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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.
Fulltext Pharmacological Management of Allergic Rhinitis: A Consensus Statement from the Malaysian Society of Allergy and Immunology

Abdullah B, Abdul Latiff AH, Manuel AM, Mohamed Jamli F, Dalip Singh HS, Ismail IH, et al.

J Asthma Allergy, 2022;15:983-1003.
PMID: 35942430 DOI: 10.2147/JAA.S374346

The goal of allergic rhinitis (AR) management is to achieve satisfactory symptom control to ensure good quality of life. Most patients with AR are currently treated with pharmacotherapy. However, knowledge gaps on the use of pharmacotherapy still exist among physicians, particularly in the primary care setting, despite the availability of guideline recommendations. Furthermore, it is common for physicians in the secondary care setting to express uncertainty regarding the use of new combination therapies like intranasal corticosteroid plus antihistamine combinations. Inadequate treatment leads to significant reduction of quality of life that affects daily activities at home, work, and school. With these concerns in mind, a practical consensus statement was developed to complement existing guidelines on the rational use of pharmacotherapy in both the primary and secondary care settings.
Fulltext Perspectives and gaps in the management of food allergy and anaphylaxis in the Asia-Pacific Region

Leung ASY, Pawankar R, Pacharn P, Wong LSY, Le Pham D, Chan G, et al.

J Allergy Clin Immunol Glob, 2024 May;3(2):100202.
PMID: 38283085 DOI: 10.1016/j.jacig.2023.100202

BACKGROUND: Food allergy (FA), which is a condition that has no effective cure and can result in severe life-threatening allergic reactions, remains a global public health concern; however, little is known about how FAs are currently managed in the Asia-Pacific region.
OBJECTIVE: The main objective of this survey was to evaluate the epidemiology of FA, as well as the availability of resources and practices for management of FA and anaphylaxis by health care providers across Asia.
METHODS: From June 2022 to September 2022, a questionnaire-based survey comprising 66 questions was electronically sent to member societies of the Asia Pacific Association of Allergy Asthma and Clinical Immunology by using Survey Monkey.
RESULTS: A total of 20 responses were received from 15 member countries and territories. Compared with the pediatric data, there was a lack of prevalence data for FA in adults. Except for Australia and Japan, most regions had between 0.1 and 0.5 allergists per 100,000 population and some had fewer than 0.1 allergists per 100,000 population. The perceived rate of FA in regions with a short supply of allergists was high. Although specific IgE tests and oral food challenges were available in all regions, the median wait time for oral food challenges at government facilities was 37 days (interquartile range = 10.5-60 days). Seven regions still relied on prescriptions of ampules and syringes of injectable adrenaline, and adrenaline autoinjectors were not accessible in 4 regions. Oral immunotherapy as FA treatment was available in half of the surveyed countries and territories.
CONCLUSIONS: Our study offers a cross-sectional evaluation of the management practices for FA in each Asia Pacific Association of Allergy Asthma and Clinical Immunology member country or territory. Urgent actions are required to enhance allergy services, improve the accessibility and affordability of adrenaline autoinjectors, and conduct robust epidemiologic studies.

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