What are the temporal and physical characteristics of locally applied vibration that modulate balance in older adults? - A systematic review of the literature.

BACKGROUND: Compromised balance is known to contribute to falls, which are associated with increased morbidity and mortality for older adults. Evidence suggests that the application of local vibration to the lower limbs of older adults has the potential to modulate balance. RESEARCH QUESTION: To identify the temporal and mechanical parameters of vibration applied locally to the lower limbs of older adults that modulate measures of balance, and to define the short- and long-term effects of vibration on balance in this population. METHODS: The PRISMA 2020 guidelines were used to conduct a systematic search including the PUBMED, EMBASE, and Scopus databases to identify peer-reviewed literature where vibration was applied to the lower limbs of older adults to modulate balance. Data was extracted using a study-specific data extraction form and risk of bias assessed. Where possible, effect sizes were calculated. RESULTS: Of 7777 records screened, ten randomised controlled trials and 43 prospective laboratory-based studies met the inclusion criteria. Vibration frequencies ranged from 1 to 272 Hz, most studies (n=41) used ≤100 Hz. Amplitude ranged from 0.2 to 3.0 mm, most studies (n=28) used ≤1 mm. Effects of short-term vibration (applied for seconds to hours) were measured during and/or immediately after application. Short-term suprathreshold perceived muscle/tendon vibration had a 'large' destabilising effect size on balance in healthy older adults, but little or no effect on older fallers. Short-term subthreshold vibration to the soles of the feet had a 'small' stabilising effect size. Suprathreshold muscle, tendon or sole vibration applied for 10-30 min over days to weeks improved balance measures, but most (8 of 10) had increased risk of bias. SIGNIFICANCE: The heterogeneity of methodology, populations, and vibration and balance parameters precluded conclusions about the relative effects of lower limb vibration in older adults. However, these results suggest that the application of local vibration to the lower limbs of older adults can modulate balance in the short- and long-term.

Administration of ß-lactam antibiotics to patients with reported penicillin allergy in the emergency department.

BACKGROUND: ß-lactam antibiotics are amongst the most commonly prescribed medications in the Emergency Department (ED) due to their role in empiric sepsis therapy; however, inferior therapeutic options are often utilized due to a reported allergy; penicillin (PCN) being most frequent. In the United States, 10% of the population endorses an allergic reaction to PCN while <1% experience IgE-mediated reactions. This study aimed to evaluate the frequency and outcome of patients in the ED whose PCN allergies were challenged with ß-lactam antibiotics. METHODS: We conducted a retrospective chart review of patients in the ED at an academic medical center aged ≥18, and who received a ß-lactam despite a reported PCN allergy between January 2015 and December 2019. Patients who did not receive a ß-lactam or did not report a PCN allergy prior to administration were excluded. The primary outcome was the frequency of IgE-mediated reactions in response to ß-lactam administration. A secondary outcome assessed the frequency of continuation of ß-lactams upon admission from the ED. RESULTS: 819 patients were included (66% female) with prior reported PCN reactions: hives (22.5%), rash (15.4%), swelling (6.2%), anaphylaxis (3.5%), other (12.1%), or undocumented on medical electronic record (40.3%). No patients experienced an IgE-mediated reaction to the ß-lactam administered in the ED. Previously reported allergies had no effect on the continuation of ß-lactams when admitted or discharged (OR: 1, 95% CI: 0.7-1.44). Patients who had a history of an IgE-mediated penicillin allergy were frequently continued (77%) on a ß-lactam after leaving the ED via admission or discharge. CONCLUSION: ß-lactam administration in patients with previously reported PCN allergies did not result in any IgE-mediated reactions nor in an increase in adverse reactions. Our data contributes to the body of evidence that supports the administration of ß-lactams to patients with documented PCN allergies.

Analysis of Ignition Sites for the Explosives 3,3'-Diamino-4,4'-azoxyfurazan (DAAF) and 1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane (HMX) Using Crush Gun Impact Testing.

The handling safety characteristics of energetic materials must be measured in order to ensure the safe transport and use of explosives. Drop-weight impact sensitivity measurements are one of the first standardized tests performed for energetics. They utilize a small amount of the explosive sample and a standard weight, which is dropped on the material from various heights to determine its sensitivity. While multiple laboratories have used the impact sensitivity test as an initial screening tool for explosive sensitivity for the past 60 years, variability exists due to the use of different instruments, different methods to determine the initiation, and the scatter commonly associated with less-sensitive explosives. For example, standard explosives such as 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX) initiate reliably and consistently on the drop-weight impact test, whereas insensitive explosives such as 3,3'-diamino-4,4'-azoxyfurazan (DAAF) exhibit variability in sound levels and the expended material. Herein we investigate the impact sensitivity of DAAF and HMX along with a more detailed investigation of ignition sites using a novel "crush gun" apparatus: a pneumatically powered drop-weight tower with advanced diagnostics, including high-speed visual and infrared cameras. Using this crush gun assembly, the ignition sites in HMX and DAAF were analyzed with respect to the effects of particle size and the presence of a source of grit. The formation of ignition sites was observed in both explosives; however, only HMX showed ignition sites that propagated to a deflagration at lower firing speeds. Finally, the presence of grit particles was shown to increase the occurrence of ignition sites in DAAF at lower firing speeds, though propagation to a full reaction was not observed on the time scale of the test. These results enable a better understanding of how ignition and propagation occurs during the impact testing of DAAF.