Growth and Physiological Responses of Triticum aestivum and Deschampsia caespitosa Exposed to Petroleum Coke     

Colin Nakata  Clara Qualizza  Mike MacKinnon  Sylvie Renault 《Water, air, and soil pollution》2011,214(1-4):59-72

Methylibium petroleiphilum PM1, which is capable of degrading of methyl tert-butyl ether (MTBE), was immobilized in calcium alginate gel beads. Various applications were explored to increase the mechanical strength of these gel beads. The introduction of 0.3 mol/L calcium chloride into the crosslinking solution, 0.002 mol/L calcium chloride into the growth medium, and 0.2% polyethyleneimine (PEI) as chemical crosslinking agent increased the stability of the Ca-alginate gel beads under the operation conditions of the bioreactor. The degradation rates of MTBE by the immobilized cells in the bioreactor system operated in batch and continuous mode , respectively, were compared. A MTBE biodegradation rate of 5.79 mg/L·h was reached for over 400 h (50 batches), and the immobilized cells in the bioreactor removed >96% MTBE during 50 days of operation. Molecular analysis of the PM1 cells revealed that microbial growth occurred predominantly as microcolonies in the outer area of the beads during the first 20 days of operation. The results of this study show that a continuous-mode, fixed-bed bioreactor reactor coupled with PM1-immobilized cells is a promising technology for remediating MTBE-contaminated groundwater.  相似文献   

Survey of potato spindle tuber viroid in seed potato growing areas of the United States     

Mike Sun  Susan Siemsen  William Campbell  Pablo Guzman  Robert Davidson  Jonathan L. Whitworth  Terry Bourgoin  Jeff Axford  Willem Schrage  Gary Leever  Alan Westra  Steve Marquardt  Hossien El-Nashaar  Jeff McMorran  Oscar Gutbrod  Tom Wessels  Robert Coltman 《American Journal of Potato Research》2004,81(3):227-231

Fourteen United States (U.S.) seed potato certification agencies surveyed all U.S. seed potato growing areas for presence of the potato spindle tuber viroid (PSTVd). The survey included general surveillance, which involved searching for the occurrence of PSTVd in state seed potato certification records from 1990 through 2000, and a field survey, which involved testing selected crops for PSTVd infection by nucleic acid dot blot hybridization during 1999 through 2001. No PSTVd incident was documented in any of the state certification records, nor was PSTVd detected in the field surveys. All U.S. seed-growing areas were determined to be free of PSTVd. It is concluded that PSTVd has been eradicated and freedom from potato spindle tuber viroid has been successfully maintained in all of the seed potato growing areas in the United States.  相似文献   

Height-diameter models with random coefficients and site variables for tree species of Central Maine   总被引：1，自引：0，他引：1  

Mike R. Saunders  Robert G. Wagner 《Annals of Forest Science》2008,65(2):203-203

Height-diameter models were developed for nine tree species common to the northeastern United States: Abies balsamea, Acer rubrum, Betula papyrifera, B. populifolia, Picea rubens, P. mariana, Pinus strobus, Populus tremuloides, and Tsuga canadensis. Stem heights and diameters were collected from 6 146 trees (between 136 and 2615 trees per species) on 50 plots within 10 structurally diverse stands that are part of a long-term silvicultural experiment in central Maine. The models were developed using both generalized nonlinear least squares (GNLS) and multi-level, mixed-effects approaches. Mixed-effects approaches were superior to GNLS, with inclusion of site covariates (tree density and basal area) accounting for some of the variability explained by the random coefficients in the full mixed-effect models. Analysis of plot-level parameter estimates suggested that differences in stand structure (even-aged vs. uneven-aged silvicultural practices) had a significant influence on the height-diameter relationships.  相似文献   

Endomycorrhizas: edited by F. E. Sanders,Barbara Mosse and P. B. Tinker. Publ. Academic Press,London, New York,San Francisco. 626 pp. no index. £9.60. 1975. (Proceedings of symposium,Leeds July 1974)     

Mike Swift 《Soil biology & biochemistry》1977,9(6):429

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Habitat overlap of juvenile and adult lake trout of Great Bear Lake: Evidence for lack of a predation gradient?     

Louise Chavarie  Kimberly L. Howland  Les N. Harris  Mike J. Hansen  Colin P. Gallagher  William J. Harford  William M. Tonn  Andrew M. Muir  Charles C. Krueger 《Ecology of Freshwater Fish》2019,28(3):485-498

A range of organisms, from plankton to fish, commonly shift their habitat distributions horizontally or vertically due to predation risk. Juvenile lake trout, Salvelinus namaycush, are generally viewed as occupying deep areas of lakes to decrease predation pressure from adults. In contrast, we found that juvenile lake trout from Great Bear Lake, NT, Canada, occupied a variety of habitats and from shallow to deep depths (0–150 m), overlapping with adult lake trout. No evidence occurred for a length depth‐based segregation (e.g., ontogenetic shift). Genetic variation was also similar among juveniles in the different depth zones. However, isotopic niches and C:N ratios among juveniles showed some variability in niche widths and positions for individuals caught from the 51–150 m zone compared to juvenile individuals caught from 0–20 m and 21–50 m zones. The uniformly distributed adult lake trout in Great Bear Lake may evenly distribute predation pressure (including cannibalism) across shallow‐ and deep‐water habitats more than in other lakes. As a result, juveniles may respond to differences in foraging opportunities rather than predation risks. Juvenile lake trout did not appear to conform to the general pattern of juveniles seeking a deep‐water refuge to reduce predation risks. In contrast, juvenile lake trout of Great Bear Lake displayed broad resource use across all depths and habitats.  相似文献   

