Artificial intelligence algorithms predict the efficacy of analgesic cocktails prescribed after orthopedic surgery.

BACKGROUND: Mixtures ('cocktails') of various analgesics are more effective in controlling post-operative pain because of potential synergetic effects. Few studies have investigated such effects in large combinations of analgesics and no studies have determined the probabilities of effectiveness. METHODS: We used one-hot encoding of the categorical variables reported pain levels and the administered cocktails (from a total of eight analgesics) and then applied an unsupervised neural network and then the unsupervised DBSCAN algorithm to detect clusters of cocktails. We used Bayesian statistics to classify the effectiveness of these cocktails. RESULTS: Of the 61 different cocktails administered to 750 patients, we found that four combinations of three to four analgesics were by far the most effective. All these cocktails contained Metamizole and Paracetamol; three contained Hydromorphone and two contained Diclofenac and one Diclofenac-Orphenadrine. The ML probability that these cocktails decreased pain levels ranged from 0.965 to 0.981. Choice of a most effective cocktail involves choosing the optimum in a 4-dimensional parameter space: maximum probability of efficacy, confidence interval about maximum probability, fraction of patients with increase in pain levels, relative number of patients with successful pain level decrease. CONCLUSIONS: We observed that administering one analgesic or at most two is not effective. We found no statistical indicators that interactions between analgesics in the most effective cocktails decreased their effectiveness. Pairs of most effective cocktails differed by the addition of only one analgesic (Diclofenac-Orphenadrine for one pair and Hydromorphone for the other). We conclude that the listed cocktails are to be recommended.

Left/right asymmetries and open/closed differences of interdental forces in the mandible.

The aim of the present investigation was to study the variation in interdental forces between mandibular canines and lateral incisors of 19 volunteers (9 males and 10 females) aged 20-26 years for four configurations (mandible open/closed and left/right side). These forces were derived by pulling a stainless steel matrix strip between these teeth, six times per configuration, and registering the time variation with a high-resolution transducer. The repeated median smoothing algorithm was applied to find the maximum of each curve and a bootstrap method estimated the 95 per cent confidence intervals (CIs) for all 76 configurations. Seventy-six per cent of all paired force differences were found to be significant. Asymmetry phenomena were observed: the interdental forces differed significantly between the left and right sides and also between the open and closed position of the mandible. The interdental forces (4-21 N) showed a pattern modulated by volunteer-specific features: in 91 per cent of the configurations, the interdental forces were larger when the mouth was open. This observed pattern contributes to the instability observed in clinical practice, thus necessitating permanent fixed lower retainer wear.

Secular trends in the European male facial skull from the Migration Period to the present: a cephalometric study.

Secular trends in the facial skull over three Central European samples spanning more than 13 centuries were examined. Data were 43 conventional cephalometric landmark points for samples dating from 680 to 830 AD (29 male Avars), from the mid-19th century (49 adult Hapsburg Monarchy males), and from the 20th century (54 living Austrian young adult males). Analyses by standard methods of geometric morphometrics demonstrated shape differences by data and by size, with a strong interaction of these with sample, in that group mean differences were different for small and large individuals (allometry is different from period to period). The oldest sample, from the Migration Period, exhibited allometric features that may possibly be Turkic. There are implications for the orthodontist interested in growth trends or growth predictions in ethnically mixed patient samples.

Mathematical analysis techniques of frontal sinus morphology, with emphasis on Homo.

Of all the paranasal sinuses, frontal sinus (FS) morphology, volumes, outlines, and cross-sectional areas vary most and so their statistical noise presents particular challenges. To assess and control this statistical noise requires a suite of mathematical techniques that: model their volume and cross-sectional area ontogeny, determine the uniqueness and fractal dimensions of their outlines (useful in forensics), smooth their outlines via Singular Value Decomposition (SVD), and model their expansion via percolation cluster models (PCMs). Published data sets of FS outlines, cross-sectional areas and volumes of Neanderthal and modern crania (obtained via CT-imaging techniques) are utilized here for application of these novel mathematical methods, which necessitate a modeling approach. Results show that: FS noisiness can be explained as cluster growth, their fractal outlines have properties similar to closed random walks (Brownian bridges) about predefined curves, and the PCMs can simulate the emergence of lamellae. The statistical properties derived from the analysis techniques presented here suggest that an emergence of the lamellae via PCMs (with pinning and quenching-correlated noise) resolves the masticatory stress debate by showing that the lamellae are indeed responses to masticatory stresses, but these are of so low a level that they cannot be measured with strain gauges. PCMs and Brownian bridges, defined by local rules, lead to the emergence of macroscopically observable morphologies. The methodologies presented here contribute to research in emergence phenomena and are not confined to morphological analyses of frontal sinuses.

