Biography:

In the past M.E. King has collaborated on articles with A.F. Vakakis and R.D. Barton. One of their most recent publications is Non-enzymic formation of diazotizable amine from ribosyladenine. Which was published in journal Biochimica et Biophysica Acta.

More information about M.E. King research including statistics on their citations can be found on their Copernicus Academic profile page.

M.E. King's Articles: (15)

Non-enzymic formation of diazotizable amine from ribosyladenine

AbstractAdenosine is cleaved non-enzymically in the presence of ketopentose, Cu++, and pyrophosphate at 70° to yield small amounts of 5-amino-1-ribosyl imidazole. A similar diazotizable amine may be produced non-enzymically from ATP under conditions found in biological experiments. The preparation and characterization of the imidazole derived from adenosine are described. Two additional adenosine derivatives which are produced during the reaction have been partially characterized as 6-amino substituted compounds.

Non-enzymic formation of diazotizable amine from ribosyladenine

AbstractAdenosine is cleaved non-enzymically in the presence of ketopentose, Cu++, and pyrophosphate at 70° to yield small amounts of 5-amino-1-ribosyl imidazole. A similar diazotizable amine may be produced non-enzymically from ATP under conditions found in biological experiments. The preparation and characterization of the imidazole derived from adenosine are described. Two additional adenosine derivatives which are produced during the reaction have been partially characterized as 6-amino substituted compounds.

Forced localization in a periodic chain of non-linear oscillators

AbstractForced localization in a periodic system consisting of an infinite number of coupled non-linear oscillators is examined. A “continuum approximation” is used to reduce the infinite set of ordinary differential equations of motion to a single approximate, non-linear partial differential equation. The structure of the propagation and attenuation zones of the linearized system is found to affect the non-linear localization. Harmonic excitations with general spatial distributions are considered and the localized responses of the chain are studied using exact and asymptotic techniques. Only certain classes of forcing distributions lead to spatial confinement of the forced responses, whereas other types of excitation give rise to spatially periodic or even chaotic harmonic motions of the chain. Systems with weak coupling between particles and/or strong non-linear effects have more profound localization characteristics. The theoretical predictions of the analysis are verified by direct numerical simulations of the equations of motion.

Two vernier time-interval digitizers

AbstractTwo vernier time-interval digitizers are described. One, made of EG&G modules, has a minimum useful channel width of about 200 ps. The other, made of MECL II integrated circuitry, works at channel widths greater than 10 ps. They are inexpensive, easily made, linear, stable and fast. In many applications their digitizing rate of 20 MHz (which is variable) yields shorter total busy times than for a TAC-ADC system because of the absence of a leading dead time. For anyone with access to an on-line computer, the MECL II device reduces the cost of digitizing time intervals by more than an order of magnitude over commercially available systems and the device is so easily assembled that almost anyone can make his own. Their range of applicability is discussed and shown to cover all the practical nuclear lifetime and time of flight situations.

A simple non-linear pulse height compensator for use with a time to amplitude converter

AbstractA simple non-linear pulse height compensator for use with a time to amplitude converter is reported. It consists of two resistances, a diode and a linear amplifier. Using a 60Co source we obtain a smooth residual walk curve with maximum time shift ≤330 ps over the upper 75% of the energy range. About 50% of the energy range is well fit by a straight line with total droop of (3 ± 3) ps from end to end. The circuit makes practical the walk corrections required in the delayed coincidence measurement of short lifetimes.

