Levels of Arsenic and Other Trace Elements in Southern Libyan Agricultural Irrigated Soil and Non-irrigated Soil Projects

The levels of As and various other trace elements found in the irrigated agricultural soil (Tsoil) of southern Libya were compared with non-irrigated soil (Csoil) from the same sampling campaign collected between April and May 2008. The soil samples represented agronomic practice in the southern Libyan regions of Maknwessa (MAK), Aril (ARL) and Taswaa (TAS), and were analyzed by Inductively coupled plasma mass spectrometry (ICP-MS) for Co, Ni, Cu, Se, Mo, Zn, As, Pb, Cd and P. Concentrations of P and As in TAS and MAK were found to be higher in Tsoil compared to Csoil, while the opposite was true for ARL. In general, As concentrations in these areas were 2-3 times lower than the global average. In ARL, the average P concentrations of the Csoil samples were significantly higher than those of Tsoil samples: this site is composed mainly of pasture for animal production, where phosphate fertilizers are used regularly. Distance from the source of irrigation was found to be of an important influence on the heavy metal concentration of the soil, with greater concentrations found closer to the irrigation source. It can be concluded from the results that irrigation water contains elevated levels of As, which finds its way into the soil profile and can lead to accumulation of As in the soil over time.

Current therapeutic strategies to mitigate the eNOS dysfunction in ischaemic stroke

Impairment of endothelial nitric oxide synthase (eNOS) activity is implicated in the pathogenesis of endothelial dysfunction in many diseases including ischaemic stroke. The modulation of eNOS during and/or following ischaemic injury often represents a futile compensatory mechanism due to a significant decrease in nitric oxide (NO) bioavailability coupled with dramatic increases in the levels of reactive oxygen species that further neutralise NO. However, applications of a number of therapeutic agents alone or in combination have been shown to augment eNOS activity under a variety of pathological conditions by potentiating the expression and/or activity of Akt/eNOS/NO pathway components. The list of these therapeutic agents include NO donors, statins, angiotensin-converting enzyme inhibitors, calcium channel blockers, phosphodiesterase-3 inhibitors, aspirin, dipyridamole and ellagic acid. While most of these compounds exhibit anti-platelet properties and are able to up-regulate eNOS expression in endothelial cells and platelets, others suppress eNOS uncoupling and tetrahydrobiopterin (an eNOS stabiliser) oxidation. As the number of therapeutic molecules that modulate the expression and activity of eNOS increases, further detailed research is required to reveal their mode of action in preventing and/or reversing the endothelial dysfunction.

Effect of controlled periodic-based illumination on the photonic efficiency of photocatalytic degradation of methyl orange

The use of controlled periodic illumination with UV LEDs for enhancing photonic efficiency of photocatalytic decomposition processes in water has been investigated using methyl orange as a model compound. The impact of the length of light and dark time periods (T _ON/T _OFF times) on photodegradation and photonic efficiency using a UV LED-illuminated photoreactor has been studied. The results have shown an inverse dependency of the photonic efficiency on duty cycle and a very little effect on T _ON or T _OFF time periods, indicating no effect of rate-limiting steps through mass diffusion or adsorption/desorption in the reaction. For this reactor, the photonic efficiency under controlled periodic illumination (CPI) matches to that of continuous illumination, for the same average UV light intensities. Furthermore, under CPI conditions, the photonic efficiency is inversely related to the average UV light intensity in the reactor, in the millisecond time regime. This is the first study that has investigated the effect of controlled periodic illumination using ultra band gap UV LED light sources in the photocatalytic destruction of dye compounds using titanium dioxide. The results not only enhance the understanding of the effect of periodic illumination on photocatalytic processes but also provide a greater insight to the potential of these light sources in photocatalytic reactions. 

