Mining regional co-location patterns with kNNG

Spatial co-location pattern mining discovers the subsets of features of which the events are frequently located together in geographic space. The current research on this topic adopts a distance threshold that has limitations in spatial data sets with various magnitudes of neighborhood distances, especially for mining of regional co-location patterns. In this paper, we propose a hierarchical co-location mining framework accounting for both variety of neighborhood distances and spatial heterogeneity. By adopting k-nearest neighbor graph (kNNG) instead of distance threshold, we propose “distance variation coefficient” as a new measure to drive the mining operations and determine an individual neighborhood relationship graph for each region. The proposed mining algorithm outputs a set of regions with each of them an individual set of regional co-location patterns. The experimental results on both synthetic and real world data sets show that our framework is effective to discover these regional co-location patterns.     

Failure Behavior of Riprap Layer at Bridge Piers under Live-Bed Conditions

Experiments conducted under live-bed conditions show that a riprap layer at a cylindrical bridge pier will fail in either one of the following two modes: Total disintegration or embedment. The former refers to the break-up of the entire riprap layer where the stones are washed away by the flow field generated at the pier. The latter relates to the embedment of the riprap layer where it is buried in the sediment bed. The study proposes a criterion to demarcate the limiting condition between the two types of failure. It also identifies that embedment failure is a more common failure mode of riprap layer under live-bed conditions. The causes of embedment failure are twofold: (1) bed feature destabilization; and (2) differential mobility. Bed level fluctuations caused by the propagating bed features resulted in bed feature destabilization, whereas differential mobility is due to the different response of the riprap stones and bed sediments to the flow field. Experimental results also show that the riprap layer can degrade to an equilibrium level for a given flow condition. Finally, the study proposes a semiempirical equation to compute the maximum depth of riprap degradation, which occurs at the upper end of dune regime.     

Vancomycin-resistant enterococci

Vancomycin-resistant enterococci (VRE) are gaining much attention in the West, chiefly because of the lack of available antimicrobial therapy for VRE infections as most VRE are also resistant to drugs previously used to treat such diseases (e.g. aminoglycosides and ampicillin), the possibility that the vancomycin-resistant genes present in VRE can be transferred to methicillin-resistant Staphylococcus aureus (MRSA), and increasing reports of VRE and the trend towards endemicity in North America. There are three case reports and a study showing stool carriage of more than 10% from Singapore. One of the case reports is notable as the VRE isolated from the urinary tract is community-acquired. In Europe, there is a strong association between the use of avoparcin (a glycopeptide) in animal feeds and the emergence of VRE. Clonal dissemination resulting in nosocomial transmission is also demonstrated. Prior vancomycin use is a risk factor for the subsequent development of VRE bacteraemia. The laboratory plays an important role, namely, a) detection of VRE, and b) determination of susceptibilities of antimicrobials whereby possible therapeutic options may be instituted when antimicrobial intervention is indicated. There is a need to evaluate existing infection control measures against VRE to prevent it from becoming endemic in Singapore as had happened in North America.     

Technical and economic evaluation of the conjunctive use of surface and groundwater in the Campaspe Valley,north-central Victoria,Australia

This paper describes a technical and feasibility study of increasing groundwater usage to supplement surface water use in the Campaspe Valley in south-eastern Australia. An integrated model which simulates the surface and groundwater processes, as well as the interactions between the processes, is used to determine the sustainable long-term groundwater pumping yields. The model also provides estimates of groundwater fluxes for various management options of increasing groundwater usage. These estimates are used to assist an economic analysis to determine the relative merits of various options for the conjunctive use of surface and groundwater resources. The pumping costs, value of water and tangible salinity benefits from lowering high water-tables and reducing salt load are considered in the economic analysis. The methodology is also relevant for other studies looking into the conjunctive use of surface and groundwater resources throughout the Murray Basin and elsewhere.     

Mode-Dependent Templates and Scan Order for H.264/AVC-Based Intra Lossless Coding

In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.     

