This study aims to assess clinical characteristics in FD with spleen deficiency syndrome and metabolic perturbations involved in FD progress. We combined metabolic biomarkers and clinical features into a better prediction for FD with Spleen Deficiency syndrome.A total of 276 people were recruited, including 215 FD patients and 61 healthy control group (HC). The clinical characteristics and gastric emptying rate were compared between spleen deficiency-FD group and non-spleen deficiency-FD. The serum lipids metabonomics analysis was performed to determine the metabolic differences in spleen deficiency-FD group and HC.The symptoms of postprandial discomfort in Spleen Deficiency group were more severe (P < 0.05), and delayed gastric emptying was more pronounced (P < 0.05) vs. non-Spleen deficiency. Decreased motilin  0.982–0.997) was independent risk factor related to Spleen Deficiency group. We identified 15 metabolites for spleen deficiency group vs. HC, majority of those biomarkers belonged to the glycerophospholipid metabolic pathway. The combination of 15 metabolics could diagnose spleen deficiency-FD, with the AUC of 0.9943, 95% CI 0.9854–1.0000), and the combination of 15 metabolics and motilin could diagnose spleen deficiency-FD, with the AUC of 0.9615, 95% CI 0.9264–9967).This study provides supportive evidence that Spleen deficiency syndrome was associated with delayed gastric emptying and the glycerophospholipid metabolic pathway was perturbed in FD patients. The combination of metabolic biomarkers and clinical features provided us with new ideas for multidimensional diagnosis of FD.Trial registrationhttp://www.chictr.org.cn, no: ChiCTR-TRC-13003200. clinicaltrials.gov, no: NCT02762136The online version of this article (10.1186/s13020-019-0238-9) contains supplementary material, which is available to authorized users. Functional dyspepsia (FD) is a chronic disorder of the gastroduodenal region, which is one of the most prevalent functional gastrointestinal disorders. FD affects up to 15–20% of the worldwide population , especiaWe conducted our study from two aspects: first, we profiled the clinical characteristics in order to investigate the clinical features related to FD with spleen deficiency syndrome; second, we performed a serum metabonomics analysis using ultra performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS), investigating slight metabolic changes in the progress of FD and identifying specific biomarkers for FD with spleen deficiency syndrome. The combination of clinical features and metabolic biomarkers might facilitate clinical diagnosis for FD with spleen deficiency syndrome.The Additional file This study was approved by the by the Ethical Review Committee of Xiyuan Hospital of China Academy of Chinese Medical Sciences 2013XL013-2) and conducted in accordance with the principles of the Declaration of Helsinki. All enrolled patients were confirmed to have signed informed consent after enrollment. Patients were recruited from the outpatients of three hospitals  in China between July 2013 and July 2016. Participants were recruited through advertising media, direct calls, and health promotion events. Advertisements were placed on notice boards and homepages of the hospitals and local newspapers. Patients were required to provide their medical history, receive a physical examination and laboratory safety tests, and undergo a gastroscopy. Only the patients who fulfilled the Rome III criteria  and 100 g of milk powder  with 1100 mL of warm water, and the entire test meal volume was 1120 mL. This esculent liquid contained 26.5 g of protein, 29.1 g of fat and 75.5 g of carbohydrate . This mixed liquid meal consisted of 13% proteins, 48% carbohydrates and 39% lipids and was used at a caloric density of 0.75 kcal/mL. The liquid test meal was administered orally as tolerated at a fixed rate of 50 mL/min, and all participants were allowed to sit on a chair for approximately 5 min while drinking this test meal. The subjects were scanned in a half-sitting position, sitting on an examining chair and leaning back at an angle of approximately 120°. Subjects were instructed not to move and to hold their breath at the end of expiration to permit diaphragmatic rising and restoration of the gastric configuration.The proximal stomach and distal stomach volumes of each subject were scanned at six time points, which were fasting, maximum satiety, and 30 min, 60 min, 90 min, and 120 min after beginning ingestion.The GE rate was calculated as follows: (Amax − A)/Amax × 100 (%), where Amax is the volume of maximum satiety after the meal in the proximal stomach or distal stomach, and A is the volume at other time points after the meal in the proximal stomach or distal stomach.g for 15 min at 4° C to separate the supernatant, and the supernatant was centrifuged at 3500g for 8 min at 4° C, and the supernatant obtained at the end served as the plasma sample. The plasma samples were collected and stored at − 80 °C for the metabonomic analysis.Before the samples were collected, all participants were fasted for 12 h but were allowed to drink water to avoid the effects of food on the final outcome. Blood from both the healthy control group (n = 61) and spleen deficiency group (n = 90)were sampled via the antecubital vein, from which 5 mL was collected into heparinized test tubes and centrifuged at 3000μL of plasma, 450 L of methanol was added, vortexed for 30 s and allowed to stand for 10 min. The mixture was centrifuged at 12,000 rpm, 4 °C for 10 min, and the supernatant was injected for UPLC-Q-TOF/MS analysis. In addition, 400 μL of the supernatant was dried with nitrogen, reconstituted in 75 μL of ultrapure water, vortexed for 30 s, allowed to stand for 10 min, and centrifuged at 12,000 rpm at 4 °C for 10 min, and 10 μL of the supernatant was placed in a vial containing an inner liner for later use.Plasma samples stored at − 80 °C were thawed at room temperature. To 150 −1.WATERS ACQUITY UPLC I-CLASS Liquid System, Column HSS T3 Column , column temperature 40 °C, elution system 0.1% formic acid water (a): 0.1% formic acid acetonitrile (B), gradient elution program: 0 ~ 1 min, 1%B ~ 1%B; 1 ~ 2 min, 1B%–45%B; 2 ~ 5 min, 45B ~ 70%B; 5 ~ 9 min, 70%B ~ 90%B; 9 ~ 12 min, 90%B ~ 99%B; 12 ~ 15 min, 99%B ~ 99%B; 15–15.1 min, 99%B ~ 1%B; 15.1 ~ 17 min, 1%B ~ 1%B. The sample chamber temperature was 4 °C, the injection volume was 2.0 μL, and the flow rate was 0.30 mL minSYNAPT G2-SI Q/TOF tandem quadrupole time-of-flight mass spectrometry system used ESI positive and negative ion mode detection. The accurate mass was determined with leucine-enkephalin. The scanning range was 50–1200 Da. The data acquisition mode was 3D data acquisition in continuum mode. Low energy channel collision voltage: 6 V, high energy channel collision voltage: 10–40 V. In positive ion mode, capillary (kV): 3.0, sampling cone: 30 V, source offset: 80, source temperature: 100 °C, desolvation temperature: 400 °C, cone gas: 40 (L/h), desolvation gas flow (L/h): 800, nebulizer (bar): 7.0. In negative ion mode, capillary (kV): 2.2, other parameters are the same as the parameters in positive ion mode.https://www.metaboanalyst.ca/) was utilized to describe the involved metabolic pathways of the biomarkers.UPLC-Q-TOF/MS raw data were analyzed using Progenesis QI software. The software performed baseline calibration, peak alignment, peak identification, feature peak extraction, and normalization operations. The raw data were converted into a three-dimensional matrix containing tR-m/z ion pairs, sample names, and peak intensities. The acquired data were imported into multivariate statistical software EZinfo 2.0 for multivariate data analysis . Metabolite with variable importance plot (VIP) > 1 was screened as a potential biomarker. An independent sample -test was later performed using SPSS 17.0 software to determine the statistical significance of metabolites. By comparison with authentic standards, MS/MS fragmentation, and HMDB, the significantly varied biomarkers were identified. Next, the biomarkers were optimized using the receiver operating characteristic (ROC) curve by SPSS. Finally, MetPA  and early satiety  symptoms compared with the non-spleen deficiency group  and 120 min (p < 0.01); moreover, the gastric emptying rate of the distal stomach (GERDG) in the spleen deficiency group decreased at 120 min (p < 0.01).The results indicated that gastric emptying occurred more frequently in FD with spleen deficiency  in the spleen deficiency group significantly decreased at 90 min , gastrin , ghrelin , motilin  were significantly reduced and the level of cholecystokinin  was increased in the spleen deficiency group. Further studies showed that compared with the non-spleen deficiency group, the level of pepsinogen , gastrin , motilin  were significantly reduced and the level of cholecystokinin  was increased in the spleen deficiency group. No significant difference was found between the spleen deficiency-FD group and the non-spleen deficiency-FD group regarding the level of ghrelin (p = 0.065 > 0.05)  was performed Fig. . Figure The ROC presentations for spleen deficiency-FD vs. HC appear in Table Metabonomics data were integrated with clinical data to improve the prediction for spleen deficiency in FD. Results of multivariate logistic regression analyses are shown in Table Large-scale studies reported a 10–30% prevalence of FD worldwide . The patIn the present study, a total of 215 FD patients with or without spleen deficiency syndrome and 61 healthy people were enrolled. According to our data, the spleen deficiency group had more severe postprandial fullness and early satiety symptoms, and delayed gastric emptying occurred more often in the spleen deficiency group than in the non-spleen deficiency group. The rate of proximal gastric emptying at 90 and 120 min and the distal gastric emptying rate at 120 min were significantly lower than those of the non-spleen deficiency group (P < 0.05).Because delayed gastric emptying is considered a pathophysiological mechanism of functional dyspepsia , some exRecently, evidence has accumulated that delayed gastric emptying rate is closely associated with altered gastrointestinal hormones , 23 in tMost studies have shown that motilin and ghrelin accelerate gastric emptying and cholecystokinin slows gastric emptying. In our study, multivariate logistic regression showed that only decreased motilin was an independent risk factor related to spleen deficiency in patients with FD. Our findings confirm and extend the connection between spleen deficiency syndrome and a delayed gastric emptying rate.Metabolic profiling revealed significant metabolic differences between the spleen deficiency-FD group and the healthy control group. The OPLS-DA score plots of all samples displayed clear separations for the spleen deficiency-FD group vs. HC