A Comprehensive Evaluation of Flavor Instability of Beer (Part 1): Influence of Release of Bound State Aldehydes

Flavor instability of pale lager beer depends decisively on aroma-active aldehydes from the Maillard reaction, Strecker degradation, and lipid oxidation, which are formed in various oxidative and non-oxidative reactions. Therein, aldehydes can be formed de novo and be released from bound states to a free, aroma-active form during aging. During malting and brewing, proteolysis affects the amount of soluble nitrogen and thus flavor instability in different ways (e.g., precursors for de novo formation and binding agents for bound states). To isolate nitrogen-related aging processes, beers from malts (two barley varieties, three proteolytic malt modifications) were produced on a 50 L scale in part 1 of this study. Sensory analysis revealed increased flavor instability for beers with higher amounts of soluble nitrogen. Especially Strecker aldehydes significantly increased with malt modification. The release of bound state aldehydes revealed most free aldehydes in fresh beers and with higher malt modification. During aging, the equilibrium between free and bound state aldehydes shifted toward the free form. These results reveal a nitrogen-dependent bound pool of aldehydes that is depleted during aging and is responsible for aged aroma, especially in the early and medium stages of aging. Therefore, bound state aldehydes are indicators of the early-stage prediction of flavor instability already in a fresh condition.

Accepting the Incomprehensible: What Samuel Beckett Can Tell Psychiatrists Today

ABSTRACT

The aim of this article is to propose that reading Samuel Beckett's novels can improve compassionate acceptance of mental phenomena and human behavior deemed incomprehensible. In a narrative inquiry into all of Beckett's novels, we could discern nihilism and existential insecurity as themes both central to Beckett's prose and relevant in working with people with severe mental disorders. By deconstructing narrative structures and struggling to say the unsayable, Beckett can provide a perspective that goes beyond rational understanding. Beckett's prose can extend our imagination of mental and embodied phenomena by describing absurd and incomprehensible aspects of human experience and behavior. His unique sense of humor in dealing with bleak, meaningless situations and the acceptance and perseverance that his characters show in their struggles could help promote compassionate therapeutic relationships and improve clinical teaching in psychiatry. This can help psychiatrists and patients to face the existential aspects of mental illness, "limit situations" according to Jaspers, in a manner both respectful and open to subjective views.

The Influence of Proteolytic Malt Modification on the Aging Potential of Final Wort

The dynamic changes in beer flavor are determined by its aging potential, which comprises of present free and bound-state aldehydes and their precursors. Rising flavor-active aging compounds cause sensory deterioration (flavor instability). These compounds are mainly formed upstream in the brewing process through the Maillard reaction, the Strecker degradation, or lipid oxidation. Wort boiling is an especially critical production step for important reactions due to its high temperature and favorable pH value. Amino acid concentration, as an important aging-relevant precursor, is variable at the beginning of wort boiling, mainly caused by the malt modification level, and can further influence the aging potential aging formation during wort boiling. This study investigated the effect of the proteolytic malt modification level on the formation of precursors (amino acids and dicarbonyls) and free and bound-state aldehydes during wort boiling. Six worts (malt of two malting barley varieties at three proteolytic malt modification levels) were produced. Regarding precursors, especially Strecker, relevant amino acids and dicarbonyls increased significantly with an enhanced malt modification level. Concentrations of free and bound aldehydes were highest at the beginning of boiling and decreased toward the end. A dependency of malt modification level and the degree of free and bound aldehydes was observed for 2-methylpropanal, 2-methylbutanal, and 3-methylbutanal. Generally, a higher proteolytic malt modification level tended to increase free and bound aldehyde content at the end of wort boiling. Conclusively, the aging potential formation during boiling was increased by an intensified malt modification level.