Effect of stage of the estrous cycle on interval to estrus after PGF2α in beef cattle☆

AbstractEffect of stage of the estrous cycle at the time of prostaglandin F2α (PGF2α) (b) injection on subsequent reproductive events in beef females was studied in four trials involving 194 animals. Cycling animals were given two injections of 25 mg PGF2α 11 days apart or, in some cases, the interval was altered to allow the second injection to fall on a specific day of the cycle. Day of estrous cycle at time of the second injection was determined by estrous detection. Interval from the second PGF2α injection to the onset of estrus (interval to estrus) was shorter (P<.01) in heifers than in cows. Both cows and heifers injected on days 5 to 9 (early cycle) had a shorter (P<.01) interval to estrus (estrus = day 0) than did those injected on days 10 to 15 (late cycle). Conception rate was lower (P<.05) for early-cycle heifers than for late-cycle heifers inseminated by appointment at 80 hours. There was no significant difference in conception rate of early-or late-cycle heifers or cows inseminated according to estrous detection or early- or late-cycle cows inseminated at 80 hours. Progesterone concentrations in blood samples collected in heifers at 4-hour intervals after the second PGF2α injection on either day 7 or day 14 declined linearly (P<.05) through 36 hours. Day of the estrous cycle at PGF2α injection had no effect on rate of progesterone decline, even though heifers injected on day 7 had a shorter (P<.05) interval to estrus. All animals whose cycle length was not affected by the second PGF2α injection were treated on days 5 through 8 of the cycle, indicating that PGF2α was less effective in regressing the corpus luteum between days 4 and 9 of the cycle than later in the cycle.

Synchronization of estrus in embryo transfer recipients receiving demi-embryos with Syncro-Mate B or estrumate

AbstractOne hundred thirty-five crossbred heifers were used to compare the effectiveness of Estrumatea and Syncro-Mate Bb in synchronizing estrus in recipient heifers for transfer of demi-embryos. A higher percentage (P<0.01) of Syncro-Mate B heifers showed estrus within 5 d following treatment than did Estrumate heifers (100.0 vs 85.1%). Demi-embryos were transferred to 41 and 26 heifers treated with Syncro-Mate B and Estrumate, respectively. The pregnancy rate of heifers synchronized with Estrumate was higher (P<0.01) than that of heifers synchronized with Syncro-Mate B (64.3 vs 27.8%). A single blood sample was collected on the day of embryo transfer from all heifers receiving demi-embryos, and progesterone concentration was determined. There were no significant differences in mean serum progesterone concentrations either between heifers synchronized with Syncro-Mate B and Estrumate or between pregnant and open heifers within synchronization treatment. There was no relationship between serum progesterone concentration and pregnancy rate in the Estrumate recipients (P>0.10). However, 25.0% of the Syncro-Mate B recipients had serum progesterone levels <1.00 ng/ml, and these heifers had a lower pregnancy rate (P<0.05) than Syncro-Mate B heifers with serum progesterone levels between 1.00 to 3.00 ng/ml. It appears that the Syncro-Mate B heifers with <1.00 ng/ml progesterone had either a delay in corpora lutea function or a continuously reduced concentration of serum progesterone which altered the uterine environment of these heifers and caused the lower pregnancy rate in the Syncro-Mate B group. Based on the large difference in pregnancy rates, Estrumate appears to be a more effective method to synchronize estrus in recipient heifers receiving demi-embryos.

Comparison of two MGA-PGF2α systems for synchronization of estrus in beef heifers

AbstractYearling beef heifers (n = 193) were used to evaluate reproductive performance attained with 2 MGA-PGF2α synchronization systems. These treatments were compared with an untreated control group. The 14-d MGA heifers were synchronized by feeding 0.5 mg MGA/h/d for 14 d. At 17 d after the last MGA feeding, these heifers were injected with PGF2α (25 mg, im). Heifers in the 7-d MGA treatment group were fed 0.5 mg MGA/h/d for 7 d and received a 25-mg, im injection of PGF2α on the last day of the MGA feeding period. Heifers in all 3 treatment groups were observed for estrus every 12 h for 7 d beginning 24 h after the PGF2α injection. Heifers observed in estrus during this 7-d period were artificially inseminated approximately 12 h after the onset of estrus.The percentages of heifers in estrus during the 7-d synchronized period were 75.4, 56.3 and 17.2% for the 14-d MGA, 7-d MGA and control groups, respectively. The estrous responses were significantly different in each treatment. The percentage of heifers in estrus during the peak 24-h period was higher (P < 0.05) in heifers synchronized with the 14-d MGA system than in heifers synchronized with the 7-d MGA system (75.5 vs 50.0%). The synchronized conception rate of the 14-d MGA heifers was significantly higher (65.3%) than that of both the 7-d MGA (41.7%) and control (45.4%) heifers. Synchronized conception rates were similar (P = 0.79) in the 7-d MGA and control treatments. Synchronized pregnancy rates were 55.2, 32.4 and 15.2% for the 14-d MGA, 7-d MGA and control groups, respectively. Both synchronization treatments resulted in significantly higher synchronized pregnancy rates compared with that of the controls. The synchronized pregnancy rate was higher (P < 0.05) in the 14-d MGA group than it was in the 7-d MGA group. The mean day of conception within the breeding season was 11.5 and 9.3 d shorter in the 14-d MGA heifers than in the 7-d MGA and control heifers, respectively. Our results indicate that using the 14-d MGA system to synchronize estrus in beef heifers results in better reproductive performance than that attained in heifers synchronized with the 7-d MGA system or in control heifers.

