Xanthopsin-Like Systems via Site-Specific Click-Functionalization of a Retinoic Acid Binding Protein

The use of light-responsive proteins to control both living or synthetic cells, is at the core of the expanding fields of optogenetics and synthetic biology. It is thus apparent that a richer reaction toolbox for the preparation of such systems is of fundamental importance. Here, we provide a proof-of-principle demonstration that Morita-Baylis-Hillman adducts can be employed to perform a facile site-specific, irreversible and diastereoselective click-functionalization of a lysine residue buried into a lipophilic binding pocket and yielding an unnatural chromophore with an extended π-system. In doing so we effectively open the path to the in vitro preparation of a library of synthetic proteins structurally reminiscent of xanthopsin eubacterial photoreceptors. We argue that such a library, made of variable unnatural chromophores inserted in an easy-to-mutate and crystallize retinoic acid transporter, significantly expand the scope of the recently introduced rhodopsin mimics as both optogenetic and "lab-on-a-molecule" tools.

Acute toxic exposures in children: analysis of a three year registry managed by a Pediatric poison control Center in Italy

Introduction

Acute pediatric poisoning is an emerging health and social problem. The aim of this study is to describe the characteristics of a large pediatric cohort exposed to xenobiotics, through the analysis of a Pediatric Poison Control Center (PPCc) registry.

Methods

This study, conducted in the Pediatric Hospital Bambino Gesù of Rome, a reference National Pediatric Hospital, collected data of children whose parents or caregivers contacted the PPCc by phone (group “P”), or who presented to the Emergency Department (group “ED”), during the three-year period 2014–2016. Data were prospectively and systematically collected in a pre-set electronic registry. Comparisons among age groups were performed and multivariable logistic regression models used to investigate associations with outcomes (hospital referral for “P”, and hospital admission for “ED”group).

Results

We collected data of 1611 children on group P and 1075 on group ED. Both groups were exposed to both pharmaceutical and non-pharmaceutical agents. Pharmaceutical agent exposure increased with age and the most common route of exposure was oral. Only 10% among P group were symptomatic children, with gastrointestinal symptoms. Among the ED patients, 30% were symptomatic children mostly with gastrointestinal (55.4%) and neurologic symptoms (23.8%). Intentional exposure (abuse substance and suicide attempt), which involved 7.7% of patients, was associated with older age and Hospital admission.

Conclusions

Our study describes the characteristics of xenobiotics exposures in different paediatric age groups, highlighting the impact of both pharmacological and intentional exposure. Furthermore, our study shows the utility of a specific PPCc, either through Phone support or by direct access to ED. PPCc phone counselling could avoid unnecessary access to the ED, a relevant achievement, particularly in the time of a pandemic.

Stability Studies of New Caged bis-deoxy-coelenterazine Derivatives and Their Potential Use as Cellular pH Probes

The synthesis of new bis-deoxy-coelenterazine (1) derivatives bearing ester protective groups (acetate, propionate and butyrate esters) was accomplished. Moreover, their hydrolytic stability at room temperature was evaluated in dimethylsulfoxide (DMSO) as solvent, using the nuclear magnetic resonance (NMR) spectra of the key products at different time intervals. The results showed an increasing hydrolysis rate according to longest aliphatic chain, with a half-life of 24 days of the more stable acetate derivative (4a). Furthermore, the analysis of the experimental data revealed the greater stability of the enol tautomer in this aprotic polar solvent. This result was confirmed by theoretical calculations using the density functional theory (DFT) approach, which gave us the opportunity to propose a detailed decomposition mechanism. Additionally, the derivatives obtained were tested by bioluminescence luciferase assays to evaluate their potential use as extracellular pH-sensitive reporter substrates of luciferase. The biological data support the idea that further structural modifications of these molecules may open promising perspectives in this field of research.

