RNA polymerase II transcription complex assembly in nuclear extracts

Variation in superovulatory responses in cattle may be related to the stage of follicular growth at the time of gonadotropin treatment. Waves of follicle growth are regulated by both follicle-stimulating hormone (FSH) and oestradiol. The objective of experiment 1 was to determine the dynamics of follicle wave emergence and the relationship with FSH and oestradiol concentrations, after treatment of heifers with oestradiol benzoate (ODB) in the presence of an intravaginal progesterone-releasing device (CIDR-B). Experiment 2 examined the superovulatory response, embryo yield and quality following treatment with porcine follicle-stimulating hormone (pFSH) at different times relative to ODB injection. In experiment 1, 28 beef heifers were treated with a CIDR for 9 days and allocated at random to one of four groups to receive either: (I) CIDR only, or 5 mg ODB given as a single intramuscular injection at (II) day 0 (d0); (III) day 1.5 (d1.5); or (IV) day 3 (d3) post CIDR insertion. Ovaries were examined using daily ultrasound and blood samples were collected twice daily for 11 days. In experiment 2, 96 heifers were treated with a CIDR and 5 mg ODB as in experiment 1, and were allocated using a 4 x 3 factorial design plan to a superovulation programme using three doses (400 IU; 600 IU; 800 IU) of pFSH. FSH was given for 4 days at 12-h intervals beginning 6.5 days after CIDR insertion. Heifers received prostaglandin analogue 12 h before CIDR removal and were inseminated (AI) at 48 and 60 h post CIDR withdrawal and embryos were recovered 7 days after AI. In experiment 1, the interval from CIDR insertion to follicle wave emergence (FWE) was longer (P < 0.05) in heifers treated with ODB at d1.5 (5.4 +/- 0.4 days) and d3 (5.1 +/- 0.6 days) compared to heifers treated with CIDR only (2.4 +/- 0.4 days). On the basis of time to proposed injection of pFSH heifers would have had follicle emergence 4.4, 2.3, 1.5 and 1.4 days prior to pFSH for groups I, II, III and IV, respectively. In experiment 2, heifers treated with ODB at d1.5 had a higher (P < 0.05) superovulatory response (18.2 +/- 1.7) than heifers treated at d3 (12.8 +/- 1.7), but superovulatory response in both groups did not differ (P > 0.05) from heifers treated at d0 (14.4 +/- 2.0) or with CIDR only (15.0 +/- 1.8). There were fewer (P < 0.05) freezable-grade embryos recovered from heifers treated with ODB at d0 (1.5 +/- 0.7) and d3 (2.1 +/- 0.5) compared to heifers treated at d1.5 (3.0 +/- 0.6) or in heifers treated with CIDR only (3.4 +/- 0.7). Increasing the dose of pFSH caused a linear increase in the superovulatory response (11.7 +/- 1.0, 15.8 +/- 1.4 and 18.0 +/- 1.9) and in the number of embryos recovered (5.8 +/- 0.9, 7.0 +/- 0.8 and 9.1 +/- 1.0) for 400 IU, 600 IU and 800 IU, respectively. In conclusion, heifers treated with ODB had wide variation in time to follicle wave emergence and there was not a consistent beneficial effect of pretreatment with ODB on embryo yield and quality following superovulation.     

Five-level GTO inverters for large induction motor drives

The development of large induction motor drives with low torque ripple and fast dynamic response for new or retrofit applications has been limited by the device ratings and problems of series connections. This paper investigates the use of a five-level GTO voltage-sourced inverter for large induction motor drives. The advantages of such a drive are that single GTO thyristors may be used at each level, thereby avoiding the need for series connection of the thyristors. The thyristors are well protected from overvoltages by the clamping action of the DC supply capacitors. The disadvantages are that each DC level requires a separate supply, four in the case of the five-level inverter, and that the devices are not equally loaded. This paper reviews the basic operation of the five-level inverter and possible PWM voltage/frequency control techniques for the specific application of induction motor drives. The simulation results clearly show the unequal loading of the devices and the need for independent voltage supplies for the five levels. It is shown that a combination of several PWM techniques offers the best solution for the drives application. The conclusions indicate that large induction motors with ratings up to 22 MVA, 7.46 kV may be supplied by the five-level inverter using available 4.5 kV, 3.0 kA GTO thyristors. The recommended supply for such an inverter with full regenerative operation over the complete speed range is four, four-quadrant converters in a quasi-24-pulse configuration     