The influence of neonatal health on weaning weight of Colarado, USA beef calves☆

AbstractThe effect of morbidity during early life on the weaning weight of calves in Colorado beef herds was investigated as part of a prospective longitudinal observational study. A total of 2609 calves born in nine participating herds during the 1990 and 1991 calving seasons were monitored for disease events and subsequently weighed at weaning as a measure of performance. Morbidity outcomes of interest and their observed incidence rates were: general neonatal (to 45 days) morbidity, 2.6%; neonatal diarrhea, 1.0%; neonatal respiratory disease, 1.0%; and mothering problems/weak calves, 0.4%. Mean calf weaning weight was 244±46 kg. Weaning weight data were adjusted by multiple regression for the effects of the herd, year, age of the calf, age of the dam, calf sex, frame size of the dam, and twin birth. General morbidity during the neonatal period resulted in a 15.9 kg reduction (P<0.01) in calf weaning weight. When morbidity was investigated as more specific disease conditions, calves that were classified as mothering problems/weak calves (i.e. calves that experienced maternal neglect, abandonment, or starvation, and weak calves) weighed 24.4 kg less (P<0.01) at weaning than did non-afflicted calves. Respiratory conditions and diarrhea during the neonatal period resulted in 16.5 kg (P<0.01) and 10.7 kg (P<0.05) reductions in weaning weight, respectively. Thus, disease occurrence during the early life of the calf had a detrimental effect on weaning weight.

Original articleDifferences in particle deposition between the two lungs

AbstractCertain inhalational diseases show a predilection for a particular region of one or the other lung that may be related to the site of deposition of inhaled particles. We conducted inhalation studies with monodispersed aerosol particles in 22 healthy student volunteers to determine how deposition varied between the two lungs. Ventilation lung scans were obtained with the subjects seated in front of a gamma camera while breathing radiolabelled particles. Subsequently we made paired comparisons of the radioactivity deposited in corresponding regions of the right and left lungs. Although regional differences in deposition between the left and right lung were often statistically significant, they were not always consistent between individuals. Particle deposition and the degree of penetration differed between the two lungs with there being generally more deposition in the perihilar region of the right lung. We suggest that the anatomy of the central airways may influence the pattern of deposition, thereby introducing disparities in particle deposition between the two lungs.The present findings lend support to experimental lung cast data and to the concept that anatomical differences between the two lungs influence the site of deposition.

Lambing rates and litter sizes following intrauterine or cervical insemination of frozen/thawed semen with or without oxytocin administration