Design, synthesis and biological evaluation of 7-substituted 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f] [1,4]diazepines as safe anxiolytic agents

A series of 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f][1,4]diazepine-7-carboxylate esters were synthesized and tested as central benzodiazepine receptor (CBR) ligands by the ability to displace [³H]flumazenil from rat cortical membranes. All the compounds showed high affinity with IC₅₀ values ranging from 5.19 to 16.22 nM. In particular, compounds 12b (IC₅₀ = 8.66 nM) and 12d (IC₅₀ = 5.19 nM) appeared as the most effective ligands being their affinity values significantly lower than that of diazepam (IC₅₀ = 18.52 nM). Compounds 12a-f were examined in vivo for their pharmacological effects in mice and five potential benzodiazepine (BDZ) actions were thus taken into consideration: anxiolytic, anticonvulsant, anti-amnesic, hypnotic, and locomotor activities. All the new synthesized compounds were able to induce a significant antianxiety effect and, among them, compound 12f protected pentylenetetrazole (PTZ)-induced convulsions in a dose-dependent manner reaching a 40% effect at 30 mg/kg. In addition, all the compounds were able to significantly prevent the memory impairment evoked by scopolamine, while none of them was able to interfere with pentobarbital-evoked sleep and influence motor coordination. Moreover, title compounds did not affect locomotor and exploratory activity at the same time and doses at which the anti-anxiety effect was observed. Finally, molecular docking simulations were carried out in order to assess the binding mode for compounds 12a-f. The obtained results demonstrated that these compounds bind the BDZ binding site in a similar fashion to flumazenil.

Design, synthesis, structure, and photophysical features of highly emissive cinnamic derivatives

New cinnamic derivatives 1a–c were designed starting from the chromophores working in polybenzofulvene derivatives poly-6-DMFL-BF3k, poly-6-MCBZ-BF3k, and poly-6-TPA-BF3k endowed with outstanding optoelectronic performances.

Hyaluronan Graft Copolymers Bearing Fatty-Acid Residues as Self-Assembling Nanoparticles for Olanzapine Delivery

In order to evaluate the potential of a technology platform based on hyaluronan copolymers grafted with propargylated ferulate fluorophores (HA-FA-Pg) in the development of drug delivery systems, the propargyl groups of HA-FA-Pg derivatives were employed with oleic acid (OA) or stearic acid (SA) residues across a biocompatible hexa(ethylene glycol) (HEG) spacer. The designed materials (i.e., HA-FA-HEG-OA or HA-FA-HEG-SA) showed clear-cut aggregation features in an aqueous environment, as confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM), generating nanoaggregate systems. In fact, HA-FA-HEG-OA and HA-FA-HEG-SA derivatives showed the property to create self-assembled cytocompatible nanostructured aggregates in water, thanks to the simultaneous presence of hydrophilic portions in the polymeric backbone, such as hyaluronic acid, and hydrophobic portions in the side chains. Furthermore, the designed materials interact with living cells showing a high degree of cytocompatibility. The potential ability of nanosystems to load pharmacologically active molecules was assessed by the physical entrapment of olanzapine into both polymeric systems. The drug loading evaluation demonstrated that the nanoparticles are able to incorporate a good quantity of olanzapine, as well as improve drug solubility, release profile, and cytocompatibility.

Radiosynthesis and Preclinical Evaluation of 11C-VA426, a Cyclooxygenase-2 Selective Ligand

Cyclooxygenase-2 (COX-2) is involved in the inflammatory response, and its recurrent overexpression in cancers as well as in neurodegenerative disorders has made it an important target for therapy. For this reason, noninvasive imaging of COX-2 expression may represent an important diagnostic tool. In this work, a COX-2 inhibitor analogue, VA426 [1-(4-fluorophenyl)-3-(2-methoxyethyl)-2-methyl-5-(4-(methylsulfonil)phenyl)-1H-pyrrole], was synthesized and radiolabelled with the 11C radioisotope. The ex vivo biodistribution profile of 11C-VA426 was evaluated in the brain and periphery of healthy rats and mice and in brain and periphery of inflammation models, based on the administration of LPS. 11C-VA426 synthesis with the tBuOK base showed optimal radiochemical yield (15 ± 2%) based on triflate activity, molar activity (range 37-148 GBq/μmol), and radiochemical purity (>95%). Ex vivo biodistribution studies showed a fast uptake of radioactivity but a rapid washout, except in regions expressing COX-2 (lungs, liver, and kidney) both in rats and in mice, with maximum values at 30 and 10 minutes p.i., respectively. LPS administration did not show significant effect on radioactivity accumulation. Celecoxib competition experiments performed in rats and mice treated with LPS produced a general target unrelated reduction of radioactivity concentration in all peripheral tissues and brain areas examined. Finally, in agreement with the negative results obtained from biodistribution experiments, radiometabolites analysis revealed that 11C-VA426 is highly unstable in vivo. This study indicates that the compound 11C-VA426 is not currently suitable to be used as radiopharmaceutical for PET imaging. This family of compounds needs further implementation in order to improve in vivo stability.