Spitzer observations of the asteroid-comet transition object and potential spacecraft target 107P (4015) Wilson-Harrington

Context: Near-Earth asteroid-comet transition object 107P/ (4015) Wilson-Harrington is a possible target of the joint European Space Agency (ESA) and Japanese Aerospace Exploration Agency (JAXA) Marco Polo sample return mission. Physical studies of this object are relevant to this mission, and also to understanding its asteroidal or cometary nature. Aims: Our aim is to obtain significant new constraints on the surface thermal properties of this object. Methods: We present mid-infrared photometry in two filters (16 and 22 μm) obtained with NASA's Spitzer Space Telescope on February 12, 2007, and results from the application of the Near Earth Asteroid Thermal Model (NEATM). We obtained high S/N in two mid-IR bands allowing accurate measurements of its thermal emission. Results: We obtain a well constrained beaming parameter (η = 1.39±0.26) and obtain a diameter and geometric albedo of D = 3.46±0.32 km, and pV = 0.059±0.011. We also obtain similar results when we apply this best-fitting thermal model to single-band mid-IR photometry reported by Campins et al. (1995, P&SS, 43, 733), Kraemer et al. (2005, AJ, 130, 2363) and Reach et al. (2007, Icarus, 191, 298). Conclusions: The albedo of 4015 Wilson-Harrington is low, consistent with those of comet nuclei and primitive C-, P-, D-type asteorids. We establish a rough lower limit for the thermal inertia of W-H of 60 Jm-2s-0.5 K-1 when it is at r = 1 AU, which is slightly over the limit of 30 Jm-2 s-0.5 K-1 derived by Groussin et al. (2009, Icarus, 199, 568) for the thermal inertia of the nucleus of comet 22P/Kopff.

Structural and electrical anisotropy of (001)-, (116)-, and (103)-oriented epitaxial SrBi2Ta2O9 thin films on SrTiO3 substrates grown by pulsed laser deposition

Epitaxial SrBi2Ta2O9 (SBT) thin films with well-defined (001), (116), and (103) orientations have been grown by pulsed laser deposition on (001)-, (011)-, and (111)-oriented Nb-doped SrTiO3 substrates. X-ray diffraction pole figure and phi -scan measurements revealed that the three-dimensional epitaxial orientation relation SBT(001)parallel to SrTiO3(001), and SBT[1(1) over bar 0]parallel to SrTiO3[100] is valid for all cases of SET thin films on SrTiO3 substrates, irrespective of their orientations. Atomic force microscopy images of the c-axis-oriented SET revealed polyhedron-shaped grains showing spiral growth around screw dislocations. The terrace steps of the c-axis-oriented SET films were integral multiples of a quarter of the lattice parameter c of SBT (similar to 0.6 nm). The grains of (103)-oriented SET films were arranged in a triple-domain configuration consistent with the symmetry of the SrTiO3(111) substrate. The measured remanent polarization (2P(r)) and coercive field (2E(c)) of (116)-oriented SBT films were 9.6 muC/cm(2) and 168 kV/cm, respectively, for a maximum applied electric field of 320 kV/cm. Higher remanent polarization (2P(r)=10.4 muC/cm(2)) and lower coercive field (2E(c)=104 kV/cm) than those of SBT(116) films were observed in (103)-oriented SET thin films, and (001)-oriented SET revealed no ferroelectricity along the [001] axis. The dielectric constants of (001)-, (116)-, and (103)-oriented SBT were 133, 155, and 189, respectively. (C) 2000 American Institute of Physics.

European Cystic Fibrosis Society Standards of Care: Quality Management in cystic fibrosis

Since the earliest days of cystic fibrosis (CF) treatment, patient data have been recorded and reviewed in order to identify the factors that lead to more favourable outcomes. Large data repositories, such as the US Cystic Fibrosis Registry, which was established in the 1960s, enabled successful treatments and patient outcomes to be recognized and improvement programmes to be implemented in specialist CF centres. Over the past decades, the greater volumes of data becoming available through Centre databases and patient registries led to the possibility of making comparisons between different therapies, approaches to care and indeed data recording. The quality of care for individuals with CF has become a focus at several levels: patient, centre, regional, national and international. This paper reviews the quality management and improvement issues at each of these levels with particular reference to indicators of health, the role of CF Centres, regional networks, national health policy, and international data registration and comparisons. 