at the three centers, suggesting that the spleen deficiency-FD group had a common series of metabolic changes at all three centers. A total of 15 overlapping potential biomarkers were identified through Venn plots. Further research showed that most of them were found to be PC (phosphatidylcholine), PE (phosphatidylethanolamine), PA (phosphatidic acid), and PS (phosphatidylserine).Metabolic pathways were determined for potential biomarkers using the MetPA website, and the majority of these 15 metabolites biomarkers belonged to the glycerophospholipid metabolic pathway. The AUC of 15 biomarkers for spleen deficiency-FD vs. HC ranged from 0.6790 to 0.9926, and the combination of 15 metabolics strengthened the prediction capacity for spleen deficiency-FD with an AUC of 0.9943, suggesting that these 15 metabolites as biomarkers were robust. Although there was no increase in the prediction capacity for spleen deficiency-FD, the combination of metabolic biomarkers and motilin provided us with new ideas for multidimensional diagnosis of FD.Regarding the results of lipid metabolism, our findings are consistent with Wu Qiaofeng’S . In her The present study has several limitations, in which no external sample set was used for validation, and there were uncertain causal relationships between the biomarkers and the occurrence of spleen deficiency syndrome. Although the combination of metabonomics data and clinical features did not show a good predictive function, to the best of our knowledge, this report describes the first human study investigating not only the clinical features but also metabolic changes of spleen deficiency-FD using an UPLC-Q-TOF-MS/MS based metabonomics approach. Future studies will focus on the combination of clinic characteristics and metabolic features, leading to a more complete understanding of FD with spleen deficiency syndrome. Additional research directed towards biological interpretation are expected regarding which biomarkers are related to the severity of clinical symptoms in FD and which metabolite levels are affected by drug intervention.In conclusion, the clinical analysis revealed that decreased motilin was an independent risk factor in spleen deficiency-FD; furthermore, the serum metabonomics analysis yielded novel insights into small-molecule metabolic alterations in its progression, with 15 metabolites biomarkers continuously varying across the progression of FD, which could be applied as an additional diagnostic tool for detecting delayed gastric emptying of FD in practical clinic cases.This report describes the first human study investigating not only the clinical features but also metabolic changes of spleen deficiency-FD using an UPLC-Q-TOF-MS/MS based metabonomics approach, furthermore, this study provides supportive evidence that Spleen deficiency syndrome was associated with delayed gastric emptying and the glycerophospholipid metabolic pathway was perturbed in FD patients. The combination of metabolic biomarkers and clinical features provided us with new ideas for multidimensional diagnosis of FD.Additional file 1. Minimum Standards of Reporting Checklist.Additional file 2. Additional data.


A survey of biogenic amine (BA) profiles in opened wine bottles has been established to monitor the level of biogenic amines (BAs) in opened bottles against time and other conditions. Bottles of red and white wine were submitted to different temperatures, stopper type , and use of vacuum devices. A total of six wines made from a variety of grapes were obtained from vineyards from regions across Poland. Dispersive liquid-liquid microextraction-gas chromatography-mass spectrometry (DLLME-GC-MS) procedure for BAs determination was validated and applied for wine sample analysis. The total content of BAs from the set of immediately opened wine samples ranged from 442 to 929 µg/L for white wines, and 669 to 2244 µg/L for red wines. The most abundant BAs in the analysed wines were histamine and putrescine. Considering the commercial availability of the analysed wines, there was no relationship between the presence of BAs in a given wine and their availability on the market. However, it was observed and confirmed by chemometric analysis that the different storage conditions employed in this experiment affect not only the BAs profile, but also the pH. Biogenic amines (BAs) are compounds which are naturally synthesized in microorganisms, animals, and plants and may be generally considered as a food hazard. Although there is not a threshold for these biomolecules in European legislation (except for histamine in fish and its products), many scientists are currently researching this area. BAs can influence the important physiological processes/functions in an organism, but the amount required is limited, thus, excess concentrations taken via food ingestion are reported to cause toxicological effects to the organisms . BAs alsBiogenic amines are mainly produced by microbial decarboxylation of some amino acids, but also volatile amines can be formed by amination and transamination of aldehydes and ketones . As BAs Alcohol is an inhibitor of monomine oxidase, thus the monitoring and control of BAs in fermented beverages, including wine, is very important for the health of consumers. In fact, the content of BAs in wine could also impact on commercial import and export procedures. Three possible origins of BAs in wine are reported . BAs canOther reaction-influencing factors include pH, temperature, oxygen content, and salt and sugar content. For example, it has been reported that decarboxylase activity of amino acids is stronger in an acidic environment . PreviouIt is a popular problem that wine consumers many often drink wine several days after opening the wine bottle and sometimes the wine is kept at room temperature. Moreover, in the restaurant sector, wine is frequently stored in opened bottles. It is therefore important to monitor the level of BAs in opened bottles against time and other conditions. Therefore, this work is focused on evaluation of the profile of selected biogenic amines  in opened bottles of red and white wine exposed to different temperatures, types of stopper , and the use of vacuum devices. Even though information on BAs is currently not included in wine composition databases, information on their existence, distribution, concentration, and knowledge of existing relationships between BAs and other parameters is crucial and useful for the food industry, health professionals, and consumers .The profiling of biogenic amine occurrence and their levels was evaluated in opened wine bottles over time. Wine bottles were stored under different conditions in terms of temperature and type of stopper. The monitoring of BA occurrence and levels was performed in just-opened bottles, seven days after opening and thirty days after opening. Information on the concentration of BAs determined in the different wine samples by GC-MS technique are summarised in In fact, red wines coming from Regent grapes have similar total BA content: 669 and 671 µg/L , while in those obtained from Frontenac grapes were about three times higher (2244 µg/L). White wines obtained from the same type of grapes (Solaris) had different total concentration of BAs. The most abundant BAs in the six analysed wines were histamine and putrescine, as expected . HoweverConsidering white wine samples, there was no similarity in its characterisation of BAs profile. Considering the commercial availability of the analysed wines, there was no relationship between the presence of BAs in a given wine and their availability on the market.Considering different storage conditions of opened wine bottles, slight changes were observed in the profile of BAs and pH .In the all red wines, the total amount of BAs showed a significant downward trend with time when storage was at room temperature. When samples were maintained at 4 °C, the total BA content also decreased, however, changes in concentration were small. The type of stopper impacted the concentration of all BAs. Those samples kept in cork-stoppered bottles showed a significant downward trend with time, while those kept under vacuum conditions did not show significant changes in the total concentrations of BAs. Samples kept in a screw-cap bottle also showed a downward trend with time, but these changes were not as big as for cork-stoppered samples. In all red wines, the same trend in changes of concentration in appropriate BAs was observed. These trends were as follows:2-PE increased with time, but greater differences were visible between 7 and 30 days after opening, especially when wines were kept at room temperature;putrescine, tryptamine, and histamine decreased with time in all conditions, but these changes were more significant for histamine and putrescine when samples were maintained at room temperature;cadaverine content slightly decreased from the opening day to the seventh day, and then increased significantly from the seventh to the tenth day in all cases.The changes in concentration of BAs maintained at 4 °C were so low that they do not affect the total concentrations. Like red wines, white wines show a clear and significant, but different trend in the total content of BAs. While higher concentrations of BAs were noted in red wines for just-opened bottles, in white wines, higher total concentrations of BAs were observed in samples seven days after opening under all storage conditions. The content of putrescine and cadaverine slightly increased over time, but these changes were not significant for refrigerated samples or those kept under vacuum. A significant increase in histamine concentrations from the opening day to seventh day was observed, while from seventh day to thirtieth day the concentration decreased significantly. The same trend was observed for 2-phenylethylamine and tyramine  compared with red wines . TryptamDespite the fact that changes in concentration levels of BAs in white wine samples kept at 4 °C were smaller than those kept at room temperature, the total concentration of BAs was higher in these samples. A lower concentration of BAs was found in samples maintained at room temperature under vacuum.In general, the evolution of BAs in the six analysed wines shows a clear common trend. It should be pointed out that the concentration of only one compound, namely putrescine, decreased in all wine samples, red or white. Other BAs concentrations differed between white and red wines . For exaMoreover, it was observed that the different storage conditions employed in this experiment affect not only the BAs profile, but also the pH. In red wines, the pH was higher in wines kept at room temperature than those kept at 4 °C. The pH differed with the type of stopper used at different temperatures, pH was higher when a screw cap was used than in the case of a cork stopper, but