Secular trends in the facial skull from the 19th century to the present, analyzed with geometric morphometrics.

INTRODUCTION: Over the last 100 years, Austrian facial form has changed for various reasons, including changes in growth pattern, changes in shape pattern, or a combination of these. In this study, we explored and contrasted these 2 explanations. METHODS: We compared cephalograms from 54 recruits in the present-day Austrian Federal Army to those from 49 dry skulls of soldiers from the Imperial Hapsburg army. Body height was measured or acquired from military records. Forty-three landmarks were located on each lateral cephalogram. Secular change and growth allometry were analyzed with standard Procrustes methods. RESULTS: Body height correlated only weakly with size of the facial skull in these samples, and secular change in facial size (4.5% over a century) was proportionately less than that in height. Growth allometry was nearly unchanged over the century, emphasizing the typical changes of vertical to horizontal proportions and bimaxillary prognathism. Secular changes over the century took the form of far more localized remodeling around the coronoid process and the anterior maxilla. The large-scale differences, in contrast, were opposite to those one would expect from the size change. CONCLUSIONS: The observed trends shed considerable light on secular changes in the range of dysmorphologies for clinical orthodontic correction. At the same time, the dissociation between within-century and between-century allometry is an important possibility that was hitherto typically observed only at far greater time scales than the 150 years spanned by these data.

Season of birth contributes to variation in university examination outcomes.

Epidemiological studies show that birth season influences a wide range of biological parameters such as growth, reproduction, mental illnesses, dyslexia, personality, and success in school. The present study is aimed at examining birth season's relationship to examination marks achieved at a university in a very large contemporary sample of male and female undergraduate students. We find that female university students born in spring and summer achieve better marks than those born in autumn and winter. Male students born in spring receive worse marks than those born in other seasons of the year. Furthermore, we find a birth-week periodicity in examination results of female students, with highest examination results for those born in May. We suppose that biological mechanisms might explain part of the observed effects.

Timing of pubertal maturation and the onset of sexual behavior among Zimbabwe school boys.

The relationship between reproductive maturation and the onset of sexual behavior in boys across cultures is unclear. To explore the relative timing of pubertal events and their relationship to the onset of sexual behavior, we used data collected from 442 Zimbabwe school boys aged 12-18 years. Measures of reproductive maturation included self-reported spontaneous nocturnal emission, secondary sexual characteristics, and salivary testosterone. Behavioral measures included age at first sexual fantasies, non-coital sexual behavior, and coitus. Sigmoid interpolation curve techniques indicated a median age of first erection at 10.75 +/- 0.11 years, first sexual fantasy at 12.66 +/- 0.03 years, first spontaneous nocturnal emission at 13.02 +/- 0.03 years, and adult levels of blood testosterone at 17.2 +/- 0.7 years. First reported spontaneous nocturnal emission was significantly related to all measures of sexual behavior. Multiple regression models indicated that first reported spontaneous nocturnal emission was a stronger predictor of sexual behavior than variation in secondary sexual characteristics. In addition, testosterone was a significant predictor of sexual fantasies and intercourse, independent of first reported spontaneous nocturnal emission. These results confirm earlier findings in other populations that self-reported spontaneous nocturnal emissions can be used as a marker of pubertal timing among adolescent boys. They also suggest that variation in testosterone plays a role in the onset of sexual behavior among boys, beyond its relationship to developmental timing. The behavioral mechanisms represented by the significant effects of testosterone reported here remain to be investigated.

A new learning paradigm elicits fast visual discrimination in pigeons.

The authors describe a novel multistimulus, multiple-matching learning paradigm for pigeons, which they believe not only simulates pigeons' natural foraging behavior but also more realistically shows their visual discrimination ability. A touch screen thin film transistor panel shows a stimulus configuration consisting of a 2-dimensional array of bitmap images that changes from trial to trial. The pigeon's task during each trial is to peck at images that are defined as positive by the experimenter. An experiment exploring the ability of pigeons to discriminate between achromatic male and female human faces demonstrated the effectiveness of the procedure. In contrast to 12 pigeons that show little improvement over 60 hr of go/no-go discrimination training, 14 multiple-matching pigeons mastered the problem within a few hours.

Macro- and mesomorphology of frontal sinuses in humans: noisiness models relating to their ontogeny.

