Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

USEFUL PATH-INDEPENDENT INTEGRALS ASSOCIATED WITH TEM-MODE TRANSMISSION-LINES AND A PROCEDURE FOR COMPUTATION OF RATE OF VARIATION OF CAPACITANCE WITH A CROSS-SECTIONAL DIMENSION

Some path-independent integrals are shown to exist in the potential field of transmission lines in the TEM mode. These integrals have physical significance that can be used effectively in design, optimisation and inspection. In particular, they will be useful in sensitivity analysis of capacitance or impedance with cross-sectional dimensions, and the ordering of relative importance of cross-sectional dimensions. Each represents the rate of decrease of potential energy of the system with an increase in a dimension of the conductor. In the paper, the integrals are defined, and their relationship with line parameters such as capacitance or impedance are given. Examples are included to illustrate the validity of path independence. An alternative method, the stiffness derivative procedure, for a numerical calculation of the line integrals is also presented

MULTILAYERED DIELECTRIC STRIPLINE

The effective dielectric constant and the characteristic impedance of a stripline filled with a number of dielectrics has been investigated. Their dependence on some of the geometric parameters is presented

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Morphological Changes in an Acidophilic Bacterium Induced by Heavy Metals

The Acidiphilium strains inhabit acidic mine regions where they are subjected to occasional environmental stresses such as high and low temperatures, exposure to various heavy metals, etc. Change in morphology is one of the strategies that bacteria adopt to cope with environmental stresses; however, no study on this aspect has been reported in the case of Acidiphilium sp. This work is an attempt using the acidophilic heterotrophic bacterium Acidiphilium symbioticum H8. It was observed that the maximum alterations in size occurred when the bacterium was exposed to sub-inhibitory concentrations of Cu and Cd. Loosely packed coccobacillus-type normal cells formed characteristic chains of coccoidal lenticular shape with constrictions at the junctions between them in the presence of Cd; Cu induced transformation of cells to become round shaped; Ni caused the cells to aggregate, but Zn showed no effect. Respective metal depositions on the cell surface were confirmed by scanning electron microscopy equipped with energy dispersive X-ray analysis. Cell bound Ca2+ ions were replaced by these metal ions and measured by inductively coupled plasma mass spectrometry from the culture filtrate. Cell shape changed only after the addition of sub-inhibitory concentrations of the metals, but in growth inhibitory concentrations it was similar to the normal cells