Recombinant protein linker production as a basis for non-invasive determination of single-cell yeast age in heterogeneous yeast populations

The physiological and metabolic diversity of a yeast culture is the sum of individual cell phenotypes. As well as environmental conditions, genetics, and numbers of cell divisions, a major factor influencing cell characteristics is cell age. A postcytokinesis bud scar on the mother cell, a benchmark in the replicative life span, is a quantifiable indicator of cell age, characterized by significant amounts of chitin. We developed a binding process for visualizing the bud scars of Saccharomyces pastorianus var. carlsbergensis using a protein linker containing a polyhistidine tag, a superfolder green fluorescent protein (sfGFP), and a chitin-binding domain (His6-SUMO-sfGFP-ChBD). The binding did not affect yeast viability; thus, our method provides the basis for non-invasive cell age determination using flow cytometry. The His6-SUMO-sfGFP-ChBD protein was synthesized in Escherichia coli, purified using two-stage chromatography, and checked for monodispersity and purity. Linker-cell binding and the characteristics of the bound complex were determined using flow cytometry and confocal laser scanning microscopy (CLSM). Flow cytometry showed that protein binding increased to 60 455 ± 2706 fluorescence units per cell. The specific coupling of the linker to yeast cells was additionally verified by CLSM and adsorption isotherms using yeast cells, E. coli cells, and chitin resin. We found a relationship between the median bud scar number, the median of the fluorescence units, and the chitin content of yeast cells. A fast measurement of yeast population dynamics by flow cytometry is possible, using this protein binding technique. Rapid qualitative determination of yeast cell age distribution can therefore be performed.

Structural basis of l-tryptophan-dependent inhibition of release factor 2 by the TnaC arrest peptide

In Escherichia coli, elevated levels of free l-tryptophan (l-Trp) promote translational arrest of the TnaC peptide by inhibiting its termination. However, the mechanism by which translation-termination by the UGA-specific decoding release factor 2 (RF2) is inhibited at the UGA stop codon of stalled TnaC-ribosome-nascent chain complexes has so far been ambiguous. This study presents cryo-EM structures for ribosomes stalled by TnaC in the absence and presence of RF2 at average resolutions of 2.9 and 3.5 Å, respectively. Stalled TnaC assumes a distinct conformation composed of two small α-helices that act together with residues in the peptide exit tunnel (PET) to coordinate a single L-Trp molecule. In addition, while the peptidyl-transferase center (PTC) is locked in a conformation that allows RF2 to adopt its canonical position in the ribosome, it prevents the conserved and catalytically essential GGQ motif of RF2 from adopting its active conformation in the PTC. This explains how translation of the TnaC peptide effectively allows the ribosome to function as a L-Trp-specific small-molecule sensor that regulates the tnaCAB operon.

Challenges in the Development of Soft Sensors for Bioprocesses: A Critical Review

Among the greatest challenges in soft sensor development for bioprocesses are variable process lengths, multiple process phases, and erroneous model inputs due to sensor faults. This review article describes these three challenges and critically discusses the corresponding solution approaches from a data scientist’s perspective. This main part of the article is preceded by an overview of the status quo in the development and application of soft sensors. The scope of this article is mainly the upstream part of bioprocesses, although the solution approaches are in most cases also applicable to the downstream part. Variable process lengths are accounted for by data synchronization techniques such as indicator variables, curve registration, and dynamic time warping. Multiple process phases are partitioned by trajectory or correlation-based phase detection, enabling phase-adaptive modeling. Sensor faults are detected by symptom signals, pattern recognition, or by changing contributions of the corresponding sensor to a process model. According to the current state of the literature, tolerance to sensor faults remains the greatest challenge in soft sensor development, especially in the presence of variable process lengths and multiple process phases.

Blended Care in In-Patient Acute Psychiatric Care. The Example of a Group Training for Social Competences in Adults-A Pretest-Posttest Feasibility Study

INTRODUCTION

Deficits in social skills can be an important modulating factor in the development and progress of various mental disorders. However, limited resources in inpatient care often impede effective social skills training. This study investigates the feasibility of a blended group training for social skills (SST) in an inpatient psychiatric setting. Methods and Analysis: For this one-group pretest-posttest trial, inpatients with a diagnosed mental disorder were recruited. Participation in the blended SST lasted four weeks and took place within usual inpatient psychiatric care. The blended intervention comprised four face-to-face group sessions and three complementary online modules within four weeks. Assessments took place before (t1) and after (t2) the training. Feasibility outcomes (use, acceptance, satisfaction, implementability into usual psychiatric inpatient care) and effectiveness outcomes regarding social skills were assessed.

