The Role of the Nano-Environmental Interface in ZnO and CeO2 Nanoparticle Ecotoxicology

An increase in nanotechnology has seen an associated rise in nanoparticles released into the environment. Their potential toxicity and exposure to humans and the environment, the field of nanoecotoxicology, is not yet well understood. The interactions at the nanoparticle surface will play a fundamental role in the nanoparticle behaviour once released into the environment. This study aims to characterise the particle surface interaction, determining key parameters influential in the nanoparticle fate. Evanescent Wave Cavity Ring Down Spectroscopy techniques have been applied to study molecular interactions at the silica-water charged interface. The adsorption of the electronic spectrum of Crystal Violet has demonstrated the formation of a monolayer with different binding site orientation at the interface. The binding affinity for the chromophore was calculated as 29.15 ± 0.02 kJmol-1 at pH 9 and this was compared with other interface structures involving both inorganic and organic components. The study of the model interface was extended to the properties of CeO2 nanoparticles, where the surface charge density was determined to be 1.6 ± 0.3 e- nm-2.The nanoparticle surface charge controls the suspension stability which was measured for CeO2 nanoparticles giving a stability half-life of 330 ± 60 hours in pure water, and 3.6 ± 0.6 hours in ISOFish water. Studies were extended to the toxicity of ZnO nanoparticles. An assay was developed to quantify the photo-electron production for nanoparticles exposed to UV light both in deionised water and soil suspensions with a photo-radical production yield of 19 ± 2 % and an electron production of 709 e-s-1np-1 for a 100 mgL-1 suspension. The species-specific photo-radical assay was subsequently used to determine the rate of ZnO nanoparticle dissolution in water and soil suspensions. Comparable dissolution rates in complex cell growth media were also measured, detecting total zinc by Inductively Coupled Plasma Atomic Emission Spectroscopy, with comparable dissolution rates derived

The influence of flow discharge variations on the morphodynamics of a diffluence-confluence unit on a large river: Impacts of discharge variation on a diffluence-confluence unit

© 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. Bifurcations are key geomorphological nodes in anabranching and braided fluvial channels, controlling local bed morphology, the routing of sediment and water, and ultimately defining the stability of their associated diffluence–confluence unit. Recently, numerical modelling of bifurcations has focused on the relationship between flow conditions and the partitioning of sediment between the bifurcate channels. Herein, we report on field observations spanning September 2013 to July 2014 of the three-dimensional flow structure, bed morphological change and partitioning of both flow discharge and suspended sediment through a large diffluence–confluence unit on the Mekong River, Cambodia, across a range of flow stages (from 13 500 to 27 000 m 3 s −1 ). Analysis of discharge and sediment load throughout the diffluence–confluence unit reveals that during the highest flows (Q = 27 000 m 3 s −1 ), the downstream island complex is a net sink of sediment (losing 2600 ± 2000 kg s −1 between the diffluence and confluence), whereas during the rising limb (Q = 19 500 m 3 s −1 ) and falling limb flows (Q = 13 500 m 3 s −1 ) the sediment balance is in quasi-equilibrium. We show that the discharge asymmetry of the bifurcation varies with discharge and highlight that the influence of upstream curvature-induced water surface slope and bed morphological change may be first-order controls on bifurcation configuration. Comparison of our field data to existing bifurcation stability diagrams reveals that during lower (rising and falling limb) flow the bifurcation may be classified as unstable, yet transitions to a stable condition at high flows. However, over the long term (1959–2013) aerial imagery reveals the diffluence–confluence unit to be fairly stable. We propose, therefore, that the long-term stability of the bifurcation, as well as the larger channel planform and morphology of the diffluence–confluence unit, may be controlled by the dominant sediment transport regime of the system. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

Extreme flood-driven fluvial bank erosion and sediment loads: direct process measurements using integrated Mobile Laser Scanning (MLS) and hydro-acoustic techniques: Direct measurement of flood-driven erosion using MLS and MBES

