Search

In recent years, there has been a large-scale boom in mining in the present-day Swedish part of Sapmi, leading to protests from Sami activists as well as environmentalist groups. To the protesters, issues of Swedish colonialism and Sami indigeneity are central, and history becomes important. Taking its starting point in the mining conflicts, this article discusses Sami archaeology and claims for Sami indigenous land and cultural rights. We argue that it is important to further explore the colonial history in Sapmi, and its meaning and consequences today. Archaeology can contribute with new perspectives on colonial histories and relations, and connections between past and present in Sapmi. At the same time, many issues concerning the ethics and politics of archaeology need to be discussed. Furthermore, in discussions on Sami archaeology and heritage management in Sapmi, it is important to consider experiences from the international fields of postcolonial studies and indigenous archaeology.

Resume La chirurgie orthopedique et traumatologique est une des chirurgies les plus exposees aux plaintes des patients. Une etude retrospective de 791 declarations de plaintes aupres d’une meme assurance survenues a une cohorte de 794 chirurgiens sur une periode de cinq ans (2002–2007) fournit un cadre d’analyse des dimensions du risque de l’exercice professionnel. Dans la base consideree, 6,8 % des chirurgiens concentrent 46,8 % des declarations de plaintes ; ils en ont eu cinq ou plus en cinq ans, et representent 64,1 % du cout a charge pour l’assurance. Inversement 65 % des chirurgiens n’ont eu aucune declaration dans cette periode. Le « sur-risque » concerne particulierement la chirurgie du rachis et de la hanche alors que la chirurgie du membre superieur est au contraire sous-representee. La discussion analyse les limites de l’etude et propose une comprehension des causes profondes de ces sinistres selon trois dimensions du risque : le type de chirurgie, le type d’exercice professionnel (etablissement, organisation de l’activite) et des facteurs personnels (competence a communiquer, traces de vie, etc.).

Summary Introduction Knee arthrodesis may be the last possible option for infected total knee arthroplasty (TKA) patients and in revision cases involving severe bone loss and/or extensor mechanism damages. Success in these situations depends on achieving good fixation assembly stability. We report bone fusion results using a fixation technique combining cross-pinning by two Steinman pins with a single-frame external fixator. Remission of infection at long-term follow-up was an additional criteria assessed for those cases initially treated for sepsis. Hypothesis This fixation modality improves fusion rates. Patients and methods In six of this series of eight patients (mean age: 59 years), surgery was performed in a context of infection: five cases of infected TKA, and one case of septic arthritis. In the other two cases, arthrodesis was respectively indicated for a severe post-traumatic stiffness compounded by extensor system rupture and for a fracture combined to a complete mechanical implant loosening. In three of the six infection cases, arthrodesis was performed as a single-stage procedure. All patients were operated on using the same technique: primary arthrodesis site stabilization by frontal cross-pinning with two Steinman pins, followed by installation of a sagittal external fixator frame. Results were assessed at a mean 8 year follow-up. Results All the arthrodeses showed fusion at a mean 3.5 months (range: 2.5 to 6 months) postoperative delay without reintervention. Weight-bearing was resumed at 2 to 3 months. The external fixator was removed at a mean 5.2 months. No recurrence of infection was observed over a mean follow-up of 8.2 years (range: 1 to 15 years). Three complications occurred: one hematoma, managed surgically; one supracondylar fracture treated orthopedically; and one osteitis, managed by surgical curettage. Discussion This knee arthrodesis technique proved effective, with no failures in this short series, especially in cases of primary infection. It is a reproducible means of osteosynthesis, with little subsequent morbidity. Fixation in two orthogonal planes seemed to provide the stability required to achieve bone fusion. This assembly avoids internal fixation, which is never risk-free in a context of primary sepsis. Level of evidence Level IV. Retrospective study.