Learning cell biology with close-up views or connecting lines: Evidence for the structure mapping effect

Different visualization strategies for structuring non-hierarchical learning tasks in hypermedia are used until now. Do these strategies differ in learning effectiveness? In the present study, a hypermedia learning environment about cell biology was investigated. The graphical properties of a content module were created in two different ways, either depicting close-up views of the cell organelles or with connecting lines between the cell organelles and their respective technical terms within the graphic of the whole cell. Students’ post test performance indicate that connecting lines fostered auditory recall, that is remembering and understanding of narrative information, more efficiently than close-up views. In the case of visual recall, that is identification of electron microscopic pictures depicting cell structures, there was no difference in performance between these two visualization techniques. Transfer performance depended on an interaction between visualization technique and students’ spatial ability: Only students with high spatial ability benefited from the connecting lines variant. With respect to auditory recall and transfer performance, the present study supports the structure mapping effect as proposed by the integrated model of text and picture comprehension. Especially students with low spatial ability seem to be prone to an illusion of knowing.     

Dissociation of musical tonality and pitch memory from nonmusical cognitive abilities.

Replicated, validated, and extended measures of sensitivity to musical pitch and examined whether performance on tests of tonal structure and pitch memory was related to, or dissociated from, performance on tests of nonmusical cognitive skills (standardized tests of cognitive abstraction, vocabulary, and memory for digits and nonrepresentational figures). Factor analyses of data from 100 neurologically intact Ss (aged 18–40 yrs) revealed a dissociation between music and nonmusic variables, both for the full data set and a set for which the possible contribution of levels of music training was statistically removed. A 40-yr-old female with neurological impairment scored within the range of matched controls on nonmusic tests but much lower than controls on music tests. It is concluded that this study provides further evidence of a functional specificity for musical pitch abilities. Examples of melodies and chord progressions are appended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of caffeine on the serum insulin level during intravenous glucose tolerance test in patients with chemical diabetes

A small but significant number of tritiated thymidine labelled cells were found, by autoradiography, in the glomeruli of rats with Masugi nephritis or chronic serum sickness nephritis. There were no labelled glomerular cells in sections of untreated animals. The findings favour the contention that in proliferative glomerulonephritis, glomerular hypercellularity is due to infiltration of monocytic cells into the tufts where they divide.     

Effect of water of hydration on the measurement of the protein efficiency ratio of casein and soybean protein with rats

The hydration of soybean protein or casein prior to mixing of the diet improves the apparent protein efficiency ratio (PER). The PER of soybean protein was improved more than that of casein, so that an increase in adjusted PER of soybean protein was observed also. The improvement did not appear to be associated with digestibility. It is theorized that some diets with dry protein isolates may be less acceptable to the rat due to the dusty nature of the isolate. Consequently, diets with such isolates may have a lower PER. The effect can be overcome by hydrating the protein isolates prior to mixing the diet.     

Cerebral artery dissection

The main symptom of arterial dissection is intense acute unilateral headache. The pain is commonly located around the eye, in the temple or the front with a carotid artery dissection [CAD] and in the posterior neck and occiput with a vertebral artery dissection [VAD]. Transient or persistent cerebral ischemic symptoms are similarly frequent but usually occur later in the time course. Horner's syndrome indicating a lesion of perivascular sympathetic fibres represents the third leading symptom and occurs in more than one third of the patients. Compression of local structures such as lower nerve or radicular palsies is rare. This constellation of symptoms in a young patient without vascular risk factors should rise suspicion of a dissection, in particular, if there is a preceding 'trivial' trauma. Characteristic features on Doppler/duplex sonography provide the diagnosis of dissection in almost all CAD and the majority of VAD. MRI demonstrating the mural hematoma allows reliable confirmation of the suspected diagnosis. Angiography is necessary only in selected cases, more often in VAD than in CAD. Brain infarction may be prevented, if premonitory symptoms, which occur in 60 to 80% of the patients, are recognized as such. Therefore, if there is clinical and sonographic suspicion of CAD or VAD, anticoagulation therapy with heparin should should be started before other imaging procedures finally prove the diagnosis. Because immediate anticoagulation may prevent cerebral embolism, this treatment strategy seems appropriate, although its efficacy has not been established by a controlled study. Anticoagulation should be continued until resolution of the dissection.