Golden Shiner Notemigonus crysoleucas× Rudd Scardinius erythrophthalmus Hybrids: Gonad Histology and Spawning Trials     

Andrew E.  Goodwin John M.  Grizzle  Douglas  Tave  Mike D.  Gibson  Jimmy  Barnett  Don H.  Fiegel Berry F.  Beavers 《Journal of the World Aquaculture Society》1994,25(2):230-235

Hybrid fish were produced in ponds by crossing golden shiners × rudd ( Notemigonus crysoleucas × Scardinius erythrophthalmus ) and rudd × golden shiners. Histologically, testes from the hybrids contained spermatocytes that resembled those of the parental species, but no sperm were observed. Lack of sperm in hybrids could have been a seasonal effect. The ovaries of both types of hybrids contained variable numbers of morphologically normal, vitellogenic oocytes and numerous abnormal oocytes in the chromatin nucleolar stage. Abnormal oocytes were necrotic or had irregularly shaped nuclei and clumped chromatin. Many oocyte nests contained infiltrating macrophnges. Spawning trials with F₁ hybrids did not result in spawning behavior or production of F₂ generation fish. Colden shiner × rudd hybrids are of reduced fecundity, but sterility was not conclusively demonstrated.  相似文献   

Subtourniquet pressures generated by application of wide‐rubber tourniquets in standing,sedated horses     

Amanda H. Plunkett  Mike J. Schoonover  Jenna M. Young  Jared D. Taylor  Todd C. Holbrook 《Veterinary surgery : VS》2019,48(3):417-423

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FEASIBILITY FOR ULTRASOUND‐GUIDED INJECTION OF THE COLLATERAL LIGAMENTS OF THE DISTAL INTERPHALANGEAL JOINT IN HORSES          下载免费PDF全文

Danyse Lewis  Mike Scott  Carrie D. Fischer  Stephanie L. Bond  Renaud Léguillette 《Veterinary radiology & ultrasound》2016,57(3):299-305

Desmitis of the collateral ligament of the distal interphalangeal joint is a cause of lameness in performance horses. The objective of this prospective, experimental, ex vivo feasibility study was to evaluate the success of ultrasound‐guided injection of the collateral ligaments of the distal interphalangeal joint in the equine forelimb. Seventy‐six ultrasound‐guided dye injections of the collateral ligament of the distal interphalangeal joint were performed on horses’ cadaver limbs. The hooves were sectioned transversely to verify the location of the dye relative to the collateral ligaments and surrounding structures. Evaluations of transverse sections were performed independently by two experienced observers. A scoring system was used to assess injection of the collateral ligament of the distal interphalangeal joint at the proximal, middle, and distal aspect over the length of the ligament. The collateral ligament was injected at any point in 97.4% of cases. The ligament was injected over the entire scored length in 43.2% of cases (32/74), over two scored length areas in 45.9% of cases (34/74), and in one area in 10.8% of cases (8/74). The distal interphalangeal joint and the common digital extensor tendon were also injected in 81.6% (62/76) and 43.4% (33/76) of the cases, respectively. Use of the ultrasound had a positive and negative predictive value of 98% and 9%, respectively. In this study, ultrasound guidance was useful for confirming injection of the collateral ligament of the distal interphalangeal joint but did not prevent injecting the distal interphalangeal joint and the common digital extensor tendon.  相似文献   

Comparative histomorphological and ultrastructural study of the luminal epithelium of the isthmus in laying and moulting domestic fowls (Gallus domesticus)          下载免费PDF全文

Mike M. Mpango  Mary‐Cathrine Madekurozwa 《Anatomia, histologia, embryologia》2018,47(5):444-455

This study describes ciliated, nonciliated and mitochondrial luminal epithelial cells of the isthmus in laying and moulting domestic fowls using histological and ultrastructural techniques. The ciliated cells were nonsecretory, while numerous electron‐dense secretory granules were present in the nonciliated cells of laying birds. Mitochondrial cells, occurring in two morphologically distinct forms, constituted the third type of epithelial cell present in the isthmus. The SEM study showed that the luminal epithelium was dominated by ciliated cells, the cilia of which partially obscured adjacent nonciliated cells. The involution of the luminal epithelium in moulting birds occurred via autophagy, apoptosis and necrosis. Autophagic inclusions, which included autophagosomes and autolysosomes, were present in the early degenerative phases of ciliated, nonciliated and mitochondrial cells. Nonciliated cells underwent degeneration via apoptosis, which was characterized by nuclear and cytoplasmic condensation. Apoptotic and necrotic ciliated cells were evident during the intermediate and advanced stages of regression. The presence of apoptotic cell death was confirmed using the TUNEL assay. Loss of cilia via the formation of cilia packets was observed using TEM and SEM. Necrotic cell death occurred in mitochondrial cells during the intermediate and late stages of degeneration. In conclusion, the findings of the study on isthmus involution in moulting birds suggest that autophagy is a process confined to the early stages of degeneration, while apoptosis and/or necrosis occur in the terminal stages of regression.  相似文献   

Evaluation of pulse pressure variation and pleth variability index to predict fluid responsiveness in mechanically ventilated isoflurane‐anesthetized dogs          下载免费PDF全文

Hiroki Sano BVSc  Joonbum Seo BVSc  Paul Wightman BVSc  Nick J. Cave BVSc  PhD  DACVN  Mike A. Gieseg BVSc  PhD  Craig B. Johnson BVSc  PhD  Paul Chambers BVSc  PhD 《Journal of Veterinary Emergency and Critical Care》2018,28(4):301-309

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