Silicon, the silver bullet for mitigating biotic and abiotic stress, and improving grain quality, in rice?

Adequate silicon fertilization greatly boosts rice yield and mitigates biotic and abiotic stress, and improves grain quality through lowering the content of cadmium and inorganic arsenic. This review on silicon dynamics in rice considers recent advances in our understanding of the role of silicon in rice, and the challenges of maintaining adequate silicon fertility within rice paddy systems. Silicon is increasingly considered as an element required for optimal plant performance, particularly in rice. Plants can survive with very low silicon under laboratory/glasshouse conditions, but this is highly artificial and, thus, silicon can be considered as essential for proper plant function in its environment. Silicon is incorporated into structural components of rice cell walls were it increases cell and tissue rigidity in the plant. Structural silicon provides physical protection to plants against microbial infection and insect attack as well as reducing the quality of the tissue to the predating organisms. The abiotic benefits are due to silicon's effect on overall organ strength. This helps protect against lodging, drought stress, high temperature (through efficient maintenance of transpiration), and photosynthesis by protecting against high UV. Furthermore, silicon also protects the plant from saline stress and against a range of toxic metal stresses (arsenic, cadmium, chromium, copper, nickel and zinc). Added to this, silicon application decreases grain concentrations of various human carcinogens, in particular arsenic, antimony and cadmium. As rice is efficient at stripping bioavailable silicon from the soil, recycling of silicon rich rice straw biomass or addition of inorganic silicon fertilizer, primarily obtained from iron and steel slag, needs careful management. Silicon in the soil may be lost if the silicon-cycle, traditionally achieved via composting of rice straw and returning it to the land, is being broken. As composting of rice straw and incorporation of composted or non-composted straw back to land are resource intensive activities, these activities are declining due to population shifts from the countryside to cities. Processes that accelerate rice straw composting, therefore, need to be identified to aid more efficient use of this resource. In addition, rice genetics may help address declining available silicon in paddy soils: for example by selecting for characteristics during breeding that lead to an increased ability of roots to access recalcitrant silicon sources from soil and/or via selection for traits that aid the maintenance of a high silicon status in shoots. Recent advances in understanding the genetic regulation of silicon uptake and transport by rice plants will aid these goals.

Irradiation of bioresorbable biomaterials for controlled surface degradation

Bioresorbable polymers increasingly are the materials of choice for implantable orthopaedic fixation devices. Controlled degradation of these polymers is vital for preservation of mechanical properties during tissue repair and controlled release of incorporated agents such as osteoconductive or anti-microbial additives. The work outlined in this paper investigates the use of low energy electron beam irradiation to surface modify polyhydroxyacid samples incorporating beta tricalcium phosphate (β-TCP). This work uniquely demonstrates that surface modification of bioresorbable polymers through electron beam irradiation allows for the early release of incorporated agents such as bioactive additives. Samples were e-beam irradiated at an energy of 125 keV and doses of either 150 kGy or 500 kGy. Irradiated and non-irradiated samples were degraded in phosphate buffered saline (PBS), to simulate bioresorption, followed by characterisation. The results show that low energy e-beam irradiation enhances surface hydrolytic degradation in comparison to bulk and furthermore allows for earlier release of incorporated calcium via dissolution into the surrounding medium.

An aggregated fridge-freezer peak shaving and valley filling control strategy for enhanced grid operations

The need for fast response demand side participation (DSP) has never been greater due to increased wind power penetration. White domestic goods suppliers are currently developing a `smart' chip for a range of domestic appliances (e.g. refrigeration units, tumble dryers and storage heaters) to support the home as a DSP unit in future power systems. This paper presents an aggregated population-based model of a single compressor fridge-freezer. Two scenarios (i.e. energy efficiency class and size) for valley filling and peak shaving are examined to quantify and value DSP savings in 2020. The analysis shows potential peak reductions of 40 MW to 55 MW are achievable in the Single wholesale Electricity Market of Ireland (i.e. the test system), and valley demand increases of up to 30 MW. The study also shows the importance of the control strategy start time and the staggering of the devices to obtain the desired filling or shaving effect.