Physicochemical Properties of A New PEGylated Polybenzofulvene Brush for Drug Encapsulation

A new polymer brush was synthesized by spontaneous polymerization of benzofulvene macromonomer 6-MOEG-9-T-BF3k bearing a nona(ethylene glycol) side chain linked to the 3-phenylindene scaffold by means of a triazole heterocycle. The polymer structure was studied by SEC-MALS, NMR spectroscopy, and MALDI-TOF MS techniques, and the results supported the role of oligomeric initiatory species in the spontaneous polymerization of polybenzofulvene derivatives. The aggregation features of high molecular weight poly-6-MOEG-9-T-BF3k-FE were investigated by pyrene fluorescence analysis, dynamic light scattering studies, and transmission electron microscopy, which suggested a tendency towards the formation of spherical objects showing dimensions in the range of 20-200 nm. Moreover, poly-6-MOEG-9-T-BF3k-FE showed an interesting cytocompatibility in the whole concentration range tested that, besides its aggregation features, makes this polybenzofulvene brush a good polymer candidate for nanoencapsulation and delivery of drug molecules. Finally, the photo-physical features of poly-6-MOEG-9-T-BF3k-FE could allow the biodistribution of the resulting drug delivery systems to be monitored by fluorescence microscopy techniques.

Functionalization of protein hexahistidine tags by functional nanoreactors

The reactivity of functional nanoreactors was evaluated in CRB0137 as a model protein to develop a new methodology for the site-specific PEGylation of proteins bearing poly-histidine tags.

Nanoreactors for the multi-functionalization of poly-histidine fragments

Water-soluble MBHA derivatives self-assemble to generate aggregates showing reactive core–shell architectures.

Densely PEGylated Polybenzofulvene Brushes for Potential Applications in Drug Encapsulation

The technique of grafting side chains onto a linear polymeric backbone is commonly used to confer to the new polymeric material with desired properties, such as tunable solubility, ionic charge, biocompatibility, or specific interactions with biological systems. In this paper, two new polybenzofulvene backbones were assembled by spontaneous polymerization of the appropriate benzofulvene monomers (4,6-PO-BF3k and 4',6-PO-BF3k) bearing two clickable propargyloxy groups in different positions of the 3-phenylindene scaffold. Poly-4,6-PO-BF3k and poly-4',6-PO-BF3k were grafted with monomethyl oligo(ethylene glycol) (MOEG) to prepare two new polybenzofulvene brushes (i.e., poly-4,6-MOEG-9-TM-BF3k and poly-4',6-MOEG-9-TM-BF3k) by means of a "grafting onto" approach, that were characterized from the point of view of their macromolecular features, aggregation liability, and in a preliminary evaluation of biocompatibility. The obtained results make these PEGylated polybenzofulvene brushes (PPBFB) derivatives potentially useful as nanocarriers for nanoencapsulation and delivery of drug molecules.

Structural Manipulation of the Conjugated Phenyl Moiety in 3-Phenylbenzofulvene Monomers: Effects on Spontaneous Polymerization

Spontaneous polymerization is an intriguing phenomenon in which pure monomers begin their polymerization without initiators or catalysts. Previously, 3-phenylbenzofulvene monomers were found to polymerize spontaneously after solvent removal. Here, eight new 3-substituted benzofulvene monomers 1a⁻h were synthesized in order to investigate the effects of differently substituted aromatic rings in position 3 of the benzofulvene scaffold on spontaneous polymerization. The newly synthesized monomers maintained the tendency toward spontaneous polymerization. However, monomer 1a, bearing an ortho-methoxy substituted phenyl, polymerized hardly, thus producing low polymerization yields, inhomogeneous structure, and low molecular weight of the obtained polymeric material. This result suggested the importance of the presence of hydrogen atoms in the 2'-position to achieve productive interactions among the monomers in the recognition step preluding the spontaneous polymerization and among the monomeric units in the polybenzofulvene backbones. Moreover, this study paves the way to modify the pendant rings in position 3 of the indene scaffold to synthesize new polybenzofulvene derivatives variously decorated.

