Anaerobic mercury methylators inhabit sinking particles of oxic water columns

Increased concentration of mercury, particularly methylmercury, in the environment is a worldwide concern because of its toxicity in severely exposed humans. Although the formation of methylmercury in oxic water columns has been previously suggested, there is no evidence of the presence of microorganisms able to perform this process, using the hgcAB gene pair (hgc⁺ microorganisms), in such environments. Here we show the prevalence of hgc⁺ microorganisms in sinking particles of the oxic water column of Lake Geneva (Switzerland and France) and its anoxic bottom sediments. Compared to anoxic sediments, sinking particles found in oxic waters exhibited relatively high proportion of hgc⁺genes taxonomically assigned to Firmicutes. In contrast hgc⁺members from Nitrospirae, Chloroflexota and PVC superphylum were prevalent in anoxic sediment while hgc⁺ Desulfobacterota were found in both environments. Altogether, the description of the diversity of putative mercury methylators in the oxic water column expand our understanding on MeHg formation in aquatic environments and at a global scale.

Dissociative and Epileptic seizures: how to distinguish them?

Introduction

Dissociative seizures (DS) are classified as dissociative convulsions within the group of dissociative disorders. Although they share many features with epileptic seizures (ES), they are not a consequence of abnormal brain discharges and may be related to psychogenic causes. DS represent a common diagnostic and are often confounded with ES.

Objectives

The aim of this study is to review the current evidence about the differential diagnosis between DS and ES.

Methods

We conducted a non-sytematic review on the topic, using Pubmed/Medline database.

Results

Studies emphasize a correct diagnosis before treatment of seizures. DS and ES respond differently to anticonvulsant medication and early or incorrect prescription of can even exacerbate DS. Clinical features and a neuropsychiatric history can also help. The presence of a dissociative “stigmata”, such as unexplained sensory loss, may support a non-epileptic diagnosis. EEG videorecording method is the gold standard diagnosis for DS, however often displays rhythmic movement artifacts that may resemble seizure activity and confound the interpretation. The absence of ictal EEG discharges characteristic of epilepsy is a sign of DS. However, this may not be true for some partial ES, particularly those from temporal lobes, whom also tend to report shorter duration of seizures, whereas patients with DPD often describe experiences lasting for hours or longer.

Conclusions

Distinguish DS from ES can be challenging. However, there are features that can help in the differential diagnosis. A correct diagnosis is essential for an adequate therapeutic approach, better prognosis, reduction of medical costs and also a referral to the right medical specialty.

Disclosure

No significant relationships.

Self-perceived functional impairment or disability in Delusional Disorder – Case Reports

Introduction

Delusional disorder (DD) is a psychotic disorder with an estimated prevalence of less than one percent,traditionally characterized by systematized delusional ideas with no cognitive deterioration.However, some studies have been reporting impairment of neurocognitive system (social cognition,learning and memory, expressive language,complex attention, executive function) that might have an impact functionality both in social and work domains..

Objectives

This work aims to review clinical evidence on self-perceived functional impairment or disability in DD and to present two clinical cases evaluated at a psychiatric unit.

Methods

We report two clinical cases based on patients’ history and clinical data, and reviewed clinical records using PubMed® database with search terms of “Delusional Disorder”,“Cognition Impairment in Persistent DD”.

Results

We present two clinical cases of patients who were admitted to psychiatric unit after developing psychotic symptoms namely persecutory delusions about neighbors.A persistent delusional disorder was established and antipsychotic treatment was initiated.The 74-years-old men presented deficits in executive and memory processes; ended up institutionalized after two months of being discharged.The 47-years-old woman, despite remaining as a lawyer, noticed a decrease in work capacity and so she ended up being responsible for less demanding cases.Cases of delusional disorder showed a poor performance in most cognitive tests and some of the cognitive deficits seem to affect functionality namely memory, expressive language and attention.

Conclusions

Although classical literature has not systematized an association between DD and personality deterioration,there are some evidences of loss of functionality and cognitive commitment in this disorder.This suggests the importance of cognitive interventions to improve functional prognosis in this clinical population.

Disclosure

No significant relationships.

Heart failure inpatient"s self-care behaviour: mulricenter approach focousing on gender differences

Funding Acknowledgements

Type of funding sources: None.

Introduction

Heart failure is often characterized by low exercise capacity and great impairment on performance in activities of daily living. The correct management of the disease can prevent the worsening of symptoms and promote a better quality of life. Self-care behaviour plays an important role on patient"s quality of life.

