Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

A hybrid genetic-gravitational search algorithm for a multi-objective flow shop scheduling problem

Many real-world problems in manufacturing system, for instance, the scheduling problems, are formulated by defining several objectives for problem solving and decision making. Recently, research on dispatching rules allocation has attracted substantial attention. Although many dispatching rules methods have been developed, multi-objective scheduling problems remain inherently difficult to solve by any single rule. In this paper, a hybrid genetic-based gravitational search algorithm (GSA) in weighted dispatching rule is proposed to tackle a scheduling problem by achieving both time and job-related objectives. Genetic algorithm (GA) is used to select two appropriate dispatching rules to combine as a weighted multi-attribute function, while the GSA is used to optimize the contribution weightage of each rule in each stage of the flow shop. The results show that the proposed algorithm is significantly better than the traditional dispatching rules and the rules allocation algorithm. The proposed algorithm not only improved the quality of the schedule in multi-objective problems but also maintained the advantages of traditional dispatching rules in terms of ease of implementation

Vertical fit of HR practices and organizational culture: a case of a large-sized Korean conglomerate

Purpose The purpose of this paper is to contribute to the human resources (HR) literature by using exploratory network analysis (ENA), a data-driven technique. This technique was employed to discover how the perceived effectiveness of HR practices interrelate with employee perceptions on organizational cultural factors to enhance organizational commitment. Design/methodology/approach The authors used data from 1,459 employees of a large South Korean conglomerate and studied how individual HR practices could be enhanced by specific organizational cultural factors. The data were analyzed using ENA, which is an inductive approach. Findings The authors found that organizational commitment is associated with the positive perceptions of employees on the effectiveness of HR practices, such as performance appraisal, training and development, and compensation. Results show that when both HR practices and organizational cultural factors are considered, they appear to influence organizational commitment independently. Research limitations/implications Data were collected from a large conglomerate. The authors were limited by the use of the scales developed by a consulting firm. Therefore, readers should be cautious about the generalizability of the findings. Originality/value The application of a data-driven technique (ENA) highlights the potentially fertile methodological grounds for HR research. Literature on strategic HR management may benefit from inductive approaches, wherein data serve as primary foundation for the design and development of new theories

A Longitudinal Study of Growth Patterns in Schoolchildren in One Taipei District II: Sitting Height, Arm Span, Body Mass Index and Skinfold Thickness

It has been suggested that longitudinal rather than cross-sectional growth standards be used to assess individual growth patterns. Thus, the aim of this study was to follow boys and girls throughout their pubertal years, so that a mixed longitudinal growth curve of height, weight, sitting height, arm span, skinfold thickness, body mass index (BMI), and the ratio of sitting height or arm span to stature, could be obtained. Methods: A defined group of 1,139 healthy schoolchildren (570 boys and 569 girls) from the Shih-Pai district of Taipei were followed longitudinally for 4 years. Anthropometric measurements of height, weight, sitting height, arm span, skinfold thickness, and BMI, were obtained for each child. Results: Peak sitting-height velocities of 6.1 cm/year (boys) and 6.3 cm/year (girls) were seen at 8.5 years. The second peak of sitting-height velocity occurred at a mean age of 12.5 years for boys and 11.5 years for girls. Sitting-height velocity for the whole year covering the second peak was 4.6 cm in boys and 3.2 cm in girls. Peak arm-span velocity was seen at 13.5 years for boys and 8.5 years for girls, and arm-span velocity for the whole year covering this peak was 8.4 cm/year for boys and 8.1 cm/year for girls. Conclusion: These data provide growth patterns for Chinese children aged 8–18 years living in a Taipei district, with percentile charts for sitting height, arm span, BMI, and skinfold thickness

Computer-Aided Diagnosis of Skin Lesions Using Conventional Digital Photography: A Reliability and Feasibility Study

<div><p>Background</p><p>Computer-aided diagnosis (CADx) software that provides a second opinion has been widely used to assist physicians with various tasks. In dermatology, however, CADx has been mostly limited to melanoma or melanocytic skin cancer diagnosis. The frequency of non-melanocytic skin cancers and the accessibility of regular digital macrographs have raised interest in developing CADx for broader applications.</p><p>Objectives</p><p>To investigate the feasibility of using CADx to diagnose both melanocytic and non-melanocytic skin lesions based on conventional digital photographic images.</p><p>Methods</p><p>This study was approved by an institutional review board, and the requirement to obtain informed consent was waived. In total, 769 conventional photographs of melanocytic and non-melanocytic skin lesions were retrospectively reviewed and used to develop a CADx system. Conventional and new color-related image features were developed to classify the lesions as benign or malignant using support vector machines (SVMs). The performance of CADx was compared with that of dermatologists.</p><p>Results</p><p>The clinicians' overall sensitivity, specificity, and accuracy were 83.33%, 85.88%, and 85.31%, respectively. New color correlation and principal component analysis (PCA) features improved the classification ability of the baseline CADx (p = 0.001). The estimated area under the receiver operating characteristic (ROC) curve (Az) of the proposed CADx system was 0.949, with a sensitivity and specificity of 85.63% and 87.65%, respectively, and a maximum accuracy of 90.64%.</p><p>Conclusions</p><p>We have developed an effective CADx system to classify both melanocytic and non-melanocytic skin lesions using conventional digital macrographs. The system's performance was similar to that of dermatologists at our institute. Through improved feature extraction and SVM analysis, we found that conventional digital macrographs were feasible for providing useful information for CADx applications. The new color-related features significantly improved CADx applications for skin cancer.</p></div