. Download Ebook Molecular Genetics Of Bacteria 4th Edition Snyder ... Library: There are over one million free books here, all available in PDF, ePub, Daisy, .... Snyder, Larry (Author). Molecular Genetics of Bacteria (3rd Edition). Washington, DC, USA: ASM Press, 2007. p 1. http://.... BACTERIAL DISEASES—ALSO SEE APPENDIX B. Disease. Organism ... Larry Snyder, Michigan State University. Joseph M. Sobek ... Genetics and Molecular Biology. 18 ... magnifications up to 300X and were remarkably free of distortion.. lung infection and near absolute clearance of bacteria within 12 hours of ... immunogenicity, and lack of genetic material character- ize them as virus-like .... by A Snyder · 2014 · Cited by 3223 — Alexandra Snyder, M.D.,; Vladimir Makarov, M.D.,; Taha Merghoub, ... Immune checkpoint inhibitors are effective cancer treatments, but molecular determinants of clinical ... These findings define a genetic basis for benefit from CTLA-4 ... to many more viral and bacterial antigens in the database than were .... by A Santos-Lopez · 2019 · Cited by 42 — Bacteria growing in biofilms evolve antimicrobial resistance via ... Article PDF · Figures PDF ... by different population-genetic dynamics or molecular mechanisms, is limited. ... Download elife-47612-fig2-data1-v2.xlsx ... drug-free control populations contained no mutations that achieved ... Daniel J Snyder.. Read Download Molecular Genetics of Bacteria Third Edition (Snyder Molecular Genetics of Bacteria) PDF .... by TDR Vance · 2019 · Cited by 11 — Department of Biomedical and Molecular Science, Queen's ... Bacterial adhesins attach their hosts to surfaces through one or more ligand-binding ... A gene encoding MhPA14 was synthesized with optimal codon usage for ... in diffusion between the resin and free sugars) these Kdapp values are not .... Bookmark File PDF Molecular Genetics Bacteria 4th Edition Dale. Molecular ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, Joseph E. Peters, ISBN: ... Molecular cell biology : Lodish, Harvey F : Free Download .. Jul 2, 2021 — PDF EPUB Leggi o Scarica scritto da Larry Snyder, Title: Molecular Genetics Of Bacteria. The classic comprehensive and authoritative textbook .... The revision of this classic textbook by David Freifelder has been rewritten and updated to include the numerous and rec .. Apr 19, 2021 — Download File PDF ... Bacteria, Third Edition Snyder, ... Bacterial. Genetics. AP Biology Lab 6: Molecular Biology. 1/24/18 vlog and ... Edition : .... PDF | On Dec 1, 2012, Larry Snyder and others published Molecular Genetics of Bacteria | Find, read and cite all the ... Download full-text PDF ... Join for free.. The classic comprehensive and authoritative textbook on bacterial molecular ... Molecular Genetics of Bacteria, 4th Edition – Larry Snyder ... File Type: PDF .... Microbiology 10 of 40. Brief account on horizontal gene transfer among bacteria – transformation, transduction and ... Biochemistry and Molecular Biology, 2nd Edition,. Oxford University ... Snyder, L. and Champness, W. (1997). Molecular .... Get Free Molecular ... molecular genetics of bacteria. Thoroughly revised and updated, Molecular ... Bacteria, 4th Edition PDF ... Download, By Larry Snyder,.. by MBH Najafi · Cited by 18 — gene. In some cases, a mutation can be beneficial if a new metabolic activity arises in a microorganism, or ... grow on a histidine-free medium. ... (2003). Snyder, L. and Champness, W. Molecular Genetics of Bacteria, 2nd edition, , ASM Press,.. Access Free Molecular Genetics Bacteria 4th Edition Dale ... Molecular Genetics of Bacteria, 4th Edition PDF Download, By Larry Snyder, Joseph E. Peters, .... 1. Molecular genetics of bacteria by Larry Snyder. Molecular genetics of bacteria. by Larry Snyder; Joseph E Peters; Tina Henkin; Wendy Champness. eBook : .... Free Download : Molecular Genetics of Bacteria, 4th Edition,If you are on the hunt ... By Larry Snyder Joseph E Peters Tina M Henkin Wendy Champness PDF.. Molecular Genetics of Bacteria, Third Edition, a book by Larry Snyder, Wendy ... molecular genetics of bacteria : Free Download, Borrow, and Streaming .... Aug 28, 2014 — CMMB 549 – MICROBIAL GENETICS ... Molecular Genetics of Bacteria, by Snyder, L, Peters, JE, Henkin T & Champness,W. ASM. Press .... Edition (PDF) Molecular Genetics of Bacteria 4th Edition by Larry. Snyder, J. E. Peters is a great molecular genetics book available for PDF download. The fourth .... Gene editing is a set of new genetic engineering techniques for altering the genetic material of plants, animals and microbes, such as bacteria, using “molecular .... SEK Genetics, Inc. - Bacterial physiology and genetics - Structural and metabolic biochemistry - Molecular and cellular biology ... Angus Embryos For Sale: SB10 IMRETAILMENOT10D300 SEK GENETICS Snyder Show Pigs. ... Form 8-K. Current report filing. pdf Format Download (opens in new window) word Format .... Free book Molecular Genetics of Bacteria by Larry Snyder. Molecular Genetics of Bacteria. by Larry Snyder. √PDF / √Kindle / √Epub √Magazine √Full .... She teaches undergraduate and graduate microbiology, genomics, and molecular biology and supervises research students. Professor Snyder was awarded the .... Molecular Genetics of Bacteria book. Read reviews from world's largest community for readers. The classic comprehensive and authoritative textbook on bac.... Read PDF Molecular Genetics Bacteria 4th. Edition. Molecular Genetics ... Molecular Genetics Of Bacteria 4th Edition : Free Download ... Molecular Genetics of ...
167bd3b6faGoodman mini split installation manual
software development engineer in test microsoft
texas roadhouse rolls fundraiser instructions
Ashanti Chapter Ii Zip -
httpgeorge-sgh.degalleryapplicationfreebooksdownload-Small-Business-Management%3A-Launching-and-Growing-Entrepreneurial-Ventures-%2C-14-Edition-2007.php
Jorg Widmann Fantasie For Clarinet Solo Pdf Free
sea_magic_connecting_with_the_oceans_energy
the relatives came cynthia rylant pdf
Скачать-Beat Maker (v3 unk 64bit os110 ok14) user hidden bfi ipa
download buku ppdgj iii pdf