BeckmanPeptides

,K

;..,. "IFC,A.

#~~~ # D;

Luteinizing Hormone ReleasingHormone * Parathyroid Hormone(bovine 1-34 peptide) * AngiotensinPeptides * Somatostatin * Neuro-tensin * Thyrotropin ReleasingHormone * Bradvkinin * Tuftsin.analogs of Oxytocin. Vasopressin,Vasotocin * and many others.

Beckman -the source you cancount on for peptides of the highestpurity and consistently uniformactivity. Enjoy the convenience ofoff-the-shelf availability of twenty-five different peptides, with morebeing added all the time. For a com-plete listing, requLest Catalog PL-464

from Beckman'Beckmnan Instruments, Inc.,p,Wj/k Bioproducts Depart-

ment. 11 17 CaliforniaAve., Palo Alto, CA94306. Or call us at(415) 326-1970ext. 280.

The Source for Synthetic Peptides

Circle No. 207 on Readers' Service Card

Trace Metals Analyzer

The model 3010 will directly mea-sure lead, cadmium, and copper inblood, urine, and other materials. Afterpreparative chemistry, it will also deter-nmine other metals such as bismuth, tin,indiuLm, and thallium. Analysis is auto-matic and nondestructive. The operatorselects parameters including initial po-tential, final potential, sweep rate, re-corder set point, and integration testpoint which are displayed. The analysisis based on anodic stripping voltam-metry. Environmental Sciences Associ-ates, Incorporated. Circle 682.

Dilutor-Dispenser

Modiel ADP-30SD (Fig. 1 ) uses twoof three pUMp configurations: 2 to 20)0microliters, 20 to 1(000 microliters, and50)t) to 20).000 microliters. It is suitablefori atomilc absorption alndi enzyme anal-ysis and for repetitive volumetric op-erations as well as reagent preparation.Passaioes are nmade of reflon and Pyrex.With an accessory. the ADP-30SD canpick up from 2 microliters to 1 miilliliterand diluLte with 20 microliters to 2t)milliliters, which vields dilution ratiosup to 10,000 to Grummatn DataSystemls. Circle 683.

Fig. l. The ADP-30SD ofTers precisionand reproducibility better than one partper thousand. It is useful in radioimmuntlo-assay protocols.

Spectrophotometer Calibration

The Spectro-Standard standardiza-tion kit consists of an all glass filtersvsterm for checking and monitoringthe key performance parameters ofspectrophotometers. Wavelength, straylight, bandpass, and linearity are easyto check. Chemetrics Corporation. Cir-cle 688.

Electronic Balance

The PR70)0 is a dLual-range. top-loading balance with readability to 0..1grarn in the 0- to 700-gram range and0.01 gram in the 0- to 70-gramn range.Precision is + 0.005 gram and + 0.0`gram in the 700- and 70-graimi ranges,respectively. A touch bar controls on-off, tare and zero set and the range isselected with push-buttons. IThe re-sponse time is less than 2 seconids.Mettler InstruLmenits Corporation. Cir-cle 684.

Universal Test Stand

The UTSM-EL model is a tensilestrength tester that is also designed forcompression loads with a maxinmum ca-pacity of 5()0 pounds, 25t) kilograms.and 250 dekanewtons. The digital dis-plav will hold both peak force load andm1axiMum deflection. The display willread in English or metric units and out-puLt for recorder or plotter is standard.AccuLracy is to 0.25 percent of fullscale plus or minus one least signifi-cant digit. John Chatillon & Sotns.Circle 681.

Neswlysoffered instl-lumentation, aipparitts, andlahboraitory materials of initerest to rese.irchers itnill disciplitnes in ac.tdernic, indUstrial, and gov-iX nnient organizaitions at-e feati-red in this space.Fiipihasis is giveni to puirpose, chiel characteriistics,nd avsailabilios of produicts andi materials. Et-

drsFemient by Si tince or A AAS is niot iplicd(lAdditional information miav be obtainedl fiomi theIanufactit li-ers or stippliers named bs circling theappr opriate ntimhcr on the Readers' Service Ci cid(,,cc pages tl02A and 166() and placing it in themailb)x. Postage is free -RICHARD G. SioNINFR

SCIENCE, VOL. 188

/MOMMO/00///

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thenewsuperduper

It's a technical wizard.It's the quickest, simp-lest and most reliableway to make the finestquality dupes, filmstrips,

L internegs, section-al blowups andsuper- impositionswithout guesswork

U Write today toget the full storyabout

the new, more versatileBOWENS ILLUMITRAN 3

Circle No. 144 on Readers' Service Card

Now! Painless ProductPhotography

TechnalTransi-Table

Assure shadow-free product shots.Reduce costly retouching. Frostedtranslucent plastic provides sweep-ing working surface. Sturdy frame-work, easy to assemble in minutes.Overall 63" high, 48" wide. Ideal forany studio.See your dealer or write for literature.

Fig. 2. Colordip has a tungsten light sourcein the probe head which with eight filtersand a fiber optic light system enables theoperator to dispense with cuvettes, samplepreparation, and problems caused by straylight.

Colorimeter

Colordip (Fig. 2) features a fiberoptic light system in the probe whichmeasures light in a fixed path length.Eight filters in the probe head coverthe range from 445 to 620 nanometers.The panel meter displays optical dens-ity and percentage transmission onseparate scales. Shandon Southern In-struments, Incorporated. Circle 685.

