EUS-guided transluminal drainage using lumen-apposing metal stents with or without coaxial plastic stents for treatment of walled-off necrotizing pancreatitis: a prospective bicentric randomized controlled trial.

BACKGROUND AND AIMS: Lumen-apposing metal stents (LAMSs) have proven to be effective for drainage of pancreatic walled-off necrosis (WON), although associated adverse events (AEs) have been reported. Anchoring coaxial double-pigtail plastic stents (DPSs) within LAMSs have been proposed to prevent LAMS-related AEs but have not been assessed in prospective studies. We aimed to evaluate the utility of such measures with a randomized controlled trial. METHODS: We randomly assigned consecutive patients with WON indications for drainage to EUS-guided transluminal drainage using LAMSs with (group A) or without (group B) DPSs. All LAMSs were to be removed after 3 weeks had elapsed from the index procedure with a preceding CT to decide whether additional steps needed to be taken (eg, transluminal necrosectomy or placing transluminal plastic stents in patients with incomplete resolution of WON). The main outcomes were failure of the index method, defined as necessity of reintervention (endoscopic, percutaneous, or surgical) before LAMS removal because of LAMS-related AEs and/or clinical deterioration; AE rates; and mortality with the LAMS in place. Variables were evaluated using the Mann-Whitney U test, χ2 test, or Fisher exact test as appropriate. P < .05 was considered significant. RESULTS: Sixty-seven patients (37.3% women; mean age, 54 ± 14.4 years) underwent LAMS placement with (n = 34) or without (n = 33) DPS placement in 2 tertiary centers. Baseline characteristics including demographics, etiology, comorbidity, and clinical presentation (sterile vs infected necrosis) were comparable between both groups. The technical success rate in placing LAMSs and DPSs was 100%. The global rate of AEs was significantly lower in group A versus group B (20.7% vs 51.5%, respectively; P = .008). Stent occlusion was the most frequently observed AE (14.7% vs 36.3%, P = .042). Failure of the index method was lower in group A versus group B (29.4% vs 48.5%, respectively; P = .109); however, the difference did not achieve statistical significance. The same applied to the mortality rate with LAMSs in place (2.9% vs 12.1%, P = .197). CONCLUSIONS: The addition of a coaxial DPS within a LAMS was associated with a significantly lower global rate of AEs and stent occlusion rate in EUS-guided drainage of WON. (Clinical trial registration number: NCT03923686.).

[Religiosity and spirituality as ressources for head neck cancer patients]. / Religiosität und Spiritualität als Ressourcen in der Betreuung von Patienten mit Kopf-Hals-Tumoren.

OBJECTIVE: Spiritual Care is a well established part of palliative medicine. Are religiosity / spirituality also ressources of patients during the early phases of a head neck cancer (HNC) disease? MATERIAL AND METHODS: We included 113 HNC patients (27 women, 84 men, 2 divers) to a prospective study using questionnaires focused on actual burden (NRS), spirituality as ressource (SpREUK-15, spiritual needs (SpNQ-20), interpretation of illness (IIQ), and life satisfaction of patients (BMLSS-10, BMLSS-Support, WHO-5). 39 patients were still under therapy, 74 participants were cancer-survivors. RESULTS: Only 31/111 (28 %) patients feel themselve as spiritual and/or religious. 72 % are neither spiritual nor religious. 51/111 see reflexion about their cancer disease as a specific ressource to overcome their actual cancer situation. Spiritual needs are religious in 35/112, existential in 67/112, inner peace in 90/112, and generativity in 84/112 patients. The accepted own religiosity and the actual stadium of disease are highly relevant impact factors on spiritual needs and ressources. HNC patients show a high part of depressive moods (WHO-5) and are (in trend) un-satisfied with their life and support situation. CONCLUSION: Up to 90 % of HNC patients have specific spiritual needs which are often hidden. Modern concepts of integrative oncology discover them, and enourage via these ressources the quality of life and the coping of cancer patients.

