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This paper provides a high-level assessment of Vietnam's sea dike system and its prescribed dike safety standards. The assessment estimates that 65 percent of the sea dike system does not meet the safety standards and that about $2 billion in capital investment is necessary to meet the standards, mainly in the Red River Delta. It also shows that current safety standards need finetuning, especially in areas with high risk and growth. This paper acts as a technical background paper to the report Resilient Shores: Vietnam's Coastal Development between Opportunity and Disaster Risk (Rentschler et al. 2020).

Cua Dai Beach located adjacent to Cua Dai Inlet is a typical, seasonally varying tidal inlet. This famous beach has suffered extreme erosion since 1995 due to an apparent irregular-periodic process, a decrease of sediment supply from the river and its estuaries and increased squeeze by coastal developments. The main objective of this study is to unravel the physical processes that control the morphological development of Cua Dai Inlet while challenged by the fact that it is a data-limited environment. In order to identify and quantify the main processes governing the evolution of Cua Dai Beach and thereby aiming to explain the morphological changes and extreme erosion in recent years, a new approach was developed. Historical shoreline positions and sediment budget changes were derived from satellite images using empirical engineering assumptions. In addition, numerical models were used to investigate in detail sediment transports and morphodynamics under the influence of seasonal waves and rivers as well as the anthropogenically-driven impacts. Results of shoreline change rates indicate that Cua Dai Beach (located on the northern side of Cua Dai inlet) experienced an average erosion of 12m/y during the period from 2000 to 2010 and erosion continued further to the north while the southern coast of the inlet accreted with a mean rate of 11m/y. The overall system showed a significant sediment loss of about 243,000–310,000 m3/y. The annual cycle of two past morphological periods has been numerically simulated to evaluate the behavior of the system without and with human interventions. The first morphological simulation without the impact of the resorts successfully reproduced an overall erosion trend at the northern coast while the formation of an ebb tidal bar was also reproduced. The second morphological simulation reproduced the impact of the resorts that have been constructed along Cua Dai Beach. Simulations indicate that the presence of the resorts has enhanced the propagation of the existing erosion further to the north. The new approach of remote sensing combined with process-based modeling has been essential to investigate the main processes that govern the morphological changes and extreme erosion at Cua Dai inlet.

Over the last few decades, the Mekong Delta Coast has undergone many physical changes that have increased its vulnerability. Issues that have grown in importance are erosion, human occupation of coastal and estuarine mangroves, decreased sediment supply by the Mekong River and subsidence due to groundwater extraction. These issues have led to the loss of coastal and estuarine land and mangroves, increasing flood vulnerability and salinity intrusion. Recently, young and promising Vietnamese researchers have undertaken a number of in-depth studies to increase our understanding of the above issues. The objective of the present paper is to give a concise description of their work and place it into a broader context. The topics concerned are satellite mapping of coastal landuse changes, numerical simulation of the tide and wave climate and of coastal erosion, coastal and estuarine mangrove squeeze, wave and current damping in mangroves and wave transmission through bamboo fences. The main findings are that (1) coastal landuse has changed significantly over the last decades with the largest change due to conversion of mangroves to aquaculture and a modest change due to coastal erosion, (2) the understanding of the tide and wave climate and of the erosion has increased due to successful numerical modelling, (3) the role of mangrove squeeze along the coast and along the estuaries has been assessed, (4) the understanding of wave and current damping in mangroves and of wave transmission through bamboo fences has increased through the combined effort of laboratory and numerical modelling.

Neurolymphomatosis is a rare manifestation of non-Hodgkin lymphoma characterized by infiltration of peripheral nerves, nerve roots, plexus and cranial nerves by malignant lymphocytes. This report presents positron emission tomography/computed tomography (PET/CT)imaging with 2-deoxy-2-(18)F-fluoro-D-glucose ((18)F-FDG) in 3 cases of non-Hodgkin lymphoma with nerve infiltration, including one newly diagnosed lymphoma, one recurrent lymphoma in previous nerve lesions and one newly recurrent lymphoma. PET/CT could reveal the affected neural structures including cranial nerves, spinal nerve roots, brachial plexus, cervicothoracic ganglion, intercostal nerves, branches of the vagus nerve, lumbosacral plexus and sciatic nerves. There was relative concordance between PET/CT and MRI in detection of affected cranial nerves. PET/CT seemed to be better than MRI in detection of affected peripheral nerves. (18)F-FDG PET/CT was a whole-body imaging technique with the ability to reveal the affected cranial nerves, peripheral nerves, nerve roots and plexus in non-Hodgkin lymphoma. A thorough understanding of disease and use of advanced imaging modalities will increasingly detect neurolymphomatosis.

Hierarchical metal-free catalyst based on the CVD synthesis of nitrogen-doped carbon nanotubes decorated silicon carbide (N-CNTs/SiC) macroscopic host structure has been prepared. The catalyst was evaluated in the partial oxidation of H 2 S by oxygen into elemental sulfur in a fixed-bed reactor. The catalytic results indicate that the N-CNTs/SiC catalyst exhibits an extremely high desulfurization performance even under severe reaction conditions such as low temperature, high space velocity and at low O 2 -to-H 2 S molar ratio. The high desulfurization performance was attributed to the high effective surface area of the catalyst along with a short diffusion length associated with the nanoscopic dimension of the carbon nanotubes. The N-CNTs/SiC catalyst also displays a high stability as a function of time on stream which could be attributed to the strong anchoring of the nitrogen doping within the carbon matrix. The extrudates shape of the SiC support allows the direct macroscopic shaping of the catalyst for use in conventional fixed-bed reactor without facing problems linked with catalyst handling, transportation and pressure drop across the catalyst bed as encountered with nanoscopic carbon-based catalyst.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)., The synthesis and properties of an oxygen reduction catalyst based on a unique 3-dimensional (3D) nitrogen doped (N-doped) carbon composite are described. The composite material is synthesised via a two-step hydrothermal and pyrolysis method using bio-source low-cost materials of galactose and melamine. Firstly, the use of iron salts and galactose to hydrothermally produceiron oxide (Fe2O3) magnetic nanoparticle clusters embedded carbon spheres. Secondly, magnetic nanoparticles diffused out of the carbon sphere when pyrolysed in the presence of melamine as nitrogen precursor. Interestingly, many of these nanoparticles, as catalyst-grown carbon nanotubes (CNTs), resulted in the formation of N-doped CNTs and N-doped carbon spheres under the decomposition of carbon and a nitrogen environment. The composite material consists of integrated N-doped carbon microspheres and CNTs show high ORR activity through a predominantly four-electron pathway.