Resume Introduction L’arthrodese de genou est parfois la seule solution therapeutique chez les patients presentant une prothese totale de genou infectee ou une perte osseuse majeure avec rupture de l’appareil extenseur. La reussite de cette intervention est correlee a l’obtention d’une bonne stabilite du montage d’osteosynthese. Nous avons etudie les resultats en termes de fusion osseuse d’une technique d’osteosynthese associant un brochage en croix par deux clous de Steinmann et un fixateur externe monoplan. Nous avons secondairement evalue le controle de la remission infectieuse au dernier recul pour les cas operes en contexte septique. Hyothese Le montage preconise ameliore le taux de consolidation. Patients et methodes Dans cette serie de huit patients, (âge moyen de 59 ans), six patients ont ete operes dans un contexte infectieux : cinq infections sur une prothese totale de genou et une osteoarthrite. Les deux autres indications d’arthrodese etaient une raideur post-traumatique associee a une rupture d’appareil extenseur et une fracture sur prothese descellee. Pour trois des six infections, l’arthrodese a ete realisee en un seul temps operatoire. Tous les patients ont ete operes selon la meme technique chirurgicale : stabilisation premiere du foyer d’arthrodese par deux clous de Steinmann en croix dans le plan frontal, puis mise en place d’un fixateur externe dans le plan sagittal. Les resultats ont ete evalues a un recul moyen de huit ans. Resultats Toutes les arthrodeses ont fusionne en premiere intention dans un delai moyen de 3,5 mois (2,5 a 6 mois). La reprise de l’appui a ete autorisee dans un delai de deux a trois mois postoperatoires. Le fixateur externe a ete retire a un delai moyen de 5,2 mois. Aucun reveil infectieux n’a ete constate a un recul moyen de 8,2 ans (1 a 15 ans). On rapporte trois complications : un hematome evacue chirurgicalement, une fracture supracondylienne traitee orthopediquement et une osteite sur fiche traitee par curetage chirurgical. Discussion Cette technique d’arthrodese du genou est efficace puisqu’elle n’a pas connu d’echec dans cette courte serie, meme en contexte infectieux. Il s’agit d’une solution d’osteosynthese reproductible et grevee d’une faible morbidite. La fixation dans deux plans orthogonaux semble efficace pour obtenir la stabilite suffisante necessaire a l’obtention de la fusion osseuse. Ce type de montage evite le recours a une fixation interne toujours discutable en contexte septique. Type d’etude : etude retrospective. Niveau IV.

Streams and riparian areas in the Bowron River watershed were assessed using the riparian management routine effectiveness evaluation, a protocol developed for postharvest operational monitoring in British Columbia. Located in the British Columbia interior, the study watershed has had several decades to recover since a period of intensive salvage logging from 1977 to 1987 in response to a spruce beetle ( Dendroctonus rufipennis ) outbreak. Correlations were found with site-specific watershed characteristics and attributes that are used to answer the protocol indicator questions. Channel width was the strongest covariate, exhibiting the most significant relationships with the stream and riparian attributes. Suggestions on how to adjust standard protocols for stream size and landscape heterogeneity are discussed and include the use of appropriate reference sites for baseline data. We used correlations with watershed characteristics and multiple regressions based on regional reference sites to predict upper and lower threshold values by which attribute measurements could be compared. Sites that were assessed above or below threshold values for an attribute were considered to be outside the range of natural variation and were given a failing score. Attributes with the most failures 20–30 years postharvest were disturbed ground, bare soil, undercut banks, and shade.

Adequate (wide or marginal and uncontaminated) margins and reconstruction are difficult to achieve when performing an internal hemipelvectomy for bone sarcomas involving the sacroiliac joint. We evaluated whether adequate surgical margins could be achieved and if functional outcomes could be predicted based on the type of resection and reconstruction. Forty patients had resections of the sacroiliac joint. Vertical sacral osteotomies were through the sacral wing (n = 2), ipsilateral sacral foramina (n = 27), sacral midline (n = 9), or contralateral foramina (n = 2). Iliac resections were Type I, Type I-II with partial or total acetabular re-section, or Type I-II-III. Surgical margins were adequate in 28 of 38 patients (74%), two (7%) of whom experienced local recurrence, compared with seven of 10 (70%) patients with inadequate margins. Reconstruction consisted of restoring continuity between the spine and pelvis. Resection of the entire acetabulum and removal of the lumbosacral trunk were the two main determinants of function, as assessed using the Musculoskeletal Tumor Society score. There were no life-threatening or function-threatening complications. Internal hemipelvectomy with a limb salvage procedure can be achieved with adequate surgical margins in selected patients. Functional outcomes can be predicted based on the type of resection and reconstruction, which helps the surgeon plan the procedure and inform the patient.

