Influence of storage and temperature on endospore and enterotoxin production by Clostridium perfringens in dogs.     

S L Marks  A Melli  P H Kass  S S Jang  A Barkhoodarian  D C Hirsh 《Journal of veterinary diagnostic investigation》2000,12(1):63-67

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Impact of Probing the Reproductive Tract During Early Pregnancy on Fertility of Beef Cows     

G Pugliesi  SC Scolari  FS Mesquita  M Maturana Filho  ER Araújo  D Cardoso  JN Sales  I Martin  M Sá Filho  CM Bertan  M Binelli 《Reproduction in domestic animals》2014,49(4):e35-e39

This short communication reports the impact of endometrial biopsies, uterine flushings and follicular fluid aspiration procedures at day 6 post artificial insemination (AI) on pregnancy rates. In Experiment 1, cows were timed AI (TAI) and assigned to the following treatment groups: control (n = 37), uterine flushing (n = 35) and endometrial biopsy (n = 38). On day 30 post AI, pregnancy rates were 40.5%, 33% and 28.5%, respectively (p > 0.1). Pregnancy rate on day 60 was lower (p < 0.004) in flushed cows than in the controls. In Experiment 2, oestrus was detected and cows were assigned to flushing (n = 32) or biopsy (n = 33) treatments 6 days after AI, which resulted in pregnancy rates of 31% and 36%, respectively (p > 0.1). In Experiment 3, cows were, 6 days after TAI, randomly assigned to the following treatments: control (n = 84) or aspiration of the largest follicle (n = 73). Pregnancy rates on day 30 post AI were 63.5% for the control group and 53% for the aspirated group (p > 0.1). In conclusion, uterine flushing and endometrial biopsy negatively affect pregnancy rates, but neither procedure can be considered to be incompatible with pregnancy maintenance. Follicular aspiration during pregnancy does not interact with pregnancy success. The amount and quality of samples obtained are compatible with the use of cellular and molecular analysis of uterine variables from cows that failed or succeeded on maintaining pregnancy.  相似文献   

Retrospective: Frank Albert Cotton (1930-2007)     

Marks TJ 《Science (New York, N.Y.)》2007,316(5822):214

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Graphitic tribological layers in metal-on-metal hip replacements     

Liao Y  Pourzal R  Wimmer MA  Jacobs JJ  Fischer A  Marks LD 《Science (New York, N.Y.)》2011,334(6063):1687-1690

Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.  相似文献   

Gene encoding the beta subunit of S100 protein is on chromosome 21: implications for Down syndrome   总被引：17，自引：0，他引：17  

R Allore  D O'Hanlon  R Price  K Neilson  H F Willard  D R Cox  A Marks  R J Dunn 《Science (New York, N.Y.)》1988,239(4845):1311-1313

S100 protein is a calcium-binding protein found predominantly in the vertebrate nervous system. Genomic and complementary DNA probes were used in conjunction with a panel of rodent-human somatic cell hybrids to assign the gene for the beta subunit of S100 protein to the distal half of the long arm of human chromosome 21. This gene was identified as a candidate sequence which, when expressed in the trisomic state, may underlie the neurologic disturbances in Down syndrome.  相似文献   

Partial inversion of the initiation-promotion sequence of multistage tumorigenesis in the skin of NMRI mice     

G Fürstenberger  V Kinzel  M Schwarz  F Marks 《Science (New York, N.Y.)》1985,230(4721):76-78

Alterations in NMRI mouse skin induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate in "stage I of tumor promotion" are slowly reversible, and this reversibility has a half-time of 10 to 12 weeks. The tumor response observed in the course of an initiation-promotion experiment in vivo is independent of whether stage I of promotion occurs before or after initiation. Since the time interval between treatment with the promoter, and subsequent initiation can be extended up to at least 6 weeks, an enhancement of initiation because of promoter-induced cellular DNA synthesis seems to be unlikely. This result may be inconsistent with the two-stage model of tumor promotion because it indicates that in skin the existence of initiated cells is not required for the induction of cellular alterations that are essential for the stage of skin tumorigenesis called stage I of promotion.  相似文献   

Electrically conductive metallomacrocyclic assemblies     

Marks TJ 《Science (New York, N.Y.)》1985,227(4689):881-889

The design, synthesis, and study of electrically conductive molecular and polymeric substances constitute a new scientific endeavor involving the interaction of chemists, physicists, and materials scientists. The strategies, developments, and challenges in these two closely related fields are analyzed via a class of materials that bridges both: assemblies of electrically conductive metallomacrocycles. It is seen that efforts to rationally synthesize tailored, "metal-like" molecular arrays lead logically to structure-enforced polymeric assemblies of linked molecular subunits such as metallophthalocyanines. The properties of these assemblies and fragments thereof provide information on the relationship between atomic-level local architecture, electronic structure, and macroscopic transport properties. Electrcally conductive, processable polymeric materals also follow from these results.  相似文献   

Metapopulation dynamics, abundance, and distribution in a microecosystem     

A Gonzalez  JH Lawton  FS Gilbert  TM Blackburn  I Evans-Freke 《Science (New York, N.Y.)》1998,281(5385):2045-2047

The experimental fragmentation of landscapes of a natural ecosystem resulted in declines in the abundance and distribution of most species in the multispecies animal community inhabiting the landscapes and the extinction of many species. These declines caused the deterioration of the positive interspecific relation between local population abundance and distributional extent in this community. However, when patches were connected by habitat corridors, an immigration "rescue effect" arrested declines in both abundance and distribution and maintained the observed positive relation between them. These results demonstrate the importance of metapopulation dynamics and landscape connectivity for the persistence of populations in fragmented landscapes.  相似文献   

Revegetation following Forest Cutting: Mechanisms for Return to Steady-State Nutrient Cycling     

Marks PL  Bormann FH 《Science (New York, N.Y.)》1972,176(4037):914-915

Dense stands of a woody, successional species, Prunus pensylvanica L., develop rapidly, with early closure of canopy and rapid attainment of high values of net annual production and nutrient accumulation. Such rapid growth following disturbance tends to minimize losses of nutrients from the ecosystem, thus promoting a return to steady-state cycling characteristic of a mature forest.  相似文献   

Genetic resistance to aflatoxin in Japanese quail     

H L Marks  R D Wyatt 《Science (New York, N.Y.)》1979,206(4424):1329-1330

Progress was rapid in attempts to develop lines of quail resistant to acute aflatoxicosis induced by oral dosing with aflatoxin. After five generations of selection, 8- and 11-fold differences were present in mortality between two selected lines and their respective control lines. These quail lines should be of value in investigating the physiological basis of resistance to aflatoxin.  相似文献