Nuclear Magnetic Resonance

Spectrometer

The EM-390 has a 21.14-kilogausspermanent magnet which is temperaturecompensated, thermostated, thermallyinsulated, and magnetically shielded.Proton sensitivity for 90 megahertzstudies is 50 to 1 (5-millimeter sample,1 percent volume-to-volume ethylben-zene) and there is no loss of inherentresolving power. Resolution is 0.5 hertzor less. The device has an integraltachometer and offers sweep ranges of0.2 to 100 parts per million. VarianInstrument Division. Circle 687.

Still

Autostill 1.5 is automatic. Power andwater cut off when the receiver is full.Operator selects either complete shutdown or cycling off and on as water isremoved from the receiver. The distil-late produced is pyrogen-negative with

Circle No. 145 on Readers' Service Card

$495.At lastayou canafford.

FEATURES:* 160 steps of programming* Algebraic operation* Complete set oftrig. functions

* Full size keys and display* AC/DC operation* One day service in 365 cities-7

Monroe, The Calculator Company550 Central AvenueOrange,NewJerseyO7051

Yes. I'm interested. Havea aIsalesman call and demonstrate.Yes. I'm interested. SendDIcomplete literature.

Name - Title _

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MONROETheCaluaCompany

L- S411 J

Circle No. 98 on Readers' Service Card

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a resistivity of 1.2 megohms per squarecentimeter. Wheaton Instruments. Cir-cle 689.

Recorder-Logger

The TI-Graphics 200 is a strip-chartpotentiometric recorder. It uses thermalstyli, a stationary solid state printhead,and a stable, thermally sensitive paperto record one or two continuous traceson a 10-inch-wide chart while it printsdata over the middle of the chart.Texas Instruments. Circle 686.

Fraction Collector

The Alpha 200 occupies less than1.25 square feet of bench space whileit accommodates 200 tubes. It willautomatically shut down in case ofliquid overflow or mechanical jamming.Other features include a digital display,an event marker, and a stainless steelcollection platform. Buchler Instru-ments. Circle 680.

Literature

Liquid and Gas ChromatographySupplies includes columns, packings,syringes, purifiers, fittings, and manyother products. Alltech Associates. Cir-cle 690.11 APRIL 1975

Product Guide lists amplifiers, ana-log-digital converters, panel meters, andcircuitry for many types of instrumen-tation. Analog Devices. Circle 691.

Rotors, Tubes and Accessories forPreparative Ultracentrifuges is a 48-page catalog. Beckman Instruments.Spinco Division. Circle 692.

Optical Mounts, Positioning Slidesand Accessories includes a completeline of optical building blocks. Daedal,Incorporated. Circle 693.

Multiplier Phototubes describes de-vices for measuring ultraviolet, visible,and infrared radiant energy. EMRPhotoelectric. Circle 694.

Finnigan Spectra is a periodic news-letter. The February 1975 issue fea-tures an article on mass fragmentogra-phy and other analytic techniques.Finnigan Corporation. Circle 695.

Laboratory Catalog lists equipmentfor analytic, clinical, academic, and in-dustrial research. General LaboratorySupply. Circle 696.

Oceanographic and Limnologic Cata-log includes over 110 products and anappendix contains 14 pages of practicalreference material. InterOcean Systems.Circle 697.Power Supply Catalog features elec-

tronic apparatus for design and re-search. It has illustrations and wiringand circuit diagrams for most items.Lambda Electronics. Circle 698.

Subsurface Investigation Catalog de-scribes geophysical instruments and hasarticles on sampling and coring meth-ods. Soiltest, Incorporated. Circle 699.

Ultrasound in Radiation TherapyPlanning is a monograph devoted to thisnoninvasive, nontraumatic, diagnostictool. Unirad Corporation. Circle 701.

Wiltron Technical Review for March1975 explores system accuracy inmicrowave measurements. WiltronCompany. Circle 700.Oxygen Analyzer Handbook surveys

methods of measurement and describesavailable apparatus. Delta F Corpora-tion. Circle 884.

Electrical Maintenance Hints is a1450-page manual available for $15.Westinghouse Electric Corporation.Circle 885.Vacuum Pump Comparator Chart

provides directions and formulas forconverting vapor flow into equivalentpounds of air per hour, among otherthings. Leybold-Heraeus, Incorporated.Circle 886.Gas Chromatography Supports,

Chemicals and Accessories describes allsupplies for this means of analysis.Analabs, Incorporated. Circle 887.

NEW CATALOGFROM ISCO

instruments for highand low pressure liquidchromatography andelectrophoresis

You'll find 56 pages describingcomplete high performance liquidchromatographs, L/C components,and instruments for other separat-ing techniques used in the re-search lab. Components includeabsorbance monitors with unsur-passed performance and manyfeatures unavailable elsewhere,high and low pressure pumpsincluding models which will repro-duce any gradient program you'llever need, large and small frac-tion collectors, and a digitalelectronic integrator specificallydesigned for L/C.

Check the number below on yourreader service card for a currentISCO catalog. If you're in a hurry,write direct or phone collect [402]464-0231.

scoBOX 5347 LINCOLN, NEBRASKA 68505PHONE (402) 464-0231 TELEX 48-6453

Circle No. 186 on Readers' Service Card

173

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PRODUCTS and MATERIALS

DOI: 10.1126/science.188.4184.170 (4184), 170-173.188Science 

ARTICLE TOOLS http://science.sciencemag.org/content/188/4184/170.citation

PERMISSIONS http://www.sciencemag.org/help/reprints-and-permissions

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trademark of AAAS. is a registeredScienceAdvancement of Science, 1200 New York Avenue NW, Washington, DC 20005. The title

(print ISSN 0036-8075; online ISSN 1095-9203) is published by the American Association for theScience

1975 by the American Association for the Advancement of Science

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