294 research outputs found
Comparative radiological anatomy of human, porcine and ovine vertebrae
Osteoporotic vertebral fractures represent an important health burden in the Western world, in particular given the aging population demographics of most Western countries. At present, the treatment options for osteoporotic vertebral fractures are limited, and often conservative, relying on medical pain management. Transpedicular spinal interventional techniques such as vertebroplasty and kyphoplasty offer a minimally invasive treatment option for osteoporotic vertebral fractures. However, there has been recent controversy regarding the efficacy of vertebroplasty for pain relief. Although these percutaneous techniques continue to be used and developed, there is no consensus on the pre-clinical testing of new instruments and cements. Human cadaveric vertebrae are expensive and of limited availability, and animal vertebrae offer a more easily accessible alternative, but there is no agreement within the literature as to which species best approximates the human.
This thesis explores the currently available evidence comparing human and animal vertebrae, and performs comparison studies assessing basic morphometric measurements, bone texture, and statistical shape analysis, to decide upon the best animal model for the use in assessing novel transpedicular instruments and vertebral bone cements. The findings would also apply to developments in surgical transpedicular screws.
The morphometry showed that sheep are generally closer to humans in the thoracic spine, whereas pigs are closer in the lumbar spine. Bone texture analysis demonstrated no significant differences in trabecular thickness between humans and either sheep or pigs. Statistical shape analysis corroborated the findings of basic morphometry. Taking the findings in combination, I would suggest that for the purposes of transpedicular techniques, the sheep is a closer model to the human in the thoracic spine, and the pig is closer in the lumbar spine
Fire Resistance of Cavity Insulated Light Gauge Steel Framed Walls
Light-gauge steel framed (LSF) wall systems are made of cold-formed steel studs and tracks and lined with gypsum plasterboards. They are mostly cavity insulated to provide acoustic and thermal performance. Cavity insulation delays the temperature rise across the wall as it restrains the heat transfer. This delays the ambient plasterboard surface temperature rise and thus improves the insulation failure time of LSF walls. However, LSF walls are also used as load bearing walls. Having cavity insulation causes the fire side temperatures to increase rapidly, resulting in a higher temperature gradient across the stud depth. This leads to higher thermal bowing deflection and crack openings on the fire side plasterboard and exposing studs to higher temperatures. These effects reduce the fire performance of load bearing walls. However, most designers consider that cavity insulation is beneficial for all LSF wall configurations. Thus experimental and numerical studies were conducted to investigate the effect of cavity insulation in both load bearing and non-load bearing walls. Experimental study was conducted on four full-scale wall panels with and without cavity insulation. Fire test results showed that cavity insulation delays heat transfer and is beneficial for non-load bearing walls. However, cavity insulation significantly reduced the fire resistance of load bearing walls. Numerical study was then conducted to obtain the structural adequacy failure times for varying levels of applied loads. This paper presents the results of these studies including the stud failure times and temperatures. The results showed that the use of cavity insulation significantly reduced the fire resistance levels of load bearing walls
Hybrid Seed Production in Pigeonpea
The global distribution of pigeonpea. Cajanus cajan (L.)Millspaugh is wide, covering about 25 countries of Asia and Oceania. 35 of the African continent and 28 countries in the Americas..
Genetics of a high-selfing trait in pigeonpea
A true-breeding line characterized by free filaments of anthers and modified keel petal was derived from F2 population of an intergeneric cross between Cajanus cajan (L.) Millsp. and Atylosia lineata W. & A. This variant, designated as partial cleistogamy, favours a high level of self-fertilization. The inheritance of this trait was studied in the F1, F2, F3, and BC1F1 generations of three crosses. The results suggest that the partial cleistogamy trait is governed by a single recessive gene, designated as pct
Inheritance of dwarfness in pigeonpea
D1-type dwarf Cajanus cajan plants, identified in ICPX73081 (EC100465 X GW3-191-1), were crossed with 4 tall varieties: Prabhat and Pant A2 (early), 148 (midseason) and NP(WR)15 (late). Segregation patterns in the F1, F2 and backcross generations indicated that D1 dwarfness was a monogenic, homozygous, recessive trait., 7 ref., D1-type dwarf Cajanus cajan plants, identified in ICPX73081 (EC100465 X GW3-191-1), were crossed with 4 tall varieties: Prabhat and Pant A2 (early), 148 (midseason) and NP(WR)15 (late). Segregation patterns in the F1, F2 and backcross generations indicated that D1 dwarfness was a monogenic, homozygous, recessive trait
Cytoplasmic-Genic Male-Sterility in Interspecific Matings of Cajanus
The discovery of two stable male-sterile genes and the prevalence
of adequate insect-aided cross-pollination led to the development and
release of the first pigeonpea [Cajanus cajan (L.) Millsp.] hybrid in
India. Commercialization of this hybrid is constrained because of the
labor intensiveness of seed production and concerns about seed purity.
