Distributing and retrieving chemical information using the World-Wide Web

426 trends in analytical chemistry, vol. 14, no. 9, 1995

internet column

Distributing and retrieving chemical information using the World-Wide Web

Brian M. Tissue * Blacksburg, VA, USA

1. Chemical information on the internet

More and more chemists are distributing chemical information and chemical-education software over the internet. The information ranges from research and preprint databases, conference pro- ceedings, chemistry department information, com- pany profiles, product catalogs, and educational materials [ l-51. The information exists in many different formats, each of which require the appropriate retrieval tool. Common internet distribution and retrieval methods are electronic mailing lists, File-Transfer Protocol (FTP) , Gopher, Wide-Area Information Server (WAIS), Telnet, and Usenet News [ 6,7]. A relatively new transfer protocol is Hypertext Transport Protocol (HTTP) [ 7,8]. HTTP adds some powerful features to information transfer over the internet including support for hyperlinks between different files, graphics display, launching of external programs, and rudi- mentary interactivity. Some HTTP-client software programs, which are known as browsers, also support the older information transfer protocols. These browsers give users a single integrated tool to access a wide variety of internet services [7,8].

This article describes HTTP client and server software and its use to distribute and access chemical information over the internet. A detailed description of the analytical chemistry hypermedia at Virginia Tech illustrates some of the advantages and limitations of developing and distributing hypermedia over the internet.

2. The World-Wide Web

The World-Wide Web( W3, WWW, or Web) is an internet-based hypermedia system that origi-

* E-mail: [email protected]; http://www.chem.vt.edu/

016%9936/95/$09.50

Fig. 1. Screen capture of an HTML document using NCSA Mosaic for Windows. The hyperlinks are underlined.

nated at CERN (European Laboratory for Particle Physics) [7-lo]. The Web consists of all computer files (documents) that are archived on com- puters and accessible through HTTP server software. Each document on the Web has a Uni- form Resource Locator (URL) that identifies it by transfer protocol, internet address, and file type, e.g., http: / /computer.domain.network/filename. html, gopher: / /computer.domain.network, or news:sci.chem. To access hypermedia documents a user runs a browser program such as NCSA Mosaic [ 7,11,12] or NetScape [ 131 on a client computer with internet access. When a user opens a URL in a browser program, the browser retrieves the requested file from an HTTP server by the appropriate protocol, interprets the file type and formatting instructions, and displays the information on the client computer screen. Fig. 1 shows a screen capture of NCSA Mosaic displaying a simple hypermedia document that contains small graphic images and highlighted (underlined) hyperlinks to other documents. Clicking on one of the underlined headings with a mouse pointer retrieves and displays the selected document. Most browsers support in-line images in Graphics Inter-

0 1995 Elsevier Science B.V. All rights reserved

trends in analytical chemistry, vol. 14, no. 9, 1995 427

change Format (GIF), and can support other graphics formats, audio clips, and video clips (MPEG or QuickTime) by launching external viewer or player programs.

3. HTML

The hypermedia documents archived on HTTP servers are written in Hypertext Markup Language (HTML) [ 141. The individual HTML documents are ascii text files that contain formatting com- mands, much like early word-processing or type- setting programs. To illustrate the HTML format the source document for Fig. 1 is reproduced below. Subdirectories were left out of the filenames to simplify this example.

< HTML >

< HEAD > <TITLE> Virginia Tech Chemistry Hypermedia < /

TITLE> </HEAD>

< BODY >

<: HI > Virginia Tech Chemical Education Hypermedia < /HI >

<HR>

The main headings below lead to descriptions of the hypermedia tutorials

that are listed in the menus. A separate <A HREF= “vt-chen-course-

material.html” > Virginia Tech Chemistry Course Material < /A >

document indexes course-specific material for Va Tech chemistry students.