lower than pH of the samples under vacuum. In white wines, different stoppers did not show a clear common trend. Hierarchical and non-hierarchical cluster analyses were applied to a data set with different wines checked for the presence of six specific organic compounds. The major goal of the study was to reveal latent relationships between wine brands, the conditions for their storage, and their amine content. Altogether six wine brands were studied  for levels of 2-PE, PUT, CAD, TRYP, TYR, HIS, and, additionally, time of opening the sample bottles  and type of stopper . Temperature of storage (room temperature and 4 °C) were checked in the experimentation. This is a typical multivariate problem and, therefore, the chemical data were treated and interpreted using multivariate analysis.Hierarchical and non-hierarchical cluster analyses for all six wine brands was performed, each input set having set dimensions [18 × 6]. The different conditions applied to a specific brand  were involved as objects and the concentrations of the six amines as variables. It is important to note that in some cases not all six variables were used since some did not show any change with the variation of the experimental conditions and were actually not detected in the brand. This decreased the number of the variables used. Clustering of chemical compounds  is presented in The example of clustering is presented in It could be concluded that for all wines kept at 4 °C (refrigerator) the data structure is determined by two conditional factors: the one related to the correlation between 2-PE and CAD (“cadaverine factor”) and the other related to the correlation between PUT, HIS, and TRYP (“histamine factor”). TYR is not a significant variable. All these are red wines from REGENT and Frontenac grapes.For wines kept at room temperature  the first conditional factor related to wine quality is again “cadaverine factor” but correlated to putrescine; the second is “histamine” factor being correlated strongly to tryptamine. TYR and 2-PE are not significant variables. The non-hierarchical clustering confirmed entirely the non-supervised hierarchical procedure. In order to understand the role of the BAs as indicators for wine quality for different conditions of production and storage, the same multivariate statistical analysis was applied to cluster the objects of the study.An example of a hierarchical dendrogram for a wine sample (Wine A) is presented in The results of hierarchical clustering could be summarized as follows .The hierarchical classification is almost the same for each of the brands studied. Cluster 1 includes all samples of bottles opened immediately, the second—after 7 days of storage and the third—after 30 days of storage. It shows convincingly that the role of storage factor is substantial. It is important to note that samples C and F (for 7 and 30 days of storage) belong to Cluster 1 along with the samples after immediate opening. This underlines the significance of the type of stopper as these samples are stoppered by vacuum pump. Once again, the complete similarity of the brands D, E, and F is confirmed. In Wine brands D–F have absolutely one and the same classification pattern, cluster 1: pattern 1 (just-opened bottles) indicated by high concentrations of CAD and 2-PE; pattern 2—(7 days of storage after opening) high levels of HIS, TRYP, and PUT; and pattern 3 (30 days of storage) lowest concentrations of all amines. Obviously, the wines lose their amine content after opening. The case with the other three wine brands is very similar. Wines B and C have very similar clustering with highest levels of TRYP and HIS for time after opening and lowest PUT and CAD. For the period after opening, it was found that the concentrations of PUT and CAD increase and those of TRYP and HIS decrease. The impact of the other two chemical compounds (2-PE and TYR) is not significant. Finally, wine A shows slightly different patterns as all six variables are significant. The just-opened cluster is characterized by highest levels of HIS; the 7 days after opening pattern by highest levels of TRYP, TYR, 2-PE, and HIS, and the last cluster (30 days after opening) by high PUT levels. Chloroform, pyridine, isobutyl chloroformate (IBCF), and biogenic amine standards  and internal standard (hexylamine) were obtained from Sigma Aldrich . Methanol , 32% hydrochloric acid, and sodium hydroxide (purity 98–100.5%) were obtained from Fluka . Other chemicals were of analytical grade. The solution of alkaline methanol was prepared by dissolving KOH in methanol until saturation. Ultrapure water was obtained from a Milli–Q water purification system . The amine standard solutions (1.0 mg/mL) were prepared individually by dissolving the pure compounds in deionized water. Concentrated solutions of amine standards were prepared by diluting the standard solution with water. The solutions were stored at 4 °C in silanized screw-capped vials with solid PTFE-lined caps .v/v) ethanol and pH 3.09; commercially available white wine comprising with 100% Solaris grapes from Kuyavian-Pomeranian region (Poland), containing 17% (v/v) ethanol and pH 3.43; commercial white wine comprising with 100% Bianca grapes from Kuyavian-Pomeranian region (Poland), containing 12% (v/v) ethanol and pH 3.25; commercial red wine elaborated with 100% Regent grapes from Kuyavian-Pomeranian region (Poland), containing 13.5% (v/v) ethanol and pH 4.02; non-commercial red wine elaborated with 100% Regent grapes from Masovian region (Poland), containing 12% (v/v) ethanol and pH 3.5; non-commercial red wine comprising with 100% Regent grapes from Masovian region (Poland), containing 12% (v/v) ethanol and pH 3.5; non-commercial red wine comprising with 100% Frontenac grapes from Masovian region (Poland), containing 13% (v/v) ethanol and pH 3.37. A total of 6 samples made from different varieties of grapes were obtained from vineyards in different regions of Poland. The wine samples were considered as follows: non-commercially available white wine comprising with 100% Solaris grapes from West Pomeranian region (Poland), containing 12.9%  or refrigerated temperature (4 °C), while three strategies were applied to stoppering the bottles: a stopper cork, a stopper screw cap, and a stopper with a vacuum pump that extracts the air from the bottle (Vacu Vin). The samples were coded as A (Room temperature and cork stopper), B (Room temperature and screw cap), C (Room temperature and vacuum), D (refrigeration temperature and cork stopper), E (refrigeration temperature and screw cap), and F (refrigeration temperature and vacuum). An aliquot of 50 mL was taken from each bottle 0, 7, and 30 days after it was opened, and immediately frozen. Thirty days were set as the maximum reasonable time for an opened bottle to be consumed since many people store the opened bottles of wine for this extended time. The analysis of BAs from each sample was carried out in duplicate. v/v) and IBCF  was rapidly injected into the sample tube. After 15 min, 400 μL of chloroform (extractive solvent) was added and shaken by hand (1 min). 150 μL of the bottom layer was taken for further analysis performed by GC-MS. The procedure reported by Płotka-Wasylka  was applA gas chromatograph 7890A  equipped with an electronically controlled split/splitless injection port was interfaced to an inert mass selective detector  with electron impact ionization chamber. GC separation was performed on ZB-5MS capillary column  . The injection was made in splitless mode (injection pressure 32 psi) at 230 °C. Helium was the carrier gas with a constant pressure of 30 psi. The oven temperature program was as follows: 50 °C held for 1min, ramped to 280 °C at 15 °C/min and held for 9 min (280 °C). Total run time was 25.3 min. The MS transfer line temperature was held at 280 °C. Mass spectrometric parameters were set as follows: electron impact ionization with 70 eV energy; ion source temperature, 250 °C. The MS system was routinely set in selective ion monitoring mode and each analyte was quantified based on peak area using one target and one or more qualifier ion(s) . All the2) ranging from 0.9968 to 0.9989. The recovery was determined by comparing unspiked wine samples to spiked for two concentration levels . The average recovery values ranged from 76% to 99% as can be seen in The method linearity was determined by a regression analysis of the relative area (ratio between peak area of BAs to the peak area of the IS) versus the amine concentration. Thus, ten aqueous solutions containing all analytes with concentrations ranging from 0.05 to 1.0 mg/L and 1.0 to 10.0 mg/L were submitted to the whole analytical procedure. The results obtained showed that linearity was excellent for all the compounds with correlation coefficients  is one of the most frequently applied chemometric methods for multivariate data interpretation . HierarcIt is common for consumers to drink wine several days after opening the bottle and having sometimes stored it at room temperature. Moreover, in the restaurant sector, wine is also often kept in opened bottles, thus it is important to monitor the levels of BAs in wine stored in opened bottles under different conditions. This work evaluates the profile of selected BAs in opened bottles of wine kept in different storage conditions (six samples). From the data obtained in this study, the following conclusions could be reached:slight changes were observed in the profiles of BAs and pH;the type of stopper impacted the concentration of all BAs;all red wines displayed the same trend in changes of concentration of appropriate BAs;white wine showed a clear and significant trend in the total content of BAs, however, this trend differed depending on the type of BAs;the concentration of only one compound, namely putrescine, decreased in all wine samples over time, no matter if it was red or white wine;chemometric analysis confirmed that the samples were grouped according to their storage time and the storage conditions.Generally, total concentrations of BAs in red wines are higher than in white wines. This fact is due to the malolactic fermentation that takes place in all red wines and just in some white wines, converting malic acid into lactic acid and increasing the medium pH. This reaction is performed by lactic acid bacteria, which are the main producers of BAs and, in addition, their decarboxylase enzymes improve their activity with a higher pH. In addition, the obtained results suggest that the concentrations of BAs in opened wine bottles suffered slight changes during storage. Further analysis of chemical stability together with microbiology research is therefore recommended to determine which factors significantly affect the evolution of BAs during storage. In addition, it is recommended to analyse more samples to confirm the results obtained here.


