[Osteoporosis-Definition, risk assessment, diagnosis, prevention and treatment (update 2024) : Guidelines of the Austrian Society for Bone and Mineral Research]. / Osteoporose ­ Definition, Risikoerfassung, Diagnose, Prävention und Therapie (Update 2024) : Leitlinie der Österreichischen Gesellschaft für Knochen- und Mineralstoffwechsel.

BACKGROUND: Austria is among the countries with the highest incidence and prevalence of osteoporotic fractures worldwide. Guidelines for the prevention and management of osteoporosis were first published in 2010 under the auspices of the then Federation of Austrian Social Security Institutions and updated in 2017. The present comprehensively updated guidelines of the Austrian Society for Bone and Mineral Research are aimed at physicians of all specialties as well as decision makers and institutions in the Austrian healthcare system. The aim of these guidelines is to strengthen and improve the quality of medical care of patients with osteoporosis and osteoporotic fractures in Austria. METHODS: These evidence-based recommendations were compiled taking randomized controlled trials, systematic reviews and meta-analyses as well as European and international reference guidelines published before 1 June 2023 into consideration. The grading of recommendations used ("conditional" and "strong") are based on the strength of the evidence. The evidence levels used mutual conversions of SIGN (1++ to 3) to NOGG criteria (Ia to IV). RESULTS: The guidelines include all aspects associated with osteoporosis and osteoporotic fractures, such as secondary causes, prevention, diagnosis, estimation of the 10-year fracture risk using FRAX®, determination of Austria-specific FRAX®-based intervention thresholds, drug-based and non-drug-based treatment options and treatment monitoring. Recommendations for the office-based setting and decision makers and institutions in the Austrian healthcare system consider structured care models and options for osteoporosis-specific screening. CONCLUSION: The guidelines present comprehensive, evidence-based information and instructions for the treatment of osteoporosis. It is expected that the quality of medical care for patients with this clinical picture will be substantially improved at all levels of the Austrian healthcare system.

Identification of the Brucea javanica Constituent Brusatol as a EGFR-Tyrosine Kinase Inhibitor in a Cell-Free Assay.

Inhibitors of the tyrosine kinase (TK) activity of the epidermal growth factor receptor (EGFR) are routinely used in cancer therapy. However, there is a need to discover a new TK inhibitor. This study evaluated extracts from Brucea javanica and its components for their potential as novel EGFR-TK inhibitors. The cytotoxic effect of a g aqueous extract and its fractions was assessed by MTT assays with A549 lung cancer cells. The two fractions with the highest cytotoxicity were analyzed by LC/MS and 1H NMR. Brusatol was identified as the main constituent of these fractions, and its cytotoxic and pro-apoptotic activities were confirmed in A549 cells. To elucidate the inhibitory activity of brusatol against EGFR-TK, a specific ADP-GloTM kinase assay was used. In this assay, the IC50 value for EGFR-TK inhibition was 333.1 nM. Molecular dynamic simulations and docking experiments were performed to identify the binding pocket of brusatol to be located in the intracellular TK-domain of EGFR. This study demonstrates that brusatol inhibits EGFR-TK and therefore harbors a potential as a new therapeutic drug for the therapy of EGFR-depending cancers.

What Do People Know about Food, Nutrition and Health?-General Nutrition Knowledge in the Austrian Population.

BACKGROUND: Only limited information is available on the nutrition knowledge of the general Austrian population and how this relates to the nutrition knowledge of health professionals (medical doctors, pharmacists, nutritionist, dieticians) and school teachers. METHODS: Adolescents and adults at the age of 14-75 years (n = 1000), medical doctors (n = 307), pharmacists (n = 295), nutritionists (n = 124), dieticians (n = 160) and school teachers (n = 873) completed an online survey using a German version of the General Nutrition Knowledge Questionnaire-Revised (GNKQ-R) including self-reported data on sex, age, BMI, and health status. Adolescent and adult participants were recruited by a research agency to be representative for the Austrian population for age, sex, and education. A convenience sample was used for health professionals (medical doctors, pharmacists, nutritionist, dieticians) and school teachers. All participants completed a computer-assisted web-based interviewing (CAWI) survey. RESULTS: Total scores for nutrition knowledge of the general population (61.4%) were significantly lower than scores from all other groups (medical doctors 81.3%, pharmacists 83.0%, dieticians 87.5%, nutritionists 85.6%, school teachers 74.5%). The main drivers for better nutritional knowledge were female sex, higher age, and higher level of education, while BMI classification and self-reported health status had no impact. In regard to single questions, the most striking result was the misclassification of sugar as the nutrient with the most calories by 41.4% of the general population while only 29.0% correctly identified fat to be the nutrient with the most calories. CONCLUSIONS: The nutritional knowledge of the general population should be significantly improved in order to lay a basis for better dietary behavior. In view of the relatively low scores of teachers, their nutrition education should be improved in order to enable transfer of sound education in schools.

