IT'S EASIER

TO CONCENTRATE

WITH S&Sthe only system to CO ILLO IIONuse for simultane-

ous concentration

and dialysis. TheS&S system of collodion bags andapparatus is the simplest and fastestway to concentrate proteins and nucleic acids. The bagsare available in MW retentions of 10,000, 25,000 and75,000, and offer fast, convenient concentration and easycollection of the fraction. Recovery is greater than withother systems.The collodion bag system can reduce protein solutions

to near-zero volumes. For instance, the UH 1 00/25 bagswith a 25,000 MW cutoff are ideal for use in concentra-tion of antibodies, enzymes, blood fractions, and concen-tration of urine, synovial and cerebral spinal fluids.

Contact your laboratory supply dealer or write forBulletin M-82. Schleicher & Schuell, Inc., Keene, NH03431. (603) 352-3810. With S&S, it's in the bag.

Schleicher& Schuell

Circle No. 206 on Readers' Service Card

VSll

Circle No. 202 on Readers' Service Card

-UE I

A The world's first. Packaged complete.

Naturally it is more convenient than assembling the componentsyourself. But even more important is its reliability.

For example, the EcoRi DNA Polymerase I is cloned in ourlaboratories to ensure extremely high reproducibility. The dCTP, [a_32p]_

is tested for nick translation by our Biological Testing Laboratory. (Typical incorporationis 40%, and we guarantee 1 x 108 dpm/,ug DNA.) The supercoil PBR322 PlasmidDNA control we use to test each lot of systems is included so you can checkyours. Finally, the DNAse 1, dNTP mixture, stop-buffer, and sterile deionized

water are optimized for compatibility and stability. Approximately twenty assays can be run.A bulletin describing this exclusive system is yours for the asking.

,¢1 New England Nuclear549 Albany Street, Boston, Mass. 02118, Toll-free: 800-225-1572(In Massachusetts and International: 617-482-9595)

NEN Chemnlcal mbH: D-6072 Dreieich, W. Germany, Postfach 401240, Telephone (06103) 85034, Telex 4-17993 NEN D,NEN Canada Ltd., 2453 46th Avenue, Lachine, Que H8T 3C9, Telephone 514-636-4971, Telex 05-821808

1AUUT197 iceN.25o

FREE CatalogNew 4-way relief from problems withminicomputer supplies and accessories.

1. One-stop shopping.nmac (formerly known as

Minicomputer AccessoriesCorporation) has a catalogof over800 products. Every-thing from racks and line-printer paper to connectorsand cables. Each designedto help keep your minicom-puter or word processing 1system up and running.

2. Hassle-free ordering.Inmac lets you order by"

mail or phone. So keep ourSummer '79 catalog close. It makes those once-tough taskslike ordering magnetic media easy, fast and foolproof.3. Fast shipment of just the quantity you need.Inmac ships your order within 36 hours from centers in

California and New Jersey. In a bind? Call us for manyspecial services that insure you get your order to yourinstallation within 24 hours. Call now and give us a chance.4. Field-proven quality means precision performance.

Inmac guarantees every product in these 70 pages forat least 45 days. And even some for up to ten years.

Send for your FREE

Inmac catalog or call

"WWf"wi _fA A-.* C-p-- (408) 727-1970 todayl2465 Augustine Drive, P.O. Box 4780, Santa Clara, CA 95051

0 1979 International Minicomputer Accessories Corporation

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j17 AUGUST 1979 Circle No. 235 on Readers'Servies Card

Ohaus Brainweigsh 300Never before, for so little, could you get so muck.

The Ohaus Brainweigh 300 costs only$1,195 and gives you a capacity of 300gwith a readability of 0.01 g. (If you wantto find out how much that price is goingto save you, just check what our com-petitors are charging for balances withsimilar capabilities.)

And we didn't stop with just eco-nomy We went on to design in featuresthat would be costly "extras" on anyother balance on the market-if youcould even get them.

Like extended visibilityfl§ Stand up; sit down; go

to the back of the room. The|~| display on the Ohaus 300 is*~ still easy to read. That's

because the no-glare window with thebig, easy-to-read digits is deliberatelyangled for maximum visibility whereveryou are. And that can save a lot of head-aches whether you're in a lab, or on theline or in a classroom.

It tells you when it's ready-and when you've goofed

_0 No more guessing-X whether the balance has

settled down; no moreannoying digit flutter. When the "g"appears beside the digits-in 3 secondsor less -it's your guarantee that thereading is stable.

And if the pan is overloaded ordislodged, you'll get an error sign inthe window

The 300 is a new generationbalance

This new, low-* profile balance is only a

little larger than an ordi-nary desk phone. Butpacked inside is enough

advanced technology to make the Ohaus300 a generation ahead of any otherbalance on the market. Its state-of-the-artelectronic components are almost en-tirely plug-in for easy service. And thereare fewer of them-for better reliabilityand more dependable performance.

Want a BCD interface now-or later? Youdon'thaveto

worry about it. Unlikeother electronic bal-

ances, every Ohaus Brainweigh comesequipped tb handle a BCD option. Youcan add a BCD interface right away-orwhenever you come to need it.