RESULTS

N = 15 participants were recruited. Most patients completed all questionnaires (93%) and all modules of the blended SST concept (60%). All participants (100%) would recommend the blended intervention to a friend. Regarding social skills, exploratory analyses revealed a non-significant medium-sized effect (Cohen's d = 0.5 95%CI 0.3 to 1.25, p = 0.08).

DISCUSSION

This trial shows that a blended care SST is feasible for the use in acute psychiatric inpatient care setting. Although the wards were acute, with high turnover and change of inpatients, 60% of participants were treated per protocol over four weeks. Overall, the evidence on blended care concepts in psychiatric care settings is extremely poor to date. Hence, this trial should encourage intensified blended inpatient psychiatric care research.

Antidepressant treatment effects and country income: meta-regression analysis of individual participant data from duloxetine trials

OBJECTIVE

In recent decades, significant numbers of pharmaceutical trials have gradually been relocated to low- and middle-income countries. However, there is little evidence regarding the transferability of trial outcomes across countries. Analysing duloxetine randomised controlled trials (RCTs) conducted in different countries, we investigated whether per capita gross national income (GNI) and healthcare expenditure (HE) are associated with pre-post mean changes of depression severity and differences in duloxetine-placebo effect sizes.

METHOD

Meta-analyses included RCTs investigating duloxetine efficacy in patients with depression. Individual participant data (IPD) from multi-centre duloxetine trials were provided by the manufacturer. Data extracted from published reports also entered analyses in case of trials conducted in only one country. A meta-regression approach was applied to analyse associations of GNI and HE with standardised pre-post mean change using raw score standardisation (SMCR) and comparative effect size, that is, the mean differences (MD) in pre-post effect size between duloxetine and placebo treatment.

RESULTS

23 trials with 8417 randomised participants entered analyses. Regression coefficients indicated a negative linear relationship of SMCR with GNI (z-standardised β = -3.61, R²  = 14.8%, p < 0.001) and HE (β = -4.72, R²  = 24.8%, p < 0.001) for participants treated with duloxetine. Similar associations were found for placebo treatment (GNI: β = -3.52, R²  = 23.8%, p < 0.001; β = -3.34, R²  = 21.0% p < 0.001). Neither GNI nor HE was associated with the MD between duloxetine and placebo pre-post differences.

CONCLUSIONS

Findings challenge the idea of the universal transferability of antidepressant trial outcomes across countries. Understanding the results of antidepressant RCTs demands more sophisticated clarification of context factors involved in determining effectiveness of antidepressant medication and should be discussed with a view to socio-economic context in their countries of origin.

Texture design of gluten-free bread by mixing under controlled headspace atmosphere

Gluten-free breads often show a reduced specific bread volume, in comparison to gluten-containing products, caused by non-adapted processing technologies of gluten-free dough. In this investigation, different mixing speeds and durations (600–3000 rpm for 3 min, 5 min or 8 min, respectively) as well as variations in the pressure (prel – 50 to prel + 130 kPa) in the headspace atmosphere during mixing (Stephan mixer) and pressure ratios of overpressure/negative pressure of 8 min mixing (20/80, 50/50, 80/20) were studied to determine their impact on the gas volume fraction of dough and specific volume of breads. A pressure rise of prel 50 kPa, prel 100 kPa or prel 130 kPa increased the gas volume fraction in dough of 60%, 100% or 120%, respectively, and led to a significant higher specific bread volume (7%) and the reduction of crumb hardness (35%) at prel 130 kPa. A linear correlation (R2 = 0.843) between the pressure and specific volume of breads was found. An extended first mixing phase at overpressure resulted in the formation of a very fine pore structure, whereby a short overpressure phase caused the formation of big pores. Thus, the control of the headspace atmosphere during mixing is a suitable parameter to adjust the density of dough and consequently, the pore size distribution for a specific texture design.

