Conductivity dependence on the thickness of hydrogenated, amorphous silicon-carbon films

We report experimental results on the dependence of conductivity on thickness in hydrogenated amorphous silicon and hydrogenated amorphous silicon carbon thin film alloys. The analysis of multilayer structures indicates that band bending at the vacuum-him interface accounts for most of the conductivity changes. The film-substrate interface seems to play a minor role in the conductivity experiments. The behavior of the sub-gap absorption coefficient of thin films shows that the material near the interfaces and in the bulk has the same defect density. (C) 1997 Elsevier Science S.A.2954167128729

The le fort system revisited: Trauma velocity predicts the path of le fort i fractures through the lateral buttress

© 2015 Canadian Society of Plastic Surgeons. All rights reserved. Objective: To examine the effect of trauma velocity on the pattern of Le Fort I facial fractures. Method: A retrospective medical record review was conducted on a consecutive cohort of craniofacial traumas surgically treated by a single surgeon between 2007 and 2011 (n=150). Of these cases, 39 Le Fort fractures were identified. Patient demographic information, method of trauma and velocity of impact were reviewed for these cases. Velocity of impact was expressed categorically as either \u27high\u27 or \u27low\u27: High-velocity fractures were those caused by a fall from \u3e1 story or a motor vehicle collision; lowvelocity fractures were the result of assaults with a blunt weapon, closed fist or falls from standing height. The vertical position of each fracture was measured at its point of entry on the lateral buttress and its point of exit on the piriform aperture. To allow for comparison across individuals, values were expressed as ratios based on their location on the face relative to these landmarks. A Wilcoxon rank-sum test was used to compare the fracture heights caused by high-and low-velocity trauma. Results: The results revealed that high-velocity traumas to the face create Le Fort I fractures at a higher point in the lateral buttress compared with low-velocity traumas. There was no difference between heights at the piriform aperture. Conclusions: High-velocity trauma resulted in higher Le Fort I fracture patterns compared with low-velocity trauma

Caspase-2 deficiency accelerates chemically induced liver cancer in mice

Aberrant cell death/survival has a critical role in the development of hepatocellular carcinoma (HCC). Caspase-2, a cell death protease, limits oxidative stress and chromosomal instability. To study its role in reactive oxygen species (ROS) and DNA damage-induced liver cancer, we assessed diethylnitrosamine (DEN)-mediated tumour development in caspase-2-deficient (Casp2−/−) mice. Following DEN injection in young animals, tumour development was monitored for 10 months. We found that DEN-treated Casp2−/− mice have dramatically elevated tumour burden and accelerated tumour progression with increased incidence of HCC, accompanied by higher oxidative damage and inflammation. Furthermore, following acute DEN injection, liver injury, DNA damage, inflammatory cytokine release and hepatocyte proliferation were enhanced in mice lacking caspase-2. Our study demonstrates for the first time that caspase-2 limits the progression of tumourigenesis induced by an ROS producing and DNA damaging reagent. Our findings suggest that after initial DEN-induced DNA damage, caspase-2 may remove aberrant cells to limit liver damage and disease progression. We propose that Casp2−/− mice, which are more susceptible to genomic instability, are limited in their ability to respond to DNA damage and thus carry more damaged cells resulting in accelerated tumourigenesis.S Shalini, A Nikolic, CH Wilson, J Puccini, N Sladojevic, J Finnie, L Dorstyn and S Kuma

Assessing and managing intensification in smallholder dairy systems for food and nutrition security in Sub-Saharan Africa

Smallholder farmers play an important part in the dairy value chain in Sub-Saharan Africa. Three technological approaches have been used to improve productivity. These are through, applying agricultural ecological processes (ecological intensification), utilising modern livestock breeding (genetic intensification), and socio-economic intensification. Ecological intensification includes continuous housing of cows applying a cut-and-carry feeding system, introduction of purpose-bred forages and pastures, and the introduction of agro-forestry within the dairy systems. Genetic intensification strategies include: importation of dairy breeds such as Holstein–Friesian (HF) and cross-breeding of the indigenous breeds with HF. Training and capacity-building activities to create sustainable livelihoods have been initiated for farming and technological practices of animal husbandry, but also to enhance appropriate leadership and corporative-building skills that would create and support an enabling environment for sustainability. These improvements and initiatives in the service delivery have been championed by national governments, development partner institutions, or non-governmental organisations through different programmes. Challenges of intensification include matching management to genetic potential of imported and cross-bred improved dairy breeds, ensuring low post-harvest losses, proper utilisation, and reducing environmental impact. Using examples from Kenya, Malawi, Mozambique, Tanzania, and Zambia, this paper reviews the management and assessment approaches used in fostering smallholder dairy development strategies and dairy’s contribution to sustainable livelihoods in the face of intensification