<: HR>

< H3 > < IMG SRC = “VT-Web.gif” > < A

HREF= “Overview.html” > Overview of the Chemistry Hypermedia

Project < /A > < /H3 >

<HR>

<: H3 > < IMG SRC = “VT-ac-Flasks.gif ’ > < A HREF = “ac-

ho.ne.html” > Analytical Chemistry Hypermedia< /A > < /H3 >

< UL>

i: ,I > < H7 > < A HREF= “ac-intro.html” > Introduction to Analytical

Chemistry < IA > < lH7 >

< ._I > < H7 > < A HREF= “ac-basicshtml” > Analytical Chemistry

Basics</A> <lH7>

<: ._I > < H7 > < A HREF= “ac-methodshtml” > Encyclopedia of

Instrumental Methods < /A > < /H7 >

<: _I > < H7> < A HREF= “ac-spectroscopy.html” > Advanced

Analytical Spectroscopy < /A > < /H7 >

( ‘UL>

<HR>

<’ H3 > < IMG SRC= “OrgChem.gif” > <A HREF = “org-

home.html” > Organic Chemistry Hypermedia < /A > < /H3 >

< ADDRESS > Professor Brian Tissue, Department of Chemistry,

Virginia Polytechnic Institute and State University, Blacksburg, VA

24061-0212/(540)231-3786/[email protected]< /ADDRESS>

< /BODY >

< /HTML>

The < > brackets contain the formatting instructions that the browser interprets for displaying the document on the screen. For example: < H# > . . . < /H# > define headers, < HR > places horizontal rules, the < UL > < LI > . . . < /UL > structure defines an unordered list, and < IMG SRC = “filename” > is the file source for an inline image. < A HREF = “filename” > . . . < /A > is an anchor that defines a hyperlink. The browser highlights the text between anchor brackets (underlined in Fig. 1) , and clicking on the highlighted text instructs the browser to retrieve the file listed in the anchor. The file could be another HTML document, an expanded graphic image, or an audio or video clip. The user controls the final display of an HTML document by selecting browser viewing options, such as font and font size.

The current HTML 2.0 specification has some limitations for scientific writing. NCSA Mosaic currently supports the ascii character set, accented characters, superscripts, and subscripts, but not advanced math symbols or Greek letters. HTML 3, which currently exists as an Internet draft, will include tables, figures, text layout. control, and mathematical equations [ 141. Specific browsers may currently support more or fewer features than the “official” HTML standard. HTML is easy to write with a text editor or with stand-alone hypertext editors, word-processor templates, or conver- sion programs, e.g., Rich-Text Format (RTF) to HTML. The Web is expanding so rapidly that it is difficult to stay current on the availability and status of these software tools. The most up-to-date information about HTML authoring and HTTP server and browser software is found on the Web itself [ 81, and in a WWW-FAQ (Frequently-Asked Questions) in the alt.hypertext and camp. infosystems.www.users newsgroups.

4. The Chemistry Hypermedia Project at Virginia Tech

Hypermedia and network delivery have several potential advantages in education and training [ 151. Hypermedia provides links not only to related topics but also to remedial or advanced

428 trends in analytical chemistry, vol. 14, no. 9, 1995

material. The hyperlinks are placed in-context and therefore provide help specifically where it is needed. The hyperlinks also illustrate the connections between advanced and basic topics, which continually reinforces the basic principles and helps students to see the “big picture.” The incor- poration of multimediain instructional material can be more effective than textual descriptions alone [ 16,171. However, multimedia is best used in a supportive role with appropriate text in order to convey the chemical concept and not just a flashy picture.

Distributing educational material via an internet server allows authors to update and append material continuously, provides a record of student use, and allows integrated e-mail communication with authors or instructors. The cost-effectiveness of server delivery versus CD-ROM distribution depends on the scale of the distribution and is difficult to predict. The personnel time required to develop specialized multimedia material will usually exceed eventual distribution costs. The disad- vantage of internet delivery is that it requires the network and computer infrastructure, which is not available to many would-be users, especially K- 12 students. Network bandwidth also places a practi- cal limit on video use, and we use video only when it is necessary to convey a sequence of events such as operation of an instrument.

The goal of the Chemistry Hypermedia Project is to develop and evaluate hypermedia for chemical education. Individual hypermedia documents con- sist of basic theoretical and experimental descriptions of a chemistry topic with links to related topics, basic concepts, and advanced examples [ 15,181. The individual documents are specific and self-contained to allow flexibility in piecing them together for different applications. Keeping the documents short (typically 3-5 computer screens) also minimizes internet transfer time. Fig. 2 shows part of a hypermedia document on simple UV-Vis absorption spectroscopy. The document is mostly text (out of view) describing typ- ical UV-Vis applications and instrumental components such as light sources, monochroma- tors, and detectors. There are hyperlinks to the theory of absorption measurements and the Beer- Lambert law at the beginning of the document and a link to dual-beam absorption spectroscopy at the end of the document. The small window in the lower right of the figure shows a movie player playing a video clip that gives operating instructions for a single-beam spectrophotometer. The

Fig. 2. Screen capture of part of an HTML document on UV-Vis absorption spectroscopy. A movie player is visible in the lower right part of the screen.

browser program launches the player and transfers the video file when a user clicks on a hyperlink (out of view in Fig. 2). The file size for this 30- second movie is 1.3 Mbyte, which takes approximately one minute to transfer to a client with an ethernet connection.