Very Early Development and Recognition of Coronary Involvement in a Febrile Infant with Typical Signs of Kawasaki Disease

Kawasaki disease (KD) is an acute, self-limited, inflammatory disease affecting medium-sized arteries and particularly the coronary arteries in about 25% of untreated cases. KD is a clinical diagnosis based on the presence of ≥5 days of fever and the presence of ≥4 of the 5 principal clinical criteria. We described, for the first time to our knowledge, a case of a very early development (on day 1) of typical KD with transient coronary involvement, diagnosed on day 2 of disease and treated with aspirin and steroids on day 3, with complete resolution of clinical signs and coronary involvement.

Electrochemical and optoelectronic properties of terthiophene- and bithiophene-based polybenzofulvene derivatives

The electrochemical behavior of some polybenzofulvene derivatives bearing bithiophene (BT) or terthiophene (TT) side chains was investigated by cyclic voltammetry. Very interestingly, the presence of unsubstituted terminal thiophene moieties allowed poly-6-BT-BF3k and poly-6-TT-BF3k to be cross-linked by electrochemical procedures. Conductive films were obtained by electrodeposition from solutions of these polymers onto electrode surfaces through the formation of covalent cross-linking due to dimerization (i.e. electrochemical oxidation) of the BT or TT side chains. The films showed electrochromic features and switched from yellow-orange (neutral) to green (positively charged) by switching the potential, and were stable to tenths of cycles, without degradation in the wet state in the electrolyte solution. Finally, the thin film obtained by electrodeposition of poly-6-TT-BF3k on a indium tin oxide (ITO) glass substrate showed in the neutral state a significantly red-shifted photoluminescence (PL) emission (∼40 nm red-shifted with respect to that of the corresponding film obtained by casting procedures), which was consistent with the presence of more conjugated moieties produced by the oxidative dimerization of the TT side chains. The innovative architecture and the easy preparation could lead to a broad range of applications in optoelectronics and bioelectronics for these cross-linked hybrid materials based on π-stacked polybenzofulvene backbones bearing oligothiophene side chains.

The electrochemical behavior of some polybenzofulvene derivatives bearing bithiophene (BT) or terthiophene (TT) side chains was investigated by cyclic voltammetry and cross-linked materials were obtained by dimerization of the BT or TT side chains.

Hyaluronan-based graft copolymers bearing aggregation-induced emission fluorogens

In order to develop a technology platform based on two natural compounds from biorenewable resources, a short series of hyaluronan (HA) copolymers grafted with propargylated ferulic acid (HA–FA–Pg) were designed and synthesized to show different grafting degree values and their optical properties were characterized in comparison with reference compounds containing the same ferulate fluorophore. Interestingly, these studies revealed that the ferulate fluorophore was quite sensitive to the restriction of intramolecular motion and its introduction into the rigid HA backbone, as in HA–FA–Pg graft copolymers, led to higher photoluminescence quantum yield values than those obtained with the isolated fluorophore. Thus, the propargyl groups of HA–FA–Pg derivatives were exploited in the coupling with oleic acid through a biocompatible nona(ethylene glycol) spacer as an example of the possible applications of this technology platform. The resulting HA–FA–NEG–OA materials showed self-assembling capabilities in aqueous environment. Furthermore, HA–FA–NEG–OA derivatives have been shown to interact with phospholipid bilayers both in liposomes and living cells, retaining their fluorogenic properties and showing a high degree of cytocompatibility and for this reason they were proposed as potential biocompatible self-assembled aggregates forming new materials for biomedical applications.

A new technology platform has been developed with hyaluronan playing the role of the macromolecular carrier and ferulate the central role of natural small molecule fluorogenic clickable linker.

Development of subnanomolar-affinity serotonin 5-HT4 receptor ligands based on quinoline structures

A structure–affinity relationship study led to the discovery of 7h–j as novel 5-HT₄ receptor ligands showing K_i values in the subnanomolar range.

Poly-histidine grafting leading to fishbone-like architectures

A small series of Morita–Baylis–Hillman derivatives was synthesized and made to react with N-acetylhexahistidine to give polymeric materials characterized by the presence of biadduct residues.

Development of Imidazole-Reactive Molecules Leading to a New Aggregation-Induced Emission Fluorophore Based on the Cinnamic Scaffold

In order to obtain new fluorophores potentially useful in imidazole labeling and subsequent conjugation, a small series of Morita-Baylis-Hillman acetates (3a-c) was designed, synthesized, and reacted with imidazole. The optical properties of the corresponding imidazole derivatives 4a-c were analyzed both in solution and in the solid state. Although the solutions display a very weak emission, the powders show a blue emission, particularly enhanced in the case of compound 4c possessing two methoxy groups in the cinnamic scaffold. The photophysical study confirmed the hypothesis that the molecular rigidity of the solid state enhances the emission properties of these compounds by triggering the restriction of intramolecular motions, paving the way for their applications in fluorogenic labeling.