Holocene landscape intervention and plant food production strategies in island and mainland Southeast Asia

In the areas adjacent to the drowned Pleistocene continent of Sunda – present-day Mainland and Island SE Asia – the Austronesian Hypothesis of a diaspora of rice cultivators from Taiwan ∼4200 years ago has often been linked with the start of farming. Mounting evidence suggests that these developments should not be conflated and that alternative explanations should be considered, including indigenous inception of complex patterns of plant food production and early exchange of plants, animals, technology and genes. We review evidence for widespread forest disturbance in the Early Holocene which may accompany the beginnings of complex food-production. Although often insubstantial, evidence for incipient and developing management of rainforest vegetation and of developing complex relationships with plants is present, and early enough to suggest that during the Early to mid-Holocene this vast region was marked by different approaches to plant food production. The trajectory of the increasingly complex relationships between people and their food organisms was strongly locally contingent and in many cases did not result in the development of agricultural systems that were recognisable as such at the time of early European encounters. Diverse resource management economies in the Sunda and neighbouring regions appear to have accompanied rather than replaced a reliance on hunting and gathering. This, together with evidence for Early Holocene interaction between these neighbours, gives cause for us to question some authors continued adherence to a singular narrative of the Austronesian Hypothesis and the ‘Neolithisation’ of this part of the world. It also leads us to suggest that the forests of this vast region are, to an extent, a cultural artefact.

The 'human revolution' in lowland tropical Southeast Asia:the antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, Borneo)

Recent research in Europe, Africa, and Southeast Asia suggests that we can no longer assume a direct and exclusive link between anatomically modern humans and behavioral modernity (the 'human revolution'), and assume that the presence of either one implies the presence of the other: discussions of the emergence of cultural complexity have to proceed with greater scrutiny of the evidence on a site-by-site basis to establish secure associations between the archaeology present there and the hominins who created it. This paper presents one such case study: Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 in the West Mouth of the Great Cave of a modern human skull, the 'Deep Skull,' controversially associated with radiocarbon dates of ca. 40,000 years before the present. A new chronostratigraphy has been developed through a re-investigation of the lithostratigraphy left by the earlier excavations, AMS-dating using three different comparative pre-treatments including ABOX of charcoal, and U-series using the Diffusion-Absorption model applied to fragments of bones from the Deep Skull itself. Stratigraphic reasons for earlier uncertainties about the antiquity of the skull are examined, and it is shown not to be an `intrusive' artifact. It was probably excavated from fluvial-pond-desiccation deposits that accumulated episodically in a shallow basin immediately behind the cave entrance lip, in a climate that ranged from times of comparative aridity with complete desiccation, to episodes of greater surface wetness, changes attributed to regional climatic fluctuations. Vegetation outside the cave varied significantly over time, including wet lowland forest, montane forest, savannah, and grassland. The new dates and the lithostratigraphy relate the Deep Skull to evidence of episodes of human activity that range in date from ca. 46,000 to ca. 34,000 years ago. Initial investigations of sediment scorching, pollen, palynomorphs, phytoliths, plant macrofossils, and starch grains recovered from existing exposures, and of vertebrates from the current and the earlier excavations, suggest that human foraging during these times was marked by habitat-tailored hunting technologies, the collection and processing of toxic plants for consumption, and, perhaps, the use of fire at some forest-edges. The Niah evidence demonstrates the sophisticated nature of the subsistence behavior developed by modern humans to exploit the tropical environments that they encountered in Southeast Asia, including rainforest. (c) 2006 Elsevier Ltd. All rights reserved.

Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene

South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene. 

Predictors of adherence to treatment in bronchiestasis

Objectives

We aimed to determine if beliefs about treatment, clinical factors and quality of life predicted adherence to treatment in patients with bronchiectasis.

Methods

We recruited participants with confirmed bronchiectasis to a one-year study. We calculated adherence to treatment using medication possession ratios and self-report. Baseline Beliefs about Medicines, clinical, demographic and Quality of Life Questionnaire-Bronchiectasis data were collected. We used logistic regression to determine predictors of adherence to treatment during the subsequent year.

Results

Seventy-five participants were recruited. Beliefs about harm, age and total number of prescribed medications were predictors of adherence to inhaled antibiotics. Concerns about medication, age and Quality of Life Questionnaire-Bronchiectasis Treatment Burden were predictors of adherence to other respiratory medicines. Beliefs about necessity of airway clearance and age were predictors of adherence to airway clearance.

Conclusion

Beliefs about treatment, age, number of prescribed medications and perceived treatment burden predicted subsequent adherence in bronchiectasis, thereby, providing potential targets for future interventions in this population. Clinicians can use these data to identify patients with bronchiectasis who might be at risk of non-adherence i.e. those who are younger, have concerns about medications, who do not think airway clearance is necessary or who are prescribed numerous medications.

Novel titania sol-gel derived film for luminescence-based oxygen sensing.

