Close Cassini flybys of Saturn's ring moons Pan, Daphnis, Atlas, Pandora, and Epimetheus.

Saturn's main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons' morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons' surfaces are determined by two competing processes: contamination by a red material formed in Saturn's main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.

[Swallowing-related quality of life in oral cavity cancer. The German version of the Anderson Dysphagia Inventory]. / Schluckbezogene Lebensqualität bei Mundhöhlenkarzinomen. Anderson-Dysphagia-Inventory, deutsche Version.

BACKGROUND: The objective of this study was to validate the German version of the Anderson Dysphagia Inventory (ADI), as well as to grade it by using health-related quality of life as an external criterion. PATIENTS AND METHODS: A total of 102 patients (26 women, 76 men) aged 34-90 years (61.1+/-10.8) with a treated squamous cell carcinoma of the oral cavity participated in the study. All study participants independently completed the German version of the ADI and the SF-36 questionnaire on health-related quality of life. The German ADI was tested for its validity and reliability, and subjected to a factor analysis. RESULTS: The internal consistency reliability of the ADI was calculated using Cronbach's alpha coefficient and was equal to 0.942. In the split-half reliability the Spearman-Brown coefficient scored 0.916. Factor analysis showed a one-factor result. The correlation coefficients between the point scores of the German ADI and the following clinical parameters demonstrated construct validity: radiation (p<0.001), T-classification (p=0.002), surgical method (p=0.018), not, however, tumor site (p=0.115). The grading system was as follows: scores <55 are regarded as "definitely noticeable"; scores 55-70 are considered as "more noticeable than not"; while scores >70 are classified as " more unnoticeable than not". CONCLUSION: The German translation of the ADI is a validated and reliable method to assess swallowing-related quality of life.

Automatic, computer-based speech assessment on edentulous patients with and without complete dentures - preliminary results.

Dental rehabilitation of edentulous patients with complete dentures includes not only aesthetics and mastication of food, but also speech quality. It was the aim of this study to introduce and validate a computer-based speech recognition system (ASR) for automatic speech assessment in edentulous patients after dental rehabilitation with complete dentures. To examine the impact of dentures on speech production, the speech outcome of edentulous patients with and without complete dentures was compared. Twenty-eight patients reading a standardized text were recorded twice - with and without their complete dentures in situ. A control group of 40 healthy subjects with natural dentition was recorded under the same conditions. Speech quality was evaluated by means of a polyphone-based ASR according to the percentage of the word accuracy (WA). Speech acceptability assessment by expert listeners and the automatic rating of the WA by the ASR showed a high correlation (corr = 0.71). Word accuracy was significantly reduced in edentulous speakers (55.42 +/- 13.1) compared to the control group's WA (69.79 +/- 10.6). On the other hand, wearing complete dentures significantly increased the WA of the edentulous patients (60.00 +/- 15.6). Speech production quality is significantly reduced after complete loss of teeth. Reconstitution of speech production quality is an important part of dental rehabilitation and can be improved for edentulous patients by means of complete dentures. The ASR has proven to be a useful and easily applicable tool for automatic speech assessment in a standardized way.

Distribution and excretion of BisGMA in guinea pigs.

Bisphenol-A-glycidyldimethacrylate (BisGMA) is used in many resin-based dental materials. It was shown in vitro that BisGMA was released into the adjacent biophase from such materials during the first days after placement. In this study, the uptake, distribution, and excretion of [(14)C]BisGMA applied via gastric and intravenous administration (at dose levels well above those encountered in dental care) were examined in vivo in guinea pigs to test the hypothesis that BisGMA reaches cytotoxic levels in mammalian tissues. [(14)C]BisGMA was taken up rapidly from the stomach and intestine after gastric administration and was widely distributed in the body following administration by each route. Most [(14)C] was excreted within one day as (14)CO(2). The peak equivalent BisGMA levels in guinea pig tissues examined were at least 1000-fold less than known toxic levels. The peak urine level in guinea pigs that received well in excess of the body-weight-adjusted dose expected in humans was also below known toxic levels. The study therefore did not support the hypothesis.

The dust halo of Saturn's largest icy moon, Rhea.

Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete rings or arcs of material.

In vitro embryotoxicity assessment with dental restorative materials.

