Capacitation of Frozen Thawed Buffalo Bull (Bubalus bubalis) Spermatozoa with Higher Heparin Concentrations     

A Mehmood  M Anwar  SM Saqlan Naqvi 《Reproduction in domestic animals》2007,42(4):376-379

The present study was conducted to examine the effect of high heparin concentration on capacitation of buffalo spermatozoa with a short incubation time. Frozen thawed spermatozoa from three buffalo bulls were pooled and treated with either 50, 100 or 200 microg/ml heparin for 30 min. Capacitation was evaluated by acrosome reaction of spermatozoa and in vitro fertilization rate (per cent cleavage rate, per cent cleavage index). Acrosome reaction was induced in heparin treated spermatozoa with calcium ionophore A23187 and staining was carried out with Coomassie G-250 to evaluate the response as compared with control (0 heparin + calcium ionophore). Significantly higher percentage of acrosome reaction (AR) spermatozoa was noted after heparin treatment (36.8-48.2%) as compared with control (8.1% ; p < 0.05) but differences among the three heparin concentrations were non-significant. However, a significantly higher in vitro fertilization rate was recorded in spermatozoa capacitated by 50 and 100 microg/ml heparin (80.4 and 75.9% cleavage rate, respectively) as compared with 200 microg/ml heparin (47.2% cleavage rate; p < 0.001). It is concluded that buffalo spermatozoa capacitated with 50-100 microg/ml heparin had significantly higher ability to improve in vitro fertilization rate in buffalo.  相似文献   

The treatment of pannus in dogs by use of a corneal-scleral graft     

E L Kuhns  W F Keller  G L Blanchard 《Journal of the American Veterinary Medical Association》1973,162(11):950-952

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The use of hydrophilic contact lenses in corneal diseases of the dog and cat: A preliminary report     

G. M. Schmidt  G. L. Blanchard  W. F. Keller 《The Journal of small animal practice》1977,18(12):773-777

ABSTRACT
Two types of hydrophilic contact lenses were tested in dogs and cats as part of the therapeutic régime of recurrent corneal erosions, superficial corneal ulcers and keratoconjunctivitis sicca. It was found that the lenses are well tolerated by these species when properly fitted to the cornea. If the lenses were not properly fitted, they were lost before their therapeutic effectiveness could be evaluated. The use of hydrophilic contact lenses appeared to be beneficial in the treatment of superificial corneal ulcers and recurrent corneal erosions in the dog and cat, but ineffective in the treatment of keratoconjunctivitis sicca.  相似文献   

Structures of the bacterial ribosome in classical and hybrid states of tRNA binding     

Dunkle JA  Wang L  Feldman MB  Pulk A  Chen VB  Kapral GJ  Noeske J  Richardson JS  Blanchard SC  Cate JH 《Science (New York, N.Y.)》2011,332(6032):981-984

During protein synthesis, the ribosome controls the movement of tRNA and mRNA by means of large-scale structural rearrangements. We describe structures of the intact bacterial ribosome from Escherichia coli that reveal how the ribosome binds tRNA in two functionally distinct states, determined to a resolution of ~3.2 angstroms by means of x-ray crystallography. One state positions tRNA in the peptidyl-tRNA binding site. The second, a fully rotated state, is stabilized by ribosome recycling factor and binds tRNA in a highly bent conformation in a hybrid peptidyl/exit site. The structures help to explain how the ratchet-like motion of the two ribosomal subunits contributes to the mechanisms of translocation, termination, and ribosome recycling.  相似文献   

SECTION D--ENGINEERING     

Blanchard AH 《Science (New York, N.Y.)》1917,45(1164):389-392

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The Case for a Hubble Constant of 30 km s-1 Mpc-1     

Bartlett JG  Blanchard A  Silk J  Turner MS 《Science (New York, N.Y.)》1995,267(5200):980-983

Although recent determinations of the distance to the Virgo cluster based on Cepheid variable stars represent an important step in pinning down the Hubble constant, after 65 years a definitive determination of the Hubble constant still eludes cosmologists. At present, most of the observational determinations place the Hubble constant between 40 and 90 kilometers per second per megaparsec (km s(-1) Mpc(-1)). The case is made here for a Hubble constant that is even smaller than the lower bound of the accepted range on the basis of the great advantages, all theoretical in nature, of a Hubble constant of around 30 kilometers per second per megaparsec. Such a value for the Hubble cures all of the ills of the current theoretical orthodoxy, that is, a spatially flat universe composed predominantly of cold dark matter.  相似文献   