Scalable Production of Extracellular Vesicles and Its Therapeutic Values: A Review

Extracellular vesicles (EVs) are minute vesicles with lipid bilayer membranes. EVs are secreted by cells for intercellular communication. Recently, EVs have received much attention, as they are rich in biological components such as nucleic acids, lipids, and proteins that play essential roles in tissue regeneration and disease modification. In addition, EVs can be developed as vaccines against cancer and infectious diseases, as the vesicle membrane has an abundance of antigenic determinants and virulent factors. EVs for therapeutic applications are typically collected from conditioned media of cultured cells. However, the number of EVs secreted by the cells is limited. Thus, it is critical to devise new strategies for the large-scale production of EVs. Here, we discussed the strategies utilized by researchers for the scalable production of EVs. Techniques such as bioreactors, mechanical stimulation, electrical stimulation, thermal stimulation, magnetic field stimulation, topographic clue, hypoxia, serum deprivation, pH modification, exposure to small molecules, exposure to nanoparticles, increasing the intracellular calcium concentration, and genetic modification have been used to improve the secretion of EVs by cultured cells. In addition, nitrogen cavitation, porous membrane extrusion, and sonication have been utilized to prepare EV-mimetic nanovesicles that share many characteristics with naturally secreted EVs. Apart from inducing EV production, these upscaling interventions have also been reported to modify the EVs’ cargo and thus their functionality and therapeutic potential. In summary, it is imperative to identify a reliable upscaling technique that can produce large quantities of EVs consistently. Ideally, the produced EVs should also possess cargo with improved therapeutic potential.     

High-Resolution 3D Deposition of Electrospun Fibers on Patterned Dielectric Elastomers

Electrostatic patterning has improved the performance of devices incorporating electrospun fibers in a wide variety of applications. However, the impact of process parameters on the final fiber pattern in these systems is rarely analyzed. Herein, a systematic analytical approach is developed to define quantitative metrics related to fiber patterning. Three-dimensional patterned dielectric elastomer collectors are fabricated via solution-casting polydimethylsiloxane with embedded carbon black or liquid metal droplets. Fiber patterning metrics are used to evaluate the effect of collector parameters such as insulating layer thickness, electrical ground surface area, and three-dimensional pattern geometry. Dielectric layer parameters such as conductive material concentration and particle diameter are also investigated. Using this framework, the best-performing collector is shown to improve selectivity 30-fold, uniformity ninefold, reproducibility eightfold, and increase fiber volume by one order of magnitude. Furthermore, eutectic gallium indium liquid metal and scaled-up pattern geometries demonstrate the tunability of this approach and broad applicability of systematic fiber pattern analysis. This rational approach to patterned fiber development can be applied to virtually any method or pattern to better understand the fiber patterning processes.     

Design process knowledge for crisis-driven information systems solutions: Insights on building digital resilience from an action design research study

As global disruptions escalate, digital resilience (DR)—the capacity to anticipate, absorb, and adapt to external shocks by leveraging Information Systems (IS)—has become crucial for individuals and organisations confronting and managing unprecedented crises. This research advances understanding on how to develop DR, drawing on insights from an Action Design Research (ADR) study conducted during the COVID-19 pandemic. Our research explores a particular facet of DR: the capacity to manage exogenous shocks through the design  of new IS solutions. We introduce the ADAPT framework, comprising five key enablers—Agility, Designation, Alignment, Participation, and Trust—recommended to support design teams developing IS solutions during and for crises. Our ADR project, which resulted in the creation of a telemonitoring system used by over 115 frontline healthcare workers to monitor the symptoms of more than 1000 COVID-19 patients, demonstrates the instrumental role these five enablers play in supporting a crisis-propelled IS design process that is urgent, resource-limited, and multi-partite. By presenting new design process knowledge and practical recommendations that guide crisis-driven IS design, we aim to equip design teams with the understanding they need to effectively navigate similar challenges in the future. We also hope to inspire and support IS researchers to apply their expertise in the design, deployment, and use of IS solutions to contribute to crisis-driven design endeavours that tackle the pressing and urgent challenges of our time.     

A Study of Starch Granular Aggregation

The aggregation behavior of starch granules during cooking was investigated. Granular aggregation was found to depend mainly on water content and degree of conversion (cooking) of starch. There were threshold values of water content and degree of conversion for powdery starch to undergo a phase transition from a nonaggregated to an aggregated state. A method for determining such threshold values of the transition was developed. A mathematical model was also developed to describe the aggregation behavior of cooked starch. Its potential application to food systems, especially to the simulation of starch extrusion process, was discussed.