For each gas molecules, various adsorption positions were considered. The most stable adsorption depended on position, adsorption energy, charge transfer, and work function. SO2 gas molecules had the best adsorption energy, the shortest distance for BAs surface in the atmospheric gas molecule, and a certain amount of charge transfer. The calculation of work function was important for exploring the possibilities of adjusting the electronic and optical properties. Our results presented BAs materials can be the potential gas sensor of SO2 with high sensitivity and selectivity.Different atmospheric gas molecules (e.g., N Cheng et al. [2, NO, and NO2 due to the existence of the desorption process. Kamaraj and Venkatesan [BAs  is composed of groups III and V elements. The groups of III–V elements have excellent properties, such as excellent photoelectric properties, mechanical properties, and large band gap . The prog et al.  showed tnkatesan  studied 2, O2, N2, H2O, NO, NO2, NH3, CO, and SO2) on BAs based on first principle calculations. Our work demonstrated the apparent adsorption behavior, moderate charge transfers, and unique transmission characteristics of SO2 adsorption on BAs. The results suggested that monolayer BAs possessed great potential for SO2 sensing application.In this work, we firstly investigated the gas sensing properties to fully exploit the possibilities of BAs as gas sensors by density functional theory (DFT) calculations. We predicted the adsorption properties of atmospheric gases  of adsorbed systems, which was defined as:To evaluate the interaction between gas molecules and adsorption sheet surface, we calculated the adsorption energy , the top of an arsenic atom (As), and the center of a hexagonal B-As (center), as indicated in Fig. First of all, the geometric structure of pristine BAs monolayer had been optimized, and as shown in Fig. Meanwhile, we had analyzed the adsorption energy, the charge transfer, and the distance between the molecules and BAs surface. The final result was as shown in Table N2adsorption: Adsorption of N2 gas molecule on BAs was studied for three configurations of N2/BAs, viz. top side of the B atom, top side of As atom, and the center of a hexagonal ring above the BAs surface, and the nearest distance was 3.764 Å, 3.549 Å, and 3.65 Å and corresponding adsorption energy was − 0.24 eV, − 0.27 eV, and − 0.24 eV, respectively. The center had the best adsorption energy and the most stable structure. The adsorption energy of N2BAs was − 0.24 eV, the charge transfer from BAs to N2 gas molecule was 0.014e, and the distance of the N2-BAs was 3.65 Å. Fig. 2 gas molecule had four peaks, which had a certain influence on BAs, mainly from − 5 to 0 eV, and had great contributions to the DOS. Overall, the effect of N2 gas molecule adsorption on BAs was poor.O2adsorption: O2 gas molecule tended to adsorb on the central point. The adsorption energy of O2/BAs was − 0.35 eV, and the distance of the O2-BAs was 2.90 Å. The total band structure and DOS for O2/BAs were plotted in Fig. 2 gas molecule had a peak at − 1 to 0 eV and had an effect on the density of states above the Fermi level. The population analysis for Mulliken charge transfer showed that − 0.172e was transferred from BAs surface to the O2 gas molecule, suggesting that O2 gas molecule acted as an acceptor. In general, the O2 gas molecule adsorption on BAs was better than N2.CO2adsorption: CO2 gas molecule tended to adsorb on the top of As atom. The adsorption energy of CO2/BAs was − 0.28 eV, the charge transfer from BAs to CO2 gas molecule was − 0.018e, and the distance of the CO2-BAs was 3.55 Å. As shown in Fig. 2 gas molecule by BAs. The results showed that the adsorption effect and sensitivity of BAs to CO2 gas molecule were general.H2O adsorption: H2O gas molecule tended to adsorb on the top of As atom. The adsorption energy of H2O/BAs was − 0.38 eV, the charge transfer from BAs to H2O gas molecule was − 0.03e, and the distance of the H2O-BAs was 3.63 Å. As shown in Fig. 2O gas molecule adsorption on BAs was ignored.CO adsorption: CO gas molecule tended to adsorb on the top of As atom. The adsorption energy of CO/BAs was − 0.27 eV, the charge transfer from BAs to CO gas molecule was − 0.024e, and the distance of the CO-BAs was 3.50 Å. The total density of states (DOS) and band structure for BAs-CO were plotted in Fig. NO adsorption: NO gas molecule tended to adsorb on the top of B atom. The adsorption energy of NO/BAs was − 0.18 eV, the charge transfer was − 0.01e from NO gas molecule to BAs, and the distance of the NO-BAs was 2.86 Å. There were a lot of lines upon the Fermi energy level. It found that the energy gap in the middle band reduced the band gap value. From the density diagram of states, there was an extra wave peak above the Fermi energy level, but there was little change under the Fermi energy level, relatively stable in Fig. NO2adsorption: NO2 gas molecule tended to adsorb on the top of As atom. The adsorption energy of NO2/BAs was − 0.43 eV, and the distance of the NO2-BAs was 2.47 Å. The interesting was that the zero point in the band crossed a straight line directly after the adsorption of NO2 gas molecule, which meant that the BAs, which is a semiconductor, was transformed into the gold attribute; band gap was 0 eV. There was no great change in the whole, and a peak was generated at about − 3 eV due to NO2 gas molecular adsorption. There was some obvious wave crest of the energy of − 7 eV and 2 eV, which had great contributions to the DOS. In general, the adsorption of NO2 by BAs was better than that of several molecules above.NH3adsorption: NH3 gas molecule tended to adsorb on the top of As atom. The adsorption energy of NH3/ BA was -0.34 eV, the charge transfer from NH3 gas molecule to BA was 0.007e, and the distance of the NH3-BA was 3.27 Å. There was no clear change in the energy band and the density of states, except that there was an obvious peak of adsorption of NH3 gas molecule below the Fermi level. The NH3 gas molecule had a little impact on BAs at − 8 to − 4 eV, forming a 15 eV peak. The adsorption effect and sensitivity of its BAs to NH3 gas molecule were general.SO2adsorption: SO2 gas molecule tended to adsorb on the central point, the adsorption energy of SO2/BAs was − 0.92 eV, and the population analysis for Mulliken charge transfer showed that − 0.179e charge was transferred from BAs surface to the SO2 gas molecule, suggesting that SO2 gas molecule acts as an acceptor. The distance of the SO2/BAs was 2.46 Å. Compared to other gas molecules, the SO2/BAs had the biggest adsorption energy, the second largest electron transfer, and the shortest distance of the SO2-BAs. As shown in Fig. 2 gas molecule, it could be seen from the density of states that there was one more wave peak at − 7.5 eV and certain transfer at the Fermi level. The adsorption of SO2 by BAs had the excellent effect.2/BAs and the electron local overlap between BAs and SO2 gas molecule. On this basis, we drew the conclusion that the adsorption of SO2 by BAs was physical adsorption. The calculation of WF shown in Fig. 3 gas molecules were donors in charge transfer, and their work function decreased; the work function was 4.80 eV and 4.68 eV, respectively. The work function of N2/BAs, CO2/BAs, and CO/BAs was the same as that of BAs. The work function of O2/BAs, NO2/BAs, and SO2/BAs was higher than BAs. Combined with the above adsorption energy, distance of gas molecules and BAs surface, charge transfer, and work function, we found that SO2 gas molecule was most suitable for BAs materials.Fig. 2, O2, CO2, H2O, CO, NO, NO2, NH3, and SO2 gas molecule, using density functional theory method. In the adsorption energy, SO2 > NO2 > H2O > O2 > NH3 > CO2 > CO > N2 > NO and SO2 < NO2 < NO<O2 < NH3 < CO < CO2 < H2O < N2 in the adsorption distance. NO2 has the largest Q and work function, maybe it could be detected by the proposed material because of good electrical response. SO2 gas molecule had the best adsorption energy, the shortest distance for gas molecule and BAs surface, and a certain amount of charge transfer. Combined with the above adsorption energy, distance of gas molecule and BAs surface, charge transfer, and work function, the current and the adsorption-induced current change of BAs exhibit strong anisotropic characteristics. Such sensitivity and selectivity to SO2 gas molecule adsorption make BAs a desirable candidate as a superior gas sensor.We have presented the structural and electronic properties of BAs with adsorbents N


Network meta-analysis (NMA) is increasingly recognized as a promising evidence synthesis method commonly allowing stronger conclusions on the comparative effectiveness of healthcare interventions than conventional pairwise meta-analysis . Its stra priori so as to improve transparency and perform a rigorous risk of bias assessment within and across studies as well as an evaluation of the quality of evidence. As Hui et al. are among the pioneers of applying NMA to the field of nutrition research, we draw on their article to highlight some methodological challenges that require specific attention when performing NMA.Nutrition research can substantially profit from the potential of NMA. However, it is crucial that authors meticulously plan, conduct, and report NMA , 6; in pSummary effects from NMA are usually presented in a league table including all comparisons: Hui et al.  identifiThe extent to which NMA allows valid indirect inference depends on the extent to which the fundamental assumption of NMA usually called the ‘transitivity’, assumption is likely to be plausible. Transitivity requires that the trials comparing different sets of interventions are appreciably comparable in characteristics (other than the interventions being compared) which may affect the outcome , 9. TranThey did, however, apply a number of approaches  to examine statistical incoherence . The cohAddressing publication bias in NMA is as difficult as in pairwise meta-analysis; thus, priority must be given to the exhaustive search for unpublished studies. Assessment of small-study effects is usually the first step in the formal investigation of reporting biases . Hui el http://cinema.ispm.ch/) framework, which is an improvement of a previously suggested approach [Hui and colleagues  also assapproach , can greapproach .In view of its potentials, there is a risk that NMA is applied in cases, where the scarcity of available data precludes the estimation of precise results and the evaluation of its assumptions. Specifically, in the absence of direct evidence for several comparisons transitivity and incoherence cannot be formally tested, although transitivity can always be evaluated clinically and epidemiologically. In that case, the resulting relative effects would possibly be estimated with large uncertainty and the relative rankings might be meaningless.In spite of these risks, we expect that high-quality NMAs combining the results of dietary intervention trials will become the new evidence synthesis norm also in nutrition research. While widely applied in many medical fields , its useBeyond this, NMA has recently been proposed also as a tool to plan the optimal design and the required sample size of new trials . Finally