Self-reported Resistance Training Is Associated With Better HR-pQCT-derived Bone Microarchitecture in Vegan People.

CONTEXT: A plant-based lifestyle is a global trend; lower bone mineral density and increased fracture risk in vegan people are reported. OBJECTIVE: The primary objective was to assess trabecular and cortical bone microarchitecture in vegans and omnivores. Secondary objectives were to evaluate relationships between bone microarchitecture, nutrition parameters, and physical activity. METHODS: This was an observational study at the Medical Department II, St. Vincent Hospital (tertiary referral center for gastrointestinal, metabolic, and bone diseases, and teaching hospital of the Medical University of Vienna), including 43 healthy nonobese female and male subjects on a plant-based diet for at least 5 years, and 45 healthy nonobese female and male subjects on an omnivore diet for at least 5 years. The main outcome measures were the parameters of trabecular and cortical bone microarchitecture (high-resolution peripheral quantitative computed tomography), serum markers of bone turnover, nutrient intake (nutrition protocol), and self-reported resistance training (physical activity questionnaires). RESULTS: In the vegan group, trabecular and cortical structure were altered compared with omnivores. Vegans not reporting resistance training had diminished bone microarchitecture compared with omnivores not reporting resistance training. In vegans and omnivores reporting resistance training, bone structure was similar. In both vegan subgroups (resistance training and not resistance training), a small number of correlations between nutrient intake and bone microarchitecture were observed without a conclusive pattern. CONCLUSION: Bone microarchitecture in vegans differed from matched omnivores but could not be explained solely by nutrient uptake. These differences were attenuated between the subgroups reporting resistance training. In addition to a well-planned diet, progressive resistance training on a regular basis should be part of the vegan lifestyle.

A Comparison of the Impact of Restrictive Diets on the Gastrointestinal Tract of Mice.

The rate of gut inflammatory diseases is growing in modern society. Previously, we showed that caloric restriction (CR) shapes gut microbiota composition and diminishes the expression of inflammatory factors along the gastrointestinal (GI) tract. The current project aimed to assess whether prominent dietary restrictive approaches, including intermittent fasting (IF), fasting-mimicking diet (FMD), and ketogenic diet (KD) have a similar effect as CR. We sought to verify which of the restrictive dietary approaches is the most potent and if the molecular pathways responsible for the impact of the diets overlap. We characterized the impact of the diets in the context of several dietary restriction-related parameters, including immune status in the GI tract; microbiota and its metabolites; bile acids (BAs); gut morphology; as well as autophagy-, mitochondria-, and energy restriction-related parameters. The effects of the various diets are very similar, particularly between CR, IF, and FMD. The occurrence of a 50 kDa truncated form of occludin, the composition of the microbiota, and BAs distinguished KD from the other diets. Based on the results, we were able to provide a comprehensive picture of the impact of restrictive diets on the gut, indicating that restrictive protocols aimed at improving gut health may be interchangeable.

Gender, Age, Hunger, and Body Mass Index as Factors Influencing Portion Size Estimation and Ideal Portion Sizes.

Portion sizes of meals have been becoming progressively larger which contributes to the onset of obesity. So far, little research has been done on the influence of body weight on portion size preferences. Therefore, we assessed whether Body Mass Index (BMI), as well as other selected factors, contribute to the estimation of food portions weight and the subjective perception of portion sizes. Through online questionnaires, the participants were asked to estimate the weight of pictured foods in the first study. In the second study, the participants indicated how the depicted varying portion sizes of different meals relate to their actual consumed real-life portion sizes. A total of 725 and 436 individuals were included in the statistical analysis in the first and second study, respectively. BMI and gender had a small effect on the capacity to estimate the weight of foods. The main predictor for portion size choices was the factor gender with men estimating ideal portion sizes as larger than women. Further, age and hunger together with external and restrictive eating behaviors were among the deciding factors for portion size choices. As expected, externally motivated eaters chose bigger portions while restrictive individual smaller ones. Gender- and age-related differences in portion size preferences likely reflect distinct energy requirements. The individuals with a higher BMI do not differ strongly from other BMI groups in their portion-related preferences. Therefore, other factors such as meal frequency, snacking, or a lifestyle, may contribute more to the onset, development, and maintenance of overweight.