Therapeutic targeting of the mTOR-signalling pathway in cancer: benefits and limitations

The mammalian target of rapamycin (mTOR) plays an important role in the regulation of protein translation, cell growth and metabolism. The mTOR protein forms two distinct multi-subunit complexes: mTORC1 and mTORC2. The mTORC1 complex is activated by diverse stimuli, such as growth factors, nutrients, energy and stress signals; and essential signalling pathways, such as PI3K and MAPK, in order to control cell growth, proliferation and survival. mTORC1 also activates S6K1 and 4EBP1, which are involved in mRNA translation. The mTORC2 complex is resistant to rapamycin inhibitory activity and is generally insensitive to nutrient- and energy-dependent signals. It activates PKC-α and Akt and regulates the actin cytoskeleton. Deregulation of the mTOR-signalling pathway (PI3K amplification/mutation, PTEN loss of function, Akt overexpression, and S6K1, 4EBP1 and eIF4E overexpression) is common in cancer, and alterations in components of the mTOR pathway have a major role in tumour progression. Therefore, mTOR is an appealing therapeutic target in many tumours. Here we summarize the upstream regulators and downstream effectors of the mTORC1 and mTORC2 pathways, the role of mTOR in cancer, and the potential therapeutic values and issues related to the novel agents targeting the mTOR-signalling pathway.

Diabetes and Obesity as Independent Risk Factors for Osteoporosis in Postmenopausal Women: A Population Study

We aimed to analyze bone mineralization and the effect of different risk factors for osteoporosis in postmenopausal women. We studied 2,756 postmenopausal subjects out of ≥10,000 records from the ROIS registry in the frame of the PROF Project, a population study carried out in Salento (Taranto, Brindisi, Lecce) from 2009 to 2012. All subjects were assessed by phalangeal Quantitative Ultrasound (QUS) to evaluate their bone mineralization (assessed by Amplitude Dependent Speed of Sound, AD-SoS) and the association between demineralization and the presence of other conditions or risk factors. Mean age was 64±9.5 years and mean BMI was 28.7±3.5 Kg/m2. Pearson correlation analyses revealed a negative association between bone mineralization (AD-SoS) and BMI (P<0.001). By using multivariate logistic regression analysis, we observed significant values of Odds Ratios of osteoporosis (adjusted for age, physical activity and the use of drugs known to increase the risk of fractures) in subjects with diabetes and obesity: 1.39 (CI: 1,05–1,83) and 1.46 (CI: 1.20–1.78), respectively. A statistically significant linear trend of higher Odds Ratios of osteoporosis was found for increasing values of BMI. The percent change in the odds of vertebral fractures per single SD decrease of AD-SoS was 47% (P<0.001). Diabetes and obesity in postmenopausal women are likely to represent independent risk factors for osteoporosis. Phalangeal QUS showed a good power of predictivity in identifying subjects with vertebral fractures.

Validation of suitable internal control genes for expression studies in aging

Quantitative data from experiments of gene expression are often normalized through levels of housekeeping genes transcription by assuming that expression of these genes is highly uniform. This practice is being questioned as it becomes increasingly clear that the level of housekeeping genes expression may vary considerably in certain biological samples. To date, the validation of reference genes in aging has received little attention and suitable reference genes have not yet been defined. Our aim was to evaluate the expression stability of frequently used reference genes in human peripheral blood mononuclear cells with respect to aging. Using quantitative RT-PCR, we carried out an extensive evaluation of five housekeeping genes, i.e. 18s rRNA, ACTB, GAPDH, HPRT1 and GUSB, for stability of expression in samples from donors in the age range 35-74 years. The consistency in the expression stability was quantified on the basis of the coefficient of variation and two algorithms termed geNorm and NormFinder. Our results indicated GUSB be the most suitable transcript and 18s the least for accurate normalization in PBMCs. We also demonstrated that aging is a confounding factor with respect to stability of 18s, HPRT1 and ACTB expression, which were particularly prone to variability in aged donors.

