Applying univariate vs. multivariate statistics to investigate therapeutic efficacy in (pre)clinical trials : a Monte Carlo simulation study on the example of a controlled preclinical neurotrauma trial

Background Small sample sizes combined with multiple correlated endpoints pose a major challenge in the statistical analysis of preclinical neurotrauma studies. The standard approach of applying univariate tests on individual response variables has the advantage of simplicity of interpretation, but it fails to account for the covariance/correlation in the data. In contrast, multivariate statistical techniques might more adequately capture the multi-dimensional pathophysiological pattern of neurotrauma and therefore provide increased sensitivity to detect treatment effects. Results We systematically evaluated the performance of univariate ANOVA, Welch’s ANOVA and linear mixed effects models versus the multivariate techniques, ANOVA on principal component scores and MANOVA tests by manipulating factors such as sample and effect size, normality and homogeneity of variance in computer simulations. Linear mixed effects models demonstrated the highest power when variance between groups was equal or variance ratio was 1:2. In contrast, Welch’s ANOVA outperformed the remaining methods with extreme variance heterogeneity. However, power only reached acceptable levels of 80% in the case of large simulated effect sizes and at least 20 measurements per group or moderate effects with at least 40 replicates per group. In addition, we evaluated the capacity of the ordination techniques, principal component analysis (PCA), redundancy analysis (RDA), linear discriminant analysis (LDA), and partial least squares discriminant analysis (PLS-DA) to capture patterns of treatment effects without formal hypothesis testing. While LDA suffered from a high false positive rate due to multicollinearity, PCA, RDA, and PLS-DA were robust and PLS-DA outperformed PCA and RDA in capturing a true treatment effect pattern. Conclusions Multivariate tests do not provide an appreciable increase in power compared to univariate techniques to detect group differences in preclinical studies. However, PLS-DA seems to be a useful ordination technique to explore treatment effect patterns without formal hypothesis testing

Aerosol exposure of staff during dental treatments: a model study

Background: Due to exposure to potentially infectious aerosols during treatments, the dental personnel is considered being at high risk for aerosol transmitted diseases like COVID-19. The aim of this study was to evaluate aerosol exposure during different dental treatments as well as the efficacy of dental suction to reduce aerosol spreading. Methods: Dental powder-jet (PJ; Air-Flow (R)), a water-cooled dental handpiece with a diamond bur (HP) and water-cooled ultrasonic scaling (US) were used in a simulation head, mounted on a dental unit in various treatment settings. The influence of the use of a small saliva ejector (SE) and high-volume suction (HVS) was evaluated. As a proxy of aerosols, air-born particles (PM10) were detected using a Laser Spectrometer in 30 cm distance from the mouth. As control, background particle counts (BC) were measured before and after experiments. Results: With only SE, integrated aerosol levels [median (Q25/Q75) mu g/m(3) s] for PJ [91,246 (58,213/118,386) mu g/m(3) s, p 0.05] and US [6558 (6002/7066) mu g/m(3) s; p > 0.05] did not increase aerosol levels significantly. The use of HVS significantly decreased aerosol exposure for PJ [37,170 (29,634/51,719) mu g/m(3) s; p < 0.01] and HP [5476 (5066/5638) mu g/m(3) s; p < 0.001] compared to SE only, even reaching lower particle counts than BC levels for HP usage (p < 0.001). Conclusions: To reduce the exposure to potentially infectious aerosols, HVS should be used during aerosol-forming dental treatments

Antibacterial mono- and sesquiterpene esters of benzoic acids from Iranian propolis

<p>Abstract</p> <p>Background</p> <p>Propolis (bee glue) has been used as a remedy since ancient times. Propolis from unexplored regions attracts the attention of scientists in the search for new bioactive molecules.</p> <p>Results</p> <p>From Iranian propolis from the Isfahan province, five individual components were isolated: the prenylated coumarin suberosin <b>1</b>, and four terpene esters: tschimgin (bornyl <it>p</it>-hydroxybenzoate) <b>2</b>, tschimganin (bornyl vanillate) <b>3</b>, ferutinin (ferutinol <it>p</it>-hydroxybenzoate) <b>4, </b>and tefernin (ferutinol vanillate) <b>5</b>. All of them were found for the first time in propolis. Compounds <b>2 </b>- <b>5 </b>demonstrated activity against <it>Staphylococcus aureus</it>.</p> <p>Conclusions</p> <p>The results of the present study are consistent with the idea that propolis from unexplored regions is a promising source of biologically active compounds.</p

Applying univariate vs. multivariate statistics to investigate therapeutic efficacy in (pre)clinical trials: A Monte Carlo simulation study on the example of a controlled preclinical neurotrauma trial.