Feasibility and Acceptability of Photographic Food Record, Food Diary and Weighed Food Record in People with Serious Mental Illness

People with serious mental illness (SMI) experience challenges that may make typical dietary assessment methods less feasible and accurate. This study aims to determine the feasibility, acceptability and preliminary validity of a 3-day photographic food record (PR), a 1-day food diary (FD) and a 1-day weighed food protocol (WR) in people with SMI. Participants completed measures at two timepoints, with a 4-week interval. Feasibility and acceptability for each method were measured through four outcomes: percent of completers, quality assessment, number of participants requiring technical devices and satisfaction questionnaire. Relative validity was measured by agreement in estimated energy intake between methods, using Bland–Altman analysis and WR as the benchmark, and prevalence of misreporting, using the Goldberg cut-off method, updated by Black. In total, 63 participants were recruited, with a dropout rate of 19.0% prior to timepoint 1 and additional 6.4% prior to timepoint 2. Quality deficits were identified for all methods. The FD was most acceptable to participants, followed by the PR. The difference in estimated energy intake between assessment methods was not statistically significant, though there was considerable individual variability. Underreporting was considerable across all methods but appeared highest in the PR. A FD and PR present as feasible and acceptable methods for assessing dietary intake in people with SMI. Further validity testing is required. In addition, clear guidance for completion and removal of potential barriers is required for participants.

Aroma and color development during the production of specialty malts: A review

Specialty malts comprise a promising field for innovative approaches concerning their potential in terms of color, aroma, and taste influence on the composition of beer and other beverages. Nevertheless, poor reproducibility of aroma and taste is a recurrent struggle between maltsters, leaving color as a practical parameter for quality control. However, malts with similar coloration can present distinct aroma profiles, leaving open questions concerning key aroma compounds, their dynamic responses to malting process variations and to what extent they may vary in a certain color range. Key aroma volatiles have been identified in the matrix of barley malt, comprising a variety of products of non-enzymatic browning reactions (e.g., caramelization, pyrolysis, and Maillard reactions). Here, water plays a crucial role together with the intensity of the temperature regimes. Nevertheless, the final aroma profile of a malt product is the result of a balance between aroma formation and losses. Therefore, the correlation between color and aroma is of big complexity. That being the case, the present article questions if key aroma compounds responsible for the peculiar flavors of specialties have been defined by scientific literature and whether their production dynamics is unveiled. In this manner, this work proposes an overview of the aroma compounds present in specialty malt products studied up to the current date. More specifically, the process production of specialty malts and its potential impact on the formation of aroma and taste is studied alongside the key aroma-active compounds, their correlation to color, and trending analytical techniques for aroma and color assessment.

Systematic evaluation of the 'efficacy-effectiveness gap' in the treatment of depression with venlafaxine and duloxetine

OBJECTIVE

Evidence of larger drug effects in highly standardized studies (efficacy) compared to clinical routine (effectiveness) is discussed as efficacy-effectiveness gap. This study aimed to quantify effect size differences of RCTs and non-RCTs in the treatment of depression with venlafaxine and duloxetine and to identify effect modifying predictors.

METHODS

A comprehensive systematic review and meta-analysis was conducted, including all prospective trials, which evaluated the treatment effects of duloxetine or venlafaxine in patients with depression. The primary outcome was the pre-post effect size after acute therapy, which were compared between RCTs and non-RCTs. Moreover, an exploratory analysis of predictors in a mixed meta-regression model within an information-theoretic approach was performed.

RESULTS

171 RCTs and 74 non-RCTs were included. The pre-post effect size differed significantly between RCTs and non-RCTs (-3.04 vs. -2.62, Δ = 0.41, p = 0.012, high heterogeneity). Study characteristics were very similar between RCTs and non-RCTs. Most important variables to predict effect sizes were 'depression severity', 'dose' and 'number of participants'.

CONCLUSION

Despite differences in effect sizes between RCTs and non-RCTs, study design is not clearly an important predictor for the effect sizes. Our results question the common assumption that non-RCTs are generally better suited to describe a drug's effectiveness in clinical practice than RCTs. Future studies and their reporting should put more emphasis on the description of external validity, in order to allow better assessments of clinical relevance.

Prognostic significance of high mobility group A2 (HMGA2) in pancreatic ductal adenocarcinoma: malignant functions of cytoplasmic HMGA2 expression

PURPOSE

HMGA2 has frequently been found in benign as well as malignant tumors and a significant association between HMGA2 overexpression and poor survival in different malignancies was described. In pancreatic ductal adenocarcinoma (PDAC), nuclear HMGA2 expression is associated with tumor dedifferentiation and presence of lymph node metastasis. Nevertheless, the impact of HMGA2 occurrence in other cell compartments is unknown.