The aim of integrating hypermedia into the chemistry curriculum is to improve the efficiency and effectiveness of students’ study time outside of class and their time in laboratory [ 15,181. We are developing hypermedia tutorials that supply remedial material for students with background deficiencies and pre-lab exercises to improve students’ understanding of an experiment before com- ing to the laboratory. The graphics and video clips in the hypermedia documents illustrate the actual laboratory equipment that students use in their experiments. Students access the individual hypermedia documents from entry-point documents that resemble menus of course topics. A tutorial for a non-laboratory graduate spectroscopy course provides lecture notes with links to remedial material on spectroscopy, optics, and quantum mechanics. It is designed for students who did not have an instrumental analysis course in their undergraduate curriculum. A similar tutorial is under development for senior-level instrumental analysis. It will contain pre-lab assignments that complement the experiment handouts with graphics and video. The pre-labs will also contain multiple choice and simple answer questions for the students to answer that the server can correct. The first full-scale implementation of hypermedia in instrumental analysis (24-36 students) is scheduled for Fall 1995.

trends in analytical chemistry, vol. 14, no. 9, 7995

Student use and feedback in this pilot project will guide plans for further integration of hypermedia into the lower-level analytical and general chemistry curriculum.

There are currently three stand-alone analytical chemistry tutorials (under continuous development) that are designed for outside users [ 181. An Analytical Chemistry Basics tutorial follows a typ- ical course syllabus for sophomore-level analytical chemistry with links to introductory documents on gravimetry, titration, electrochemistry, spectroscopy, and separations. An Encyclopedia of Instru- mental Methods is a menu of instrumental techniques, and an Advanced Analytical Spectros- copy tutorial is a subset of the encyclopedia with additional spectroscopy theory. In keeping with a modular design, these tutorials use the same documents as the course material but arrange them differently.

As of July 1995 the Virginia Tech server is aver- aging over 2400 connections per day, and the number of connections is increasing 20-30% per month (one connection is one file transfer, the number of different clients accessing the server is > 200 per day) [ 191. Approximately 40% of users are from USA educational institutions, 30% are international, and 20% are US commercial. The access patterns range from users who are just “looking around” to users who take an in-depth look at Departmental information or the hypermedia tutorials. An average access load of approximately 1500 connections per day began to saturate a PowerMac 6 100/60AV and MacHTTP software. Our server is now a Silicon Graphics Indy work- station with WebForce server software, and our bottleneck for outside users at peak times appears to be the Virginia Tech link to the internet.

5. Summary

HTML is a relatively easy multimedia authoring language and the popularity and platform-inde- pendence of the Web will make it a stable system for distributing chemical information. The multimedia support of the HTTP protocol greatly enhances the capability of information distribution over the internet and on-line publishing, confer- ences, and education will become more common [5 1. The rapid increase in users currently puts a heavy load on network bandwidth and server hard- ware that requires application designs that mini- mize file-transfer time.

429

Acknowledgements

I gratefully acknowledge the other contributors to the Chemistry Hypermedia Project at Virginia Tech; C.-W. Yip, Y.-L. Wong, R.L. Ear-p, andM.R. Anderson; and financial support from the NSF Division of Undergraduate Education, DUE- 9455382.