Individual Sweet Taste Perception Influences Salivary Characteristics After Orosensory Stimulation With Sucrose and Noncaloric Sweeteners.

Emerging evidence points to a major role of salivary flow and viscoelastic properties in taste perception and mouthfeel. It has been proposed that sweet-tasting compounds influence salivary characteristics. However, whether perceived differences in the sensory properties of structurally diverse sweet-tasting compounds contribute to salivary flow and saliva viscoelasticity as part of mouthfeel and overall sweet taste perception remains to be clarified. In this study, we hypothesized that the sensory diversity of sweeteners would differentially change salivary characteristics in response to oral sweet taste stimulation. Therefore, we investigated salivary flow and saliva viscoelasticity from 21 healthy test subjects after orosensory stimulation with sucrose, rebaudioside M (RebM), sucralose, and neohesperidin dihydrochalcone (NHDC) in a crossover design and considered the basal level of selected influencing factors, including the basal oral microbiome. All test compounds enhanced the salivary flow rate by up to 1.51 ± 0.12 g/min for RebM compared to 1.10 ± 0.09 g/min for water within the 1st min after stimulation. The increase in flow rate was moderately correlated with the individually perceived sweet taste (r = 0.3, p < 0.01) but did not differ between the test compounds. The complex viscosity of saliva was not affected by the test compounds, but the analysis of covariance showed that it was associated (p < 0.05) with mucin 5B (Muc5B) concentration. The oral microbiome was of typical composition and diversity but was strongly individual-dependent (permutational analysis of variance (PERMANOVA): R 2 = 0.76, p < 0.001) and was not associated with changes in salivary characteristics. In conclusion, this study indicates an impact of individual sweet taste impressions on the flow rate without measurable changes in the complex viscosity of saliva, which may contribute to the overall taste perception and mouthfeel of sweet-tasting compounds.

Establishment of an In Vitro Co-Culture Model of the Piglet Gut to Study Inflammatory Response and Barrier Integrity.

In intensive farming, piglets are exposed to various challenges that activate intestinal inflammatory processes, negatively affecting animal health and leading to economic losses. To study the role of the inflammatory response on epithelial barrier integrity, co-culture systems that mimic in vivo complexity are more and more preferred over cell monocultures. In this study, an in vitro gut co-culture model consisting of intestinal porcine epithelial cells and porcine peripheral blood mononuclear cells was established. The model provides an appropriate tool to study the role of the inflammatory response on epithelial barrier integrity and to screen for feed and food components, exerting beneficial effects on gut health. In the established model, inflammation-like reactions and damage of the epithelial barrier, indicated by a decrease of transepithelial electrical resistance, were elicited by activation of peripheral blood mononuclear cells via one of 3 stimuli: lipopolysaccharide, lipoteichoic acid, or concanavalin A. Two phytogenic substances that are commonly used as feed additives, licorice extract and oregano oil, have been shown to counteract the drop in transepithelial electrical resistance values in the gut co-culture model. The established co-culture model provides a powerful in vitro tool to study the role of intestinal inflammation on epithelial barrier integrity. As it consists of porcine epithelial and porcine blood cells it perfectly mimics in vivo conditions and imitates the inter-organ communication of the piglet gut. The developed model is useful to screen for nutritional components or drugs, having the potential to balance intestinal inflammation and strengthen the epithelial barrier integrity in piglets.

Colonic Medium-Chain Fatty Acids Act as a Source of Energy and for Colon Maintenance but Are Not Utilized to Acylate Ghrelin.