In order to take advantage of the potential offered by the medium of virtual reality (VR), it will be essential to develop an understanding of how to maximize the desirable experience of “presence” in a virtual space (“being there”), and how to minimize the undesirable feeling of “cybersickness” (a constellation of discomfort symptoms experienced in VR). Although there have been frequent reports of a possible link between the observer’s sense of presence and the experience of bodily discomfort in VR, the amount of literature that discusses the nature of the relationship is limited. Recent research has underlined the possibility that these variables have shared causes, and that both factors may be manipulated with a single approach. This review paper summarizes the concepts of presence and cybersickness and highlights the strengths and gaps in our understanding about their relationship. We review studies that have measured the association between presence and cybersickness, and conclude that the balance of evidence favors a negative relationship between the two factors which is driven principally by sensory integration processes. We also discuss how system immersiveness might play a role in modulating both presence and cybersickness. However, we identify a serious absence of high-powered studies that aim to reveal the nature of this relationship. Based on this evidence we propose recommendations for future studies investigating presence, cybersickness, and other related factors. Unlocking the potential of VR will largely depend on our ability to understand, then to solve, these substantial and enduring hindrances. A large body of research has emerged from attempts to identify whether presence and CS are deterministically linked through a positive or negative association. However, these results are highly discordant, and no consensus currently exists regarding the nature of the relationship between CS and presence.Around 30 years ago, the process of simulating a user’s sensory environment gained the popular term “virtual reality”1 . Althoug1 . Fifty y1 . Their sThis review has three aims. In the first part of this article we describe in brief the concepts of presence and CS and outline techniques that are commonly used to measure both factors (Section “Introduction”). We intend this to provide the reader with relevant context for interpreting studies that are discussed later in the review. The concepts of CS and presence are discussed below , but in brief, these are complex phenomena with a multitude of individual differences  and external factors  thought to influence their occurrence. Each factor has been targeted using several measurement techniques, all of which vary with respect to how the measured variable is operationalized.The second part of this review highlights studies that have directly measured the link between presence and CS, which we identified through a scoping literature search (Section “Evidence of a Presence-Cybersickness Relationship”). Given the large and historic importance of understanding and improving the issues of presence and CS, numerous studies have measured both factors and have even identified relationships between them. However, while approaches to solving the problems of presence and CS in VR have been tackled separately in large numbers of recent research papers and reviews, evidence of a possible link between them has seen very little discussion, particularly in recent years. VR has developed rapidly since its first implementation in the 1960s, and as such, early reports on the link between presence and CS may not apply to the current state of VR.The third part of the review constitutes a broad overview of the associations between presence, CS, and other variables, since a large number of contradictory findings have been reported in the literature. These confounding factors emerge in part due to the rapid rise of VR, the multifactorial nature of both CS and presence, and the influence of other modulating factors such as sensory mismatch, display factors, and personal characteristics (Section “Associations with Other Variables”).In our final section, and throughout the article, we aim to provide a synthesis of the research, with a special focus on unifying the discrepant findings about the nature of the presence-CS association. Our conclusions can be summarized as follows. First, there is more compelling evidence in support of a negative association between CS and presence than alternative relationships. The experimental results indicating a positive correlation between the two factors may be attributed to the necessity for settings to be “immersive” before CS can emerge. Second, there is considerable evidence for the role of sensory mismatch in both presence and CS. We also discuss the likelihood that sensory mismatch modulates a variety of factors that have been empirically linked with presence and CS . The strength of our conclusion is tempered by a need for additional high-powered studies in future research.Our objective with this review is to provide an answer to the following question: What is the relationship between presence and CS in VR? Note that this review does not constitute a review of CS see  or of prcybernetic approach to VR; Physical presence, the sense of physical relocation of the observer  without feeling presence; similarly, the degree to which an individual is shut-off from the real world by a VR system (immersion) may not determine presence , behavioral measures , or measurements related to task performance in the virtual environment. multi-item scales include the “Presence Questionnaire”  on a four-point scale . Common practice with the SSQ is to generate a total sickness score as well as scores for each subscale of oculomotor discomfort, disorientation, and nausea. A shortened version of the SSQ , or task-performance based measures . Here we describe these approaches to measuring both factors, and discuss how the overlap between measurement approaches causes difficulty with interpreting the true relatedness of the factors.Physiological methods have been applied to the measurement of both presence and CS, which presents a significant potential problem in understanding how the two factors are related. Indices of autonomic nervous system activity offer reliable measures of the stress response, and this stress/alarm response is linked to both presence and CS. Physiological correlates of acute CS symptomatology  reflect the neuroendocrine stress response . EquallyFeeling present in a virtual space appears to enhance task performance. It has been shown that feeling presence is related to improved performance in the game of chess in VR , human iThe inverse correlation between CS and task performance is well-supported, with several studies showing that symptoms of sickness are linked to decreased task performance . UltimatUsing task performance to measure both CS and presence leads to some obvious problems in interpreting their relatedness. The evidence suggests that task performance is more indicative of CS than presence, although a conservative approach should be considered: Since task performance measures are likely to conflate multiple constructs, they are not ideal for use in isolation and should be used in conjunction with other metrics. Note that this caution applies equally to measures such as “enjoyment” as indices of presence or CS e.g., .There are a number of documented efforts to record presence and CS concurrently. Within this literature there is significant disagreement with respect to the strength and direction of the relationship. Here we outline a literature search of studies that report positive, negative, or null correlations between presence and CS, obtained using a structured literature search . We repovirtual reality), including terms related to CS , and terms related to presence . Initially, there were 478 results returned. Our general method followed The PRISMA Statement , which pAs demonstrated by We describe the studies that we identified with the literature search below. We also describe the original authors’ conclusion about the nature of the presence-CS association based on their findings, where this information was available. Following this summary, we outline our interpretation of how presence and CS are related based on a synthesis of the literature that we reviewed here (see Section “Conclusion: How Are Presence and Cybersickness Related?”).Reports of negative correlations between presence and CS were reported early by In a study carried out by A negative relationship between subjective ratings of presence and sickness severity was obtained by Stanney ; reported informally by Stanney (2002). A negative correlation of a similar magnitude was obtained during virtual town navigation by A brief report of a large-sample study by A study using a partial least-squares regression method identified an inverse association between presence and CS in a driving simulation task . The autN = 8), the authors took the evidence as support for the utility of a multisensory cueing approach to improve presence and reduce the severity of sickness in VR.A recent study from As described above, As described above, Some studies have reported null correlations between presence and CS. These reports are very sparse, possibly due to a bias for significant results e.g., , 2015. MIn an investigation by A recent study found a null correlation between presence and CS while participants observed an animated avatar in a virtual café using a head-mounted display . It is uThe balance of evidence favors the interpretation that presence and CS are negatively related. There are several reasons for this. First, the number of research studies that report the existence of a negative correlation outweighs the number of studies that report the opposite. Studies that describe an inverse relationship also tend to provide more compelling results: Where studies have observed a positive correlation between presence and CS, the study often fails to confirm this relationship in another section of the same study e.g., . In someAlthough a positive correlation between presence and CS has been anticipated or assumed by some researchers e.g., , it is lWhat mechanism causes this inverse association between CS and presence? It has been claimed that the sense of presence suppresses CS, since attention is directed away from intrusive factors such as sensory conflict e.g., . Alternaa priori power analysis was conducted, a desired power of 80%, which is on the low-end of “adequate”  are used to perform continuous updating about the estimated state of the world and of the body . TherefoThe understanding of how sensory mismatch contributes to CS and presence has historically been limited due to the challenge of directly manipulating or measuring sensory conflict in experimental settings . For insHowever, to our knowledge, there is little research on the disruption of presence when multimodal cues are in conflict. The most relevant literature in that context relates to vection, a strong correlate of presence . The eviIt has been theorized that CS in VR is produced as a result of mismatches in information across sensory streams, or conflicts between observed and expected sensory cues, particularly with respect to visual-vestibular cue conflict . The linReports show that visual display characteristics such as frame rate and field-of-view influence both presence and CS. Higher frame rates are associated with higher self-reported presence ratings due to the increased realism afforded by smooth motion . Low visd = 0.24) and spatial presence  increases presence (SUS) compared to conditions where participants remained relatively stationary , but that sickness scores (SSQ) are unaffected by the same manipulation . This suNarrative is often used to provide context and framing to a VR application, and there is evidence that the inclusion of narrative impacts both presence and CS. The influence of a “preamble” on presence has recently been established : When paThe effect of context on presence has been frequently studied with respect to the mediating effect of anxiety on presence. There