BackgroundSmall sample sizes combined with multiple correlated endpoints pose a major challenge in the statistical analysis of preclinical neurotrauma studies. The standard approach of applying univariate tests on individual response variables has the advantage of simplicity of interpretation, but it fails to account for the covariance/correlation in the data. In contrast, multivariate statistical techniques might more adequately capture the multi-dimensional pathophysiological pattern of neurotrauma and therefore provide increased sensitivity to detect treatment effects.ResultsWe systematically evaluated the performance of univariate ANOVA, Welch's ANOVA and linear mixed effects models versus the multivariate techniques, ANOVA on principal component scores and MANOVA tests by manipulating factors such as sample and effect size, normality and homogeneity of variance in computer simulations. Linear mixed effects models demonstrated the highest power when variance between groups was equal or variance ratio was 1:2. In contrast, Welch's ANOVA outperformed the remaining methods with extreme variance heterogeneity. However, power only reached acceptable levels of 80% in the case of large simulated effect sizes and at least 20 measurements per group or moderate effects with at least 40 replicates per group. In addition, we evaluated the capacity of the ordination techniques, principal component analysis (PCA), redundancy analysis (RDA), linear discriminant analysis (LDA), and partial least squares discriminant analysis (PLS-DA) to capture patterns of treatment effects without formal hypothesis testing. While LDA suffered from a high false positive rate due to multicollinearity, PCA, RDA, and PLS-DA were robust and PLS-DA outperformed PCA and RDA in capturing a true treatment effect pattern.ConclusionsMultivariate tests do not provide an appreciable increase in power compared to univariate techniques to detect group differences in preclinical studies. However, PLS-DA seems to be a useful ordination technique to explore treatment effect patterns without formal hypothesis testing

CLINICAL ASSESSMENT OF THE EFFECT OF LOW LEVEL LASER TREATMENT OF ORAL MUCOSA DECUBITUS ULCERS

Decubitus ulcers in the oral mucosa tend to be very painful causing discomforting sensation in patients in speaking and eating. Low energy lasers can provide an alternative method for the treatment of these ulcers.The aim of the present paper was to assess clinically the healing effect of low level laser irradiation on oral mucosa decubitus ulcers.Material and methods: A total of 90 patients with decubitus ulcers were treated in the present study; they were randomly assigned to three groups: group I included 30 patients treated with low level laser (LLL) irradiation (wavelength of irradiation 658 nm); group II - 30 patients treated with laser irradiation of 904 nm; and group III (controls) - 30 patients who received a standard conventional treatment with "granofurin" and "solcoseryl".The treatment sessions in all three groups were administered once daily. The patients in groups I and II were irradiated with focused irradiation at an angle from a distance using a conically shaped light probe 3 mm in diameter. The irradiated area was 0.5 cm2. The light was focused on the oral mucosa ulcer and the surrounding inflamed mucosa at a distance of 0.5 to 1 cm. Diode lasers were used in the study. The dosage of irradiation was 1.2 J/cm2.Results and discussion: The treatment effect was evaluated by changes in the studied parameters: pain intensity, erythema, and epithelialization. They were assessed at baseline, and at days 1, 3 and 5. Conclusions: LLLT administered with the proposed methodology manages pain rapidly and accelerates the process of epithelialization of decubitus ulcers in the soft tissues of the mouth

Coal Share Reduction Options for Power Generation during the Energy Transition: A Bulgarian Perspective