[Oncology Services for Patients with Head Neck Cancer during Corona-Times - Patients' Perspective]. / Auswirkungen der COVID-19-Pandemie auf die Versorgung von HNO-Tumoren ­ die Patientenperspektive.

OBJECTIVE: COVID-19 pandemic has impact on the oncology service system for tumor patients. What is the view of head and neck cancer patients (HNC) on this situation and which coping strategies were developed? MATERIAL & METHODS: In study 1 PRIO asked 433 tumor patients regarding their impressions/fears during the lockdown between April 15 and May 15, 2020 (online, standardized questionnaire). In 2nd study 292 tumor patients reported their pandemic-induced perceived changes and coping strategies by established questionnaires (WHO-5, MLQ, GrAw-7). An analysis of the HNC-data obtained by standardized questionnaires was performed. RESULTS: Study 1 had 91 HNC, study 2-84 HNC. Study 1 shows high stress levels for the majority of HNC (53,8 %). Personal fears regarding the own disease and therapies (39.6 %) are a central problem. The participants await physical (24.7 %) as well as psychological (21.3 %) consequences due to the pandemic and its current management. During the lockdown the isolation (banned visitors at any hospital) was discussed as critical main point by 58.5 % of HNC patients. Study 2 (after lockdown) underlined the mental stress caused by pandemic. Intensified relations within the families (58/100 points) as well as more intensive experience of nature and silence (58/60 points) are the most perceived changes in corona-times. HNC showed increased own inactivity (MLQ) and depressed well-being (WHO-5) and attention to the moment (GrAw-7). CONCLUSIONS: HNC patients have had high burden and fears due to the COVID-19 pandemic in spring 2020. Their views are important for further strategies to organize and stabilize the oncology service system during further pandemic periods.

Raman imaging of microbial colonization in rock-some analytical aspects.

Raman imaging allows one to obtain spatially resolved chemical information in a nondestructive manner. Herein, we present analytical aspects of effective in situ and in vivo Raman imaging of algae and cyanobacteria from within their native rock habitats. Specifically, gypsum and halite inhabited by endolithic communities from the hyperarid Atacama Desert were analyzed. Raman imaging of these phototrophic colonization reveals a pigment composition within the aggregates that helps in understanding some of their adaptation strategies to survive in this harsh polyextreme environment. The study is focused on methodical aspects of Raman imaging acquisition and subsequent data processing. Point imaging is compared with line imaging in terms of their image quality, spatial resolution, spectral signal-to-noise ratio, time requirements, and risk of laser-induced sample alteration. The roles of excitation wavelength, exposure time, and step size of the imaging grid on successful Raman imaging results are also discussed. Graphical abstract.

Norepinephrine transporter-derived homing peptides enable rapid endocytosis of drug delivery nanovehicles into neuroblastoma cells.

