INTERACTION WITH A VISCOUS CONTACT WHEN CUTTING AUSTENITIC STEEL WITH A CARBIDE TOOL

On the microsections of chip roots (oblique slices) obtained when turning austenitic steel, carbide tool, studies of the microhardness of the contact area on the front surface. It is established that at zone of viscous-fluid contact when a minimum distance from the front surface the microhardness of the contact area is not change not only along the length of the contact but as the distance from the front surface.

Calcified tissue structure in the distal condyle of the third metacarpal bone in young Thoroughbred horses

Aims: To determine improvements in third metacarpal (Mc3) condylar microanatomy attributable to preconditioning exercise. To investigate developmental causes of Mc3 condylar fracture.Methods: Twelve Thoroughbred horses were raised at pasture; six received preconditioning exercise from 10 days. Calcein labels were administered 19 and 11 days prior to euthanasia at 18 months. Six horses also received 2 seasons of race-training and were euthanised at 3 years. Slices were taken from the distal Mc3 condyle in the frontal and dorsal- and palmar-oblique frontal planes, scanned with DXA and macerated (frontal slices) or embedded in PMMA (oblique slices). Articular calcified cartilage (ACC) and subchondral bone (SCB) in oblique slices were imaged using confocal scanning light microscopy and quantitative backscattered electron scanning electron microscopy. ACC and SCB in the palmar slice lateral parasagittal grooves were imaged using μCT and nanoindentation tested.Results: Characteristic spatial variations in ACC and SCB histomorphometric parameters were present, none of which was significantly related to preconditioning exercise. Thickened, aberrantly mineralised ACC was found in 13/24 parasagittal grooves in the palmar slices and on the sagittal ridge of 4/12 dorsal slices of 18-month-old horses. Deep to thickened ACC, SCB had an open marrow structure, having not adopted the buttress morphology of the normal SCB plate. SCB in 3-year-old horses had incorporated early ACC defects as notches in parasagittal grooves and a hyaline cartilage island in a sagittal ridge. ACC was less stiff and SCB more stiff in affected than unaffected parasagittal grooves. Chondroclastic resorption in the parasagittal groove may be retarded as early as 3-6 months, possibly due to localised inhibition of ACC mineralisation. Linear defects in the Mc3 parasagittal groove may develop prior to entry to race training and are not significantly affected by preconditioning exercise. Early identification of affected individuals should aid in reducing condylar fracture risk.Catalogued by Queen Mary University of London at https://qmro.qmul.ac.uk/xmlui/handle/123456789/28654Publications arising from the thesis work:1.Doube M, Boyde A, Firth EC, Bushby AJ. 2010 Combined nanoindentation testing and scanning electron microscopy of bone and articular calcified cartilage in an equine fracture predilection site. Eur. Cell. Mater. 19, 242–251. (doi:10.22203/eCM.v019a23)2.Firth EC, Doube M, Boyde A. 2009 Changes in mineralised tissue at the site of origin of condylar fracture are present before athletic training in Thoroughbred horses. N Z Vet J 57, 278–283. (doi:10.1080/00480169.2009.58621)3.Doube M, Firth EC, Boyde A. 2007 Variations in articular calcified cartilage by site and exercise in the 18-month-old equine distal metacarpal condyle. Osteoarth Cart 15, 1283–1292. (doi:10.1016/j.joca.2007.04.003)4.Doube M, Firth EC, Boyde A. 2005 Registration of confocal scanning laser microscopy and quantitative backscattered electron images for the temporospatial quantification of mineralization density in 18-month old thoroughbred racehorse articular calcified cartilage. Scanning 27, 219–26. (doi:10.1002/sca.4950270502)

Effect of source-sink manipulation on yield and related yield components in cassava, Manihot esculenta Crantz

The distribution of nutrients and assimilates in different organs and tissues is in a constant state of flux throughout the growth and development of a plant. At key stages during the life cycle, profound changes occur, and perhaps one of the most critical of these is during tubers filling. The purpose of this study was to examine the effect of sources- sink manipulation to related yield and yield components of cassava cultivars Singgah. Experiment manipulation source using number of branches cropping (S) which consists of three levels i.e. S1: 1 branch planting; S2: 2 branches planting; S3: 3 branches planting and manipulation at the bottom of that manipulation of the bottom with the model sliced the bottom of the cuttings (L) which consists of three levels i.e. L1: Sliced flat cuttings; L2: Sliced oblique cuttings; L3: Sliced cuttings of two sloping sides. In the cassava plant there is a relationship between the source and the bottom. Manipulation treatment plant cassava with two branches crop resources, if interaction the bottom with the model manipulation cuttings incision flat base capable of increasing biomass as well as the amount of cassava tuber crop plant varieties Singgah. The diameter of the tubers if interaction with wedge base model of cuttings oblique slices one general interaction and manipulation of two branches crop with all models of the base of the cuttings slice significantly improves weight of tuber crop.Int. J. Agril. Res. Innov. & Tech. 6 (2): 69-76, December, 2016

Engagement of Rat Striatal Neurons by Cortical Epileptiform Activity Investigated With Paired Recordings

The striatum is thought to play an important role in the spreading of epilepsy from cortical areas to deeper brain structures, but this issue has not been addressed with intracellular techniques. Paired recordings were used to assess the impact of cortical epileptiform activity on striatal neurons in brain slices. Bath-application of 4-amynopyridine (100 μM) and bicuculline (20 μM) induced synchronized bursts in all pairs of cortical neurons (≤5 mm apart) in coronal, sagittal, and oblique slices (which preserve connections from the medial agranular cortex to the striatum). Under these conditions, striatal medium spiny neurons (MSs) displayed a strong increased spontaneous glutamatergic activity. This activity was not correlated to the cortical bursts and was asynchronous in pairs of MSs. Sporadic, large-amplitude synchronous depolarizations also occurred in MSs. These events were simultaneously detected in glial cells, suggesting that they were accompanied by considerable increases in extracellular potassium. In oblique slices, cortically driven bursts were also observed in MSs. These events were synchronized to cortical epileptiform bursts, depended on non– N-methyl-d-aspartate (NMDA) glutamate receptors, and persisted in the cortex, but not in the striatum, after disconnection of the two structures. During these bursts, MS membrane potential shifted to a depolarized value (59 ± 4 mV) on which an irregular waveform, occasionally eliciting spikes, was superimposed. Thus synchronous activation of a limited set of corticostriatal afferents can powerfully control MSs. Cholinergic interneurons located <120 μm from simultaneously recorded MSs, did not display cortically driven bursts, suggesting that these cells are much less easily engaged by cortical epileptiform activity.