Real-time 3D tracking of swimming microbes using digital holographic microscopy and deep learning.

The three-dimensional swimming tracks of motile microorganisms can be used to identify their species, which holds promise for the rapid identification of bacterial pathogens. The tracks also provide detailed information on the cells' responses to external stimuli such as chemical gradients and physical objects. Digital holographic microscopy (DHM) is a well-established, but computationally intensive method for obtaining three-dimensional cell tracks from video microscopy data. We demonstrate that a common neural network (NN) accelerates the analysis of holographic data by an order of magnitude, enabling its use on single-board computers and in real time. We establish a heuristic relationship between the distance of a cell from the focal plane and the size of the bounding box assigned to it by the NN, allowing us to rapidly localise cells in three dimensions as they swim. This technique opens the possibility of providing real-time feedback in experiments, for example by monitoring and adapting the supply of nutrients to a microbial bioreactor in response to changes in the swimming phenotype of microbes, or for rapid identification of bacterial pathogens in drinking water or clinical samples.

Nanodroplet vaporization with pulsed-laser excitation repeatedly amplifies photoacoustic signals at low vaporization thresholds.

Nanodroplets' explosive vaporization triggered by absorption of laser pulses produces very large volume changes. These volume changes are two orders of magnitude higher than those of thermoelastic expansion generated by equivalent laser pulses, and should generate correspondingly higher photoacoustic waves (PAW). The generation of intense PAWs is desirable in photoacoustic tomography (PAT) to increase sensitivity. The biocompatibility and simplicity of nanodroplets obtained by sonication of perfluoropentane (PFP) in an aqueous solution of bovine serum albumin (BSA) containing a dye make them particularly appealing for use as contrast agents in clinical applications of PAT. Their usefulness depends on stability and reproducible vaporization of nanodroplets (liquid PFP inside) to microbubbles (gaseous PFP inside), and reversible condensation to nanodroplets. This work incorporates porphyrins with fluorinated chains and BSA labelled with fluorescent probes in PFP nanodroplets to investigate the structure and properties of such nanodroplets. Droplets prepared with average diameters in the 400-1000 nm range vaporize when exposed to nanosecond laser pulses with fluences above 3 mJ cm-2 and resist coalescence. The fluorinated chains are likely responsible for the low vaporization threshold, ∼2.5 mJ cm-2, which was obtained from the laser fluence dependence of the photoacoustic wave amplitudes. Only ca. 10% of the droplets incorporate fluorinated porphyrins. Nevertheless, PAWs generated with nanodroplets are ten times higher than those generated by aqueous BSA solutions containing an equivalent amount of porphyrin. Remarkably, successive laser pulses result in similar amplification, indicating that the microbubbles revert back to nanodroplets at a rate faster than the laser repetition rate (10 Hz). PFP nanodroplets are promising contrast agents for PAT and their performance increases with properly designed dyes.

Key factors behind various specific phobia subtypes.

While it has been suggested that more than a quarter of the whole population is at risk of developing some form of specific phobia (SP) during their lives, we still know little about the various risk and protective factors and underlying mechanisms. Moreover, although SPs are distinct mental disorder categories, most studies do not distinguish between them, or stress their differences. Thus, our study was manifold. We examined the psychometric properties of the Specific Phobia Questionnaire (SPQ) and assessed whether it can be used for screening in the general population in a large sample (N = 685). Then, using general linear modeling on a second sample (N = 432), we tested how potential socio-demographic, cognitive emotion regulatory, and personality variables were associated with the five SP subtypes. Our results show that the SPQ is a reliable screening tool. More importantly, we identified transdiagnostic (e.g., younger age, female gender, rumination, catastrophizing, positive refocusing) as well as phobia-specific factors that may contribute to the development and maintenance of SPs. Our results support previous claims that phobias are more different than previously thought, and, consequently, should be separately studied, instead of collapsing into one category. Our findings could be pertinent for both prevention and intervention strategies.

Numerical Simulations of the Low-Velocity Impact Response of Semicylindrical Woven Composite Shells.