BACKGROUND: Currently, the diagnosis and treatment of neuroblastomas-the most frequent solid tumors in children-exploit the norepinephrine transporter (hNET) via radiolabeled norepinephrine analogs. We aim to develop a nanomedicine-based strategy towards precision therapy by targeting hNET cell-surface protein with hNET-derived homing peptides. RESULTS: The peptides (seq. GASNGINAYL and SLWERLAYGI) were shown to bind high-resolution homology models of hNET in silico. In particular, one unique binding site has marked the sequence and structural similarities of both peptides, while most of the contribution to the interaction was attributed to the electrostatic energy of Asn and Arg (< - 228 kJ/mol). The peptides were comprehensively characterized by computational and spectroscopic methods showing ~ 21% ß-sheets/aggregation for GASNGINAYL and ~ 27% α-helix for SLWERLAYGI. After decorating 12-nm ferritin-based nanovehicles with cysteinated peptides, both peptides exhibited high potential for use in actively targeted neuroblastoma nanotherapy with exceptional in vitro biocompatibility and stability, showing minor yet distinct influences of the peptides on the global expression profiles. Upon binding to hNET with fast binding kinetics, GASNGINAYLC peptides enabled rapid endocytosis of ferritins into neuroblastoma cells, leading to apoptosis due to increased selective cytotoxicity of transported payload ellipticine. Peptide-coated nanovehicles significantly showed higher levels of early apoptosis after 6 h than non-coated nanovehicles (11% and 7.3%, respectively). Furthermore, targeting with the GASNGINAYLC peptide led to significantly higher degree of late apoptosis compared to the SLWERLAYGIC peptide (9.3% and 4.4%, respectively). These findings were supported by increased formation of reactive oxygen species, down-regulation of survivin and Bcl-2 and up-regulated p53. CONCLUSION: This novel homing nanovehicle employing GASNGINAYLC peptide was shown to induce rapid endocytosis of ellipticine-loaded ferritins into neuroblastoma cells in selective fashion and with successful payload. Future homing peptide development via lead optimization and functional analysis can pave the way towards efficient peptide-based active delivery of nanomedicines to neuroblastoma cells.

Spatial and Temporal Variability of Plant Leaf Responses Cascade after PSII Inhibition: Raman, Chlorophyll Fluorescence and Infrared Thermal Imaging.

The use of photosystem II (PSII) inhibitors allows simulating cascade of defense and damage responses, including the oxidative stress. In our study, PSII inhibiting herbicide metribuzin was applied to the leaf of the model plant species Chenopodium album. The temporally and spatially resolved cascade of defense responses was studied noninvasively at the leaf level by combining three imaging approaches: Raman spectroscopy as a principal method, corroborated by chlorophyll a fluorescence (ChlF) and infrared thermal imaging. ChlF imaging show time-dependent transport in acropetal direction through veins and increase of area affected by metribuzin and demonstrated the ability to distinguish between fast processes at the level of electron transport (1 - Vj) from slow processes at the level of non-photochemical energy dissipation (NPQ) or maximum efficiency of PSII photochemistry (Fv/Fm). The high-resolution resonance Raman images show zones of local increase of carotenoid signal 72 h after the herbicide application, surrounding the damaged tissue, which points to the activation of defense mechanisms. The shift in the carotenoid band indicates structural changes in carotenoids. Finally, the increase of leaf temperature in the region surrounding the spot of herbicide application and expanding in the direction to the leaf tip proves the metribuzin effect on slow stomata closure.

A Novel Ruthenium Based Coordination Compound Against Pathogenic Bacteria.

The current epidemic of antibiotic-resistant infections urges to develop alternatives to less-effective antibiotics. To assess anti-bacterial potential, a novel coordinate compound (RU-S4) was synthesized using ruthenium-Schiff base-benzimidazole ligand, where ruthenium chloride was used as the central atom. RU-S4 was characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. Antibacterial effect of RU-S4 was studied against Staphylococcus aureus (NCTC 8511), vancomycin-resistant Staphylococcus aureus (VRSA) (CCM 1767), methicillin-resistant Staphylococcus aureus (MRSA) (ST239: SCCmecIIIA), and hospital isolate Staphylococcus epidermidis. The antibacterial activity of RU-S4 was checked by growth curve analysis and the outcome was supported by optical microscopy imaging and fluorescence LIVE/DEAD cell imaging. In vivo (balb/c mice) infection model prepared with VRSA (CCM 1767) and treated with RU-S4. In our experimental conditions, all infected mice were cured. The interaction of coordination compound with bacterial cells were further confirmed by cryo-scanning electron microscope (Cryo-SEM). RU-S4 was completely non-toxic against mammalian cells and in mice and subsequently treated with synthesized RU-S4.

Raman imaging in geomicrobiology: endolithic phototrophic microorganisms in gypsum from the extreme sun irradiation area in the Atacama Desert.