Resume L’etude rapporte les resultats d’une serie continue, prospective, multicentrique de 425 protheses Wallaby I ® conservant le ligament croise posterieur, posees par le groupe Guepar de 1992 a 1995. Le composant femoral de cette prothese presente des condyles asymetriques et divergents pour se rapprocher le plus possible de la cinematique du genou normal. Le plateau tibial en polyethylene est fixe. L’âge moyen des patients (70,5 ans), la repartition homme (28,3 %) et femme (71,7 %), l’etiologie (91 % d’arthrose primitive ou secondaire) et la deviation preoperatoire des genoux (65,6 % de varus > a 3° et 24 % de valgus > a 4°) etaient identiques a ceux qui sont publies dans la litterature pour ce type de prothese. Vingt-six protheses ont ete suivies moins de 1 an, 84 moins de 5 ans et 315 5 ans ou plus. Parmi les 399 genoux suivis plus de 1 an, il y a eu 4 infections (1 %) dont 3 ont necessite le changement de prothese, 3 fractures du femur toutes post-traumatiques, 2 descellements (1 global et 1 tibial) ayant necessite une reprise, 1 descellement tibial et 3 descellements rotuliens non-repris. Trois patients presentaient des douleurs anterieures du genou traitees avec succes par 2 resurfacages secondaires de la rotule et 1 section de l’aileron rotulien externe. Dix-neuf fractures de rotules (4,7 %) (dont 17 decouvertes fortuitement) constituaient la complication la plus frequente, sans retentissement fonctionnel. Le score moyen IKS genou postoperatoire etait de 90,5 points et le score moyen IKS fonction de 61,6 points. La mobilite moyenne etait de 110,5° ; 72,9 % des genoux etaient axes suivant la classification radiologique IKS, La survie de cette prothese a 8 ans (suivant Kaplan Meier) etait de 97,7 % quelle que soit la raison du changement de prothese et de 98,5 % en ne prenant comme evenement que la reprise pour descellement aseptique. Ces bons resultats corroborent ceux qui sont publies dans la litterature concernant les protheses conservant le ligament croise posterieur a plateau tibial fixe.

Resume L’objectif de ce travail etait de comparer les enregistrements electrogoniometriques de la marche d’un groupe temoin de 9 sujets et de 2 groupes de sujets porteurs de protheses totales de genou, conservant ou sacrifiant le ligament croise posterieur (LCP), comportant respectivement 10 et 6 patients. La marche a ete etudiee en terrain plat a 3 vitesses differentes. Nous avons recueilli les angles de flexion-extension du genou et les principaux parametres spatio-temporaux de la marche. La marche s’effectuait de la meme facon avec les protheses conservant ou sacrifiant le LCP, malgre les differences theoriques de cinematique articulaire entre les deux implants. Il existait une modification de la phase d’appui, pendant laquelle l’amplitude de flexion etait liee a la vitesse et etait diminuee dans le groupe des protheses. Cette diminution d’amplitude se repercutait probablement sur la qualite de la marche car elle etait correlee avec une diminution des parametres spatio-temporaux en rapport avec la performance de la marche. Nous avons attribue cette diminution d’amplitude pendant la marche, que la mobilite sans appui ne laissait pas prevoir, par une interaction entre la cinematique articulaire, le systeme musculo-ligamentaire et le schema locomoteur.

Remote dipole effects as a means to accelrate ru (aminoalcohol)-catalyzed transfer hydrogenation of ketones

2-Azanorbornyl-derived amino alcohols were prepared and evaluated as ligands in the Ru(II)-catalyzed asymmetric transfer hydrogenation of aromatic ketones. To improve selectivity and rate, the structure of the ligand was optimized. Acetophenone was reduced using 0.5 mol % catalyst in 40 min in 94% ee. This system was also able to reduce a wide range of aromatic ketones to the corresponding alcohols, while maintaining high enantioselectivities and yields. The effects of catalyst loading and the presence of cosolvents in the reaction vessel were examined, and a linearity study was also done.