This paper presents an efficient and reliable approach to study the low-velocity impact response of woven composite shells using 3D finite element models that account for the physical intralaminar and interlaminar progressive damage. The authors' previous work on the experimental assessment of the effect of thickness on the impact response of semicylindrical composite laminated shells served as the basis for this paper. Therefore, the finite element models were put to the test in comparison to the experimental findings. A good agreement was obtained between the numerical predictions and experimental data for the load and energy histories as well as for the maximum impact load, maximum displacement, and contact time. The use of the mass-scaling technique was successfully implemented, reducing considerably the computing cost of the solutions. The maximum load, maximum displacement, and contact time are negligibly affected by the choice of finite element mesh discretization. However, it has an impact on the initiation and progression of interlaminar damage. Therefore, to accurately compute delamination, its correct definition is of upmost importance. The validation of these finite element models opens the possibility for further numerical studies on of woven composite shells and enables shortening the time and expenses associated with the experimental testing.

The role of self-reported fear and disgust in the activation of behavioral harm avoidance related to medical settings.

Introduction: Although adaptive defense mechanisms are useful in helping us avoid getting injured, they are also triggered by medical interventions and procedures, when avoidance is harmful. A body of previous results showed that both fear and disgust play a pivotal role in medical avoidance. However, the underlying mechanisms are not fully understood. Thus, the aim of the current study was to examine the effects of experience, perceived control, and pain on medical avoidance with disgust and fear as mediating factors from an evolutionary perspective. Methods: We assessed participants' knowledge of and experience with medical procedures, former negative medical experiences, and health-related information; their life history strategy variation; pain-related fear and anxiety of medical procedures; perceived control over emotional reactions and extreme threats; disgust sensitivity; blood-injury-injection phobia and medical treatment avoidance. Results: We found that more knowledge, experience, and a slower life strategy were linked to a greater level of perceived control and attenuated emotional reactions. Further, better ability to control affective and stress reactions to negative experiences was linked to reduced disgust and fear of pain, and thus might mitigate the level of perceived threat, and diminish fear and disgust reactions. Discussion: More knowledge and experiences, better perceived control together with reduced disgust and fear of pain can decrease the probability of avoiding medical situations. Implications to treatment are discussed. Results support the importance of targeting these contextual factors in prevention to increase the likelihood of people attending regular screenings or seeking medical care when needed.

An ethologically based view into human fear.

The quality of the defensive response to a threat depends on the elements that trigger the fear response. The current classification system of phobias does not account for this. Here, we analyze the fear-eliciting elements and discern the different types of fears that originate from them. We propose Pain, Disgust, Vasovagal response, Visual-vestibular and postural interactions, Movement and Speed, Distance and Size, Low and mid-level visual features, Smell, and Territory and social status. We subdivide phobias according to the fear-eliciting elements most frequently triggered by them and their impact on behavior. We discuss the implications of a clinical conceptualization of phobias in humans by reconsidering the current nosology. This conceptualization will facilitate finding etiological factors in defensive behavior expression, fine-tuning exposure techniques, and challenging preconceived notions of preparedness. This approach to phobias leads to surprising discoveries and shows how specific responses bear little relation to the interpretation we might later give to them. Dividing fears into their potentially fear-eliciting elements can also help in applying the research principles formulated by the Research Domain Criteria initiative.

Hypothesis testing in multivariate normal models with block circular covariance structures.

In this article, we address the problem of simultaneous testing hypothesis about mean and covariance matrix for repeated measures data when both the mean vector and covariance matrix are patterned. In particular, tests about the mean vector under block circular and doubly exchangeable covariance structures have been considered. The null distributions are established for the corresponding likelihood ratio test statistics, and expressions for the exact or near-exact probability density and cumulative distribution functions are obtained. The application of the results is illustrated by both a simulation study and a real-life data example.

Estimulação elétrica transcraniana nos transtornos depressivos: determinação de parâmetros para a prática clínica / Effectiveness of transcranial electric stimulation in depressive disorders: parameters determination for clinical practice

A estimulação elétrica transcraniana (EET) é uma técnica de neuromodulação não invasiva, que tem sido utilizada como coadjuvante no tratamento de transtornos depressivos devido à sua capacidade de modificar a excitabilidade cortical. Objetivo: Analisar os efeitos da EET nos transtornos depressivos e propor parâmetros para a prática clínica. Métodos: Estudo de revisão sistemática no qual foram incluídos ensaios clínicos randomizados que utilizaram a EET no tratamento dos transtornos depressivos, publicados entre 2010 e junho de 2018, nas línguas inglesa e portuguesa. Resultados: Foram encontrados 14.775 estudos, sendo selecionados para a amostra apenas 15 trabalhos. Todos os estudos selecionados utilizaram a EET por corrente contínua e apresentaram semelhanças em relação aos demais parâmetros elétricos de tratamento e locais de aplicação dos eletrodos. Em 12 dos 15 estudos avaliados foi observada melhora significativa (p < 0,05) dos sintomas depressivos e, em relação aos efeitos adversos, constatou-se que são inferiores aos tratamentos convencionais. Conclusão: A EET apresenta eficácia no tratamento dos transtornos depressivos e que isto está diretamente relacionado ao uso adequado dos parâmetros e técnicas de aplicação da corrente elétrica. (AU)

Fear inoculation among snake experts.