The Raman imaging method was successfully applied for mapping the distribution of biomolecules (e.g., pigments) associated with cryptoendolithic and hypoendolithic microorganisms, as well as the inorganic host mineral matrix that forms the habitat for the biota. To the best of our knowledge, this is the first comprehensive study in the field of geomicrobiology based on this technique. The studied microbial ecosystem was located nearly 3000 m above sea level within the driest desert on Earth, the Atacama in Chile. Enhancement of carotenoid Raman signal intensity close to the surface was registered at different areas of endolithic colonization dominated by algae, with cyanobacteria present as well. This is interpreted as an adaptation mechanism to the excessive solar irradiation. On the other hand, cyanobacteria synthesize scytonemin as a passive UV-screening pigment (found at both the hypoendolithic and cryptoendolithic positions). The distribution of the scytonemin Raman signal was mapped simultaneously with the surrounding mineral matrix. Thus, mapping was done of the phototrophic microorganisms in their original microhabitat together with the host rock environment. Important information which was resolved from the Raman imaging dataset of the host rock is about the hydration state of Ca-sulfate, demonstrated on the presence of gypsum (CaSO4·2H2O) and the absence of both anhydrite (CaSO4) and bassanite (CaSO4·1/2H2O). Obtaining combined "in situ" simultaneous information from the geological matrix (inorganic) together with the microbial biomolecules (organic) is discussed and concluded as an important advantage of this technique. We discuss how selection of the laser wavelength (785 and 514.5-nm) influences the Raman imaging results.

[Overview of current modalities of colorectal cancer screening]. / Prehled soucasných metod screeningu kolorektálního karcinomu.

There are one-step and two-steps programs for colorectal cancer screening. The aim of all screening examinations is to detect early stage of the disease in asymptomatic patient. The aim of this article is actual review of current screening modalities such as fecal occult blood test, flexible sigmoideoscopy, colonoscopy, CT colonography, capsule endoscopy, blood-based tests and stool DNA tests. Colonoscopy still remains the gold standard for detection of colorectal neoplasias. In majority of countries worldwide programs for colorectal cancer screening are based on immunochemical fecal occult blood test followed by colonoscopy when positive.

The efficacy of treatment of local residual neoplasia under standardized conditions.

OBJECTIVES: Piecemeal endoscopic mucosal resection (EMR) is frequently used for the treatment of non-poly-poid colorectal lesions larger than 20 mm. Nevertheless, local residual neoplasia occurs (LRN) in as much as 15 % of cases. The aim of our prospective interventional study was to evaluate the efficacy of treatment of LRN under standardized conditions. METHODS: In two high volume non-university endoscopy centers, LRN has been treated according to the newly proposed classification based on endoscopic appearance by argon plasma coagulation (APC), endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD). Primary outcome, efficacy of LRN treatment, was defined as both endoscopic and histological absence of neoplastic tissue in the post-EMR site 6 months after LRN treatment session. RESULTS: Twenty-five patients with 25 LRN lesions were enrolled. Among them, 12 (48 %), 8 (32 %) and 5 (20 %) were treated by APC, EMR and ESD, respectively, with efficacy in 10 (90.9 %), 7 (87.5 %) and 4 (100 %), respectively. CONCLUSIONS: Using standardized approach based on therapy directed by LRN morphology, LRN may be eradicated in 91.3 % during one session. KEY WORDS: colonoscopy - endoscopic mucosal resection - local residual neoplasia.

Use of Raman spectroscopy for identification of compatible solutes in halophilic bacteria.