The mechanism of the Ru(arene)(amino alcohol)-catalyzed transfer hydrogenation of ketones using isopropyl alcohol as the hydrogen source has been studied by means of hybrid density functional methods (B3PW91). Three mechanistic alternatives were evaluated, and it was shown that the reaction takes place via a six-membered transition state, where a metal-bound hydride and a proton of a coordinated amine are transferred simultaneously to the ketone. Further calculations provided a general rationale for the rate of the reaction by comparison of steric effects in the ground and transition states of the ruthenium hydride complex. It was found that the TS has a strong preference for planarity, and this in turn is dependent on the conformational behavior of the O,N-linkage of the amino alcohol ligand. Finally, a general model, rationalizing the enantioselectivity of the reaction, was developed. Experimental studies of both rate and enantioselectivity were used in order to support the computational results.

New Expedient Route to Both Enantiomers of Nonproteinogenic a-Amino Acid Derivatives from the Unsaturated 2-Aza-Bicyclo Moiety

Responders to spill accidents need to have at their fingertips a method of rapid prediction of chemical cloud dispersion behavior and other relative information to protect the public from death and injury during evacuation of the affected area. A survey of 123 chemical spill accidents in the US where evacuations occurred revealed that available mathematical models were not used to predict cloud dispersion behavior while the event was under way, although modeling was sometimes done after the fact. The evacuation distances based on a given downwind concentration (level of concern) vary considerably, depending upon the chemical released and upon atmospheric turbulence resulting from solar insolation and wind blowing across surface features. Examples are presented. The problem is complicated because available mathematical models and look-up tales often do not give the same answer under the same conditions, nor do authorities agree on the concentration levels representing a level of concern on which to base evacuations. The responders to chemical spills need to be aware of these limitations, recognizing that modeling is a tool and does not represent ultimate truth. Yet modeling is useful to responders and is required by law in the US in developing possible accident scenarios under risk managementmore » plans as part of the Clean Air Act. Western Research Institute, in surveying the problems, has determined a need to communicate the benefits of modeling in a format designed for responders and others in the decision-making processes. A system for estimating evacuation distances has been developed for a hand-held computer for field use. The major features are that the user inputs the chemical spilled, spill location, time of day, cloud cover, and source spill information; evacuation distances based on a level of concern are calculated in seconds. The system is designed for planners and emergency response personnel without special modeling or computer skills.« less

Isolated injuries of the scapho-trapezial ligament complex are not well recognized. The ligament complex comprises the stout scapho-trapezial ligament, the floor of the flexor carpi radialis (FCR) tendon sheath and the scapho-capitate ligament. Between August 1991 and May 1992, we diagnosed and treated four cases of partial chronic post-traumatic lesions of this ligament complex. There was chronic pain at the base of the thenar eminence and instability of the thumb-index-middle finger pinch. Standard X-rays were normal. The diagnosis of ligament rupture was confirmed by mid-carpal arthrography showing filling of the sheath of FCR tendon. Surgical exploration showed complete rupture of the tendon sheath of FCR in two cases, associated in the other two cases with complete rupture of the scapho-trapezial ligament. Direct repair of the ligamentous elements was performed in all cases. The tendon of FCR was sutured to the tubercle of scaphoid to protect and to reinforce the ligament repair. The patients have been followed-up for between 6 and 12 months. All four patients recovered normal pinch strength to the middle finger. One patient suffered from chronic pain at work.

A highly diastereoselective reaction of 2-azanorbornyl enolates with electrophiles has been studied. Deprotonation of 4 with LDA at low temperature affords the corresponding exocyclic lithium enolate 5, which reacts with different electrophiles such as alkyl halides, aldehydes and acyl chlorides to give the corresponding exo addition products 6. The products are formed in good yields and with diastereoselectivities above 95%.

2-Azanorbornyl alcohols: Very efficient Ligands for Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Aromatic Ketones. D. A

A highly diastereoselective reaction of 2-azanorbornyl enolates with electrophiles has been studied. Deprotonation of 4 with LDA at low temperature affords the corresponding exocyclic lithium enolate 5, which reacts with different electrophiles such as alkyl halides, aldehydes and acyl chlorides to give the corresponding exo addition products 6. The products are formed in good yields and with diastereoselectivities above 95%.