is thought to be a complex, potentially bi-directional relationship between presence and anxiety, with both being associated with general sympathetic nervous system activity . Gorini There has been considerable discussion about the effects of participant sex on presence ratings. Some have theorized that the degree to which men and women can suspend disbelief may vary , along wResearch into CS has long discussed the possibility of sex differences with respect to rates of susceptibility, although findings have proven inconclusive. In the work of Some research has examined the influence of past experience with interactive games on factors such as presence and CS. When taken together, the evidence obtained from the review above begins to clarify the type of relationship that exists between presence and CS:•Approaches that reduce sensory mismatch show potential for reducing CS and increasing presence;•Both presence and CS are increased by the addition of stereoscopy, high field-of-view display conditions, and by enhancing the likelihood that a display will evoke vection;•Increasing factors such as intuitiveness of interaction and control of navigation lead to higher presence and lower CS;•Men and individuals with more gaming experience demonstrate lower CS and higher presence, although the partial effects of sex and gaming are not fully clear.The relationship between CS and presence can be understood if the associated variables described above are considered with respect to their effect on sensory mismatch. Immersiveness (sensory submersion) likely plays a key role here: Experimental manipulations that increase immersiveness tend to produce both CS and presence, because the compelling nature of stimuli in an immersive virtual space fosters a high perceptual weighting of cues to self-motion and spatial orientation, which enhances the impact of conflicts between expected and obtained sensory signals that are generated by the compelling stimulus . Put difOn the other hand, within immersive conditions, individuals who experience high presence tend to experience low levels of CS. This relationship may be a result of differences in individual sensitivity to sensory conflicts: Higher sensitivity will result in high CS and low presence, whereas low sensitivity to cue conflicts will lead to low levels of CS and a heightened sense of presence. Individual differences in sensitivity to sensory conflicts have been documented, and there is some limited evidence that these differences relate to CS and presence , 2006. TThere is a significant challenge involved in identifying the factors that might mediate the link between presence and CS. Primarily this difficulty arises from the substantial relationships between the associated factors identified above, such as sex and gameplay experience, or vection and field-of-view. In addition to these known relationships, a number of other understudied variables may have significant associations with both presence and CS. For instance, the sense of embodiment is known to form a core aspect of presence , but thereport feeling presence or CS may not determine their experience of either factor. This is an inherent issue in questionnaire studies; according to a meta-analysis, almost 50% of questionnaire studies documented effects of social desirability on their results (Questions remain with regard to what questionnaires of presence and CS are truly measuring. Studies have identified relationships between CS and spatial presence, but no relationship between CS and immersive tendencies, which correlates highly with spatial presence e.g., . This ra results . It is t results  or devel results .Literature supports the idea that presence and CS are inversely related, and that the relationship is likely to be mediated by factors including vection, navigation control, and display factors. These factors can be unified in terms of their effect on sensory mismatch, which appears to drive presence and CS in opposite directions. This presents the possibility that interventions targeted at increasing presence could reduce CS, and vice versa. While the results obtained across studies are often discordant, with many sources reporting a positive relationship between presence and CS, these outcomes may be related to the fact that immersive displays are likely to generate both a compelling sense of “being there,” as well as symptoms of physiological discomfort. Other noise sources that may contribute to variability in findings include problematic measurement techniques, or differences in the operational definition of the underlying factors among studies.a priori considerations of effect sizes, which we have compiled here where available. An additional factor that may reduce the variability in findings across future studies is the natural emergence of standardized VR head-mounted hardware. Note, however, that the findings of studies using lower-immersive systems such as projection screens will still prove valuable, as these will help to identify the impact of immersiveness and vergence-accommodation mismatch on CS and presence. One particular gap in our understanding revealed by the current review is how presence is affected when sensory mismatch is experimentally manipulated. Given the prospective modulatory role of sensory mismatch in the association between presence and CS, future studies will need to overcome the challenges in manipulating and assessing sensory mismatch in empirical research. Through a careful consideration of the literature critique provided here, we envisage that the next wave of studies on the presence-CS link will help to make major advances toward understanding this complex relationship.How can future experimentation best serve the advancement of our understanding of the presence-CS association? The issue of measurement validity must be a major focus of future studies, where the cross-validation of metrics should be undertaken in well-controlled paradigms. Improving the robustness of findings in this area may also require a careful consideration of factors that could play a role in response bias, such as social desirability. Although a limited number of high quality studies have collected large datasets related to human factors in VR, future experiments will need to combine these measures with a modeling approach that can help to interpret the structure of the relationship between these factors. Relatedly, there is a prevalent lack of statistical power in many of the studies reviewed here, and this limits the ability for the field to infer answers about variables that are so inherently noisy. Future studies will benefit from careful SW, SK, and MB-C designed the concept of the article and conducted revisions to the manuscript. SW and SK conducted the literature search. SW wrote the initial draft of the article.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Gordon Guyatt at McMaster University in Hamilton, Canada  in 1949, “research evidence” in 1967, and “evidence‐based recommendations”  emerge in a title from 1991. Also in 1991, the term  Guyatt, . The tim Guyatt, , while i Guyatt, . By then Guyatt, .Regardless of whether the Canadians, Americans, or British invented one of the “evidence‐based” permutations, the common denominator was a perceived need for more order among an overwhelming overload of information. An added concern, at least in U.K., was that a potential iceberg of unpublished data from clinical trials was being withheld from public scrutiny. This conspiracy theory prevails even today, with fingers pointing in all directions although predominantly towards the big pharma.Oslo, Norway, is quite distant from the centres named above, and the evidence‐based movement would likely have passed unnoticed for some time if not Dr. Andy Oxman had moved directly from McMaster University to Oslo in 1994 to begin his work at the National Institute of Public Health in Norway. Soon after his arrival, the institute started organizing workshops on how to practice evidence‐based health care, and even a Nordic newsletter on EBH was launched (ISSN 0809‐5272). The National Institute of Public Health building was adjacent to the Faculty of Dentistry in Oslo, where we at the time had struggled for a decade with statistical analyses of heterogeneous clinical data from real‐life dentistry. (We are still striving!) The background was that Professor Ivar A. Mjör at the Institute for Dental Materials (NIOM) wanted to analyze accumulated data from a practice‐based research network (PBRN) among Nordic dental clinicians. Much energy was spent on rationalizing and testing statistical analyses and correct interpretation of the accumulated short‐term data versus long‐term data among an ocean of potentially explanatory variables and a range of more or less surrogate clinical outcomes. Several complex statistical approaches were attempted and discarded, including factor analyses, cluster analyses, principal component analyses, and classification and regression tree (CART) analyses. We ended up trying to explain the associations in “real‐life dentistry” by using multiple classification analysis of variance (MCA), Cox regression of survival data, and principal component analyses. Judged by the current literature, we still do not know today which statistics to apply to explain what works and what not of restorative and therapeutic care in everyday real‐life dental practice. Multilevel multivariate regression seems to become the most promising tool. I do not believe that data generated in RCTs in controlled environments by expert clinicians on highly selected study participants can be generalized to the daily situations of the ordinary general dentistry practitioner.Centre for Evidence‐based Dentistry in Oxford, UK .Also in U.K. in 1995, Dr. Alan Lawrence and Dr. Derek Richards established a https://ebd.ada.org/en). Poor computer infrastructure, access, and skills are also no longer an excuse to not learn more about EB practice. The editorial ended with a perhaps naïve statement that “As the evidence‐based approach gains momentum, it is hoped that pertinent evidence can be generated through research. Perhaps someday there is enough group data to be particularized for individual‐centered health care in a meaningful manner.” However, even if we have better evidence today in many clinical areas about the effectiveness of interventions, the overwhelming focus is on the efficacy of a device, drug or biomaterial, and less on procedures and on the prevention of oral diseases. In sum, we still have wide gaps in our evidence basis for best management of the oral health of our patients.In the inaugural issue, I remarked that many stakeholders seemed to hesitate to start practicing EBD and offered some possible explanations Jokstad, . Today, Nevertheless, I am still adamant today as I was 20 years ago that “EBD is much more than RCT, and must always be regarded as an adjunct to, and not as a substitute for sound clinical judgement and patient preferences.” We need to be reminded that every patient encounter is a unique experience and requires an individualized approach. Moreover, we must recognize that knowledge is an educated interpretation of and not synonymous with information. As clinicians, we need to be able to present to our patients relevant evidence from science in combination with our clinical knowledge acquired through experience or education and strive for shared decision‐making. From this perspective of patient empowerment, I believe that EBD has contributed to improved oral health globally over the last two decades. I do hope that the patient empowerment will continue to improve further in the next 20 years. Happy anniversary, EBD!