We explored the use of Raman spectroscopy to detect organic osmotic solutes as biomarkers in the moderately halophilic heterotrophic bacterium Halomonas elongata grown in complex medium (accumulation of glycine betaine) and in defined medium with glucose as carbon source (biosynthesis of ectoine), and in the anoxygenic phototrophic Ectothiorhodospira marismortui known to synthesize glycine betaine in combination with minor amounts of trehalose and N-α-carbamoyl glutamineamide. We tested different methods of preparation of the material: lyophilization, two-phase extraction of water-soluble molecules, and perchlorate extraction. Raman signals of glycine betaine and ectoine were detected; perchlorate extraction followed by desalting the extract on an ion retardation column gave the best results. Lyophilized cells of E. marismortui showed strong signals of carotenoid pigments, and glycine betaine could be detected only after perchlorate extraction and desalting. The data presented show that Raman spectroscopy is a suitable tool to assess the mode of osmotic adaptation used by halophilic microorganisms.

Experimental Investigation of Cohesion between UHPC and NSC Utilising Interface Protrusions.

The interaction of ultrahigh-performance concrete (UHPC) and normal-strength concrete (NSC) is one of the main issues for strengthening conventional concrete structures or other applications where NSC and UHPC are interrelated. UHPC stands out for its strength and durability, while NSC is significantly inexpensive and easier to work with. Efficiently designed structures can exploit the advantages of both mixtures. At the interface of these materials in newly designed structures, the formwork can be modified at the interface to give the concrete surface sufficient roughness and thus cohesion as required. This improves both the tensile and shear strength of the contact resulting in the enhanced capacity of the composite structure. In this study, a button foil was inserted into the formwork for the UHPC and then a part of NSC was made. The shear strength of the interface without any stress component in the transverse direction was measured on small-scale samples. It was to justify the possibility of the use of this interface in real constructions such as beams and columns. The main objective of further research is to design a composite beam using a UHPC shell as formwork for NSC and protrusions at the interface. It is expected that the U-shaped shell made of the UHPC could significantly contribute to the load-bearing capacity of the resulting composite NSC−UHPC structure and also to its enhanced durability. In addition, if the NSC is enclosed in a shell of UHPC, it can be made from various secondary materials, therefore it can decrease cement consumption by more than 50%.

Endoscopic treatment of pancreatic fluid collection in gastric heterotopic pancreas. A case report.

BACKGROUND: Heterotopic pancreas is defined as pancreatic tissue located outside the pancreatic parenchyma that lacks an anatomic or vascular connection to the normal pancreas. Symptomatic gastric heterotopic pancreas is a rare condition that can manifest as acute or chronic pancreatitis. Asymptomatic heterotopic pancreas does not require treatment, while symptomatic lesions should be resected. The modality of final resection of heterotopic pancreas depends on its size and the depth of gastric wall involvement. METHODS AND RESULTS: A 36-year-old woman was admitted for recurrent epigastralgia. Abdominal computed tomography (CT) scan revealed that an abscess had formed in the gastric antrum. After multidisciplinary discussion we decided for conservative treatment with intravenous antibiotics and further detailed endoscopic diagnostic. Esophagogastroduodenoscopy revealed a submucosal mass with a central fistula and intermittent pus secretion in the prepyloric region of the gastric antrum, which was subsequently drained with a double pigtail stent under endoscopic ultrasound (EUS) and fluoroscopy. The possibility of pancreatic fluid collection in the case of heterotopic pancreas was suggested during the EUS examination, and histology subsequently confirmed heterotopic pancreatic tissue. The patient was in good condition and without any abdominal pain. According to a control CT scan after 10 weeks, the fluid collection was completely resolved. Due to the possible recurrence of pancreatitis, resection of heterotopic pancreas was proposed to the patient. Since the lesion involved the muscularis propria of the gastric wall, surgical resection of the mass was indicated. CONCLUSION: Fluid collections after acute pancreatitis in heterotopic pancreas in the gastric antrum can be successfully managed by endoscopy.

High-frequency ultrasound probe sonography staging for colorectal neoplasia with superficial morphology: its utility and impact on patient management.