A test of comparative in vitro cerato-ulmin wilt toxin production in the aggressive and non-aggressive subgroups of the Dutch elm disease pathogen Ophiostoma ulmi was carried out by turbidity and ELISA methods. Ten non-aggressive, ten EAN aggressive and ten NAN aggressive isolates were tested from a range of geographical sources. In liquid shake cultures the non-aggressive isolates produced the greatest and the NAN aggressives the least mean biomass. Despite considerable variation in cerato-ulmin production by individual isolates in three separate experiments, both the turbidity and ELISA methods showed a clear separation of the non-aggressive and aggressive subgroups. Non-aggressive isolates produced little or no cerato-ulmin (ELISA range of means 0–56.0 ng/ml) and EAN and NAN aggressive isolates moderate to high levels (EAN 1.6–89.0 × 104 ng/ml and NAN 0.2–300 × 104 ng/ml). In the aggressive isolates no correlation was detected between cerato-ulmin production and either biomass or pathogenicity to clonal Commelin elm. The role of cerato-ulmin in the pathogenicity of O. ulmi is discussed.

Le choix de la conservation ou non du LCP repose avant tout sur des convictions personnelles et la notion d’avantages pratiques et theoriques, qui pour la plupart n’ont pas ete dementis par l’experience. Cette conservation du LCP, meme si elle ne reproduit que de facon inconstante le roulement-glissement des condyles femoraux sur le tibia, semble diminuer la frequence de l’instabilite prothetique, mais expose au risque rare de rupture secondaire. L’eclectisme en matiere de conservation ou non du LCP dans les protheses a plateau mobile peut rester la regle, meme si techniquement la quasi-totalite des genoux protheses peut beneficier, entre des mains expertes, d’une conservation en poussant loin ce type d’indication.

A cysteine protease that initiates degradation of vitellin (Vt) in the orthopteran Blattella germanica, and its proprotease precursor, were purified from yolk and partially characterized. The protease, purified 300-fold, contains three peptides of Mr 27,000, 29,000, and 31,000. A comparison of the purified enzyme's action pattern on Vt in vivo and in vitro confirmed its role in Vt processing. Protease-deficient yolk (day 0 postovulation) contained peptides of Mr 35,500, 37,000, 39,000, and 41,000, which were absent from yolk with protease activity. These were replaced by three peptides of approximately Mr 29,000, at days 2-3, the same time in development that protease expression and acidification of yolk granules occur (Nordin, J. H., Beaudoin, E. L., and Liu, X. (1991) Arch. Insect Biochem. Physiol. 18, 177-192). Acidification of purified proprotease converted it to three peptides of approximately Mr 29, 000 with cysteine protease activity. This conversion also required participation of a cysteine protease. Activated proprotease had the same pH activity profile, susceptibility to inhibitors, and cathepsin classification (L) as the protease. These results indicate that the Vt-processing protease is derived from a proprotease, which is activated in vivo by a developmentally regulated decrease in intragranular pH.

To assess the prevalence of lead intoxication in children in a defined low-risk population at the new levels recommended by the Centers for Disease Control and Prevention.During an 11-month period, whole blood lead tests were performed on 4678 children at routine well-child visits at 9 months and 2 years of age. For the last 8 months of the study, parents were asked to complete a prescreening risk factor questionnaire at these visits. The questionnaire and blood lead results were then matched. Data were collected from October 1, 1991 through August 31, 1992.The study subjects were all enrolled in Group Health, Inc, a large health maintenance organization. Its 17 staff model clinics serve urban and suburban populations in the Minneapolis-St. Paul area. More than 95% of the population had coverage based on employment, not Medicaid.Results indicated that 2.5% (n = 119) of the children had BPb levelsor = 10 micrograms/dL. Urban clinics had rates of elevated BPb levels three to eight times those of suburban clinics (P.00001), but the number of elevated BPb levels at the suburban clinics was greater than expected. BPb levels were significantly higher in summer and fall (P.00001). The prescreening questionnaire addressed five areas potentially associated with risk according to the literature: housing, siblings with lead poisoning, parental hobbies or work involving lead, proximity to highways, and use of cultural medicines. Positive correlations were found between elevated BPb levels and residences built before 1950 (P.00001). For children living in housing built before 1950, positive correlations were found between elevated blood lead levels and peeling paint (P.01) or remodeling (P.0001).Children who are at low socioeconomic risk but who live in housing built before 1950 are at increased risk for lead poisoning. The risk is greater if the house has peeling paint and especially if there is recent or ongoing renovation. Recommendations based on these results and the Centers for Disease Control and Prevention guidelines are made for screening programs in similar populations, and for the need to increase community awareness concerning this issue.