Exendin-4 attenuates adverse cardiac remodelling in streptozocin-induced diabetes via specific actions on infiltrating macrophages

In addition to its' established metabolic and cardioprotective effects, glucagon-like peptide-1 (GLP-1) reduces post-infarction heart failure via preferential actions on the extracellular matrix (ECM). Here, we investigated whether the GLP-1 mimetic, exendin-4, modulates cardiac remodelling in experimental diabetes by specifically targeting inflammatory/ECM pathways, which are characteristically dysregulated in this setting. Adult mice were subjected to streptozotocin (STZ) diabetes and infused with exendin-4/insulin/saline from 0 to 4 or 4-12 weeks. Exendin-4 and insulin improved metabolic parameters in diabetic mice after 12 weeks, but only exendin-4 reduced cardiac diastolic dysfunction and interstitial fibrosis in parallel with altered ECM gene expression. Whilst myocardial inflammation was not evident at 12 weeks, CD11b-F4/80(++) macrophage infiltration at 4 weeks was increased and reduced by exendin-4, together with an improved cytokine profile. Notably, media collected from high glucose-treated macrophages induced cardiac fibroblast differentiation, which was prevented by exendin-4, whilst several cytokines/chemokines were differentially expressed/secreted by exendin-4-treated macrophages, some of which were modulated in STZ exendin-4-treated hearts. Our findings suggest that exendin-4 preferentially protects against ECM remodelling and diastolic dysfunction in experimental diabetes via glucose-dependent modulation of paracrine communication between infiltrating macrophages and resident fibroblasts, thereby indicating that cell-specific targeting of GLP-1 signalling may be a viable therapeutic strategy in this setting.

Unsettling modernity: Shifting values and changing housing styles in the Kathmandu Valley

Abstract

Culture has always been important for the character of the cities, as have the civic and public institutions that sustain a lifestyle and provide an identity. Substantial evidence of the unique historical, urban civilisation remains within the traditional settlements in the Kathmandu Valley in Nepal; manifested in houses, palaces, temples, rest houses, open spaces, festivals, rituals, customs and cultural institutions. Indigenous knowledge and practices prescribed the arrangement of houses, roads and urban spaces giving the city a distinctive physical form, character and a unique oriental nativeness. In technical sense, these societies did not have written rules for guiding development. In recent decades, the urban culture of the city has been changing with the forces of urbanisation and globalisation and the demand for new buildings and spaces. New residential design is increasingly dominated by distinctive patterns of Western suburban ideal comprising detached or semi-detached homes and high rise tower blocks. This architectural iconoclasm can be construed as a rather crude response to the indigenous culture and built form. The paper attempts to dismantle the current tension between traditional and contemporary ‘culture’ (and hence society) and housing (or built form) in the Kathmandu Valley by engaging in a discussion that cuts across space, time and meaning of architecture as we know it.

A stacked Late Quaternary fluvio-periglacial sequence from the Axe valley, southern England with implications for landscape evolution and Palaeolithic archaeology

The current model of mid-latitude late Quaternary terrace sequences, is that they are uplift-driven but climatically controlled terrace staircases, relating to both regional-scale crustal and tectonic factors, and palaeohydrological variations forced by quasi-cyclic climatic conditions in the 100 K world (post Mid Pleistocene Transition). This model appears to hold for the majority of the river valleys draining into the English Channel which exhibit 8–15 terrace levels over approximately 60–100 m of altitudinal elevation. However, one valley, the Axe, has only one major morphological terrace and has long-been regarded as anomalous. This paper uses both conventional and novel stratigraphical methods (digital granulometry and terrestrial laser scanning) to show that this terrace is a stacked sedimentary sequence of 20–30 m thickness with a quasi-continuous (i.e. with hiatuses) pulsed, record of fluvial and periglacial sedimentation over at least the last 300–400 K yrs as determined principally by OSL dating of the upper two thirds of the sequence. Since uplift has been regional, there is no evidence of anomalous neotectonics, and climatic history must be comparable to the adjacent catchments (both of which have staircase sequences) a catchment-specific mechanism is required. The Axe is the only valley in North West Europe incised entirely into the near-horizontally bedded chert (crypto-crystalline quartz) and sand-rich Lower Cretaceous rocks creating a buried valley. Mapping of the valley slopes has identified many large landslide scars associated with past and present springs. It is proposed that these are thaw-slump scars and represent large hill-slope failures caused by Vauclausian water pressures and hydraulic fracturing of the chert during rapid permafrost melting. A simple 1D model of this thermokarstic process is used to explore this mechanism, and it is proposed that the resultant anomalously high input of chert and sand into the valley during terminations caused pulsed aggradation until the last termination. It is also proposed that interglacial and interstadial incision may have been prevented by the over-sized and interlocking nature of the sub-angular chert clasts until the Lateglacial when confinement of the river overcame this immobility threshold. One result of this hydrogeologically mediated valley evolution was to provide a sequence of proximal Palaeolithic archaeology over two MIS cycles. This study demonstrates that uplift tectonics and climate alone do not fully determine Quaternary valley evolution and that lithological and hydrogeological conditions are a fundamental cause of variation in terrestrial Quaternary records and landform evolution.