AbstractIntrauterine insemination by laparoscopy is required to achieve acceptable lambing rates in ewes when using frozen semen but the procedure has evoked welfare concerns. Oxytocin has been used to dilate the cervix as a means of accessing the uterus during conventional cervical insemination, but its effect on fertility is not well documented. Three hundred crossbred ewes were synchronised in estrus and randomly allocated to one of three insemination procedures using frozen/thawed semen containing 400×106/ml progressively motile sperm: single cervical (0.2 ml), multiple cervical (4×0.05 ml) or laparoscopic (0.05 ml per uterine horn). The effects of each insemination procedure on lambing rate (percentage of treated ewes lambing) and litter size (lambs per ewe lambing) were tested with and without oxytocin (10 IU given i.m.) prior to fixed-time insemination. Oxytocin did not permit complete cervical penetration in any ewes and neither lambing rate nor litter size was influenced by the number of inseminations. Lambing percentages were 69 and 42 (P<0.01) for the laparoscopic and cervical insemination methods, respectively, and oxytocin reduced these to 58 (NS) and 10 (P<0.001) percent, respectively. Corresponding litter sizes for ewes not receiving oxytocin were 1.91 and 1.51 and for those receiving oxytocin, 1.83 and 1.41 (laparoscopic versus cervical, P<0.02). Thus, in the absence of complete cervical penetration at insemination, 10 IU oxytocin decreased the number of ewes lambing but had no effect on their litter size.

Effect of age and dietary protein content on post-partum oestrous cyclicity in ewes lambing within their natural breeding season

AbstractThe objective was to determine the effect of age and dietary protein content on onset and pattern of oestrous cyclicity in ewes lambing within their breeding season. Twenty-four multiparous (age 4.5 yr, se = 0.61) and 24 primiparous (age 1.5 yr, se = 0.00) ewes that had lambed on 28 Oct (se 0.2 d) and were rearing 2.0 and 1.9 (se 0.13) lambs respectively were allocated equally to 4 groups. From 3 Nov, each group was housed with a raddled vasectomised ram in a strawbedded pen under natural photoperiod at 57 °N and fed ad libitum hay plus 1.2 kg/head/d concentrate containing 12.5 MJ ME/kg DM and 180 or 120 g/kg CP. Blood samples were obtained 3 times/week from all ewes for determination of plasma progesterone (P4). Data were analysed using a General Linear Model. Mean liveweights for multiparous vs primiparous ewes at allocation were 80.0 vs 58.8 kg (se 1.46) and at weaning (18 Dec) were 72.7 vs 55.1 kg (se 1.65). Liveweight loss during lactation was affected by age (P < 0.01) but not diet. There was no effect of age or diet on the onset of ovarian activity (P4 > 1 ng/ml in at least 2 consecutive samples), which commenced 14 to 43 days post-partum. Mean ± se days to onset of ovarian activity were 28.0 ± 1.53 vs 25.0 ± 1.50 for multiparous vs primiparous ewes and 26.5 ± 1.53 vs 26.6 ± 1.50 for ewes fed the 18 vs 12% CP concentrate. Within each group, 2 to 5 ewes experienced initial short luteal phases and 1 formed a persistent corpus luteum. Results demonstrate that (i) the strong seasonal drive for reproduction in sheep overrides the inhibitory effects of lactation; and ii) post-partum oestrous cyclicity is not influenced by age or dietary protein content within the range studied.

The effect of growth-promoting implant status on the sale price of beef calves sold through a livestock video auction service from 2010 through 2013

ABSTRACTData were collected to quantify the effect of implant status on the sale price of lots of beef calves marketed through a livestock video auction service from 2010 through 2013 and to calculate the percentages of implanted lots. Information describing factors that could potentially affect the sale price of lots of beef calves was obtained electronically from the auction service for 27,746 lots (2,749,406 total calves) selling in 92 video auctions. All lot characteristics that could be accurately quantified or categorized were used to develop a separate multiple-regression model for each study year using a backward selection procedure. Implant status had no effect on sale price in any of the 4 yr of the study (P = 0.53, 0.39, 0.64, and 0.12, respectively, for 2010 to 2013). The percentage of lots that were implanted in each year was 28.4, 30.3, 30.5, and 29.0 for the years 2010 to 2013, respectively, with a mean of 29.5%. The percentage of lots of beef calves that were implanted was relatively low in the West Coast, Rocky Mountain/North Central, and South Central regions of the United States ranging from 18.2 to 27.9%. However, 64.9% of the lots from the South East region were implanted. The results of this study indicated that implant status of beef calves marketed through a livestock video auction service had no effect on sale price. Approximately 30% of all lots were implanted in each year of the study with approximately 33 and 25% of the steer and heifer lots being implanted, respectively.