The galactomannan of surface grown Aspergillus niger has been isolated by alkaline extraction of hyphal walls and characterized structurally. Its elution profile, from a column of Bio-Gel P-150, reveals a broad range of molecular sizes grouped into two fractions. Gas chromatographic and colorimetric analyses indicate that each fraction is composed of approximately equimolar quantities of galactose and mannose plus 12 to 14% glucose. Both have similar low optical rotations and contain acid labile galactose. Methylation, Smith degradation, acetolysis, reactivity with concanavalin A and beta-D-galactofuranosidase, plus digestionof galactose with D-galactose oxidase, were techniques employed to determine the polysaccharide's covalent structure. Results of these studies indicate that it is composed of a series of chains, 5 to 9 hexose units in length, connected by alpha1 leads to 6 bonds between mannopyranosyl moieties. The external portion of each chain consists of a galactose tri- or tetrasaccharide of the general structure Galf beta1 leads to 4 Galp(1-2) 1 leads to 4 Galp1 leads to. This segment is connected via a (1 leads to 2) linkage to the internal portion which is a di- to pentasaccharide of mannopyranosyl units joined in alpha1 leads to 2 glycoside linkage. Combination mild acid hydrolysis and methylation experiments indicate galactofuranosyl terminal units are attached only to galactose. The organization of glucose into the overall structure of the polymer has not been determined. Structural relationships of this polysaccharide to both fungal and yeast galactomannans are discussed.

Homologous oligosaccharides with degrees of polymerization of 7 to 15 have been isolated from the nigeran-protein complex of Aspergillus awamori Nakazawa (QM873). Each contains an uneven number of glucose units, differs from its nearest homolog by two residues, and contains the sequence Glc(alpha , 1 leads to 3)Glc- (alpha , 1 leads to 4)Glc at its reducing terminus.

The chemical constitution of the carbohydrate portion of mycodextranase, an exocellular endo-alpha(1 yields 4) D-glucanase of Penicillium melinii, has been investigated. At least 80% of the carbohydrate, consisting exclusively of mannose and glucose, is released from protein by treatment of the enzyme with 0.05 M potassium hydroxide plus 1 M sodium borohydride or 0.5 M sodium hydroxide at 50 degrees. There is concomitant destruction of 60% of the threonine and 15% of the serine of the treated enzyme and an increase in absorption, at 241 nm, of the treated protein's spectrum, indicative of an O-glycosidic beta-hydroxyamino acyl linkage between untreated protein and its associated carbohydrate. Mannose is the monosaccharide involved in this linkage. Smith degradation, methylation, and glycosidase digestions of the carbohydrate indicate that it is present in mycodextranase as side chains of mannose, glucosyl alpha(1 yields 2)-mannose, and mannosyl alpha(1 yields 2)-glucosyl alpha(1 yields 2)-mannose units with each enzyme molecule bearing a calculated average of 25 side chains. Separation of pronase glycopeptides by gel filtration on Sephadex G-25 revealed that 96% of the carbohydrate is present in the highest molecular weight fraction which contains 60% of the threonine of mycodextranase but only 3.5% of the aromatic acids judged by its absorbance at 280 nm. Further fractionation of this glycopeptide component on Sephadex G-75 indicates carbohydrate is restricted to two fractions, one containing 71% by weight of the threonine and serine of mycodextranase and 56% of its carbohydrate. These results suggest carbohydrate chains of mycodextranase are clustered in a few threonin-rich regions along the polypeptide chain rather than being separated from each other by nonglycosylated areas.

(1944). Determining Sample Size. Journal of the American Statistical Association: Vol. 39, No. 228, pp. 497-506.

The authors have decided to limit this review to a report of the recent work on the enzymatic synthesis of the higher plant polysaccharides, a consideration of the general problem of polysaccharide biosynthesis, and a . review of those aspects of the chemistry of polysaccharides which have a particular bearing on biosynthetic studies. A review of the broad aspects of the chemistry and biochemistry of the polysaccharides has just appeared as this is being submitted (1) and there is little purpose in covering the same ground again.