A novel method for the preparation of titania sol–gel derived oxygen sensors based on the ruthenium(II) dye, [Ru(bpy)3]2+, is described. A titania sol–gel paste film was cast onto microscope slides, and the dye ion-paired to the deprotonated, hydroxylated groups on the film's surface from an aqueous solution of the dye at pH 11. The resulting sensor film is extremely oxygen sensitive, with a PO2 (S = 1/2) value (i.e. the partial pressure of oxygen required in order to reduce the original, oxygen free, luminescence intensity by 50%) of 0.011 atm. The sensor undergoes 95% response to oxygen in 4 s, and shows 95% recovery of its luminescence in argon within 7 s.

Powder semiconductor photocatalysis in aqueous solution: An overview of kinetics-based reaction mechanisms

A brief, historical overview of 10 apparently different, although in some cases, upon inspection, closely related, popular proposed reaction mechanisms and their associated rate equations, is given and in which the rate expression for each mechanism is derived from basic principles, Appendix A. In Appendix B, each of the 5 main mechanisms are tested using datasets, comprising initial reaction rate vs. organic pollutant concentration, [P] and incident irradiance, ρ, data, reported previously for TiO2, where P is phenol, 4-chlorophenol and formic acid. The best of those tested, in terms of overall fit, simplicity, usefulness and versatility is the disrupted adsorption kinetic model proposed by Ollis. The usual basic assumptions made in constructing these mechanisms are reported and the main underlying concerns explored.

Time-dependent tegumental surface changes in juvenile Fasciola gigantica in response to triclabendazole treatment in goat

Triclabendazole (TCBZ), the anthelmintic drug active against both mature and immature liver flukes, was used to investigate the effect of in vivo treatment on the tegumental surface of juvenile Fasciola gigantica. Five goats were infected with 150 F. gigantica metacercariae each by oral gavage. Four of them were treated with single dose of TCBZ at 10mg/kg at four weeks post-infection. They were euthanized at 0 (untreated), 24, 48, 72 and 96h post treatment. Juvenile flukes were manually retrieved from the goat livers and processed for scanning electron microscopy. In control flukes, the anterior region was adorned with sharply pointed spines projecting away from the surface, while in the posterior region, spines become shorter and narrower, loosing serration and with the appearance of distinct furrows and papillae. The dorsal surface retained the same pattern of surface architecture similar to that of ventral surface. Flukes obtained from 24h post-treatment did not show any apparent change and were still very active. However, there were limited movements and some blebbing, swelling, deposition of tegumental secretions and some flattening displayed by the flukes of 48h post-treatment. All the worms were found dead 72h post-treatment and showed advanced level of tegumental disruptions, consisting of severe distortion of spines, sloughing off the tegument to expose the basal lamina, formation of pores and isolated patches of lesions. By 96h post-treatment, the disruption was extremely severe and the tegument was completely sheared off causing deeper lesions that exposed the underlying musculature. The disruption was more severe at posterior than anterior region and on ventral than dorsal surface. The present study further establishes the time-course of TCBZ action in vivo with 100% efficacy against the juvenile tropical liver fluke.

Performance assessment of cascade control loopswith non-Gaussian disturbances using entropy information

Cascade control is one of the routinely used control strategies in industrial processes because it can dramatically improve the performance of single-loop control, reducing both the maximum deviation and the integral error of the disturbance response. Currently, many control performance assessment methods of cascade control loops are developed based on the assumption that all the disturbances are subject to Gaussian distribution. However, in the practical condition, several disturbance sources occur in the manipulated variable or the upstream exhibits nonlinear behaviors. In this paper, a general and effective index of the performance assessment of the cascade control system subjected to the unknown disturbance distribution is proposed. Like the minimum variance control (MVC) design, the output variances of the primary and the secondary loops are decomposed into a cascade-invariant and a cascade-dependent term, but the estimated ARMA model for the cascade control loop based on the minimum entropy, instead of the minimum mean squares error, is developed for non-Gaussian disturbances. Unlike the MVC index, an innovative control performance index is given based on the information theory and the minimum entropy criterion. The index is informative and in agreement with the expected control knowledge. To elucidate wide applicability and effectiveness of the minimum entropy cascade control index, a simulation problem and a cascade control case of an oil refinery are applied. The comparison with MVC based cascade control is also included.