BACKGROUND: This prospective study aimed to evaluate the impact of high-frequency ultrasound probe sonography (HFUPS) staging on the management of patients with superficial colorectal neoplasia (SCN) as determined by the endoscopic characteristics of lesions. METHODS: Consecutive patients referred for endoscopic treatment of nonpedunculated SCN were enrolled in this study. A lesion was considered high risk if a depressed area or invasive pit pattern was present. The gold standard for final staging included histology from endoscopic or surgical resection. The impact on treatment was defined as any modification of the therapeutic algorithm based on the result of the HFUPS examination compared with that based on endoscopy alone. RESULTS: In this study, 48 lesions in 48 patients were evaluated. Of these, 28 (58%) were considered high risk, and the remaining 20 (42%) were regarded as low risk. A total of seven lesions (15%) that could not be examined with HFUPS and another non-neoplastic lesion were excluded from final analysis. For the remaining 40 lesions, the overall accuracy of the HFUPS examination to predict the correct T-stage was 90% (95% confidence interval [CI], 77-96%). The HFUPS examination had a positive impact on the treatment of 0 low-risk and 11 high-risk (42%) lesions. CONCLUSION: The impact of HFUPS on the treatment of SCN depends on their endoscopic characteristics. It is negligible for low-risk SCNs, and these lesions can be treated on the basis of their endoscopic appearance alone. Nevertheless, compared with endoscopy alone, HFUPS changed the subsequent therapeutic approach in a positive way for up to 42% of high-risk lesions, including those with a depressed component and an invasive pit pattern. These endoscopic features can therefore be recommended as the entry criteria for an HFUPS examination.

Correlation between ADR of screening and all colonoscopies.

BACKGROUND AND AIMS: Colonoscopy with polypectomy are associated with a reduction in the incidence of colorectal cancer (CRC), as well as mortality, secondary to CRC. Because of the variation in physicians' performance and the risk of interval CRC after a colonoscopy, several quality indicators have been established. ADR (adenoma detection rate) is a generally accepted quality indicator. But it is also a target of possible gaming and achieving an adequate number of colonoscopies only from screening may be a problem for some practices. The aim of this study was to compare ADR for colonoscopies done for various indications and to look for correlations between the ADR of screening and all examinations. METHODS: We retrospectively assessed the quality indicators of all colonoscopies performed in a nonuniversity hospital, Frydek-Mistek, from January 2013 to December 2017. We calculated the ADR for all colonoscopies in patients over 50 years of age (subdivided into screening, surveillance, diagnostic) and separately only for screening colonoscopies. Correlations were made using the Pearson's correlation coeficient. RESULTS: The sample was composed of 6925 patients over 50 years of age (3620 men, 3305 women, mean age 66.2 years). The ADRs for screening and surveillance were higher than for diagnostic colonoscopies for all of the endoscopists, and the ADRs for all colonoscopies were lower than for screening, but sufficiently over 25%. There was a positive correlation between the ADR of screening and all colonoscopies (r=0.906, P<0.005). CONCLUSIONS: The calculation of ADR for all colonoscopies was possible in our endoscopic department, and there was a positive correlation with ADR for screening colonoscopies. ADR for all colonoscopies is a good tool for calculating real ADR from large sample sizes without gaming. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03730441).

Chlorophyll a fluorescence and Raman spectroscopy can monitor activation/deactivation of photosynthesis and carotenoids in Antarctic lichens.