THE METAL CARBONYLS     

Blanchard AA 《Science (New York, N.Y.)》1941,94(2440):311-317

When the metal carbonyls were first discovered, their properties were startling because they seemed to violate nearly all the previously recognized generalizations of chemistry. Even to-day the existence of the carbonyls is not particularly emphasized in elementary courses of chemistry because it is rather hard to reconcile them with the first presentations of the generalizations of chemistry. Nevertheless, as the student progresses deeper into the knowledge of chemistry it becomes desirable to include the knowledge of the carbonyls both because they become more comprehensible when viewed in the light of Werner's system of coordination and because they themselves contribute to the comprehension of the Werner theory. As long ago as 1931, Reiff in his discussion of cobalt nitrosyl carbonyl recognized the correlation between the effective atomic number and the volatility of carbonyls. A more recent study of charged Werner coordination complexes, that is, of complex ions, has shown a similar role of the effective atomic number. We are standing on fairly firm ground when we point out the correlation between E.A.N. and the volatility of the carbonyl complexes and the existence of complex ions. Be it noted that we have made no postulates as to the arrangement of the electrons in quantum levels. In the inert gases the outer principal quantum group is supposed always to contain eight electrons. In the carbonyls and other Werner complexes there is no compelling reason to suppose that the electrons in the coordinating layer, be this layer of eight, ten, twelve or sixteen electrons, are not all at the same energy level. Although we have confined our discussion almost exclusively to the property of volatility, the carbonyls are very interesting from the standpoint of several other properties, for example, magnetic susceptibility and dielectric constant. Enthusiasts in the interpretation of such properties try to draw conclusions as to the condition of the electrons, sometimes they become so dogmatic as to seem really.to believe in the actual existence of the condition they postulate. As Professor Smith said, "Theories come and theories go, but facts live on forever." The facts of chemistry are so multitudinous that we would be utterly helpless to use them had we not means of correlating them. Any postulates which reach beneath the surface of the directly observable to give a mechanism to correlate the facts are helpful. But a scientist without a sense of humor is pretty hopeless. Who in his right mind can regard as other than absurd the idea that an electron pair can simultaneously occupy positions in two atom shells to make up the supposedly necessary number in each atom? In fact, is not the electron itself a pretty ridiculous figment of the imagination? To be sure, we recognize the electron as a discrete entity with certain very definite properties, but in the light of comparison with any mechanism within our comprehension is not the electron perfectly impossible? By all means let us use a postulate which allows us to make a useful classification of facts, but never let us lose the sense to see how utterly ridiculous the postulate will look to one who has not like ourselves grown attached to it. We do not expect ever to discover the ultimate reason for things, but we do expect ever to make progress in correlating and classifying the facts which we have already discovered and shall continue to discover. Dogmatic belief in ridiculous postulates retards this progress.  相似文献   

Marking to weaning production aspects of lambs provided with NSAID analgesia compared with lambs receiving no analgesia at the time of elastrator ring marking     

AH Small  S Belson  H Brewer  SM Schmoelzl 《Australian veterinary journal》2021,99(1-2):40-43

The provision of analgesia at the time of marking has been adopted by the Australian sheep industry, but data on production benefits are lacking. In the current study, alternate lambs were provided with either meloxicam (non‐steroidal anti‐inflammatory drug [NSAID], n = 781) or no analgesia (NONE, n = 822) at the time of ring castration and tail docking. Six distinct management groups of lambs were studied. Lambs were weighed immediately before marking and then again at weaning. There was no significant effect of treatment on average daily gain between marking and weaning in cross‐bred lambs. In Merino lambs, average daily gain was 5 g/day lower (P < 0.005) in lambs receiving NSAID, but this may not be biologically significant. Lamb losses were significantly (P < 0.05) lower in the NSAID group (1.1%) than in the NONE group (2.7%). This observation is worth validating in larger studies, particularly considering that lamb mortality is a significant cost to production and welfare concern.  相似文献   

Formation of furfurylthiol exhibiting a strong coffee aroma during oak barrel fermentation from furfural released by toasted staves   总被引：2，自引：0，他引：2  

Blanchard L  Tominaga T  Dubourdieu D 《Journal of agricultural and food chemistry》2001,49(10):4833-4835

Furfurylthiol (FFT) is formed in white wines during alcoholic fermentation in the barrel from the furfural released by toasted staves. The quantity of furfural released into the must has a decisive effect on the quantity of FFT in the finished wine. Wines fermented in new barrels thus contain larger quantities of FFT than those fermented in used barrels. Fermentation conditions favorable to an excess production of H(2)S (hydrogen sulfide) by the yeast promote the formation of this volatile thiol. The presence of this volatile thiol in white wines is, therefore, closely related to the yeast's sulfur metabolism.  相似文献   

The remote sensing of suspended sediment concentrations of small impoundments     

H. B. Pionke  B. J. Blanchard 《Water, air, and soil pollution》1975,4(1):19-32

The suspended sediment concentrations of 14 Oklahoma impoundments were related to bands of reflected light as measured from an aircraft-borne multispectral scanner. Suspended sediment concentrations (Y) were curvilinearly related to reflectance (X) where the exponent onX exceeds one. The best relationships, upon consideration of sensitivity, range, and precision, appeared in the bands defined by 588 to 643 and 650 to 690 nm wavelength. The latter was less precise. The measured range in sediment concentration was 13 to 232 mg l^?1  相似文献