BACKGROUND: Fear acquisition of certain stimuli, such as snakes, is thought to be rapid, resistant to extinction, and easily transferable onto other similar objects. It has been hypothesized that due to increased survival chances, preparedness to instantly acquire fear towards evolutionary threats has been hardwired into neural pathways of the primate brain. Here, we compare participants' fear of snakes according to experience; from those who often deal with snakes and even suffer snakebites to those unfamiliar with snakes. METHODS: The Snake Questionnaire-12 (SNAQ-12) and Specific Phobia Questionnaire (SPQ) were administered to three groups of participants with a different level of experience with snakes and snakebites: 1) snake experts, 2) firefighters, and 3) college students. RESULTS: This study shows that individuals more experienced with snakes demonstrate lower fear. Moreover, participants who have suffered a snakebite (either venomous or not) score lower on fear of snakes (SNAQ-12), but not of all other potentially phobic stimuli (SPQ). CONCLUSIONS: Our results suggest that a harmless benign exposure might immunize people to highly biologically prepared fears of evolutionary threats, such as snakes.

Super-natural fears.

Supernatural fears, although common, are not as well-understood as natural fears and phobias (e.g., social, blood, and animal phobias) which are prepared by evolution, such that they are easily acquired through direct experience and relatively immune to cognitive mediation. In contrast, supernatural fears do not involve direct experience but seem to be related to sensory or cognitive biases in the interpretation of stimuli as well as culturally driven cognitions and beliefs. In this multidisciplinary synthesis and collaborative review, we claim that supernatural beliefs are "super natural." That is, they occur spontaneously and are easy to acquire, possibly because such beliefs rest on intuitive concepts such as mind-body dualism and animism, and may inspire fear in believers as well as non-believers. As suggested by psychological and neuroscientific evidence, they tap into an evolutionarily prepared fear of potential impending dangers or unknown objects and have their roots in "prepared fears" as well as "cognitively prepared beliefs," making fear of supernatural agents a fruitful research avenue for social, anthropological, and psychological inquires.

"Finding an Emotional Face" Revisited: Differences in Own-Age Bias and the Happiness Superiority Effect in Children and Young Adults.

People seem to differ in their visual search performance involving emotionally expressive faces when these expressions are seen on faces of others close to their age (peers) compared to faces of non-peers, known as the own-age bias (OAB). This study sought to compare search advantages in angry and happy faces detected on faces of adults and children on a pool of children (N = 77, mean age = 5.57) and adults (N = 68, mean age = 21.48). The goals of this study were to (1) examine the developmental trajectory of expression recognition and (2) examine the development of an OAB. Participants were asked to find a target face displaying an emotional expression among eight neutral faces. Results showed that children and adults found happy faces significantly faster than angry and fearful faces regardless of it being present on the faces of peers or non-peers. Adults responded faster to the faces of peers regardless of the expression. Furthermore, while children detected angry faces significantly faster compared to fearful ones, we found no such difference in adults. In contrast, adults detected all expressions significantly faster when they appeared on the faces of other adults compared to the faces of children. In sum, we found evidence for development in detecting facial expressions and also an age-dependent increase in OAB. We suggest that the happy face could have an advantage in visual processing due to its importance in social situations and its overall higher frequency compared to other emotional expressions. Although we only found some evidence on the OAB, using peer or non-peer faces should be a theoretical consideration of future research because the same emotion displayed on non-peers' compared to peers' faces may have different implications and meanings to the perceiver.

Towards Customized Footwear with Improved Comfort.