(1961). A METHOD OF REPLACEMENT ANALYSIS. The Engineering Economist: Vol. 6, No. 2, pp. 1-19.

(1971). A Review of: INTRODUCTION TO CONTEMPORARY MICROECONOMICS by Vivian Charles Walsh. The Engineering Economist: Vol. 16, No. 2, pp. 149-151.

Pion stopping power ratios are essential parameters for pion radiotherapy treatment planning. The validity of scaling proton stopping powers to pions is called into question since the pion mass is intermediate between the electron and proton masses. Direct measurements of stopping power ratios with respect to water were made for 60 MeV pions of both charges in Teflon, Plexiglas, nylon, paraffin, gelatine, tissue-equivalent plastic (Shonka A150), graphite, aluminium, steel and copper. Corrections for multiple scattering and energy dependence of the stopping power are applied. Measured stopping power ratios at an accuracy of 0.6% are in agreement to within the limits of experimental error with stopping power ratios calculated from the Bethe-Bloch equation using elemental I-values and Bragg additivity.

The chemical constitution of the carbohydrate portion of mycodextranase, an exocellular endo-alpha(1 yields 4) D-glucanase of Penicillium melinii, has been investigated. At least 80% of the carbohydrate, consisting exclusively of mannose and glucose, is released from protein by treatment of the enzyme with 0.05 M potassium hydroxide plus 1 M sodium borohydride or 0.5 M sodium hydroxide at 50 degrees. There is concomitant destruction of 60% of the threonine and 15% of the serine of the treated enzyme and an increase in absorption, at 241 nm, of the treated protein's spectrum, indicative of an O-glycosidic beta-hydroxyamino acyl linkage between untreated protein and its associated carbohydrate. Mannose is the monosaccharide involved in this linkage. Smith degradation, methylation, and glycosidase digestions of the carbohydrate indicate that it is present in mycodextranase as side chains of mannose, glucosyl alpha(1 yields 2)-mannose, and mannosyl alpha(1 yields 2)-glucosyl alpha(1 yields 2)-mannose units with each enzyme molecule bearing a calculated average of 25 side chains. Separation of pronase glycopeptides by gel filtration on Sephadex G-25 revealed that 96% of the carbohydrate is present in the highest molecular weight fraction which contains 60% of the threonine of mycodextranase but only 3.5% of the aromatic acids judged by its absorbance at 280 nm. Further fractionation of this glycopeptide component on Sephadex G-75 indicates carbohydrate is restricted to two fractions, one containing 71% by weight of the threonine and serine of mycodextranase and 56% of its carbohydrate. These results suggest carbohydrate chains of mycodextranase are clustered in a few threonin-rich regions along the polypeptide chain rather than being separated from each other by nonglycosylated areas.

A new heteropolysaccharide has been isolated by alkaline extraction of hyphal walls of Aspergillus niger NRRL 326 grown in surface culture. Its composition by weight, as determined by paper and gas chromatography and colorimetric analyses, is 70% galactose, 20% galactosamine, 6% glucose, and 1% acetyl. Two independent experiments have been used to ascertain copolymer structure: permeation chromatography in 6 M guanidinium hydrochloride, with controlled-pore glass columns of two fractionation ranges, and nitrous acid deaminative cleavage of galactosaminogalactan followed by reduction of fragments with [3H]borohydride and gel filtration chromatography. One of the tritiated fragments is tentatively identified as the disaccharide derivative galactopyranosyl 2,5-anhydrotalitol, on the basis of chromatographic properties and by kinetics of its acid hydrolysis. Smith degradation, methylation, deamination, and optical rotation studies indicate that the galactosaminogalactan consists of a linear array of hexopyranosyl units joined almost exclusively by alpha-(1 leads to 4) linkages. Hexosaminyl moieties are distributed randomly along the chains, which have an average degree of polymerization of about 100. The possible significance of this macromolecule in hyphal structure is considered.

IRIS (Image Reading Instrument System), built by SAAB-SCANIA in cooperation with Physics IV, KTH, Stockholm, has been conceived with the intent of allowing interaction between three parties: an operator, a measuring machine and a computer.