Managing myelodysplastic symptoms in elderly patients

Most patients with myelodysplastic syndromes (MDS) are elderly (median age range 65 to 70 years); as a consequence, the incidence and prevalence of these diseases are rising as the population ages. Physicians are often uncertain about how to identify patients who may benefit from specific treatment strategies. The International Prognostic Scoring System is a widely used tool to assess the risk of transformation to leukemia and to guide treatment decisions, but it fails to take into account many aspects of treating elderly patients, including comorbid illnesses, secondary causes of MDS, prior therapy for MDS, and other age-related health, functional, cognitive, and social problems that affect the outcome and managing of myelodysplastic symptoms. Patients with low-risk disease traditionally have been given only best supportive care, but evidence is increasing that treatment with novel non-conventional drugs such as lenalidomide or methyltransferase inhibitors may influence the natural history of the disease and should be used in conjunction with supportive-care measures. Supportive care of these patients could also be improved in order to enhance their quality of life and functional performance. Elderly patients commonly have multiple medical problems and use medications to deal with these. In addition, they are more likely to have more than one health care provider. These factors all increase the risk of drug interactions and the consequent treatment of toxicities. Manifestations of common toxicities or illnesses may be more subtle in the elderly, owing to age-associated functional deficits in multiple organ systems. Particularly important to the elderly MDS patient is the age-related decline in normal bone marrow function, including the diminished capacity of response to stressors such as infection or myelosuppressive treatments. Through the integration of geriatric and oncological strategies, a personalized approach toward this unique population may be applied. As with many diseases in the elderly, reliance on family members or friends to maintain the prescribed treatments, including travel to and from appointments, may place additional stressors on the patient and his/her support network. Careful evaluation and knowledge of functional status, ability to tolerate treatments, effect of disease progression, and general overall health conditions can provide the best opportunity to support these patients. Immediate assessment of daily living activities may detect deficiencies or deficits that often require early interventions.

Elevated serum ALT in children presenting to the emergency unit: Relationship with NAFLD

BACKGROUND

Non-alcoholic fatty liver disease, ranging from hepatic steatosis to necro-inflammation with or without fibrosis (non-alcoholic steatohepatitis), is a growing clinical liver disorder in children.

AIM

The goals of this study were to characterize liver disorders associated with elevated aminotransferases and establish the non-alcoholic fatty liver disease/non-alcoholic steatohepatitis prevalence in hypertransaminasemic children admitted to the emergency room.

METHODS

The medical records of 3280 children (2-17 years of age) admitted to the emergency room of Bambino Gesù Children's Hospital of Rome, and presenting with hypertransaminasemia were analysed retrospectively.

RESULTS

Elevation of serum alanine aminotransferases was present in 897 patients. Of these, 520 (58%) spontaneously normalized alanine aminotransferases, and 179/897 (20%) maintained persistently elevated alanine aminotransferases levels. Twenty-one patients were excluded because of medication or alcohol use. In the remaining 157 patients with elevated alanine aminotransferases, obesity was found in 87 (55%), viral infections in 52 (33%) and genetic diseases in 14 (9%). Obesity-related alanine aminotransferases elevation was associated with a histological diagnosis of non-alcoholic fatty liver disease in 85% of patients. In particular, steatosis was histologically confirmed in 74 patients; 43/74 (58%) had steatohepatitis, and 12/74 (16%) had fibrosis.

CONCLUSIONS

Twenty percent of children with elevated aminotransferases on routine testing may hide non-alcoholic fatty liver disease/non-alcoholic steatohepatitis. A careful diagnostic workup of persistent hypertransaminasemia in all obese subjects is warranted in the paediatric setting.

Large area interference lithography using a table-top extreme ultraviolet laser: a systematic study of the degree of mutual coherence

A prototype low cost table-top Ar capillary discharge laser source (1.5 ns pulse duration, lambda = 46.9 nm) was successfully used to produce, by means of interference lithography (with a simple Lloyd mirror setup), large area (0.1 mm(2)) regular patterns from 400 nm down to 22.5 nm (half-pitch) on PMMA/Si (PMMA: polymethylmethacrylate) substrates. The experiments allowed a systematical investigation of the degree of mutual coherence of the source, giving a clear indication that the interference lithography can be pushed down to the ultimate resolution limit of lambda/4.