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M. Kopelevich, The World-Wide Web Virtual Library: Chemistry, http://www.chem.ucla.edu/ chempointershtml G. Wiggins, Some Chemistry Resources on the Internet, http://www.rpi.edu/dept/chem/ cheminfo/chemres.html S. Bachrach, NIU Chemistry WWW Home Page, http: I lhackberry.chem.niu.edu/ A. Cairns, SciEd: Science and Mathematics Education Resources, http: I I www- hpcc.astro.washington.edu/scied/sciemce.html T.C. O’Haver, Internet Resources for Science and Mathematics Education, http://www.inform. umd.edu/UMS + State/UMD-Projects/MCTP/ Technology/Chemistry.html F.S. Varveri, J. Chem. Ed., 70 ( 1993) 204-208. B.R. Schatz and J.B. Hardin, Science, 265 ( 1994) 895-901. World-Wide Web Home, http://www.w3.org/ H.S. Rzepa, B.J. Whitaker and M.J. Winter, J. Chem. Sot., Chem. Commun., (1994) 1907- 1910. 0. Casher, G.K. Chandramohan, M.J. Hargreaves, C. Leach, P. Murray-Rust, H.S. Rzepa, R. Sayle and B.J. Whitaker, J. Chem. Sot. Perkin Trans. II, (1995) 7-l 1. B.M. Tissue, Y.-L. Wong and C.-W. Yip, J. Chem. Educ., 72 (1995) A116-A117. Available via FTP at ftp.ncsa.uiuc.edu. Use anonymous as user and e-mail address as password, browsers are in the Web/Mosaic subdirectory. Available via FTP at ftp.mcom.com. Use anonymous as user and e-mail address as password, browsers are in the Netscape subdirectory.

[ 141 D.W. Connolly, HyperText Markup Language ( HTML) : Working and Background Materials, http:llwww.w3.orglhypertext/WWW/ MarkUp/MarkUp.html

[ 151 B.M. Tissue, J. Chem. Educ., in press. [ 161 M.E. Hodges and R.M. Sasnett (Editors),

Multimedia Computing: Case Studies from MIT Project Athena, Addison-Wesley, Reading, MA, 1993.

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trends in analytical chemistry, vol. 14, no. 9, 1995

in analytical chemistry from the University of Wisconsin-Madison in 1988. He held postdoctoral positions at the University of Georgia and Los Alamos National Laboratory before beginning his current position of Assistant Professor in the Department of Chemistry at Virginia Polytechnic institute and State University (Blacksburg, VA 24061-0212, USA) in 1993. His research interests include laser-spectroscopy of nanocrystalline materials, laser-induced-plasma time-of-flight

Brian M. Tissue received a B.A. in chemistry from the Johns Hopkins University in 7 983 and a Ph.D.

mass spectrometry, and applications of computer technology in chemical education.

I 44+Mwudti - Pesticide residues in the Philippines: an analytical perspective

C.M. Bajet *, A.W. Tejada Laguna, Philippines

Pesticide regulation and pesticide residue monitoring have been pursued to varying degrees of success in the Philippines but implementation is considered inadequate. Improved regulation and implementation of policies for the monitoring of pesticide residues in foods and feeds are required for local and international trade. Farmers need education on pesticide use, handling, and the risks to humans and the environment. This should be coupled with stringent regulations for pesticide importation, formulation plants, storage, and monitoring of fields and plan- tations.

1. Introduction

In the agriculturally-based Philippines, produc- tive areas have been rapidly decreasing due to con- version of land usage for commercial, residential and industrial purposes. To increase production, the use of pesticides is therefore necessary.

Pesticide sales in 1993 were equivalent to 3.3 billion pesos, 46.17% of which was used in rice,

* Corresponding author.

The Bureau of Plant Industry (BPI) under the Department of Agriculture has a mandate to mon- itor pesticides residues in market produce but it has little or no power to confiscate and destroy food found to exceed the established limits. This is com- pounded by the fact that farmers sell their produce directly or indirectly through middlemen to the market vendor. There is no centralized marketing scheme for all agricultural produce before it goes to the retailer and finally to the consumer. Usually, the vegetables or fruits have long been sold before

0165-9936/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved

followed by banana ( 15.25%)) vegetables (15.14%), mango (9.30%) and pineapple (7.01%) . There are 16 major formulation plants handling 75 active ingredients. Except for fungi- cides, pesticide formulation is done locally [ I].

The Government Agency responsible for pesticide policy in the Philippines is the Fertilizer and Pesticide Authority (FPA) which was created in May, 1977 with a mandate to ensure the agricultural sector of an adequate supply of pesticides at a reasonable price and to protect the public from the health and environmental risks inherent to their use. The pesticide registration process, information system and agromedical program activities are pursued to varying degrees of success. Institutional and legal framework are adequate but implementation of policies, especially for regulating pesticide residues in food and feeds, is deficient.

Documents

Distributing and retrieving chemical information using the World-Wide Web