Aim

The aims of this study are to evaluate the self-care behaviour in a sample of heart failure inpatients, using the Self-Care Heart Failure Index (SCHFI) and to understand whether gender and patophisiologic characteristics does interfere on it.

Methods

Cross-sectional multicenter study enrolling 225 heart failure inpatients from eight hospitals. At admission, patient’s functional capacity was evaluated as well as their self-care behaviour, using the SCHFI Portuguese v6.2. Comparison between self-care behaviour with gender was performed. Also some correaltions were perfomed with the total sample of patients, aiming to understand which were the variables that may interfere with the socre of each sub-scale of the self-care HF index. 

Results

Patients’ mean age was 68.4 ± 10.7 years old, 68% were male and 82.3% have reduced ejection fraction. A mean value of 47.9, 35.6 and 38.8 points was found in the SCHFI score of the sections self-care maintenance (SCMt), self-care management (SCMg) and self-care confidence (SCC), respectively. Heart failure inpatients present inadequate levels of self-care behaviour. No difference was found between genders on any section of the SCHFI. Among all variables, only the number of CVRFs and the left ventricular ejection fraction had significant differences. Males had better results, but not with a statistically significant difference. Association tests (ANOVA) between different variables and the score of each section of the SCHFI were perfomred. Only in the NYHA there are variables associated with a better self-care, namely in the SCMg (p = 0.011) and in SCC (p = 0.010). Correlations were made using the numeric variables age, CVRF, BI, LCADL, SCMt, SCMg and SCC, in order to understand the influence of the variables with each other. All the three dimesnions present a positive correlation, at 99% confidence interval between them (SCMt with SCMg: r = 0.365, p < 0.000; SCMt with SCC: r = 0.272, p < 0.000 and SCMg with SCC: r = 0.670, p < 0.000). In addition, SCMt presents a positive correlation with age at a 95% confidence interval (r = 0.158, p = 0.018). Negative correlations were found between 1) BI and age (r=-0.151, p = 0.023), at a 95% confidence interval and 2) BI with LCALD (r=-0.407, p < 0.000), at a 99% confidence interval. Regarding NYHA functional class and left ventricular systolic function, only NYHA class II patients present a statistically significant difference in SCMg and SCC comparing to Class III and IV patients (who do not present differences between them). 

Conclusion

The results do not suggest a relationship between gender and pathophysiological characteristics with self-care behaviour.

Psychosis developed on a travel to china – a case report

Introduction

Psychosis it is a serious medical condition that could happen to anyone while travelling, even without a prior history of mental illness. Some psychotic episodes during travel likely are brief psychotic disorders. This is a poorly understood subject that seems to have an increasing incidence.

Objectives

This work aims to present a clinical case of a patient who developed psychotic symptoms on her visit to China, and to provide a brief update review of this subject.

Methods

We describe a case based on patient’s history and clinical data. We also searched and reviewed cases on “travel” AND “psychosis” and “tourist” AND “psychosis” using PubMed® database.

Results

We report the case of a 41-year-old woman without psychiatric antecedents or substance use who developed psychotic symptoms during a travel to China. Symptoms resolved completely soon after returning to Portugal and admission to the psychiatric emergency service where an antipsychotic treatment was initiated. Psychosis in tourists typically occur in destinations with strong symbolic or mystical connotations and in individuals who travel alone for several days. The most common symptoms are hallucinations, delusions, ideas of reference and agitation. Most patients improved and returned to previous functioning.

Conclusions

To improve the knowledge of travel-related psychosis it is important to identify the cases and the associated biological and clinical factors, later on it may be possible to identify the predictive factors of these psychosis. Further research are necessary to establish a possible association between brief psychotic episode and travel to China, as reports for tourists to Jerusalem and to Florence.

Disclosure

No significant relationships.

Preventive oral kefir supplementation protects mice from ovariectomy-induced exacerbated allergic airway inflammation

Asthma is an inflammatory lung disease that affects more women than men in adulthood. Clinical evidence shows that hormonal fluctuation during the menstrual cycle and menopause are related to increased asthma severity in women. Considering that life expectancy has increased and that most women now undergo menopause, strategies to prevent the worsening of asthma symptoms are particularly important. A recent study from our group showed that re-exposure of ovariectomised allergic mice to antigen (ovalbumin) leads to an exacerbation of lung inflammation that is similar to clinical conditions. However, little is known about the role of probiotics in the prevention of asthma exacerbations during the menstrual cycle or menopause. Thus, our objective was to evaluate the effects of supplementation with kefir, a popular fermented dairy beverage, as a preventive strategy for modulating allergic disease. The results show that the preventive kefir administration decreases the influx of inflammatory cells in the airways and exacerbates the production of mucus and the interleukin 13 cytokine. Additionally, kefir changes macrophage polarisation by decreasing the number of M2 macrophages, as shown by RT-PCR assay. Thus, kefir is a functional food that potentially prevents allergic airway inflammation exacerbations in ovariectomised mice.