The capacity of microbiota to produce medium-chain fatty acids (MCFA) and related consequences for the gastrointestinal (GI) tract have never been reported before. We verified the impact of nutrition-related factors on fatty acid (FAs) production and found that caloric restriction decreased levels of most of MCFAs in the mouse cecum, whereas overnight fasting reduced the levels of acetate and butyrate but increased propionate and laurate. A diet high in soluble fibre boosted the production of short-chain fatty acids (SCFA) and caproate whereas a high-cellulose diet did not have an effect or decreased the levels of some of the FAs. Rectal infusion of caprylate resulted in its rapid metabolism for energy production. Repeated 10-day MCFA infusion impacted epididymal white adipose tissue (eWAT) weight and lipid accumulation. Repeated infusion of caprylate rectally tended to increase the concentration of active ghrelin in mice plasma; however, this increase was not statistically significant. In Caco-2 cells, caprylate increased the expression of Fabp2, Pdk4, Tlr3, and Gpr40 genes as well as counteracted TNFα-triggered downregulation of Pparγ, Occludin, and Zonulin mRNA expression. In conclusion, we show that colonic MCFAs can be rapidly utilized as a source of energy or stored as a lipid supply. Further, locally produced caprylate may impact metabolism and inflammatory parameters in the colon.

Microbial contribution to the caloric restriction-triggered regulation of the intestinal levels of glutathione transferases, taurine, and bile acid.

Recently we showed that caloric restriction (CR) triggers an increase in the levels of free taurine, taurine-conjugated bile acids (BA), and other taurine conjugates in intestinal mucosa while decreasing glutathione (GSH) levels in wild-type male mice. In the current project, we decided to investigate whether the microbiota is involved in the response to CR by depleting gut bacteria. The antibiotics treatment diminished CR-specific increase in the levels of free taurine and its conjugates as well as upregulated expression and activity of GSH transferases (GST) in the intestinal mucosa. Further, it diminished a CR-related increase in BAs levels in the liver, plasma, and intestinal mucosa. Transplant of microbiota from CR mice to ad libitum fed mice triggered CR-like changes in MGST1 expression, levels of taurine and taurine conjugates in the mucosa of the ileum. We show for the first time, that microbiota contributes to the intestinal response to CR-triggered changes in BA, taurine, and GST levels.

Electron Waiting Times in a Strongly Interacting Quantum Dot: Interaction Effects and Higher-Order Tunneling Processes.

Distributions of electron waiting times have been measured in several recent experiments and have been shown to provide complementary information compared with what can be learned from the electric current fluctuations. Existing theories, however, are restricted to either weakly coupled nanostructures or phase-coherent transport in mesoscopic conductors. Here, we consider an interacting quantum dot and develop a real-time diagrammatic theory of waiting time distributions that can treat the interesting regime, in which both interaction effects and higher-order tunneling processes are important. Specifically, we find that our quantum-mechanical theory captures higher-order tunneling processes at low temperatures, which are not included in a classical description, and which dramatically affect the waiting times by allowing fast tunneling processes inside the Coulomb blockade region. Our work paves the way for systematic investigations of temporal fluctuations in interacting quantum systems, for example close to a Kondo resonance or in a Luttinger liquid.

Caloric restriction increases levels of taurine in the intestine and stimulates taurine uptake by conjugation to glutathione.

Our previous study indicated increased levels of taurine-conjugated bile acids (BA) in the intestine content of mice submitted to caloric restriction (CR). In the current project, we found increased levels of free taurine and taurine conjugates, including glutathione (GSH)-taurine, in CR compared to ad libitum fed animals in the mucosa along the intestine but not in the liver. The levels of free GSH were decreased in the intestine of CR compared to ad libitum fed mice. However, the levels of oxidized GSH were not affected and were complemented by the lack of changes in the antioxidative parameters. Glutathione-S transferases (GST) enzymatic activity was increased as was the expression of GST genes along the gastrointestinal tract of CR mice. In the CR intestine, addition of GSH to taurine solution enhanced taurine uptake. Accordingly, the expression of taurine transporter (TauT) was increased in the ileum of CR animals and the levels of free and BA-conjugated taurine were lower in the feces of CR compared to ad libitum fed mice. Fittingly, BA- and GSH-conjugated taurine levels were increased in the plasma of CR mice, however, free taurine remained unaffected. We conclude that CR-triggered production and release of taurine-conjugated BA in the intestine results in increased levels of free taurine what stimulates GST to conjugate and enhance uptake of taurine from the intestine.

Five Days Periodic Fasting Elevates Levels of Longevity Related Christensenella and Sirtuin Expression in Humans.

