Training and proficiency level in endoscopic sinus surgery change residents' eye movements.

Nose surgery is challenging and needs a lot of training for safe and efficient treatments. Eye tracking can provide an objective assessment to measure residents' learning curve. The aim of the current study was to assess residents' fixation duration and other dependent variables over the course of a dedicated training in functional endoscopic sinus surgery (FESS). Sixteen residents performed a FESS training over 18 sessions, split into three surgical steps. Eye movements in terms of percent fixation on the screen and average fixation duration were measured, in addition to residents' completion time, cognitive load, and surgical performance. Results indicated performance improvements in terms of completion time and surgical performance. Cognitive load and average fixation duration showed a significant change within the last step of training. Percent fixation on screen increased within the first step, and then stagnated. Results showed that eye movements and cognitive load differed between residents of different proficiency levels. In conclusion, eye tracking is a helpful objective measuring tool in FESS. It provides additional insights of the training level and changes with increasing performance. Expert-like gaze was obtained after half of the training sessions and increased proficiency in FESS was associated with increased fixation duration

Performing Intracochlear Electrocochleography during Cochlear Implantation.

Electrocochleography (ECochG) measures inner ear potentials generated in response to acoustic stimulation of the ear. These potentials reflect the residual function of the cochlea. In cochlear implant candidates with residual hearing, the implant electrode can directly measure ECochG responses during the implantation process. Various authors have described the ability to monitor the inner ear function by continuous ECochG measurements during the surgery. The measurement of ECochG signals during surgery is not trivial. There are no interpretable signals in up to 20% of cases. For a successful recording, a standardized procedure is recommended to achieve the highest measurement reliability and avoid possible pitfalls. Therefore, seamless collaboration between the CI surgeon and CI technician is key. This video consists of an overview of the system setup and a stepwise procedure of performing intracochlear ECochG measurements during CI surgery. It shows the surgeon's and the CI technician's roles in the process, and how a smooth collaboration between the two is made possible

Resistive Switching Mechanisms on TaOx and SrRuO3 Thin-Film Surfaces Probed by Scanning Tunneling Microscopy

The local electronic properties of tantalum oxide (TaO[subscript x], 2 ≤ x ≤ 2.5) and strontium ruthenate (SrRuO[subscript 3]) thin-film surfaces were studied under the influence of electric fields induced by a scanning tunneling microscope (STM) tip. The switching between different redox states in both oxides is achieved without the need for physical electrical contact by controlling the magnitude and polarity of the applied voltage between the STM tip and the sample surface. We demonstrate for TaO[subscript x] films that two switching mechanisms operate. Reduced tantalum oxide shows resistive switching due to the formation of metallic Ta, but partial oxidation of the samples changes the switching mechanism to one mediated mainly by oxygen vacancies. For SrRuO[subscript 3], we found that the switching mechanism depends on the polarity of the applied voltage and involves formation, annihilation, and migration of oxygen vacancies. Although TaO[subscript x] and SrRuO[subscript 3] differ significantly in their electronic and structural properties, the resistive switching mechanisms could be elaborated based on STM measurements, proving the general capability of this method for studying resistive switching phenomena in different classes of transition metal oxides.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Grant DMR-1419807

How Attractive Is the Girl Next Door? An Assessment of Spatial Mate Acquisition and Paternity in the Solitary Cape Dune Mole-Rat, Bathyergus suillus

Behavioural observations of reproduction and mate choice in wild fossorial rodents are extremely limited and consequently indirect methods are typically used to infer mating strategies. We use a combination of morphological, reproductive, spatial, and genetic data to investigate the reproductive strategy of a solitary endemic species, the Cape dune mole-rat Bathyergus suillus. These data provide the first account on the population dynamics of this species. Marked sexual dimorphism was apparent with males being both significantly larger and heavier than females. Of all females sampled 36% had previously reproduced and 12% were pregnant at the time of capture. Post-partum sex ratio was found to be significantly skewed in favour of females. The paternity of fifteen litters (n = 37) was calculated, with sires assigned to progeny using both categorical and full probability methods, and including a distance function. The maximum distance between progeny and a putative sire was determined as 2149 m with males moving between sub-populations. We suggest that above-ground movement should not be ignored in the consideration of mate acquisition behaviour of subterranean mammals. Estimated levels of multiple paternity were shown to be potentially as high as 26%, as determined using sibship and sire assignment methods. Such high levels of multiple paternity have not been found in other solitary mole-rat species. The data therefore suggest polyandry with no evidence as yet for polygyny

Exposure to indoor microbial agents, allergens and pets, and their relation to asthma and allergy prevalence in farmers' children and their peers from rural areas : Diploma thesis