Preventive oral supplementation with Bifidobacterium longum 51A alleviates oxazolone-induced allergic contact dermatitis-like skin inflammation in mice

Allergic contact dermatitis (ACD) is a common allergic skin disease that affects individuals subjected to different antigen exposure conditions and significantly impacts the quality of life of those affected. Numerous studies have demonstrated that probiotics suppress inflammation through immunomodulatory effects. In this study, we aimed to evaluate the effect of the probiotic Bifidobacterium longum 5^1A as a preventive treatment for ACD using an oxazolone-induced murine model. We demonstrated that B. longum 5^1A exerted a prophylactic effect on oxazolone-induced ACD-like skin inflammation via reductions in ear and dermal thickness and leucocyte infiltration. The administration of inactivated B. longum 5^1A did not affect oxazolone-induced ACD-like skin inflammation, suggesting that the bacteria must be alive to be effective. Given that B. longum 5^1A is an acetate producer, we treated mice with acetate intraperitoneally, which also prevented ear and dermal thickening. Moreover, the tissue levels of the inflammatory cytokines and chemokines interleukin (IL)-10, IL-33, tumour necrosis factor-α, chemokine (C-C motif) ligand 2/monocyte chemoattractant protein-1 and chemokine (C-C motif) ligand 5/RANTES were significantly reduced after probiotic treatment, but only IL-33 and IL-10 were reduced when the mice were treated with acetate. These results show that B. longum 5^1A exerted a potential prophylactic effect on skin inflammation and that acetate represents one potential mechanism. However, other factors are likely involved since these two treatments do not yield the same results.

Lonomia obliqua bristle extract modulates Rac1 activation, membrane dynamics and cell adhesion properties

Lonomia obliqua is a caterpillar of potential therapeutic interest whose venom is able to induce severe blood leakage and modulate leukocyte migration. Since both phenotypes are associated with changes in cytoskeleton dynamics and cell adhesion properties, the aim of this study was to analyze the effects of Lonomia obliqua bristle extract (LOBE) in cell adhesion and migration signaling. Proteomic analysis revealed that epithelial cells (CHO-K1) exposed to LOBE (30 μg/mL, 30 min) exhibited changes in levels of actin regulatory proteins, including RhoGTPases. These changes correlated with an increase in the activity of the RhoGTPase family member Rac as measured by Förster resonance energy transfer (FRET). When plated in migration promoting conditions, CHO-K1 cells exposed to LOBE (10 μg/mL) showed an increase in membrane ruffling after short (30 min) period of incubation that was accompanied by changes in the distribution of the adhesion markers paxillin, vinculin and an increase of focal adhesion kinase autophosphorylation levels (Y397), suggesting changes in cell-extracellular matrix (ECM) adhesion properties and signaling. These data suggest that LOBE possesses bioactive molecules that are capable to modulated cell migration signaling, cytoskeletal dynamics and cell-ECM properties of several cell types.

Prophylactic Bifidobacterium adolescentis ATTCC 15703 supplementation reduces partially allergic airway disease in Balb/c but not in C57BL/6 mice

Allergic asthma is a chronic disease mainly characterised by eosinophil inflammation and airway remodelling. Many studies have shown that the gut microbiota of allergic individuals differs from that of non-allergic individuals. Although high levels of bifidobacteria have been associated with healthy persons, Bifidobacterium adolescentis ATCC 15703, a gut bacteria, has been associated with allergic individuals in some clinical studies. The relationship between B. adolescentis ATCC 15703 and asthma or allergies has not been well elucidated, and its effect may be dependent on the host's genetic profile or disease state. To elucidate this question, we evaluated the role of preventive B. adolescentis ATCC 15703 treatment on experimental allergic airway inflammation in two genetically different mouse strains, Balb/c and C57BL/6 (B6). Balb/c mice display a greater predisposition to develop allergic responses than B6 mice. Oral preventive treatment with B. adolescentis ATCC 15703 modulated experimental allergic airway inflammation, specifically in Balb/c mice, which showed decreased levels of eosinophils in the airway. B6 mice did not exhibit any significant alterations in eosinophils but showed an increased influx of total leukocytes and neutrophils into the airway. The mechanism underlying the beneficial effects of these bacteria in experimental allergic mice may involve products of bacteria metabolism, as dead bacteria did not mimic the ability of live B. adolescentis ATCC 15703 to attenuate the influx of eosinophils into the airway. To conclude, preventive oral B. adolescentis ATCC 15703 treatment can attenuate the major characteristic of allergic asthma, eosinophil airway influx, in Balb/c but not B6 mice. These results suggest that oral treatment with this specific live bacterial strain may have therapeutic potential for the treatment of allergic airway disease, although its effect is mouse-strain-dependent.

