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Road to entire insulation for resonances from a forced mechanical system

Zhu G, Cao Q, Wang Z, Zhang Y, Chen Y, Woo KC

Sci Rep, 2022 Dec 07;12(1):21167.
PMID: 36477007 DOI: 10.1038/s41598-022-25691-4

The effective solution to avoid machinery damage caused by resonance has been perplexing the field of engineering as a core research direction since the resonance phenomenon was discovered by Euler in 1750. Numerous attempts have been performed to reduce the influence of resonance since the earlier of last century, by introducing a nonlinear structure or a closed-loop control system. However, the existed methodologies cannot eliminate resonance completely even extra problems were introduced inevitably, which means the technical choke-point of resonance-free remains unsolved. Here we propose a designable archetype model, which establishes a mapping between the mechanical properties and its structure. A general inverse method for structure construction is proposed based upon the required property for the system with quasi-zero stiffness of any designed finite order and the zero-stiffness properties. It is shown that an ellipse trajectory tracking of the designed model is the sufficient and necessary condition to satisfy the zero-stiffness property. Theoretical analysis shows that no resonant response happens in a zero-stiffness system to the full-band frequency excitation, or equivalently, the system can completely isolate the energy transfer between the load and environment, when the damping ratio approaches zero. Finally, an experimental rig for the prototype structure is built up according to the sufficient and necessary condition of the zero-stiffness system, for which the special dynamic behaviours are verified through experiments of frequency-sweep and random-vibration as well. Experimental results show that the prototype of the initial vibration isolation frequency of zero-stiffness system is much lower than 0.37 Hz, and the vibration attenuation of the proposed model is about 16.86 dB, 45.63 dB, and 112.37 dB at frequencies of 0.37 Hz, 1 Hz, and 10 Hz, respectively. The distinguished geometric structure of the zero-stiffness system leads to a new inspiration for the design of resonance-free in metamaterial unit and the inverse method can even adapt the design for a more targeted applications based on an arbitrary complex dynamic requirement.
Rapid diagnostic testing for antimicrobial stewardship: Utility in Asia Pacific

Apisarnthanarak A, Kim HB, Moore L, Xiao Y, Singh S, Doi Y, et al.

Infect Control Hosp Epidemiol, 2021 07;42(7):864-868.
PMID: 34128462 DOI: 10.1017/ice.2021.149

Rapid diagnostic testing (RDT) can provide prompt, accurate identification of infectious organisms and be a key component of antimicrobial stewardship (AMS) programs. However, their use is less widespread in Asia Pacific than western countries. Cost can be prohibitive, particularly in less resource-replete settings. A selective approach is required, possibly focusing on the initiation of antimicrobials, for differentiating bacterial versus viral infections and identifying locally relevant tropical diseases. Across Asia Pacific, more data are needed on RDT use within AMS, focusing on the impact on antimicrobial usage, patient morbidity and mortality, and cost effectiveness. Moreover, in the absence of formal guidelines, regional consensus statements to guide clinical practice are warranted. These will provide a regionally relevant definition for RDT; greater consensus on its role in managing infections; advice on implementation and overcoming barriers; and guidance on optimizing human resource capacity. By addressing these issues, the outcomes of AMS programs should improve.
2024 Statement from Asia expert operators on transcatheter pulmonary valve replacement

Pan W, Zhou D, Hijazi ZM, Qureshi SA, Promphan W, Feng Y, et al.

Catheter Cardiovasc Interv, 2024 Mar;103(4):660-669.
PMID: 38419402 DOI: 10.1002/ccd.30978

Transcatheter pulmonary valve replacement (TPVR), also known as percutaneous pulmonary valve implantation, refers to a minimally invasive technique that replaces the pulmonary valve by delivering an artificial pulmonary prosthesis through a catheter into the diseased pulmonary valve under the guidance of X-ray and/or echocardiogram while the heart is still beating not arrested. In recent years, TPVR has achieved remarkable progress in device development, evidence-based medicine proof and clinical experience. To update the knowledge of TPVR in a timely fashion, and according to the latest research and further facilitate the standardized and healthy development of TPVR in Asia, we have updated this consensus statement. After systematical review of the relevant literature with an in-depth analysis of eight main issues, we finally established eight core viewpoints, including indication recommendation, device selection, perioperative evaluation, procedure precautions, and prevention and treatment of complications.
Fulltext Comparative genomics of the nonlegume Parasponia reveals insights into evolution of nitrogen-fixing rhizobium symbioses

van Velzen R, Holmer R, Bu F, Rutten L, van Zeijl A, Liu W, et al.