Mapping the intake of different elements in vegetal tissues by dual-energy X-ray imaging at DaPhine synchrotron light source

This article reports on the first utilization of the soft X-ray beamline at the DaPhine synchrotron light source for mapping the intake of different elements in plant tissues. As a test, the method of dual-energy X-ray microradiography was applied to the investigation of the natural sulfur content in dried leaf and root samples. Our ultimate goal was to monitor the pollutant lead and its intake, which was added in controlled doses to the hydroponic medium of laboratory-controlled samples of vegetal species. The results obtained by the nondestructive X-ray radiographic analysis are compared to the values of concentrations determined by a standard chemical analysis utilizing atomic absorption spectroscopy. From this comparison the validity of the X-ray detection of heavy metals in biological samples has been confirmed. The superposition of the dual energy results on the simple planar radiography shows the representation of the pollutant intake directly on the sample structures. It should be pointed out that this method, developed here for plant root and leaves could be applied to any biological sample of interest, but the preparation and observation conditions necessitate different strategies according to the type of sample under analysis.

Interactions between strains of Staphylococcus xylosus and Kocuria varians isolated from fermented meats

AIMS

To evaluate the interactions of Staphylococcus xylosus on Kocuria varians strains isolated from fermented meat products.

METHODS AND RESULTS

Interactions were assessed in vitro by agar spot test, agar well diffusion assay and spectrophotometric assay. The growth of K. varians (five strains) alone was compared with that in the presence of growing cells of S. xylosus (50 strains) or in the presence of heat-treated or untreated supernatants of S. xylosus. Sixteen strains stimulated the growth of K. varians K4, while four strains inhibited the K4 strain. Heated cell-free supernatants of S. xylosus did not have any effect on K. varians. The proteolytic activity of single strains or their combinations was assessed in vitro and in vivo by sodiumdodecylsulfate-polyacrylamide gel electrophoresis of sarcoplasmic protein extracts. Combinations of stimulatory strains of S. xylosus and K. varians showed a higher proteolytic activity compared with that of S. xylosus or K. varians alone.

CONCLUSIONS

The interactions between strains may influence both the growth of the co-cultured strains and proteolysis, technologically relevant characteristics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study of interactions between coagulase-negative cocci may guide the formulation of mixed strain starters for the production of fermented sausages.

Damage and ablation of large bandgap dielectrics induced by a 46.9 nm laser beam

We applied a 0.3 mJ, 1.7 ns, 46.9 nm soft-x-ray argon laser to ablate the surface of large bandgap dielectrics: CaF2 and LiF crystals. We studied the ablation versus the fluence of the soft-x-ray beam, varying the fluence in the range 0.05-3 J/cm2. Ablation thresholds of 0.06 and 0.1 J/cm2 and ablation depths of 14 and 20 nm were found for CaF2 and LiF, respectively. These results define new ablation conditions for these large bandgap dielectrics that can be of interest for the fine processing of these materials.

Shelf life of fresh sausages stored under modified atmospheres

The aim of this study was to investigate differences in modified atmosphere packaging (MAP) for the improvement of the shelf life of fresh meat products. Three different conditions for preserving fresh sausages were tested: MAP1 (20% CO2, 70% O2, and 10% N2), MAP2 (40% CO2 and 60% O2), and MAP3 (40% CO2, 30% O2, and 30% N2). Samples from the MAP2 group had fewer spoilage bacteria, stable red color (no change of a* value), and good physical attributes (high water-holding capacity, little loss from cooking, and low shear force needed for cutting) compared with samples from other treatment groups. Thus, high concentrations of CO2 (40%) and O2 (60%) resulted in a longer shelf life for fresh sausages.

Prenatal 2-Dimensional and 3-Dimensional Ultrasonography Diagnosis and Autoptic Findings of Isolated Ectopia Cordis

Ectopia cordis is a very rare congenital malformation, commonly associated with intracardiac anomalies. It is due to a defect in fusion of the anterior chest wall resulting in an extrathoracic location of the heart. We report prenatal 2-dimensional (2D) and 3D ultrasonography diagnosis and postnatal autoptic findings of an isolated ectopia cordis with tricuspid atresia. Ectopia cordis prenatal diagnosis is easily made with ultrasound by visualizing the heart outside the thoracic cavity. 3D ultrasonography may add more detailed visualization of the heart anomaly even if the 2D ultrasonography alone permits the prenatal diagnosis. Obstetrical management should include a careful search for associated anomalies, especially cardiac, and the assessment of fetal karyotype. As this is considered a sporadic anomaly, the recurrence risk is low and no genetic origin is known.