Relationship Between Self-reported and Clinician-rated Psychopathology in Youth Psychiatric Outpatients

Introduction

Psychopathology rating scales have been widely used. Studies evaluating the congruence between self and observer-reported ratings show inconsistent results.

Objectives or aims

Determine whether there was consistency between psychopathology as assessed by patients and clinicians’ assessment in outpatients observed in the Young Adult Unit of our Psychiatry Department (Coimbra Hospital and University Centre-Portugal).

Methods

Socio-demographic characterization was undertaken with young adult outpatients observed during nineteen months (1st January 2015–31st July 2016). Brief Symptom Inventory–53 items (BSI-53) and Brief Psychiatric Rating Scale (BPRS) were applied at the first clinical evaluation. Spearman correlation coefficient between General Severity Index (GSI) of BSI-53 and BPRS total score was calculated.

Results

During the mentioned interval 255 outpatients were observed: 64.3% females and 35.7% males; aged between 17 and 39 years old (average: 20.56; median: 20). Fifty percent were diagnosed with neurotic, stress-related and somatoform disorders (ICD-10 F40-48) and 14.1% with mood disorders (ICD-10 F30-39). BPRS and BSI-53 rating scales were administered to 55 patients: 72.5% females and 27.5% males; average age 21.2. A statistical significant correlation was found between BPRS total and GSI score.

Conclusions

Several factors can determine the accuracy of psychopathology self-assessment, including diagnosis and severity of illness. In fact, studies show strong correlation between self and observer assessment of depressive and anxious psychopathology, but no correlation in psychotic psychopathological dimensions. Therefore, the correlation found in this population can be explained by the fact that the majority of patients were diagnosed with neurotic, stress-related and somatoform and mood disorders.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Socio-demographic and clinic characterization in youth psychiatric outpatients: An observational study

Introduction

Most mental disorders begin during adolescence and early adulthood (18–24-years-old), highlighting the importance of understanding the onset and progression of mental disorders among youths. Although progress has been made, namely by creating youth mental health transition services, gaps continue to exist. Locally, our recently constituted young adults unit aimed to minimize discontinuities in care.

Objectives/aims

To characterize a population of young adult psychiatric outpatients, regarding socio-demographic and clinic variables.

Methods

Socio-demographic and clinic characterization of young adult psychiatric outpatients observed during 1st January 2015–30th July 2016.

Results

Two hundred and fifty-five outpatients were observed: 64.3% females and 35.7% males, average age 20.56-years-old (median 20). Most lived in urban areas (59.4%), with their parents (27.8%), were students (80.4%), attending secondary school (36.1%). A total of, 27.5% were referenced by an emergency department, and adjustment disorders (ICD-10 F43.2) were the most frequent diagnosis (21.6%). Regarding suicidal behaviours and self-harm, 9.8% did self-cutting. A vast majority did not have previous psychiatric hospitalizations–only 5.9% outpatients had at least one. In total, 39.8% were medicated with antidepressants (1/3 of which in association with other drugs), and about 38.8% received cognitive-behavioural interventions. About 2/3 of patients (66.3%) remained in care and only about 1/6 (15.7%) were discharged.

Conclusions

Our typical youth psychiatric outpatient was of female gender, student, living with its parents. Adjustment disorders were the most frequent diagnosis, and antidepressants were the main psychopharmacologic option, often combined with other psychotropic drugs. In the future, psychotherapy interventions should be more widely available, namely group psychotherapy.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Substance use among youth psychiatric outpatients

Introduction

Portuguese young adults (15–34 years old) were more frequent engaged in substance abuse (1.2%) than the general population, according to the Portuguese substance use annual report (2014). Alcohol was the most frequent substance use on youth adults. Cannabis was the most frequent illicit substance used (23.9% of users were considered dependent), with higher prevalence than previously reported. LSD (0.4%) use was also higher among young adults than in previous studies. Cocaine (0.4%), heroine/opiates (0.4%), ecstasy (0.3%), and hallucinogenic mushrooms (1.1%) had their consumption lowered among young adults.