Lichens survive harsh weather of Antarctica as well as of other hostile environments worldwide. Therefore, this investigation is important to understand the evolution of life on Earth in relation to their stress tolerance strategy. We have used chlorophyll a fluorescence (ChlF) and Raman spectroscopy, respectively, to monitor the activation/deactivation of photosynthesis and carotenoids in three diverse Antarctic lichens, Dermatocarpon polyphyllizum (DP), Umbilicaria antarctica (UA), and Leptogium puberulum (LP). These lichens, post 4 h or 24 h of hydration, showed differences in their ChlF transients and values of major ChlF parameters, e.g., in the maximum quantum efficiency of PSII photochemistry (Fv/Fm), and yields of fluorescence and heat dissipation (Φf,d), of effective quantum efficiency of PSII photochemistry (ΦPSII) and of non-photochemical quenching (Φnpq), which may be due to quantitative and/or qualitative differences in the composition of their photobionts. For understanding the kinetics of hydration-induced activation of photosynthesis, we screened ΦPSII of these lichens and reported its non-linear stimulation on a minute time scale; half of the activation time (t1/2) was fastest ~4.05 ± 0.29 min for DP, which was followed by 5.46 ± 0.18 min for UA, and 13.95 ± 1.24 min for LP. Upon drying of fully activated lichen thallus, there was a slow decay, in hours, of relative water content (RWC) as well as of Fv/Fm. Raman spectral signatures were different for lichens having algal (in DP and UA) and cyanobacteria (in LP) photobionts, and there was a significant shift in ν1(C=C) Raman band of carotenoids post 24 h hydration as compared to their value at a dry state or post 4 h of hydration; this shift was decreased, when drying, in DP and LP but not in UA. We conclude that hydration nonlinearly activated photosynthetic apparatus/reactions of these lichens in minute time range but there was a de-novo synthesis of chlorophylls as well as of carotenoids post 24 h. Their dehydration-induced deactivation, however, was comparatively slow, in hours range, and there seemed a degradation of synthesized chlorophylls and carotenoids post dryness. We conclude that in extremophilic lichens, their photosynthetic partners, in particular, possess a complex survival and photoprotective strategy to be successful in the extreme terrestrial environments in Antarctica.

Nanoscale Zero-Valent Iron Has Minimum Toxicological Risk on the Germination and Early Growth of Two Grass Species with Potential for Phytostabilization.

Two Poaceae species, Agrostis capillaris and Festuca rubra, were selected for their potential as phytostabilizing plants in multicontaminated soils. These species are resistant to contamination and maintain high concentrations of contaminants at the root level. Nanoscale zero-valent iron (nZVI) is an engineered nanomaterial with the ability to stabilize metal(loid)s in soils; its potential toxicological effects in the selected species were studied in a germination test using: (i) control variant without soil; (ii) soil contaminated with Pb and Zn; and (iii) contaminated soil amended with 1% nZVI, as well as in an hydroponic experiment with the addition of nZVI 0, 25, 50 and 100 mg L-1. nZVI had no negative effects on seed germination or seedling growth, but was associated with an increase in shoot growth and reduction of the elongation inhibition rate (root-dependent) of F. rubra seedlings. However, applications of nZVI in the hydroponic solution had no effects on F. rubra but A. capillaris developed longer roots and more biomass. Increasing nZVI concentrations in the growing solution increased Mg and Fe uptake and reduced the Fe translocation factor. Our results indicate that nZVI has few toxic effects on the studied species.

Identification of beta-carotene in an evaporitic matrix--evaluation of Raman spectroscopic analysis for astrobiological research on Mars.

Since evaporitic rocks on the Martian surface could (or still can) serve as potential habitats for microbial life on Mars, there is a reasonable possibility that these rocks may sustain molecular remnants as evidence for the presence of extinct or extant living organisms on Mars and that beta-carotene could be a suitable biomarker. In this paper, Raman microspectrometry was tested as a nondestructive method of determining the lowest detectable beta-carotene content in experimentally prepared evaporitic matrices--namely, gypsum, halite and epsomite. Two excitation wavelengths were compared--514.5 nm, because of the resonance Raman enhancement in the carotenoid analysis, and 785 nm, as a more universal wavelength now much used in the detection of biomolecules terrestrially. Mixtures were measured directly as well as with a laser beam penetrating the crystals of gypsum and epsomite. We have obtained beta-carotene signals at the 0.1 to 10 mg kg(-1) level--the number of registered beta-carotene Raman bands differed depending on the particular mineral matrix and the excitation wavelength. Concentrations of beta-carotene of about one order of magnitude higher were identified when analysed through single crystals of gypsum and epsomite, respectively.