The debate about the role of the frontal sinuses remains unresolved. In this paper, I explore several statistical and fractal features of the frontal sinus outlines in order to better assess the spatial models of supraorbital torus formation. Although the analyses are restricted to a suite of techniques dealing with two-dimensional projections of the frontal sinuses, here I report many features that explain why it is so difficult to describe the spatial models. I show how the outline circumference scales with enclosed area, how the fractal dimensions of the outlines are distributed, how the method of singular value decomposition is used to define surrogate landmarks, and how a principal component analysis of vectors between these landmarks indicates directions of high variability in some of the inferior-distal directions. All these analysis techniques reveal regularities underlying the statistical noise. I believe that uncovering them necessitates a fresh look at the biology of noisy ontogeny phenomena.

Electronic removal of encrustations inside the Steinheim cranium reveals paranasal sinus features and deformations, and provides a revised endocranial volume estimate.

Features in the endocranium, as revealed by computed tomography (CT) scans of largely complete mid-Pleistocene crania, have helped elucidate unexpected affinities in the genus Homo. Because of its extensive encrustations and deformations, it has been difficult to repeat such analyses with the Steinheim cranium. Here, we present several advances in the analysis of this Homo heidelbergensis cranium by applying filter algorithms and image editing techniques to its CT scan. First, we show how the encrustations have been removed electronically, revealing interesting peculiarities, particularly the many directions of the deformations. Second, we point out similarities and differences between the frontal and sphenoidal sinuses of the Steinheim, Petralona, and Broken Hill (Kabwe) crania. Third, we assess the extent of the endocranial deformations and, fourth, their implications for our estimation of the braincase volume.

Statistical estimators of frontal sinus cross section ontogeny from very noisy data.

Cross-sectional areas of human frontal sinuses in the occipitofrontal projection are a good surrogate for frontal sinus volumes. This study looks at these areas in a dataset of some 200 children and 100 adults of both sexes. As measured by planimetry of roentgenograms, the areas are extremely variable ("noisy" in a statistical sense). In fact, they appear to be distributed log-normally with quite high variance. The mean of the distribution is evidently a function of age and the variances differ by sex. After logarithmic transformation, the data are adequately fitted by one sigmoid curve for each sex. Our discussion highlights implications of this finding for the biological aspects of frontal sinuses and methodological issues in ontogenetic analysis of data so noisy.

Cranial integration in Homo: singular warps analysis of the midsagittal plane in ontogeny and evolution.

This study addresses some enduring issues of ontogenetic and evolutionary integration in the form of the hominid cranium. Our sample consists of 38 crania: 20 modern adult Homo sapiens, 14 sub-adult H. sapiens, and four archaic Homo. All specimens were CT-scanned except for two infant H. sapiens, who were imaged by MR instead. For each specimen 84 landmarks and semi-landmarks were located on the midsagittal plane and converted to Procrustes shape coordinates. Integration was quantified by the method of singular warps, a new geometric-statistical approach to visualizing correlations among regions. The two classic patterns of integration, evolutionary and ontogenetic, were jointly explored by comparing analyses of overlapping subsamples that span ranges of different hypothetical factors. Evolutionary integration is expressed in the subsample of 24 adult Homo, and ontogenetic integration in the subsample of 34 H. sapiens. In this data set, vault, cranial base, and face show striking and localized patterns of covariation over ontogeny, similar but not identical to the patterns seen over evolution. The principal differences between ontogeny and phylogeny pertain to the cranial base. There is also a component of cranial length to height ratio not reducible to either process. Our methodology allows a separation of these independent processes (and their impact on cranial shape) that conventional methods have not found.

A cephalometric comparison of skulls from different time periods--the Bronze Age, the 19th century and the present.

The aim of this study was to evaluate secular trends by means of orthodontic measurements on lateral cephalograms. We use roentgenograms from three populations: 22 Bronze Age skulls from a cemetery near Hainburg/Austria, 140 soldiers who served in the Hapsburg Imperial Army in the late 19th century, and 154 contemporary recruits of the Austrian Federal Army. Using conventional morphometric analysis, no statistically significant differences could be established. But applying geometric morphometrics to the 2D-coordinates of the pentagon composed of the landmarks Sella, Nasion, Articulare, Gonion and Menton, some biologically interpretable differences were detected, the size allometry between the 19th- and 20th-century populations being the only notable one. We conclude that landmarks should be digitized directly (and many more of them) and that conventional methods used in clinical orthodontics are inappropriate for addressing the scientific questions approached here.