Objectives/aims

To characterize a population of young adult psychiatric outpatients, regarding substance use and associated risk.

Methods

Socio-demographic characterization of our young adult unit outpatient users between 1st January 2015–31st July 2016. Substance use was assessed with the Portuguese version of Alcohol, Smoking and Substance Involvement Screening Test (ASSIST).

Results

A total of 255 outpatients were observed during the timeframe; 58 outpatients were assessed with ASSIST: 44 females (75.9%) and 14 males (24.1%), aged between 16–33 years old (average: 20.95; median: 19.50). For tobacco, 3.5% had high risk, 37.9% moderate risk and 58.6% low risk; 22.4% had moderate risk of alcohol, 13.8% moderate risk of cannabis, and 20.7% moderate risk of tranquilizers. For others substances (cocaine, stimulants, inhalants, hallucinogens, and opiates) the risk was low.

Conclusions

In our sample, alcohol and cannabis use had the highest risk, as reported in the National Annual Report; however, we observed a moderate risk for tranquilizers use. In future care planning, youth mental health should address tobacco and alcohol abstinence, and preventive measures regarding anxiolytics should be undertaken, such as banning sale without medical prescription.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The role of confinement and corona crystallinity on the bending modulus of copolymer micelles measured directly by AFM flexural tests

We present an approach which makes it possible to directly determine the bending modulus of single elongated block copolymer micelles. This is done by forming arrays of suspended micelles onto microfabricated substrates and by performing three-point bending flexural tests, using an atomic force microscope, on their suspended portions. By coupling the direct atomic force microscopy measurements with differential scanning calorimetry data, we show that the presence of a crystalline corona strongly increases the modulus of the copolymer elongated micelles. This large increase suggests that crystallites in the corona are larger and more uniformly oriented due to confinement effects. Our findings together with this hypothesis open new interesting avenues for the preparation of core-templated polymer fibres with enhanced mechanical properties.

Pharmacokinetics of Polymersomes Composed of Poly(Butadiene-Ethylene Oxide); Healthy versus Tumor-Bearing Mice

Vesicles composed of block copolymers (i.e., polymersomes) are one of the most versatile nano-carriers for medical purposes due to their tuneable physicochemical properties and the possibility to encapsulate simultaneously hydrophobic and hydrophilic substances, allowing, for instance, the combination of therapy and imaging. In cancer treatment, these vesicles need to remain long enough in the blood stream to be sufficiently taken up by tumors. Here, we have investigated the biodistribution and the pharmacokinetics of polymersomes, composed of poly(butadiene-b-ethylene oxide) having dimensions around 80 nm. The polymersomes have been radiolabeled with ¹¹¹In via the so-called active loading method achieving a loading efficiency of 92.9 ± 0.9% with radionuclide retention in mouse serum of more than 95% at 24 h. The optimized ¹¹¹In containing polymersomes have been intravenously administered in healthy and tumor bearing mice for pharmacokinetic determination using microSPECT (Single Photon Emission Computed Tomography). In healthy mice these polymersomes have been found to exhibit relatively long blood circulation (> 6 h), low liver uptake (6 ± 1.5%ID/g, 48 h p.i.) and elevated spleen uptake (188 ± 30%ID/g). The blood circulation in tumor bearing mice is dramatically reduced (< 1.5 h) most likely due to elevated splenic filtration, clearly indicating the importance of in vivo studies in diseased mice. Finally, the polymersomes have been injected subcutaneously in tumor bearing mice revealing retention of 77% in the mice, primarily accumulated at the site of injection, up to 48 hours after administration.

In vivo biodistribution of stable spherical and filamentous micelles probed by high-sensitivity SPECT

Understanding how nanoparticle properties such as size, morphology and rigidity influence their circulation time and biodistribution is essential for the development of nanomedicine therapies. Herein we assess the influence of morphology on cellular internalization, in vivo biodistribution and circulation time of nanocarriers using polystyrene-b-poly(ethylene oxide) micelles of spherical or elongated morphology. The glassy nature of polystyrene guarantees the morphological stability of the carriers in vivo and by encapsulating Indium-111 in their core, an assessment of the longitudinal in vivo biodistribution of the particles in healthy mice is performed with single photon emission computed tomography imaging. Our results show prolonged blood circulation, longer than 24 hours, for all micelle morphologies studied. Dynamics of micelle accumulation in the liver and other organs of the reticuloendothelial system show a size-dependent nature and late stage liver clearance is observed for the elongated morphology. Apparent contradictions between recent similar studies can be resolved by considering the effects of flexibility and degradation of the elongated micelles on their circulation time and biodistribution.