Proc Natl Acad Sci U S A, 2018 May 15;115(20):E4700-E4709.
PMID: 29717040 DOI: 10.1073/pnas.1721395115

Nodules harboring nitrogen-fixing rhizobia are a well-known trait of legumes, but nodules also occur in other plant lineages, with rhizobia or the actinomycete Frankia as microsymbiont. It is generally assumed that nodulation evolved independently multiple times. However, molecular-genetic support for this hypothesis is lacking, as the genetic changes underlying nodule evolution remain elusive. We conducted genetic and comparative genomics studies by using Parasponia species (Cannabaceae), the only nonlegumes that can establish nitrogen-fixing nodules with rhizobium. Intergeneric crosses between Parasponia andersonii and its nonnodulating relative Trema tomentosa demonstrated that nodule organogenesis, but not intracellular infection, is a dominant genetic trait. Comparative transcriptomics of P. andersonii and the legume Medicago truncatula revealed utilization of at least 290 orthologous symbiosis genes in nodules. Among these are key genes that, in legumes, are essential for nodulation, including NODULE INCEPTION (NIN) and RHIZOBIUM-DIRECTED POLAR GROWTH (RPG). Comparative analysis of genomes from three Parasponia species and related nonnodulating plant species show evidence of parallel loss in nonnodulating species of putative orthologs of NIN, RPG, and NOD FACTOR PERCEPTION Parallel loss of these symbiosis genes indicates that these nonnodulating lineages lost the potential to nodulate. Taken together, our results challenge the view that nodulation evolved in parallel and raises the possibility that nodulation originated ∼100 Mya in a common ancestor of all nodulating plant species, but was subsequently lost in many descendant lineages. This will have profound implications for translational approaches aimed at engineering nitrogen-fixing nodules in crop plants.
Population Density and Risk of Inflammatory Bowel Disease: A Prospective Population-Based Study in 13 Countries or Regions in Asia-Pacific

Ng SC, Kaplan GG, Tang W, Banerjee R, Adigopula B, Underwood FE, et al.

Am J Gastroenterol, 2019 01;114(1):107-115.
PMID: 30177785 DOI: 10.1038/s41395-018-0233-2

INTRODUCTION: Living in an urban environment may increase the risk of developing inflammatory bowel disease (IBD). It is unclear if this observation is seen globally. We conducted a population-based study to assess the relationship between urbanization and incidence of IBD in the Asia-Pacific region.
METHODS: Newly diagnosed IBD cases between 2011 and 2013 from 13 countries or regions in Asia-Pacific were included. Incidence was calculated with 95% confidence interval (CI) and pooled using random-effects model. Meta-regression analysis was used to assess incidence rates and their association with population density, latitude, and longitude.
RESULTS: We identified 1175 ulcerative colitis (UC), 656 Crohn's disease (CD), and 37 IBD undetermined (IBD-U). Mean annual IBD incidence per 100 000 was 1.50 (95% CI: 1.43-1.57). India (9.31; 95% CI: 8.38-10.31) and China (3.64; 95% CI, 2.97-4.42) had the highest IBD incidence in Asia. Incidence of overall IBD (incidence rate ratio [IRR]: 2.19; 95% CI: 1.01-4.76]) and CD (IRR: 3.28; 95% CI: 1.83-9.12) was higher across 19 areas of Asia with a higher population density. In China, incidence of IBD (IRR: 2.37; 95% CI: 1.10-5.16) and UC (IRR: 2.63; 95% CI: 1.2-5.8) was positively associated with gross domestic product. A south-to-north disease gradient (IRR: 0.94; 95% CI: 0.91-0.98) was observed for IBD incidence and a west-to-east gradient (IRR: 1.14; 95% CI: 1.05-1.24) was observed for CD incidence in China. This study received IRB approval.
CONCLUSIONS: Regions in Asia with a high population density had a higher CD and UC incidence. Coastal areas within China had higher IBD incidence. With increasing urbanization and a shift from rural areas to cities, disease incidence may continue to climb in Asia.