Zwischgold is a gold-silver bi-layer foil that was popular in medieval European sculptures yet is poorly documented in both historical and modern literature. It is notoriously difficult to identify unambiguously and to study in detail due to its ultra-thinness and tendency to corrode. This article focuses on understanding the corrosion states and technological features of medieval Zwischgold. High-resolution scanning electron microscopy/energy-dispersive X-ray analysis was conducted on 72 Zwischgold samples taken from 47 objects, prepared with ultra-microtomy to investigate the foil structures, layer thickness, elemental composition and corrosion products. Supporting data was obtained through FTIR and Raman spectroscopy regarding the surrounding materials, especially the binding media and pigments. This article aims to fill the knowledge
gap in the history of medieval gilding technology and to provide a scientific basis for future conservation and restoration of Zwischgold artefacts in strongly corroded states.
To perform a systematic review of the emergency medicine literature to assess the appropriateness of offering routine HIV screening to patients in the emergency department (ED).The systematic review was conducted with the aid of a structured template, a companion explanatory guide, and a grading and methodological scoring system based on published criteria for critical appraisal. Two reviewers conducted independent searches using OvidR, PubMed, MD Consult, and Grateful Med. Relevant abstracts were reviewed; those most pertinent to the stated objective were selected for complete evaluation using the structured template.Fifty-two relevant abstracts were reviewed; of these, nine were selected for detailed evaluation. Seven ED-based prospective cross-sectional seroprevalence studies found HIV rates of 2-17%. Highest rates of infection were seen among patients with behavioral risks such as male homosexual activity and intravenous drug use. Two studies demonstrated feasibility of both standard and rapid HIV testing in the ED, with more than half of the patients approached consenting to testing by either method, consistent with voluntary testing acceptance rates described in other settings. Several cost-benefit analyses lend indirect support for HIV screening in the ED.Multiple ED-based studies meeting the Centers for Disease Control and Prevention Guideline threshold to recommend routine screening, in conjunction with limited feasibility trials and extrapolation from cost-benefit studies, provide evidence to recommend that EDs offer HIV screening to high-risk patients (i.e., those with identifiable risk factors) or high-risk populations (i.e., those where HIV seroprevelance is at least 1%).
I read with interest the commentary provided by Dr Wyer regarding the value of dyspnoea on exertion in congestive heart failure (HF).1 The data reveal the pooled positive likelihood ratio (+LR) for dyspnoea on exertion to be 1.3 and the negative likelihood ratio (−LR) to be 0.48. He states, “Surprisingly, the presence of dyspnoea on exertion has little effect on raising the likelihood of HF, although as expected, its absence lowers HF likelihood.” I concur that dyspnoea on exertion is not useful in raising the probability for HF considering the low +LR, but I disagree that the absence of dyspnoea on exertion lowers the likelihood of HF below a threshold probability where neither treatment nor further diagnostic intervention is warranted. If hypothetical pretest probabilities for HF are 0.60, 0.40, and 0.20, the post-test probabilities for a negative test (lack of dyspnoea on exertion) would decrease only to 0.42, 0.24, and 0.11, respectively. I doubt that …