Cytoplasmic male-steriles would effectively circumvent these constraints
and revolutionize the hybrid seed industry. This paper reports
the development of cytoplasmically determined male-sterility, which
was accomplished by two methods: wide hybridization involving conventional
backcrossing of Cajanus sericeus van der Maesen and Cajanus
cajan and multiple cross genome transfer. In these matings, two forms
of reversion to fertility were noticed, one influenced by low temperature
and high humidity, and the other probably determined by genetic
factors alone. The influence of temperature on fertility restoration as
reported for Viciafaba L. is different from that seen in species crosses
of Cajanus. The multiple cross genome transfer method resulted in
stable cytoplasmic-genic male sterility maintainable by the pigeonpea
genotypes ICPL 85030 and ICPL 90035. These male-sterile lines are
in agronomically desirable backgrounds
Predictors of posttraumatic stress symptom trajectories in parents of children exposed to motor vehicle collisions
Following child trauma, parents are at risk of developing posttraumatic stress disorder (PTSD), either owing to their direct involvement or from hearing of their child's involvement. Despite the potential impact of a parent's development of PTSD on both the parent and child, little is known about what may place a parent at increased risk.   METHOD: PTSD symptoms were assessed ≤4 weeks, 6 months, and 3 years post-trauma, along with a range of potential risk factors, in a sample of parents of 2-10-year-old children who were involved in a motor vehicle collision.   RESULTS AND CONCLUSIONS: Two symptom trajectories were identified: Those parents whose symptoms remained low across all time points and those whose symptoms remained elevated at 6 months post-trauma and declined by 3 years. Subjective threat, thought suppression, and maladaptive cognitions about damage to the child were identified as key predictors of poorer outcomes
Mathematical modelling of polyamine metabolism in bloodstream-form trypanosoma brucei: An application to drug target identification
© 2013 Gu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis article has been made available through the Brunel Open Access Publishing Fund.We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.The work was carried out under a PhD programme partly funded by Prof. Ray Welland, School of Computing Science, University of Glasgo
Identification and inheritance of a new dwarfing gene in pigeonpea
A spontaneous dwarf (D11) mutant was identified in an advanced line ICPL 146. In order to study inheritance of the dwarfness in D11 and its allelic relationship to the D1 dwarfing gene, D11 was crossed with three tall lines (ICPL 146, ICPL 85024, ICPL 85037) and a D1 dwarf (ICPL 85059) in 1986. The segregation patterns in F1, F2, backcrosses to both the parents and F3 progenies suggested that D11 dwarfness is governed by a single recessive gene in homozygous condition (t5t5). The genes in D11 and D1 were found to be nonal1elic
Relationship of plant height, days to flowering and maturity to grain yield in short-duration determinate pigeonpea
Generally, pigeonpeas of determinate growth habit and short duration are of short stature compared to the traditional indeterminate types. The association of plant height, days to flowering and maturity, and grain yield were assessed among 100 determinate short-duration pigeonpea lines derived from different genetic backgrounds. Plant height and days to maturity showed strong positive genotypic and phenotypic correlation with grain yield. Days to flowering was positively correlated with days to maturity and plant height. Tall determinate plants appeared to be promising for grain yield. However, the existence of a positive association between plant height and growth duration may cause difficulties in the selection of early flowering tall plants. Nonetheless, high selection pressurefor medium to tall determinate plants among early-flowering segregates may yield more productive genotype
- …