METHODS

Intracellular distribution of HMGA2 was analyzed in PDAC (n = 106) and peritumoral, non-malignant ducts (n = 28) by immunohistochemistry. Findings were correlated with clinico-pathological data. Additionally, intracellular HMGA2 presence was studied by Western blotting of cytoplasmic and nuclear fractions of cultured cells.

RESULTS

HMGA2 was found in the cytoplasm and in the nucleus of cultured cells. In human tumor tissue, HMGA2 was also frequently found in the cytoplasm and the nucleus of tumor cells, however, nuclear staining was generally stronger. Direct comparison from tumor tissue with corresponding non-neoplastic peritumoral tissue revealed significantly stronger expression in tumors (p = 0.003). Of note, the nuclear staining was significantly stronger in lymph node metastatic cell nuclei compared to primary tumor cell nuclei (p = 0.049). Interestingly, cytoplasmic staining positively correlated with lymph vessel (p = 0.004) and venous invasion (p = 0.046).

CONCLUSION

HMGA2 is a prognostic marker in PDAC. Firstly, we found a positive correlation for cytoplasmic HMGA2 expression with lympho-vascular invasion and, secondly, we found a significantly stronger nuclear expression of HMGA2 in cancer-positive lymph node nuclei compared to primary tumor cell nuclei. So far, the role of cytoplasmic HMGA2 is nearly unknown, however, our data lend support to the hypothesis that cytoplasmic HMGA2 expression is involved in nodal spread.

Longitudinal Analysis of Circulating Tumor Cells in Colorectal Cancer Patients by a Cytological and Molecular Approach: Feasibility and Clinical Application

Introduction

Liquid biopsies allowing for individualized risk stratification of cancer patients have become of high significance in individualized cancer diagnostics and treatment. The detection of circulating tumor cells (CTC) has proven to be highly relevant in risk prediction, e.g., in colorectal cancer (CRC) patients. In this study, we investigate the clinical relevance of longitudinal CTC detection over a course of follow-up after surgical resection of the tumor and correlate these findings with clinico-pathological characteristics.

Methods

In total, 49 patients with histologically proven colorectal carcinoma were recruited for this prospective study. Blood samples were analyzed for CTC presence by two methods: first by marker-dependent immunofluorescence staining combined with automated microscopy with the NYONE^® cell imager and additionally, indirectly, by semi-quantitative Cytokeratin-20 (CK20) RT-qPCR. CTC quantification data were compared and correlated with the clinico-pathological parameters.

Results

Detection of CTC over a post-operative time course was feasible with both applied methods. In patients who were pre-operatively negative for CTCs with the NYONE^® method or below the cut-off for relative CK20 mRNA expression after analysis by PCR, a statistically significant rise in the immediate post-operative CTC detection could be demonstrated. Further, in the cohort analyzed by PCR, we detected a lower CTC load in patients who were adjuvantly treated with chemotherapy compared to patients in the follow-up subgroup. This finding was contrary to the same patient subset analyzed with the NYONE^® for CTC detection.

Conclusion

Our study investigates the occurrence of CTC in CRC patients after surgical resection of the primary tumor and during postoperative follow-up. The resection of the tumor has an impact on the CTC quantity and the longitudinal CTC analysis supports the significance of CTC as a prognostic biomarker. Future investigations with an even more extended follow-up period and larger patient cohorts will have to validate our results and may help to define an optimal longitudinal sampling scheme for liquid biopsies in the post-operative monitoring of cancer patients to enable tailored therapy concepts for precision medicine.