New lower Palaeolithic finds from the Axe valley Dorset

The Axe Valley has long been known for its Palaeolithic finds, particularly from the site at Broom. While research has continued at Broom, other sites have also been investigated in the valley as part of the English Heritage-managed and ALSFfunded project ?Palaeolithic Rivers of South West Britain? (PRoSWeB). This project was completed in March 2007. Since then, research focussing on the Quaternary geology and Palaeolithic archaeology of the southwest region has been continued at selected locations by Prof. Tony Brown (University of Southampton), Dr Laura Basell (University of Oxford) and Dr Phil Toms (University of Gloucestershire), with assistance from Dr Ramues Gallois and Dr Richard Scrivener (formerly British Geological Survey).

Rural communities and wind farms: a contingent valuation investigation

Using the contingent valuation method, this study investigates the preferences of local people for a wind farm that is planned in the Province of Rome. We estimate the reductions in their bimonthly electrical bills over a period of time that respondents are willing to accept as compensation for the installation of the wind farm. Our results suggest that respondents who perceive that the wind farm generates substantial negative impacts on landscape beauty ask higher reductions than others, while respondents who believe that the wind farm produces economic benefits for local communities ask lower reductions than others. Finally, we find that the demand for compensative measures is influenced particularly by socio-economic factors such as age and education.

Chronic PEGylated obestatin treatment prevents the onset of high fat diet-induced hypertension and endothelial dysfunction in the absence of metabolic actions

Background: Obestatin is a gastrointestinal peptide with established metabolic actions and emerging vascular effects which involve activation of NO signalling. The aim of this study was to investigate effects of a recently-characterised stable analogue, PEGylated obestatin (PEG-OB), in the setting of diet-induced obesity which is associated with both metabolic and vascular dysfunction. Methods: Male Sprague Dawley rats (6 weeks; n=8) were maintained on standard (SD) or high fat (HF) diet (60% fat) for 8 weeks with once-daily injection of either PEG-OB (50nmol/kg/day) or saline from 2 weeks. Results: HF feeding for 8 weeks resulted in marked body weight gain which was not affected by chronic PEG-OB treatment (HF saline, 175.0±12.2; HF PEG-OB, 190.4±6.4g; P=NS). Similarly, blood glucose, as indicated by HbA1c (HF saline, 6.30±0.15; HF PEG-OB, 6.13±0.36%; P=NS) and insulin tolerance (HF saline, 105.2±52.5; HF PEG-OB, 90.3±45.4mmol/L.min; P=NS), were unaltered by PEG-OB. Despite the apparent lack of metabolic effects, chronic PEG-OB treatment markedly attenuated development of HF-induced hypertension (HF saline, 146.5±4.9mmHg; HF PEG-OB, 123.0±9.7mmHg; P<0.01), assessed by tail-cuff plethysmography. Furthermore, organ bath pharmacology in isolated aortic rings, indicated that HF diet-induced endothelial dysfunction was completely prevented by PEG-OB (acetylcholine, EC50: SD saline, 335±113; HF saline, 758±164; HF PEG-OB, 277±85nmol/L; P<0.05). However, contraction to phenylephrine and relaxation to the NO donor, sodium nitroprusside, were unaltered between groups. Conclusions: PEG-OB exerts beneficial effects on hypertension and endothelial function in diabetes independently of metabolic actions suggesting that obestatin signalling may represent a novel therapeutic target to reduce the risk of associated cardiovascular complications.

Neuropeptide Y in GCF in periodontal health and disease

Objectives: To determine whether neuropeptide Y (NPY) is present in gingival crevicular fluid (GCF) in both periodontal health and disease and to study the relationship of NPY with periodontal inflammation. Methods: GCF samples (30 s) were collected from one site with both pocket depth (>4mm) and loss of periodontal attachment (>4mm) in 20 patients with chronic periodontitis (mean age 41.4, SD 9.6 yrs; 10 m, 10 f). GCF was also collected from clinically healthy sites (< 3mm, no bleeding on probing) in 20 subjects with no periodontitis (mean age 37.4, SD 11.7; 10 m, 10 f). GCF was collected using the periopaper strip method, diluted in 500 ul of phosphate-buffered saline and stored at –70°C. Samples were analysed in duplicate for NPY by radioimmunoassay. NPY levels were compared using the Mann-Whitney test. Results: Measurable NPY was present in all the GCF samples collected from healthy subjects. NPY was below the level of detection in 4 (20%) of the diseased subjects. There was considerable variability in the amount of NPY collected from both groups. There were no differences between the levels of NPY measured in males compared with females in either the healthy or diseased groups. Significantly more (P< 0.0001) NPY (pg) was collected from healthy subjects (Median 165, IQR 80; mean 161, SD 64) than diseased subjects (Median 37.5, IQR 56.3; mean 39.8, SD 35.1). There was more variability in the NPY concentration (pg/ul) which was also significantly higher in healthy (Median 575.7, IQR 562.3; mean 645.7, SD 416.7) compared with diseased subjects (Median 43.6, IQR 117.4; mean 96.4, SD 124.5). Conclusions: It is concluded that the levels of NPY in GCF sampled