Numerous published articles show that clinicians do not follow clinical practice guidelines (CPGs). However, a few studies explore what clinicians consider evidence and how they use different forms of evidence in their care decisions. Many of these existing studies occurred before the advent of smartphones and advanced Web-based information retrieval technologies. It is important to understand how these new technologies influence the ways clinicians use evidence in their clinical practice. Mindlines are a concept that explores how clinicians draw on different sources of information  to develop collectively reinforced, internalized tacit guidelines.The aim of this paper was to explore how evidence is integrated into mindline development and the everyday use of mindlines and evidence in care.We draw on ethnographic data collected by shadowing internal medicine teams at 2 teaching hospitals. Fieldnotes were tagged by evidence category, teaching and care, and role of the person referencing evidence. Counts of these tags were integrated with fieldnote vignettes and memos. The findings were verified with an advisory council and through member checks.CPGs represent just one of several sources of evidence used when making care decisions. Some forms of evidence were predominately invoked from mindlines, whereas other forms were read to supplement mindlines. The majority of scientific evidence was accessed on the Web, often through smartphones. How evidence was used varied by role. As team members gained experience, they increasingly incorporated evidence into their mindlines. Evidence was often blended together to arrive at shared understandings and approaches to patient care that included ways to filter evidence.This paper outlines one way through which the ethos of evidence-based medicine has been incorporated into the daily work of care. Here, multiple Web-based forms of evidence were mixed with other information. This is different from the way that is often articulated by health administrators and policy makers whereby clinical practice guideline adherence is equated with practicing evidence-based medicine. Clinical Practice Guidelines (CPGs) have become ubiquitous, they provide concrete practice recommendations for care providers and are often viewed as an integral component of evidence-based medicine -3. FigurGabbay and le May’s ethnographies ,13 exploThrough interviews, Timmermans and Angell  found thGabbay and le May’s mindlines research was nominated as 1 of 20 influential BMJ papers over the last 20 years . WieringThe studies of Gabbay and le May ,13 and TThis paper is based on an integrated knowledge translation project . HospitaHospital care in Internal Medicine represents a complex, dynamic, and fast-paced environment. Attendings, residents, and medical students rotate between specialties and hospitals. Rotations range from 1 to 6 weeks, leading to high turnover as teams of workers are constantly being formed and reformed. Internal Medicine at both hospitals is called the Clinical Teaching Unit (CTU) as it is actively involved in training residents and medical students.One of this paper’s authors, BL, shadowed care providers. Shadowing involved following and observing participants during their normal work and asking them, during lull periods, to interpret actions through informal interviews ,22. BL sAll CTU members approached for this study agreed to participate. In total, 35 CTU team members consented to be shadowed or interviewed for the project. Many more CTU team members who were incidentally encountered during shadowing were recorded in fieldnotes. Shadowing occurred in 4-hour blocks to observe work processes while maintaining fieldnote quality. Shadowing was supplemented by a small number of observations of formal teaching during an annual CTU junior resident orientation. Fieldnotes were transcribed into more complete computer-typed notes at the earliest possible opportunity and imported into NVivo . Analysis of data began during data collection. A key early insight was that CPGs were 1 of many evidence sources CTU members referenced during work. This became a focus of subsequent observations and fieldnotes. By reading fieldnotes, we created evidence categories: CPGs, peer-reviewed articles, UpToDate and Lexi-Interact, Google, Pocket Medicine, phone apps, and experience. References to evidence were also categorized by events (teaching or care) and role of person referencing evidence. See We read fieldnotes tagging passages by evidence type, event, and role. Each passage could be tagged multiple times if different sources of evidence were referenced by CTU team members in discussion. Fieldnotes were reread and tags were checked. Using the NVivo query function, we created 2 matrices that counted tags of (1) evidence by event and (2) within care, evidence by role. These matrices were exported into R (the R foundation)  for furtPreliminary findings were outlined and presented to the project’s advisory committee at regular intervals for feedback. Emergent findings were also discussed with informants as a form of “member check” . ResultsWe found that scientific evidence was used differently in teaching and care. Teal [senior resident] is teaching to a room of trainees. She begins by presenting a case where a pregnant woman has a fever, feels dizzy, falls over, and gets admitted to hospital. Over the next half hour, Teal[with input from the residents in the audience] writes out a strategy to initially manage, diagnose, and treat the patient for sepsis. One of the treatment strategies for sepsis is to give patients IV fluids. Teal tells the room that this patient got 2 liters of normal saline solution and asks the audience if that's a good amount to give or if they think the patient should get more or less. She continues, saying that “I want to challenge” the amount of fluids given to a septic patient. “We were all taught the Rivers Protocol.” Teal adds “The new approach is to give a certain amount of fluids and then reassess. We were all taught to keep on giving fluids but that is now changing because fluids given above a certain point may be associated with increased mortality.” Teal compares these recommendations to the UK sepsis guidelines for pregnant women and mentions that she couldn’t find any equivalent Canadian guidelines. She reminds the room of the mantra “healthy mommy is healthy baby” and that in these types of situations the focus should be on caring for the mother not the baby.1028:30-174Teal used this session to model evidence use that predominately draws from peer-reviewed articles and CPGs. Even though the trainees in the audience graduated from medical school within 3 years, Teal told them their knowledge is out of date as scientific evidence has evolved. In another sepsis teaching session, a Fellow  acting as a guest lecturer discussed the peer-reviewed articles that support the new sepsis approach and rhetorically asked if new evidence means the Rivers dogma is broken. A resident replied by asking the following question:What protocol do we follow if we have a septic patient?0721:187-466The Fellow left this question unanswered.In formal teaching, experience was often used to fill holes and cover grey areas in scientific evidence. These were cases where guidelines were not clear:There are no clear guidelines, it’s a clinical decision.Nicola, attending, 0107:148A resident stated the following:Treatments have been used for 100 years and they work so we use themRay, attending, 0719:151Another resident stated the following about the treatment:Is empiric, based on what people do not based on a clinical trial.Adam, senior resident, 0219:65In care, some types of evidence such as experience and peer-reviewed articles were predominately invoked from mindlines, whereas other sources such as UpToDate, Lexi-Interact, Pocket Medicine, and phone apps were read. CPGs were sometimes read and sometimes invoked. The following example illustrates how evidence was invoked in care:Sara [attending] is reviewing a patient admission with Phil [medical student] in the ED. The rest of Sara's CTU team listens. The patient in question is an elderly man who is being admitted due to delirium and a fall. Phil begins to summarise the patient’s history and provisional diagnosis, listing delirium as the patient’s primary issue. He then begins to outline possible causes for the delirium using the DIMS mnemonic . Sara tells the team that “mine is DIMS UFO where U is urine, F is fecal, and O is more involved. We will go over it this afternoon during teaching but the U is based on a paper by [Sara gives the author's name] who is the Godmother of delirium.”1215:89In this example, Sara talked with trainees in a process to coconstruct an appropriate approach to caring for their patients. She made explicit her tacit thought processes and how what sorts of information were incorporated into her mindline.Other evidence was read. Attendings would read from Lexi-Interact or UpToDate during conversations with trainees to double-check medication dosing, their inferences, and supplement gaps in their mindlines. Trainees explicitly searched and read evidence when developing care plans:Fred [senior resident] stands outside of a patient’s [P2] room. Kate [medical student] comes out of P2’s room...Kate tells Fred that P2 grew e. coli in his nephrostomy tube [like a catheter but inserted directly into the kidney] and she thinks that they should prescribe antibiotics. Kate adds that she isn't sure which antibiotics to prescribe...Fred goes to UpToDate and types in the search terms “nephrostomy UTI” and then scans the first UpToDate document that comes up. He goes to the health authority’s formulary site and looks for antibiotics for catheter associated infection and skims the article and reads a section out loud to Kate saying 'do not treat positive cultures without symptoms.' Fred asks Kate if she has heard of CAUTI [catheter associated urinary tract infection] and searches for, then shows Kate, a page on UpToDate about the condition. Fred adds that he’s not sure if the same approach would apply to a nephrostomy infection. Fred then Googles nephrostomy and infection and finds an article by the Infectious Diseases Society of America about nephrostomy and infection. Kate smiles at Fred and tells him that she likes that organisation. They skim the article together but it has no recommendations about what they should do if they get a positive culture. Kate takes her IPad out and begins to search for information as well. She finds another entry in UpToDate that says that cultures in asymptomatic patients shouldn't be treated but that the tube should be changed as soon as possible. Fred looks at P2’s lab results. P2 has no white blood count and he is afebrile. Kate adds that she worries about P2 because he is immunocompromised...Fred decides that they won’t treat for the positive culture but that they might try and get P2’s tube changed.0105:431In this case, Fred and Kate sifted through various sources of evidence and personal knowledge together to make sense of a clinical problem and develop a care plan. Fred drew from his own knowledge of how to treat catheter associated urinary tract infections, but he was unsure if nephrostomy associated infections were similar enough for his knowledge to be applicable. Both Fred and Kate read to supplement what they know, using computers and iPads to access information on the Web. The information selected for reading was not peer-reviewed articles but was summaries of existing evidence with concrete recommendations. Multiple Web-based sources were skimmed for relevant information. Through discussions, Fred and Kate combined the knowledge extracted from summary documents, their nascent mindlines, patient laboratory results, and their knowledge of the patient to form a provisional care plan for P2.CPGs were invoked or read. For example, CPGs were invoked when 2 patients were admitted to the CTU for carbon monoxide poisoning. Still in the ED, the patients were scheduled for 3 hyperbaric dives (where they would be placed in a chamber with high pressured oxygen to reduce the amount of carbon monoxide in their blood). Matt (attending) told BL that he believed the carbon monoxide level in both patients was low and he was not sure if the dives were necessary. Matt greeted the ED doctor overseeing the hyperbaric chamber and asked him if the hyperbaric dives were necessary. He explained that the patients’ carbon monoxide levels were already low and asked the following question:How much does it help at this point?Matt, attendingThe ED doctor answered that current best practice said to do the 3 dives and added the following:There is absolutely no evidence but it is standard of care so we’ll do it. We’ll do 3. They’ll get the benefits that they’ll get...the literature is unclear, no consistent evidence of benefit.1023:372Here, both Matt and an ED doctor made sense of an appropriate treatment plan for 2 patients. Matt questioned the agreed-upon approach, citing specific laboratory results for these 2 patients. The ED doctor invoked “best practice” to justify his own mindline for treating carbon monoxide poisoning. In this case, “best practice” was not viewed as evidence based. Rather, the