Background In ‘westernised’ countries, the prevalence of childhood asthma and allergy have risen throughout the last three decades. Changes in lifestyle and environmental factors like an increase in exposure to air pollutants, environmental tobacco smoke, or indoor allergen and pet exposure have been considered as plausible explanations. However, little evidence in support of these causal risk factors for these common chronic childhood diseases has been found. Lower risk of hay fever and atopic sensitisation were reported in children with more siblings, and later also in children who attended day care centres early in infancy. These findings were summarised in the so-called ‘hygiene hypothesis’: limited exposure to bacterial and viral pathogens during early childhood results in a higher risk of developing allergic diseases. Recent allergy research has focused on the interaction between the innate and adaptive immunity: innate immunity receptors of pathogens seem to modulate the activation of adaptive immunity mechanisms. Three independent studies showed reduced prevalence of asthma and allergy among farmers’ children compared to their peers from the same rural areas from Switzerland, Austria, and Germany. A series of epidemiological studies in Europe, Canada, and Australia consistently confirmed and extended these findings. These results have been seen as an extension of the ‘hygiene hypothesis’, since a farm environment provides an enormous habitat for micro-organisms. A potential candidate that may explain these differences in the prevalence of childhood asthma and allergy is environmental exposure to endotoxin, a component of the outer membrane of gram-negative bacteria. Aim To assess the exposure to indoor microbial agents, allergens and pets in farmers’ children and their peers of non-farming families, and to estimate whether these exposures are associated with the prevalence of childhood asthma and allergies. Methods The ALEX (Allergy and Endotoxin) study was a cross-sectional survey in rural areas of Germany, Austria, and Switzerland. 2618 parents of 6-13 year-old children completed a standardised questionnaire including questions about asthma and allergy from the ISAAC study and questions about the child’s activities on farms, and characteristics of the home environment. Blood samples were obtained from selected children and tested for atopic sensitisation, specially for specific IgE and IgG4 antibodies to grass pollen and cat allergen. Endotoxin and cat allergen levels were measured in indoor dust samples and in settled dust from stables. Complete data were available for 812 children. In a subgroup of 553 children mattress dust muramic acid levels, another marker for exposure to bacteria, were determined. Results Higher levels of indoor endotoxin exposure were associated with reduced allergen sensitisation, decreased prevalence of hay fever, atopic asthma and wheeze in a dose-dependent manner. The associations were equally strong among the sub sample children from nonfarming families, indicating that even lower levels of endotoxin may favourably influence the risk of atopic diseases. Endotoxin levels in stables were not correlated with the amount of endotoxin measured indoors, but a dose-dependent association between the child’s activity on the farm and indoor home endotoxin levels was observed, both in farmers’ and in non-farmers’ children. Pet keeping, full time farming (compared to part time farming), and younger age of the children contributed additionally to increased indoor endotoxin levels. Endotoxin levels in stables increased with the number of cattle (but only up to the highest quartile), with hay feeding (compared to feeding of mainly silage), and additionally with provision of accommodation of horses, pigs, sheep or goats in the cattle stable. All these predictors might be surrogate measures for traditional dairy farming in hilly German speaking areas. Children’s mattress’ muramic acid levels were significantly higher in farmers’ children than in non-farmers’ children. Mattress muramic acid and endotoxin levels were partially correlated, indicating that both substances are markers for the exposure to micro-organisms. Independent of being a farmers’ child, mattress dust from homes heated with wood or coal and less frequently cleaned mattresses showed increasing muramic acid levels. Independent of the endotoxin exposure, increasing muramic acid levels in mattress dust was associated with a lower frequency of current wheeze, but not with atopic sensitisation or hay fever. The protective effect on wheeze and diagnosed asthma was more pronounced in non-sensitised children. The different effect spectrum for muramic acid and endotoxin exposure suggest that different micro-organisms might contribute to the lower prevalence of asthma and allergy among farmers’ children, compared to non-farmers’ children. Current contact to dogs was inversely associated with diagnosed hay fever, asthma, and specific sensitisation to grass pollen and to cat allergen, but not with increased IgG4 levels. Early and current exposure to cats – but not to dogs – was associated with lower frequency of wheeze and grass pollen sensitisation. None of these inverse associations were greatly affected by additionally taking into account the indoor endotoxin or cat allergen levels, but additionally adjustment for early or current exposure to farm animals attenuated the protective effects. Although pet exposure was frequent in this rural population, the protective effects of pet keeping observed in other peer-reviewed studies may be masked by frequent contact to farming environments. Conclusions and outlook Endotoxin and muramic acid may be surrogate markers of a much broader spectrum of microbial compounds. Thus, further studies have not only to confirm the lower risk of children with contact to livestock or with higher exposure to micro-organisms early in life, but also to find the relevant mixture of protective components in the farm dust. In addition, as ingestion is another plausible route of exposure to micro-organisms, epidemiology may focus on differences in nutrition and their association with childhood asthma and allergy. The PARSIFAL (Prevention of allergy – Risk factors for sensitisation in children related to farming and anthroposophic lifestyle) study offers the opportunity to do so, as this study include children’s populations growing up with different lifestyles. Experimental studies may focus on the relevant exposure route (inhalation, ingestion) of different patterns of micro-organisms. The genetic dimension has to be kept in mind in the discussion of environmental exposure to micro-organisms by identifying particularly sensitive groups through genetic investigations, as the available data in the ALEX study was limited. Current scientific evidence has not developed strongly enough to provide a reliable course of action for primary prevention or therapy. Infectious diseases resulting from exposure to pathogens continue to be a serious public health problem. Thus, the protective effect of a microbial environment on the development of asthma and atopy should be balanced against the benefits of established hygiene standards