OBJECTIVES: Resin (co)monomers may be released from restorative dental materials and can diffuse into the tooth pulp or the gingiva, and can reach the saliva and the circulating blood. Genotoxic potential of some dental composite components has been clearly documented. The genotoxic effects of xenobiotics can represent a possible step in tumor initiation and/or embryotoxicity/teratogenesis. A modified fluorescent mouse embryonic stem cell test (R.E.Tox) was used to test the embryotoxic potential of following dental restorative materials: Bisphenol A glycidylmethacrylate (BisGMA), urethanedimethacrylate (UDMA), hydroxyethylmethacrylate (HEMA), and triethyleneglycoldimethacrylate (TEGDMA), as well as some of their metabolic intermediates 2,3-epoxy-2-methyl-propionicacid-methylester (EMPME), methacrylic acid (MA), and 2,3-epoxy-2-methylpropionic acid (EMPA). METHODS: Mouse embryonic stem (ES) cells stably transfected with a vector containing the gene for the green fluorescent protein under control of the cardiac alpha-myosin heavy chain promoter were differentiated in the presence of various concentrations of the test compounds for 12 days. Fluorescence was measured using the TECAN Safire and values were expressed as percent of control values. To distinguish between cytotoxic and embryotoxic effects, all compounds were tested in a standard MTT assay. RESULTS: HEMA, TEGDMA and EMPME did not influence the differentiation process of ES cells towards cardiac myocytes. No cytotoxic effects were observed at any of the concentration levels tested. Exposure to BisGMA resulted in a 50% decrease in cell survival and a very strong inhibition of cell differentiation at 10(-5)M (p<0.01). Embryotoxic effects were also present at 10(-6) and 10(-7)M (p<0.05). EMPA induced a decrease in ES cell differentiation at 10(-5)M (p<0.01) without cytotoxic effects. No embryotoxic effects were induced at lower concentrations. Exposure to UDMA resulted in a slight decrease of cell differentiation at 10(-5)M (p<0.05). Exposure of cells to MA resulted in an increase of cardiac differentiation up to 150% (p<0.05) at 10(-5)M without cytotoxic effects. CONCLUSIONS: BisGMA induced a significant high embryotoxic/teratogenic effect over a large range of concentration. Therefore attention should be focused on this dental monomer, which should be investigated further by in vivo experiments.

Improved AOX degradation in UV oxidative waste water treatment by dialysis with nanofiltration membrane.

In this article, the wastewater treatment by UV oxidation with and without preceding desalination is compared. The influence of different chloride concentrations on the TOC degradation and AOX concentration is analyzed. Nanofiltration membrane dialysis is used to separate the chloride ions from wastewater. It is demonstrated that a reduction of the chloride concentration leads to a faster TOC degradation compared to the treatment of non-desalinated wastewater. Furthermore, the additional formation of AOX during the process could be avoided in effect leading to a significant degradation of native AOX.

Structure of the beta-glucosidase gene bglA of Clostridium thermocellum. Sequence analysis reveals a superfamily of cellulases and beta-glycosidases including human lactase/phlorizin hydrolase.

The nucleotide sequence of the Clostridium thermocellum gene bglA, coding for the thermostable beta-glucosidase A, has been determined. The coding region of 1344 bp was identified by comparison with the N-terminal amino acid squence of recombinant beta-glucosidase A purified from Escherichia coli. The deduced amino acid sequence corresponds to a protein of 51,482 Da. The coding region is flanked by putative promoter and transcription terminator sequences. The protein is unrelated to beta-glucosidase B of C. thermocellum, but has a high level of similarity with other bacterial beta-glucosidases and phospho-beta-glucosidases. Similarity is also observed with the beta-galactosidase of the archaebacterium Sulfolobus solfataricus. Unexpectedly, it was found that human lactase-phlorizin hydrolase contains three copies of a sequence closely related to C. thermocellum beta-glucosidase A (up to 40% sequence identity). These diverse beta-glucosidases can therefore be grouped into an enzyme family (BGA) of common structural design. Sequence comparison by hydrophobic cluster analysis revealed that all BGA enzymes share a well conserved region which is homologous to the catalytic domain of the widely distributed cellulase family A. A distinctive feature of this domain is the sequence motif His-Asn-Glu-Pro in which the catalytic residues His and Glu are separated by 35-55 amino acid residues. The cellulase family A and the beta-glucosidase family BGA might thus be considered as members of a protein super-family comprising beta-glucanases and beta-glycosidases from all three primary kingdoms of living organisms.

Nucleotide sequence of the Clostridium thermocellum bgIB gene encoding thermostable beta-glucosidase B: homology to fungal beta-glucosidases.

The nucleotide sequence of the bglB gene, coding for the thermostable beta-glucosidase B of Clostridium thermocellum was determined. The coding region of 2265 bp was identified by comparison with the N-terminal amino acid sequence of beta-glucosidase B purified from Escherichia coli. The derived amino acid sequence corresponding to a polypeptide of Mr 84,100 was confirmed by sequencing of the C-terminal peptide generated by cleavage with cyanogen bromide. The protein bears no resemblance to other bacterial beta-glucosidase sequences. However, extensive regions of homology were identified between the C. thermocellum enzyme and fungal beta-glucosidases. The N-terminal homologous region contains an amino acid sequence very similar to the active site of beta-glucosidase A3 from Aspergillus wentii. The striking sequence similarities between C. thermocellum beta-glucosidase B and Kluyveromyces fragilis beta-glucosidase suggest the possibility of a genetic exchange between thermophilic anaerobic bacteria and yeasts.