Copyright © 2016 John Wiley & Sons, Ltd. This methods paper details the first attempt at monitoring bank erosion, flow and suspended sediment at a site during flooding on the Mekong River induced by the passage of tropical cyclones. We deployed integrated mobile laser scanning (MLS) and multibeam echo sounding (MBES), alongside acoustic Doppler current profiling (aDcp), to directly measure changes in river bank and bed at high (~0.05 m) spatial resolution, in conjunction with measurements of flow and suspended sediment dynamics. We outline the methodological steps used to collect and process this complex point cloud data, and detail the procedures used to process and calibrate the aDcp flow and sediment flux data. A comparison with conventional remote sensing methods of estimating bank erosion, using aerial images and Landsat imagery, reveals that traditional techniques are error prone at the high temporal resolutions required to quantify the patterns and volumes of bank erosion induced by the passage of individual flood events. Our analysis reveals the importance of cyclone-driven flood events in causing high rates of erosion and suspended sediment transport, with a c. twofold increase in bank erosion volumes and a fourfold increase in suspended sediment volumes in the cyclone-affected wet season. Copyright © 2016 John Wiley & Sons, Ltd

Sustainable rice cultivation in the deep flooded zones of the Vietnamese Mekong Delta

This paper explains how the management of the full-dyke system in the deep flooded zones of the Vietnamese Mekong Delta affects rice cultivation, and outlines how alternative dyke management strategies could offer more sustainable adaptations in the face of future environmental threats. The current management of the ‘full-dyke’ network has been successful in promoting triple-cropping rice cultivation, but this practice has prevented sediment deposition on the land surface. River-borne sediments deposited on the delta land surface have high economic value because they are (i) rich in nutrients (potentially 26 million USD/yr of free fertiliser to An Giang Province) and can (ii) help to maintain the Mekong Delta land above sealevel. Without a continuing supply of sediment to the delta, triple-cropping paddies may not continue to be sustainable or profitable for the majority of rice farmers over the next 10 to 20 years. The economic value of sediment as a free fertiliser is particularly important to poor farmers, as without sediment, they run a significant risk of debt due to fluctuations in rice, fertiliser, and other input prices. With incoming loads now declining, sediment must be managed carefully as a resource. Our projections show that the best use of the remaining sediment resource can be achieved by allowing full paddy flooding only in years of high sediment potential, and this would greatly increase the sustainability of rice agriculture in the face of future environmental change. This recommended policy is an option with few regrets, in that its other benefits include maximising groundwater replenishment, ensuring freshwater availability during drought periods (including countering salt water intrusion), cleansing rice paddies of pests and disease, and tempering downstream flooding. If triple-rice-cropping continues to have priority, financial support will particularly be needed to provide help to poorer farmers coping with increases in artificial fertiliser prices

Modulation of outer bank erosion by slump blocks: Disentangling the protective and destructive role of failed material on the three-dimensional flow structure

The three-dimensional flow field near the banks of alluvial channels is the primary factor controlling rates of bank erosion. Although submerged slump blocks and associated large-scale bank roughness elements have both previously been proposed to divert flow away from the bank, direct observations of the interaction between eroded bank material and the 3-D flow field are lacking. Here we use observations from multibeam echo sounding, terrestrial laser scanning, and acoustic Doppler current profiling to quantify, for the first time, the influence of submerged slump blocks on the near-bank flow field. In contrast to previous research emphasizing their influence on flow diversion away from the bank, we show that slump blocks may also deflect flow onto the bank, thereby increasing local shear stresses and rates of erosion. We use our measurements to propose a conceptual model for how submerged slump blocks interact with the flow field to modulate bank erosion.UK Natural Environment Research Council (NERC