Post-traumatic stress disorder, human rights and access to healthcare: an analysis of judgments of the European Court of Human Rights from an ethical perspective

Background: Human rights violations such as torture are associated with a high risk of post-traumatic stress disorder (PTSD). The judgements of the European Court of Human Rights (ECtHR) include a normative perspective on PTSD and address central ethical questions. Objective: To help bridge the gap between the psycho-medical and the legal discourse on human rights violations and to illustrate their medico-ethical implications by systematically assessing and categorizing all judgements by the ECtHR dealing with PTSD. Method: The ECtHR database was searched for 'post-traumatic stress disorder'. A descriptive statistic was performed on the Articles of the European Convention on Human Rights involved and violations to these articles. In a qualitative analysis, the judgements were thematically grouped. Results: The search yielded n = 103 judgements, of which n = 90 were included. There were mostly violations of Article 3 (prohibition of torture), Article 8 (Right to respect for private and family life) and Article 6 (Right to a fair trial). PTSD in these judgements is normatively discussed with regards to ethical, social and political themes such as inadequate access to healthcare, especially in prison, matters of asylum, expulsion and extradition, protection of minorities and minors, as well as rights and duties of traumatized witnesses. Conclusion: PTSD plays a central role in a large number of ECtHR judgements. Our results show that PTSD as a medical diagnosis also encompasses legal, ethical, social, and political dimensions. This knowledge is essential for healthcare professionals working with traumatized persons, but can also be relevant for political decision-makers.

Porins as helpers in mitochondrial protein translocation

Mitochondria import the vast majority of their proteins via dedicated protein machineries. The translocase of the outer membrane (TOM complex) forms the main entry site for precursor proteins that are produced on cytosolic ribosomes. Subsequently, different protein sorting machineries transfer the incoming preproteins to the mitochondrial outer and inner membranes, the intermembrane space, and the matrix. In this review, we highlight the recently discovered role of porin, also termed voltage-dependent anion channel (VDAC), in mitochondrial protein biogenesis. Porin forms the major channel for metabolites and ions in the outer membrane of mitochondria. Two different functions of porin in protein translocation have been reported. First, it controls the formation of the TOM complex by modulating the integration of the central receptor Tom22 into the mature translocase. Second, porin promotes the transport of carrier proteins toward the carrier translocase (TIM22 complex), which inserts these preproteins into the inner membrane. Therefore, porin acts as a coupling factor to spatially coordinate outer and inner membrane transport steps. Thus, porin links metabolite transport to protein import, which are both essential for mitochondrial function and biogenesis.

Understanding the Impact of Industrial Stress Conditions on Replicative Aging in Saccharomyces cerevisiae

In yeast, aging is widely understood as the decline of physiological function and the decreasing ability to adapt to environmental changes. Saccharomyces cerevisiae has become an important model organism for the investigation of these processes. Yeast is used in industrial processes (beer and wine production), and several stress conditions can influence its intracellular aging processes. The aim of this review is to summarize the current knowledge on applied stress conditions, such as osmotic pressure, primary metabolites (e.g., ethanol), low pH, oxidative stress, heat on aging indicators, age-related physiological changes, and yeast longevity. There is clear evidence that yeast cells are exposed to many stressors influencing viability and vitality, leading to an age-related shift in age distribution. Currently, there is a lack of rapid, non-invasive methods allowing the investigation of aspects of yeast aging in real time on a single-cell basis using the high-throughput approach. Methods such as micromanipulation, centrifugal elutriator, or biotinylation do not provide real-time information on age distributions in industrial processes. In contrast, innovative approaches, such as non-invasive fluorescence coupled flow cytometry intended for high-throughput measurements, could be promising for determining the replicative age of yeast cells in fermentation and its impact on industrial stress conditions.

A unique macrophage subpopulation signals directly to progenitor cells to promote regenerative neurogenesis in the zebrafish spinal cord

Central nervous system injury re-initiates neurogenesis in anamniotes (amphibians and fishes), but not in mammals. Activation of the innate immune system promotes regenerative neurogenesis, but it is fundamentally unknown whether this is indirect through the activation of known developmental signaling pathways or whether immune cells directly signal to progenitor cells using mechanisms that are unique to regeneration. Using single-cell RNA-seq of progenitor cells and macrophages, as well as cell-type-specific manipulations, we provide evidence for a direct signaling axis from specific lesion-activated macrophages to spinal progenitor cells to promote regenerative neurogenesis in zebrafish. Mechanistically, TNFa from pro-regenerative macrophages induces Tnfrsf1a-mediated AP-1 activity in progenitors to increase regeneration-promoting expression of hdac1 and neurogenesis. This establishes the principle that macrophages directly communicate to spinal progenitor cells via non-developmental signals after injury, providing potential targets for future interventions in the regeneration-deficient spinal cord of mammals.