Depressive and Anxiety Symptoms In Youth Mental Health Outpatients: An Observational Study

Introduction

There is an increased risk to develop mental disorder during adolescence and early adulthood. Given this vulnerability, and in order to facilitate the transition from child and adolescent to adult mental health services, specific services for this age group have been developed in the last years, focusing on accessibility and early referral of young mental patients. Our Psychiatry Department (Coimbra Hospital and University Centre, Portugal) created a specific unit for young adults in order to provide better care, in accordance with the specificities of this subpopulation. The team consists of psychiatrists, psychiatry residents, nurses and a clinical psychologist. Referred patients are under 20 years old, presenting clinically relevant psychopathology or behavior disturbances.

Objectives/aims

We aimed to characterize help-seeking outpatients regarding socio-demographic variables and its relation to depressive and anxiety symptoms.

Methods

Socio-demographic characterization was undertaken with young adult psychiatric outpatients observed during eleven months (1st January to 30th November 2015). Multivariate analyses were performed to identify a relationship among socio-demographic and psychopathology variables (assessed with the Portuguese version of Brief Symptom Inventory–53 itens).

Results/conclusions

One hundred and sixty-two outpatients were observed: 97 females (59,9%) and 65 males (40,1%), ages between 17 and 31 years old (average: 19,9; median: 20). We found a positive correlation between depressive and anxiety symptoms and the education level. A negative correlation was found between depressive and anxiety symptoms and male gender and presence of mental illness in the family.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Electrorefining of U-Pu-Zr-alloy fuel onto solid Aluminium cathodes in molten LiCl-KCl

An electrorefining process in molten chloride salts using solid aluminium cathodes is being developed at ITU to recover actinides (An) from the spent nuclear fuel. The maximum possible loading of aluminium electrodes with actinides was investigated during the electrorefining of U-Pu-Zr alloy in a LiCl-KCl eutectic at 450 °C. Two different electrolytic techniques were applied during the experiment and almost 6000 C has been passed, corresponding to 3.7 g of deposited actinides. A very high capacity of aluminium to retain actinides has been proven as the average Al: An mass ratio was 1:1.58 for galvanostatic and 1:2.25 for potentiostatic mode. The obtained deposits were characterized by XRD and SEM-EDX analysis and alloys composed of (U,Pu)Al3 were detected. The influence of zirconium co-oxidation during the process was also investigated and the presence of dissolved Zr ions in the melt yielded a significant deterioration of the quality of the deposit.

Formation of aqueous molecular nematic liquid crystal phase in poly(p-sulfophenylene sulfoterephthalamide)

We report strong experimental evidence on the formation of a molecular lyotropic phase in water of a modified polyaramide, namely a fully sulfonated poly(p-phenylene terephthalamide) (Sulfo2PPTA) that exhibits similar liquid crystalline behaviour in water to its non-sulfonated counterpart (PPTA, commercially known as Kevlar or Twaron) in sulfuric acid.

Analysis of heterocyclic aromatic amines in foods by gas chromatography–mass spectrometry as their tert.-butyldimethylsilyl derivatives

A derivatization method for the analysis of 12 heterocyclic aromatic amines (HAs) in food, by gas chromatography-electron impact mass spectrometry, was developed. The amines are derivatized in a one-step reaction with N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide. The derivatives are characterized by easy-to-interpret mass spectra due to the prominent ion [M-57]+ by loss of a tert.-butyldimethylsilyl group, allowing quantification in the selected-ion monitoring mode at the picogram level. The effect of temperature, time, and reagents on the formation of the derivatives was monitored in detail. Quality parameters were evaluated in the optimum working conditions. This derivatization method is not applicable to the pyridoimidazoles Glu-P-1 and Glu-P-2 and to the beta-carboline harman due to incompletely derivatization. The instability of the imidazolquinoline and imidazoquinoxaline derivatives, requiring their injection on the same working day, is a further drawback. This simple, rapid and accurate derivatization procedure is suitable for routine analysis, as illustrated by the analysis of some common foods.