A methodology enabling the customization of shoes for comfort improvement is proposed and assessed. For this aim, 3D printed graded density inserts were placed in one of the critical plantar pressure zones of conventional insoles, the heel. A semi-automated routine was developed to design the 3D inserts ready for printing, which comprises three main stages: (i) the definition of the number of areas with different mesh density, (ii) the generation of 2D components with continuous graded mesh density, and (iii) the generation of a 3D component having the same 2D base mesh. The adequacy of the mesh densities used in the inserts was previously assessed through compression tests, using uniform mesh density samples. Slippers with different pairs of inserts embedded in their insoles were mechanically characterized, and their comfort was qualitatively assessed by a panel of users. All users found a particular pair, or a set, of prototype slippers more comfortable than the original ones, taken as reference, but their preferences were not consensual. This emphasizes the need for shoe customization, and the usefulness of the proposed methodology to achieve such a goal.

On the Nature of Fear and Anxiety Triggered by COVID-19.

Emergencies that occur during natural disasters, such as avalanches, earthquakes, and floods, tend to be sudden, unexpected, and ephemeral and recruit defensive responses, similar to the ones recruited when faced with dangerous animals. Defensive behaviors are triggered by activity in survival circuits that detects imminent threats and fear is the conscious emotion of that follows immediately. But this particular threat (COVID-19) is useable and mysterious, triggering anxieties much more than fear. We conducted a literature search on May 1, 2020 in Google Scholar, PsychInfo, and PubMed with search terms related to COVID-19 fears and found 28 relevant articles. We categorized the papers into six groups based on the content and implications: fear of the unknown, social isolation, hypochondriasis, disgust, information-driven fears, and compliance. Considering the nature of fear and anxiety, combined with the characteristics of the present COVID-19 situation, we contemplate that physicians and other health care workers of several specialties, as well as police officers, fire-fighters, and rescue personnel, and first responders might be more able to deal with COVID-19 if they have (a) some tolerance of the unknown, (b) low illness anxiety disorder, (c) tolerance to social isolation; (d) low levels of disgust sensitivity; (e) be granted financial support, (f) have priority if needed medical assistance (g) use caution relatively to the COVID-19 media coverage and (h) be trained to have high levels of efficacy. Possibilities for preventive and therapeutic interventions that can help both health care personnel and the general population are also discussed.

The emergency reaction questionnaire - First steps towards a new method.

During emergencies, people are more or less capable of performing adequately. Knowledge about human behavior while facing emergencies has become more significant nowadays. This knowledge can help improving our already present defensive responses and natural coping mechanisms when facing imminent dangers, natural disasters, and catastrophes. A new method is here offered to explore the core points of this topic. The Emergency Reaction Questionnaire (ERQ), is proposed for predicting one's reaction and behaviour in an emergency. First, a large item pool was created based on interviews with people facing emergencies on a weekly basis and related literature. The factor structure, reliability and validity were assessed on a large sample of lay people (N = 1115, 440 males) and specific groups of firefighters and people doing extreme sports (N = 85, all males). Participants were Caucasian with an age range of 18-70. We also used measures of anxiety, depression, and sensation seeking, behavioral inhibition and activation and coping in stressful situations. The ERQ was proved to be reliable and consistent in time and having sound psychometric properties both on the community and special samples. Results show that psychometric properties are satisfying; the test has excellent validity ratings. Consequently, the ERQ can be used in future research effectively and facilitate a better understanding of how people react in a highly dangerous situation. Future directions in the utilization of the new method are discussed.

Who worries about specific phobias? - A population-based study of risk factors.

Although specific phobia is one of the most prevalent lifetime anxiety disorders, little is known about the particular risk factors related to its development. The underlying goal of this study was to analyse the risk factors associated with worrying about specific phobias (SP) in a representative sample of community dwelling adults. The sample was composed of 8461 participants (mean age 47.68 years, range 18-85, 54.60% female), from the Australian National Mental Health Survey. A total of 188 participants (2.22%) reported worrying about SPs. Multivariate logistic regression analysis indicated that female sex (odds ratio (OR) = 1.98, p < 0.0001) and a comorbid diagnosis of lifetime major depression disorder (OR = 2.80, p < 0.0001) were the factors most strongly associated with worrying about SPs. Having experienced traumatic experiences involving significant others (OR = 1.18, p = 0.02), the number of chronic diseases (OR = 1.21, p < 0.01), and a comorbid diagnosis of substance use (OR = 2.80, p = 0.02) were also associated. Our results are in line with previous studies focusing on other anxiety disorders. We provide further evidence that substance dependence appears to serve as a unique risk factor for the subsequent onset of SP. Further empirical and clinical implications are discussed.