The sustainable energy transition to a low-carbon and climate-neutral economy by 2050 requires a consistent increase in the share of renewable energy sources (RESs) at the expense of the share of fossil fuels. The coal power plants in the Republic of Bulgaria have provided about one third of the annually produced electric power for decades, utilizing mainly locally available sources of lignite. The present work aimed to review the progress of the energy transition, its rejection and acceptance at the national and international scene alongside the available research for cleaner coal combustion in Bulgaria, as well as discuss a Bulgarian perspective for coal share reduction options for power generation during the energy transition. A comprehensive review was carried out, based on freely accessible data such as research and open media articles, officially published field reports, legislative and strategic acts as well as validated statistical data. Three groups of critical gaps (socioeconomic, sociotechnical and cultural and political) were indicated, claimed to be capable of guiding the just transition. Key factors influencing the process dynamics were identified and categorized in the context of the critical gaps. The peculiar policy criteria for the carbon-intensive regions are as follows: the dominant energy carriers, existing infrastructure, involved actors and choice of strategy. The observations allowed us to conclude that in addition to the efforts achieved and ambitious political will, the identification of reliable technological and socioeconomic measures is needed more than ever (accompanied by interdisciplinary research involving the technical, social and environmental and policy factors), while renewables still have long way to go towards complete substitution of the fossil fuels for power generation, transport, and manufacturing. Limited literature was found for reducing the share of coal from currently operating Bulgarian coal-fired power plants (CFPPs). Herein, short- and/or medium-term measures for carbon emission reduction were discussed, capable of promoting the limited operation of existing CFPPs, thus paving the road towards a sustainable, long-term transition. These measures concerned the typically used power units in the largest CFPPs located at the Maritsa Iztok Mining Complex (MIMC). Analyses of the biomass production, supply and cost for the same type of power units were proposed, considering the use of 100% biomass. Estimated costs, unit efficiencies and power generation were discussed along with the evaluations about the land use, ensuring a given annual productivity of wood chips from fast growing plants, e.g., Paulownia

beeRapp: an R shiny app for automated high-throughput explorative analysis of multivariate behavioral data

Animal behavioral studies typically generate high-dimensional datasets consisting of multiple correlated outcome measures across distinct or related behavioral domains. Here, we introduce the BEhavioral Explorative analysis R shiny APP (beeRapp) that facilitates explorative and inferential analysis of behavioral data in a high-throughput fashion. By employing an intuitive and user-friendly graphical user interface, beeRapp empowers behavioral scientists without programming and data science expertise to perform clustering, dimensionality reduction, correlational and inferential statistics and produce up to thousands of high-quality output plots visualizing results in a standardized and automated way

Изследване на влиянието на шаблонна матрица върху вграждане на информация в изображение

Steganography is a modern approach to protect classified data against malicious attacks and misuse. Presented, accordingly, in this paper is a novel method for steganographic embedding of information. A template matrix is used for screening the original message embedded in an image. The efficiency of the steganographic embedding depends on the length of the message. The particular dependency is, therefore, the primary focus of the proposed work. The end results of the experiment were extremely satisfactory with the percentage of successfully retrieved messages being more than 90%, and the size of the processed images with embedded messages being fully acceptable and capable of being used in a communication environment.В связи с распространением Интернета сегодня наиболее важным фактором в информационных технологиях и коммуникации является информационная безопасность. Данные были важной частью любой организации на протяжении нескольких десятилетий. Эти данные содержат некоторую секретную информацию, относящуюся к организации. Неправильное использование этих данных может нанести вред организации. Стеганография - одно из решений в этом направлении. Здесь он используется с другим подходом и методом - через матрицу шаблонов в зависимости от длины сообщения. Эта матрица используется для просмотра исходного сообщения, ранее встроенного в изображение. Экспериментальная постановка дала хорошие результаты, поскольку процент успешно извлеченных сообщений превышает 90%, а обработанные изображения со встроенными сообщениями имеют приемлемый размер, подходящий для использования в коммуникационной среде.Поради възхода на Интернет днес, най-важният фактор в информационните технологии и комуникацията е информационната сигурност. Данните са съществена част от всяка организация от няколко десетилетия. Тези данни съдържат някаква класифицирана информация, свързана с организацията. Злоупотребата с тези данни може да навреди на организацията. Стеганографията е едно от решенията в тази посока. В представения доклад се използва с различен подход и метод - чрез матрица на шаблон в зависимост от дължината на съобщението. Тази матрица се използва за екраниране на оригиналното съобщение, предварително вградено в изображение. Експерименталната постановка постигна добри резултати, тъй като процентът на успешно извлечените съобщения е над 90%, а обработените изображения с вградени съобщения са с приемлив размер, подходящ за използване в комуникационна среда