ED doctor believed that following the best practice is a prudent approach in the absence of clear evidence. In other situations, trainees read CPGs to help inform care decisions. Local guidelines are one of several Web-based evidence sources used by Fred and Kate to formulate a care plan for P2.In care, evidence use varied by role. We observed that trainees would often gather multiple kinds of information to develop a narrative of patient diagnosis and care that was presented to an attending. This formal presentation was used by attendings to review trainees’ reasoning processes and how knowledge of existing evidence was being incorporated into their developing mindlines. Attendings guided trainees on how mindlines were formed by quizzing them on how to think logically and identify and filter evidence and information when developing patient care plans.This study explored the integration of evidence into mindline development and how mindlines and evidence are used. In this study, multiple forms of Web-based evidence were accessed—often through smartphones—and mixed with other forms of information. Evidence use varied between teaching and care and, within care, by role. Teaching modeled optimal evidence use and predominately drew on peer-reviewed journals and experience. In care, attendings’ evidence use most closely approximated the evidence use modeled in teaching. Some forms of evidence—such as experience, peer-reviewed journals, and some CPGs—were predominately invoked through mindlines. Other forms of evidence—such as UpToDate, Lexi-Interact, Pocket Medicine, and phone apps—were read to supplement mindlines. As CTU team members gained experience, they increasingly incorporated evidence into their mindlines. An alternative explanation to the observed variation of evidence use by role is a cohort effect whereby trainees are more comfortable accessing Web-based information systems and using smartphones. Although a cohort effect may explain some of the observed variance, it does not explain differences in how senior and junior residents (separated by a year) consult evidence.In 1961, Becker et al  reportedThe sepsis example illustrates that the implications of evolving scientific knowledge on daily clinical practice are not always explicit . CTU teaOur research suggests that evidence-based medicine has been incorporated into the work of the CTU teams studied here, just not in the ways envisioned by health administrators and policy makers who frequently equate low CPG uptake and a lack of standardization with not practicing evidence-based medicine. Instead of drawing on CPGs, CTU teams invoke and read a variety of evidence sources, blending them together to arrive at shared understandings of patient care ,26,27. AMany insights gained from shadowing internal medicine teams were based on a small number of teams at 2 hospitals, which limits generalizability. There is a chance that participants increased their use of evidence as they knew they were being shadowed . To decrease this impact, BL maintained a neutral attitude throughout her observations, emphasized that her primary interest was to understand how work was conducted, and shadowed an internal medicine team for at least 1 week.Ethnographic research enables a rich understanding of the complex world around us. Writing fieldnotes necessarily distills from this complexity. Observing evidence use was a primary objective in these fieldnotes, but it is probable that not all instances where evidence was used were captured. By observing in depth, ethnographic work cannot capture the same breadth of data as other methodologies. The numbers for some observations—such as counts of evidence use tags by junior residents and medical students in care—are small. Specific numbers or detailed analyses of variance are not provided in the text as counts cannot be considered exact. Rather, they represent trends that were combined with memos and general observations and then checked with informants and experts to derive insight. Additional quantitative studies that track information use on phones and computers are essential to validate findings.UpToDate, Lexi-Interact, and Pocket Medicine are all published by the same private company. Combined, they represent over half of the evidence we observed being consulted. An avenue of future research is to compare the recommendations provided by this company to other sources of evidence to understand if a bias is being created in how medicine is practiced. It is unclear if the work practices observed in these 2 teaching hospitals have diffused into community-based hospitals and general practices. Further research is needed to understand whether CPGs and other tools such as order sets may be more effective vehicles to incorporate evidence into practice in other settings.This paper has responded to calls for more empirical work exploring the complex ways that evidence and mindlines are incorporated into teaching and care ,11. It s


Skin rash remains one of the most prevalent and troublesome clinical problems experienced by patients on chemotherapy and targeted therapy. To ensure high-quality care, guidelines are seen as the best guidance. Considering the quality of guidelines varies greatly, a systematical appraisal of the methodological quality of guidelines for the management of skin rash in patients on chemotherapeutic drugs and targeted anticancer therapies was undertaken, in order to identify appropriate ones for healthcare professionals.Appraisal of Guidelines for Research and Evaluation II (AGREEII).A systematic search of databases and Internet was conducted to obtain pertinent guidelines. Two reviewers independently assessed the eligibility of guidelines according to the inclusion criteria. Then the guidelines included were appraised by three researchers with the methodological quality of eligible guideline using Totally nineteen guidelines met the inclusion criteria. The quality ranged from good to acceptable in scope and purpose  and clarity of presentation domains , but not in stakeholder involvement , rigor of development , applicability , and editorial independence domains . Overall, two guidelines were classified as “recommended”.Only two guidelines were recommended to manage skin rash in patients on chemotherapy and targeted therapies, most guidelines issued were of low to moderate quality. Thus, more attention should be paid to the methodological quality of guideline development in this field. More than one hundred kinds of drugs are widely used in the clinical treatment of different cancers, and they can be divided into non-targeted agents and targeted agents . AlthougClinical practice guidelines (‘guidelines’) are defined as the systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances by the Institute of Medicine (IOM) . Many scA systematic literature search was performed. PubMed and Embase were searched to identify all possible guidelines. Articles published in English between the inception of each database and October 2018, were searched for controlled vocabulary terms specific to each database related to neoplasms, skin toxicity, rash, guidelines. Detailed search strategies were provided in Supplementary Methods  Target population: Adults patients with cancer, there were no restrictions on type, stage, or site of cancer; (2) Scope: Management strategies of skin rash in patients on chemotherapeutic drugs and targeted therapy, included prophylaxis, assessment, pharmaceutical or non-pharmaceutical treatment; (3) Development method: Guidelines were developed based on evidence, consensus and/or expert opinion; (4) Development organization: Guidelines were developed by regional, national or international professional organization or societies, or by a national or international expert panel; (5) Form: Full texts available; (6) Others: If there had updated versions, only the latest one was included. Protocol, interpretation and translation of guidelines were excluded.After removing duplicate records, two researchers  independently assessed the eligibility of all guidelines. Disagreements regarding inclusion in the final review were resolved through discussion and consensus. A third researcher (WM) was consulted if disagreement cannot be resolved between the two researchers. Besides, the guidelines included were classified into two types: evidence-based guidelines (EBGs) and consensus-based guidelines (CBGs) . If a guThe Appraisal of Guidelines for Research and Evaluation II (AGREEII) tool was used to critique the guidelines. AGREEII is a guideline quality appraisal tool with high construct validity, which consists of 23 items arranged into 6 domains: scope and purpose (3 items), stakeholder involvement (3 items), rigor of development (8 items), clarity of presentation (3 items), applicability (4 items), and editorial independence (2 items) , 16. EacOverall guideline assessment reached consensus according to the quality of the guideline. Each guideline was classified as “recommended”, “recommended with modifications” or “not recommended”.A total of 710 references were identified from electronic databases, international cancer organizations and guideline clearinghouses. Of these, 458 were excluded by screening the title and abstract, and 26 were excluded by reviewing the full texts of potentially eligible articles. Finally, 19 guidelines were included in this review . Most guidelines clearly described overall objectives, health questions and target populations.The median score for the stakeholder involvement domain was 50.15% (range: 36.11–75.00%). Only the UK 2009 guideline scored above 60% . No guidThe median score for the rigor of development domain was 23.65% (range: 6.25–70.83%). Only STSG 2011 and ONS 2017 scored over 60%, as they used systematic methods of searching for evidence and for formulating recommendations , 39. OnlThe median score in this domain was 85.38% (range: 75.00–91.67%), with all guidelines scoring over 60%. All of the guidelines included could provide specific, unambiguous and easily identifiable recommendations.The median score for the applicability domain was 23.96% (range: 4.17–52.08%), with no guideline scoring over 60%. Almost all of the guidelines failed to describe the facilitators and barriers of their applications and did not sufficiently consider the costs of applying their recommendations.The median score for the editorial independence domain was 45.18% (range: 0.00–87.50%), with six guidelines scoring above 60%. Most guidelines failed to report a statement of “the views or interests of the funding body have not influenced the final consensus or recommendations” or a “no funding” statement.The first guideline on the management of skin rash in patients on chemotherapy and targeted therapy was published in 2007. Since than, the number had grown rapidly, up to 19 guidelines in 2018. However, lots of guidelines were judged as CBG, as their recommedations were formed by expert opinion or literature review, but did not provide rating of both the quality of the evidence and strength of the recommendations, which made them less trustworthy. Thus, in order to ensure that guidelines are of a high methodological quality, it is essential to follow a evidence-based guideline development standard, such as the Grading of Recommendations Assessment, Development and Evaluation (GRADE) .Of 19 guidelines included, moderate to high scores were achieved in domains of “clarity of presentation”, “scope and purpose”, and “stakeholder involvement”. Mean scores for domian of “applicability” were the lowest, showed that a gap currently exists between the evidence provided and its applicability in the clinical setting, and was in contrast with the need for clarity and user friendliness advocated by some authors –43. RegaFirst of all, professional organizations or socities at national or international level should take responsibility and produce fewer but more trustworthy guidelines based on evidence, in order to avoid a potential waste of scarce guidelines development resources . Then, aThis is the first study to systematically review all available guidelines of the management of skin rash in patients on chemotherapy and targeted therapy, with the aim to screen guidelines with high quality, and provide healthcare professionals with evidence-based rocommendations to manage skin rash. We have performed a comprehensive search to identify relevent guidelines, and adopted well-accepted AGREEII to appraise the methodological quality and derive overall assessment of the guidelines.Although AGREEII appears to be the best methodological tool available, it does not consider the relative importance of six domains of quality. This suggests that the domains of AGREEII should not be weighed equally, such as the domain of “rigor of development” should be of more weight , 48. BesOnly two guidelines were recommended to manage skin rash in patients on chemotherapy and targeted therapy, most guidelines issued were of low to moderate quality. More attention should be paid on the methodological quality of guideline development in this field, particularly in the domains of “rigor of development”, “applicability”, and “editorial independence”.Additional file 1. Search method.Additional file 2. Internet list.