The Management of Uterine Leiomyomas

Objectives: The aim of this guideline is to provide clinicians with an understanding of the pathophysiology, prevalence, and clinical significance of myomata and the best evidence available on treatment modalities. Options: The areas of clinical practice considered in formulating this guideline were assessment, medical treatments, conservative treatments of myolysis, selective uterine artery occlusion, and surgical alternatives including myomectomy and hysterectomy. The risk-to-benefit ratio must be examined individually by the woman and her health care provider. Outcomes: Implementation of this guideline should optimize the decision-making process of women and their health care providers in proceeding with further investigation or therapy for uterine leiomyomas, having considered the disease process and available treatment options, and reviewed the risks and anticipated benefits. Evidence: Published literature was retrieved through searches of PubMed, CINAHL, and Cochrane Systematic Reviews in February 2013, using appropriate controlled vocabulary (uterine fibroids, myoma, leiomyoma, myomectomy, myolysis, heavy menstrual bleeding, and menorrhagia) and key words (myoma, leiomyoma, fibroid, myomectomy, uterine artery embolization, hysterectomy, heavy menstrual bleeding, menorrhagia). The reference lists of articles identified were also searched for other relevant publications. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date limits but results were limited to English or French language materials. Searches were updated on a regular basis and incorporated in the guideline to January 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, and national and international medical specialty societies. Benefits, Harms, and Costs: The majority of fibroids are asymptomatic and require no intervention or further investigations. For symptomatic fibroids such as those causing menstrual abnormalities (e.g. heavy, irregular, and prolonged uterine bleeding), iron defficiency anemia, or bulk symptoms (e.g., pelvic pressure/pain, obstructive symptoms), hysterectomy is a definitive solution. However, it is not the preferred solution for women who wish to preserve fertility and/or their uterus. The selected treatment should be directed towards an improvement in symptomatology and quality of life. The cost of the therapy to the health care system and to women with fibroids must be interpreted in the context of the cost of untreated disease conditions and the cost of ongoing or repeat investigative or treatment modalities. Values: The quality of evidence in this document was rated using the criteria described in the Report of the Caadian Task Force on Preventive Health Care (Table 1)

Corrigendum to ‘Guideline No. 412: Laparoscopic Entry for Gynaecological Surgery’ [Journal of Obstetrics and Gynaecology Canada 43 (2021) 376−389](S1701216320310343)(10.1016/j.jogc.2020.12.012)

The authors regret that the print version of this article contained the incorrect reference 51. Reference 51 should have been: Bernante P, Foletto M, Toniato A. Creation of pneumoperitoneum using a bladed optical trocar in morbidly obese patients: technique and results. Obes Surg. 2008 Aug;18(8):1043-6. doi: 10.1007/s11695-008-9497-8. The online version of the article has now been corrected The authors would like to apologize for any confusion this caused. DOI of original article: https://doi.org/10.1016/j.jogc.2021.03.00

A Patient Registry for the Management of Uterine Fibroids in Canada: Protocol for a Multicenter, Prospective, Noninterventional Study

Background: Uterine fibroids are the most common benign tumor in women. Among those with fibroids, approximately 30% become symptomatic, with abnormal uterine bleeding, pelvic pain, and bulk symptoms. Despite the high prevalence of fibroids, little information is available regarding symptoms, treatment choices, and outcomes for patients. Objective: A Canada-wide patient registry was established to understand the real-world practice. This registry included patient presentation and treatment preferences, health care provider attitudes, and clinical outcomes in the management of symptomatic uterine fibroids. Methods: This study is a prospective, noninterventional, observational patient registry. It will include women diagnosed with uterine fibroids and being managed for symptoms. Participant inclusion criteria were (1) at least 18 years of age, (2) premenopausal with a confirmed diagnosis of uterine fibroids, and associated symptoms, and (3) initiating treatment (drug intervention, procedure intervention, or a combination of both) or watchful waiting. Patients (or legal representative) must understand the nature of the project and provide written informed consent before enrollment. Participant exclusion criteria were (1) they have known or suspected clinically significant pelvic pathology not associated with uterine fibroids, and (2) they are undergoing an emergency hysterectomy at the initial visit. Outcomes will be evaluated in the context of routine clinical practice. Results: Participant recruitment of this registry began in July 2015. This study currently has a total sample of 1500 patients. Conclusions: This registry, a first in Canada, will accumulate evidence on the risks and benefits of watchful waiting, and medical and procedural interventions. It will contribute to enhancing access to treatment options for patients

Modulation of outer bank erosion by slump blocks: disentangling the protective and destructive role of failed material on the three-dimensional flow structure

The three-dimensional flow field near the banks of alluvial channels is the primary factor controlling rates of bank erosion. Although submerged slump blocks and associated large-scale bank roughness elements have both previously been proposed to divert flow away from the bank, direct observations of the interaction between eroded bank material and the 3-D flow field are lacking. Here we use observations from multibeam echo sounding, terrestrial laser scanning, and acoustic Doppler current profiling to quantify, for the first time, the influence of submerged slump blocks on the near-bank flow field. In contrast to previous research emphasizing their influence on flow diversion away from the bank, we show that slump blocks may also deflect flow onto the bank, thereby increasing local shear stresses and rates of erosion. We use our measurements to propose a conceptual model for how submerged slump blocks interact with the flow field to modulate bank erosion