ORIGINAL RESEARCH: Production and ManagementWeaning weight trends in the US beef cattle industry

ABSTRACTThe objective of this study was to characterize the trend over time for weaning BW in commercial cow-calf operations in the US beef cattle industry. The first data set contained weaning BW data from 4 enterprise analysis programs from 1991 to 2015. The second data set included mean forecasted delivery BW of sale lots of beef calves sold through Superior Livestock Auction from 1995 to 2016. The Superior Livestock Auction data were evaluated for 2 regions, north central/Rocky Mountain region and south central region, and were restricted to sale dates and projected delivery dates approximating those associated with spring-calving operations. The third data set included mean actual and adjusted weaning BW of commercial cow-calf operations participating in the Alabama Beef Cattle Improvement Association from 1983 to 2017. Adjusted annual weaning BW reported from the American Angus Association and American International Charolais Association were used to evaluate the trend over time for Angus and Charolais bull calves from 1995 to 2016. Annual mean weaning BW from 3 of 4 different cow-calf performance and financial analysis programs did not change over time (P > 0.16). However, there was a significant linear increase (0.5 kg per year; P = 0.01) for weaning BW in data reported by the Kansas Farm Management Association. Projected delivery BW for north central implanted calves increased (P < 0.01) until 2006 and plateaued at 268.7 kg. Similarly, projected delivery BW for north central nonimplanted calves increased (P < 0.01) until 2007 and plateaued at 249.8 kg. In contrast, projected delivery BW for nonweaned south central implanted and nonimplanted calves increased (P < 0.01) over time with no significant break point and was best characterized by a simple linear model. Adjusted and unadjusted weaning BW reported to the Alabama Beef Cattle Improvement Association increased until 1998 and 1995 and plateaued at 252.6 and 250.6 kg, respectively. The phenotypic trend for Angus and Charolais bulls was best described by a polynomial regression equation (P < 0.01) with declining rate of change in weaning BW. Substantial variation in the trend over time for weaning BW in commercial cow-calf operations exists within region and record program. Nevertheless, it is apparent that progress in calf weaning BW among commercial cow-calf operations has stabilized in some regions of the United States. Furthermore, weaning BW is substantially more variable in the southern states.

PRODUCTION AND MANAGEMENT: Original ResearchBreed composition affects the sale price of beef steer and heifer calves sold through video auctions from 2010 through 2016

ABSTRACTObjectiveThe objective was to quantify the effect of breed composition on sale price of steer and heifer calves sold through a single livestock video auction service from 2010 through 2016.Materials and MethodsData were available from steer (29,103 lots) and heifer (18,955 lots) calves sold in 164 unique video auctions through one livestock video auction service. A multiple regression model using a backward selection procedure was developed for each calf sex to quantify effects of independent factors on sale price. A value of P < 0.05 was used to maintain a factor in the final model. Lots of calves were categorized into 1 of 6 breed groups: English and English-crossed, English–Continental crossed, Black Angus-sired calves out of dams with no Brahman influence, Red Angus-sired calves out of dams with no Brahman influence, Charolais-sired calves out of dams with no Brahman influence, and Brahman influenced.Results and DiscussionBreed description of steer and heifer calf lots affected sale price (P < 0.0001). Among heifers, Red Angus-sired calves had the greatest (P < 0.05) sale price ($173.88/45.36 kg of BW) compared with heifers of other breed groups. Among steers, Charolais-sired calves ($179.09/45.36 kg of BW) were similar (P = 0.19) in value to Red Angus-sired calves ($177.86/45.36 kg of BW) and greater (P < 0.05) than Black Angus-sired calves ($177.23/45.36 kg of BW).Implications and ApplicationsSire breeds selected, buyer preferences, and marketing venues of both steer and heifer calves should be considered holistically by producers so maximal calf values are realized when sold.

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