Periodic fasting (PF) is an increasingly popular approach that assists in the management of metabolic and inflammatory diseases as well as in preventing mechanisms involved in aging. However, little is known about the effects of fasting on gut microbiota and its impact on the epigenetic regulation of metabolically relevant enzymes, especially sirtuins (SIRTs). We analyzed the effect of periodic fasting on the human gut microbiota, SIRTs expression, and mitochondrial content in 51 males and females. The participants fasted under supervision for five consecutive days following the Buchinger fasting guidelines. Ketogenesis, selected mRNAs, miRNAs, mitochondrial (mt) DNA, and gut composition were analyzed before and after PF. PF triggered a significant switch in metabolism, as indicated by the increase in ß-hydroxybutyrate (BHB) and pyruvate dehydrogenase kinase isoform 4 (PDK4) expression in the capillary blood. MtDNA, SIRT1, SIRT3, and miRlet7b-5p expression in blood cells were elevated, whereas SIRT6 and miR125b-5p were not affected. Following fasting, gut microbiota diversity increased, and a statistically significant correlation between SIRT1 gene expression and the abundance of Prevotella and Lactobacillus was detected. The abundance of longevity related Christensenella species increased after fasting and inversely correlated with age as well as body mass index (BMI). Thus, this represents the first study that showing that fasting not only changes the composition of the gut microbiota, making it more diverse, but also affects SIRT expression in humans.

Sweetness Perception is not Involved in the Regulation of Blood Glucose after Oral Application of Sucrose and Glucose Solutions in Healthy Male Subjects.

SCOPE: This study investigates the effect of the sweetness of a sucrose versus an isocaloric glucose solution in dietary concentrations on blood glucose regulation by adjusting the sweetness level using the sweet taste inhibitor lactisole. METHODS AND RESULTS: A total of 27 healthy males participated in this randomized, crossover study with four treatments: 10% glucose, 10% sucrose, 10% sucrose + 60 ppm lactisole, and 10% glucose + 60 ppm lactisole. Plasma glucose, insulin, glucagon-like peptide 1, and glucagon levels are measured at baseline and 15, 30, 60, 90, and 120 min after beverage consumption. Test subjects rated the sucrose solution to be sweeter than the isocaloric glucose solution, whereas no difference in sweetness is reported after addition of lactisole to the sucrose solution. Administration of the less sweet glucose solution versus sucrose led to higher blood glucose levels after 30 min, as reflected by a lower ΔAUC for sucrose (1072 ± 136) than for glucose (1567 ± 231). Application of lactisole leads to no differences in glucose, insulin, or glucagon responses induced by sucrose or glucose. CONCLUSION: The results indicate that the structure of the carbohydrate has a stronger impact on the regulation of blood glucose levels than the perceived sweetness.

Probabilistic risk assessment of nitrates for Austrian adults and estimation of the magnitude of their conversion into nitrites.

Nitrates occur in food naturally, as contaminants or additives. The health implications attributed to ingested nitrates result primarily from their conversion into nitrites and subsequent methemoglobinemia, carcinogenicity induced by N-nitroso-compounds and cardiovascular, endocrine, metabolic, reproductive and developmental effects. The present study comprises a probabilistic tiered risk assessment of nitrates for Austrian adults through the diet with the application of the Monte Carlo simulation method in alternative optimistic and pessimistic scenarios. Risk estimates are of concern regarding the upper exposures, which exceed the Acceptable Daily Intake (ADI) in almost all scenarios and population groups. Exposure is elevated when all dietary sources are considered and the ADI is exceeded by already the mean intake for vegetarians. Leafy vegetables are major contributors to the intake. Contribution of cured meat is very low. Estimates of the conversion of nitrates into nitrites were used to assess the combined exposure to both species. When the average intake of nitrates and nitrites is considered, the mean exposure to nitrites is lower or close to the ADI for individuals with average conversion capacity. However, upper tail combined intake can lead to a multifold exceedance of the ADI of nitrites for individuals with both high and average conversion capacity.

Electrolyte Intake and Major Food Sources of Sodium, Potassium, Calcium and Magnesium among a Population in Western Austria.

Dietary intake of sodium, potassium, calcium and magnesium has a strong impact on personal health. In order to understand possible correlations with regional occurrence of diseases and to develop new dietary strategies, it is necessary to evaluate food choices in defined geographic areas. The aim of this study was to analyze daily consumption and major food sources of electrolytes with an emphasis on dietary patterns. In this representative, cross-sectional study, daily foods of 463 adults were assessed with two nonconsecutive 24-h recalls. Our results show high sodium and low potassium consumption in all age groups in both men and women. Furthermore, more than half of investigated persons had low calcium, and 40% indicated low dietary magnesium intake. Only 1% of our study population reached the recommended values for all electrolytes, while 13% consumed adequate levels of three electrolytes. Moreover, 14% did not reach reference levels for any of the four minerals. A further comparison of dietary patterns and food preferences showed significant differences in major food groups including nonalcoholic drinks, fruits, vegetables, legumes, milk products, vegetable oil, bread and sweets. Our results are important for further evaluations of nutrition intake and the development of new dietary strategies.

Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity.

Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.

Risk assessment of nitrites for the Austrian adult population with probabilistic modelling of the dietary exposure.

Nitrites are present in the food chain as naturally occurring species or contaminants. Additionally, sodium and potassium nitrites are authorised food additives. Nitrites exert acute toxicity through methemoglobinemia or cardiovascular effects, chronic toxicity associated with endocrine, reproductive and developmental effects and have been classified as probable gastric carcinogens. Ingestion of food and water are the main sources of human exposure. This study comprises a tiered risk assessment of nitrites for the Austrian adult population, along with the identification of the food categories most contributing to their intake. The dietary exposure, based on Austrian occurrence and consumption data, was modelled with the Monte Carlo simulation method. In an additional scenario, data gaps were addressed with the usage of occurrence data published by the European Food Safety Authority and from the available literature to account for the exposure from all sources. Risk estimates regarding only the exposure to nitrite additives and to contaminated water indicate low level of concern. However, when exposure from all sources is considered, the estimated exposure is elevated and exceeds the Acceptable Daily Intake for high consumers. Mean exposure attributed to the use of nitrites as additives accounts for only a very small proportion of the total intake.

Visual stimulation with food pictures in the regulation of hunger hormones and nutrient deposition, a potential contributor to the obesity crisis.

Food cues affect hunger and nutritional choices. Omnipresent stimulation with palatable food contributes to the epidemics of obesity. The objective of the study was to investigate the impact of food cues on appetite-related hormones and to assess the functionality of the secreted hormones on macronutrient uptake in healthy subjects. Additionally, we aimed at verifying differences in the response of total and active ghrelin to stimulation with food pictures and to a meal followed by the stimulation. We were also interested in the identification of factors contributing to response to food cues. We recruited healthy, non-obese participants for two independent cross-over studies. During the first study, the subjects were presented random non-food pictures on the first day and pictures of foods on the second day of the study. Throughout the second study, following the picture session, the participants were additionally asked to drink a milkshake. Concentrations of blood glucose, triglycerides and hunger-related hormones were measured. The results showed that concentrations of several hormones measured in the blood are interdependent. In the case of ghrelin and gastric inhibitory peptide (GIP) as well as ghrelin and glucagon-like peptide-1 (GLP-1), this co-occurrence relies on the visual cues. Regulation of total ghrelin concentration following food stimulation is highly individual and responders showed upregulated total ghrelin, while the concentration of active ghrelin decreases following a meal. Protein content and colour intensity of food pictures reversely correlated with participants' rating of the pictures. We conclude that observation of food pictures influences the concentration of several appetite-related hormones. The close link of visual clues to physiological responses is likely of clinical relevance. Additionally, the protein content of displayed foods and green colour intensity in pictures may serve as a predictor of subjective attractiveness of the presented meal.

Real-Time Detection of Single Auger Recombination Events in a Self-Assembled Quantum Dot.

Auger recombination is a nonradiative process, where the recombination energy of an electron-hole pair is transferred to a third charge carrier. It is a common effect in colloidal quantum dots that quenches the radiative emission with an Auger recombination time below nanoseconds. In self-assembled QDs, the Auger recombination has been observed with a much longer recombination time on the order of microseconds. Here, we use two-color laser excitation on the exciton and trion transition in resonance fluorescence on a single self-assembled quantum dot to monitor in real-time single quantum events of the Auger process. Full counting statistics on the random telegraph signal give access to the cumulants and demonstrate the tunability of the Fano factor from a Poissonian to a sub-Poissonian distribution by Auger-mediated electron emission from the dot. Therefore, the Auger process can be used to tune optically the charge carrier occupation of the dot by the incident laser intensity, independently from the electron tunneling from the reservoir by the gate voltage. Our findings are not only highly relevant for the understanding of the Auger process but also demonstrate the perspective of the Auger effect for controlling precisely the charge state in a quantum system by optical means.