Are Humans Prepared to Detect, Fear, and Avoid Snakes? The Mismatch Between Laboratory and Ecological Evidence.

Since Seligman (1971) statement that the vast majority of phobias are about objects essential to the survival of a species, a multitude of laboratory studies followed, supporting the finding that humans learn to fear and detect snakes (and other animals) faster than other stimuli. Most of these studies used schematic drawings, images, or pictures of snakes, and only a small amount of fieldwork in naturalistic environments was done. We address fear preparedness theories and automatic fast detection data from mainstream laboratory data and compare it with ethobehavioral information relative to snakes, predator-prey interaction, and snakes' defensive kinematics strikes in order to analyze their potential matching. From this analysis, four main findings arose, namely that (1) snakebites occur when people are very close to the snake and are unaware or unable to escape the bite; (2) human visual detection and escape response is slow compared to the speed of snake strikes; (3) in natural environments, snake experts are often unable to see snakes existing nearby; (4) animate objects in general capture more attention over other stimuli and dangerous, but recent objects in evolutionary terms are also able to be detected fast. The issues mentioned above pose several challenges to evolutionary psychology-based theories expecting to find special-purpose neural modules. The older selective habituation hypothesis (Schleidt, 1961) that prey animals start with a rather general predator image from which specific harmless cues are removed by habituation might deserve reconsideration.

Attention allocation to 2D and 3D emotion-inducing scenes: A neurophysiological study.

Past research on emotions was mostly supported on emotion inducing slides, but studies in the field are moving towards more ecological stimuli, including 3D stimuli and virtual reality scenes. The present study aims to compare the effects of two-dimensional (2D) and three-dimensional (3D) emotion-inducing scenes in the modulation of attention, as indexed by the amplitude of the P3 event-related component in a dual-task paradigm. We recorded the EEG signal of 31 healthy male participants performing an active auditory oddball task, while simultaneously observing pleasant, unpleasant and neutral scenes in 2D or 3D. We analyzed the effects of emotional valence and visualization mode in the mean amplitude of the P3 component at Pz. The results revealed than revealed that 2D scenarios were as effective as 3D stimuli in capturing attention resources and this effect was consistently observed in all emotional scenes.

Interval estimation of small tail probabilities - applications in food safety.

Often in food safety and bio-surveillance it is desirable to estimate the probability that a contaminant or a function thereof exceeds an unsafe high threshold. The probability or chance in question is very small. To estimate such a probability, we need information about large values. In many cases, the data do not contain information about exceedingly large contamination levels, which ostensibly renders the problem insolvable. A solution is suggested whereby more information about small tail probabilities are obtained by combining the real data with computer-generated data repeatedly. This method provides short yet reliable interval estimates based on moderately large samples. An illustration is provided in terms of lead exposure data. Copyright © 2016 John Wiley & Sons, Ltd.

MK-801-induced behavioural sensitisation alters dopamine release and turnover in rat prefrontal cortex.

RATIONALE: Repeated exposure to psychostimulants that either increase dopamine (DA) release or target N-methyl-D-aspartate (NMDA) receptors can induce behavioural sensitisation, a phenomenon that may be important for the processes of addiction and even psychosis. A critical component of behavioural sensitisation is an increase in DA release within mesocorticolimbic circuits. In particular, sensitisation to amphetamine leads to increased DA release within well-known sub-cortical brain regions and also regulatory regions such as prefrontal cortex (PFC). However, it is unknown how DA release within the PFC of animals is altered by sensitisation to NMDA receptor antagonists. OBJECTIVES: The aims of the present study were twofold, firstly to examine whether a single dose of dizocilpine maleate (MK-801) could induce long-term behavioural sensitisation and secondly to examine DA release in the PFC of sensitised rats. MATERIALS AND METHODS: Behavioural sensitisation was assessed by measuring locomotion after drug exposure. DA release in the PFC was measured using freely moving microdialysis. RESULTS: We show that a single dose of MK-801 can induce sensitisation to subsequent MK-801 exposure in a high percentage of rats (66 %). Furthermore, rats sensitised to MK-801 have altered DA release and turnover in the PFC compared with non-sensitised rats. CONCLUSION: Schizophrenia patients have been postulated to have 'endogenous sensitisation' to psychostimulants. MK-801-induced sensitised rats, in particular when compared with non-sensitised rats, provide a useful model for studying PFC dysfunction in schizophrenia.