Parts and service are as nearas your dealer

The Ohaus 300 ismade right here in theU.S. And although itsbuilt-to-take-it die-castcase and solid state compo-nents put maintenance at a minimum,when the balance finally needs a littleattention, it's nice to know your localdealer can do the job.

Get all the factsIf you'd like to see the rest of the

reasons why the Ohaus Brainweigh 300outclasses the competition, and themany ways it can make your operationfaster, easier and more accurate, justreturn the coupon.

\ ~~~R

The weigh of the future.~~~~~~~~................ a

* ° 1979 Ohaus Scale Corporation®Ohaus Scale Corporation, Dept. 14-089

29 Hanover Road, Florham Park, N.J. 07932

(201) 377-9000

:0O Yes, show me the weigh of the future. Send me the full-color catalog on theOhaus Brainweighs.

O I'm ready to see a demonstration. Please have a dealer sales rep call me.

. NameTitle

* Organization. Address* City* Phone Numbs

Circle No. l

_zi7.er

167 on Readers' Service Card

What's the fairest way of allocating the nation'slimited funds to reduce various risks to human life andhealth? A loaded question, to be sure.

One way of evaluating a given risk-reductionprogram is to compare estimated costs with expectedbenefits, both measured in dollars. But this kind ofanalysis is controversial. For one thing, it requiresplacing a price on life itself.

Here at the General Motors Research Labora-tories, societal analysts have developed a methodwhich avoids that problem completely. It focuses onlongevity and rests on the simple logic that since alllife inevitably ends, no amount of risk reduction cansave lives ... only lengthen them.

The method involves using the extensive data forall categories of mortality risks and determining the ef-fect on longevity of each category independently. Theresults can be summarized for each risk by the equa-tion: Average Years Of Longer Life = 0.2 x AnnualDeaths Per Million Population.

This equation serves two purposes. First, it pro-vides a perspective of days or years gained fromrisk-reduction programs. Second, combined with costestimates, it helps rate the effectiveness of thoseprograms.

To illustrate its utility, we performed a study tocompare the cost-effectiveness of several medical,environmental, and safety programs presently underserious consideration. The chart above shows theextreme variation in the costs of extending life byimplementing those options.

Through such unbiased comparisons, policy-makers can obtain a clearer picture of which programsoffer the greatest potential gain for a fixed budget and,thereby, have a better basis for decision.

How to Flgure

the cost oF living

-a longer liFe

General MotorsResearch LaboratoriesWarren, Michigan 48090

SCIENCE, VOL. 205

COSTS OF EXTENDING LIFE100,000,000 PROGRAM

t- I~~- 1 Coronaryco _ _-AmbulanceY _ ~~~~~~~~~~~~~~~~~System;~10,000,000 System

c) _ _ i Early Lung3 Cancero Detection

3 Tuberculosisad1) _ __" _ Control

4 Home

O ~~~~~~~~~~~~~~~Smoke0 10000 DetectorsA0 H 100 000(D > _ _ _ _ 5 Mandatory AutoCL ._ Lap-Shouldero -H __ _|-BeltsCc 10,000 _c~6 SulturStackO o' __10,0

Scrubbers

C ___l7 HighwayOD XL _ _ _ f l Accident

1000

x

i Rescue Cars

-2 111i1 11 8KidneyX) 111 _ t 1 _ _ _ 111 W Dialysis

ts100 9 Lighting of= _ _ ] _ All XwaysCl ~ ~ - 10 1981 Automotive

CO Standard1 Minute 1 Hour 1 Day 1 Month 1 Year

Average Longevity Gain For Total U.S. Population

648

Calculating the mean weight ornet wei.ghtoU48weighed samplestakes time.Ona Sartorius, it takes I second.On other scales or balances, determining

the average weight of 48 individually-weighedsamples takes time. It may also take a pad andpencil, an adding machine or a calculator.

On a new Sartorius MP Balance, thesame determination takes only seconds. Aftereach sample weighing, simply press a singlekey on the Sartorius keyboard programmer.When all samples have been weighed, press therecall keys for instant display of the meanweight or the number of samples weighed.If printed results are required, simply connectthe balance to an inexpensive Sartorius Printer.

The memory capability of the new SartoriusMP Balances permits the determination of netor fill weights by automatically deducting tareor container weights. Automatic mean weight

and net weight determinations make thesebalances ideally suited for the weighing

2/ of pharmaceuticals, cosmetics,F 4 packaged foods, electronic com-

ponents, industrial parts, routine packaging andfilling, and numerous other applications.

Utilizing built-in microprocessors,Sartorius MP Balances with optional plug-inkeyboard programmers are today's most ad-vanced and versatile electronic weighinginstruments. They are available in single rangeand dual range models with a weighingrange/readability from 0-160g/0.001 g to0-30,000g/1 .0g.

For literature, just write: SartoriusBalances Division, Brinkmann Instruments, Inc.,Cantiague Road, Westbury, N.Y. 11590.

New Sartorius MPElectronic Balanceswith plug-in key-bxoard programmers.

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