Propulsion Mechanisms for Leidenfrost Solids on Ratchets

We propose a model for the propulsion of Leidenfrost solids on ratchets based on viscous drag due to the flow of evaporating vapor. The model assumes pressure-driven flow described by the Navier-Stokes equations and is mainly studied in lubrication approximation. A scaling expression is derived for the dependence of the propulsive force on geometric parameters of the ratchet surface and properties of the sublimating solid. We show that the model results as well as the scaling law compare favorably with experiments and are able to reproduce the experimentally observed scaling with the size of the solid

Prevention of Travelers' Diarrhea by Nonantibiotic Drugs

Travelers have resorted to a variety of drugs for prevention of diarrhea. No beneficial prophylactic effect has been confirmed for halogenated hydroxyquinolines, lactobacilli, antimotility drugs, ethacridine, and various other agents. In contrast, bismuth subsalicyate (BSS) in liquid form reduced the incidence of diarrhea in students from the United States living in Mexico and in tablet form in volunteers challenged by enterotoxigenic Escherichia coli. In tourists visiting various developing countries, a randomized, double-blind study was conducted in which 390 persons received a total of 2.1 or 1.05 g of BSS daily or placebo in tablet form in two doses. BSS reduced the incidence of diarrhea by 41% in the high-dose group and by 35% in the low-dose group without causing important adverse reaction

Untersuchungen zur präventiven Magen-Darm-Strongyliden- Kontrolle bei Milchziegen mittels Esparsettenpellets

Dairy goats, naturally infected with gastrointestinal nematodes, were fed 700g sainfoin- or alfalfa-pellets per day, additionally to a non-tanniferous basic diet. The effect of the feeding on the parasite egg excretion per gramm faeces (EPG) was monitored over a period of 7 weeks. The trial was conducted in parallel at two sites; in France and in Switzerland. At both sites the same quality of sainfoin- and alfalfapellets were used. Compared to the alfalfa group the EPG of the sainfoin fed goats were reduced by 12% in France andby 18% in Switzerland. A repeated measurement analysis revealed no significant difference between the feeding groups at neither site. As it is very likely that the effect of condensed tannins on gastrointestinal nematodes is dose dependent, the relatively low absolute condensed tannin concentration might be jointly responsible for the absence of a significant effect

Markers of Inflammation in Bacterial Diarrhea among Travelers, with a Focus on Enteroaggregative Escherichia coli Pathogenicity

The intestinal inflammatory response of traveler's diarrhea acquired in Goa, India, and Guadalajara, Mexico, was studied. Fecal lactoferrin was found in stool samples in which enteroaggregative Escherichia coli (EAEC), enterotoxigenic E. coli, or Salmonella or Shigella species were isolated, with Shigella-positive cases showing the highest level. Samples from cases of Shigella-associated diarrhea had the highest concentrations of fecal cytokines. Travelers to India who had EAEC-associated diarrhea showed elevated levels of interleukin (IL)-8 (median, 341.15 pg/mL) and IL-1β (median, 749.90 pg/mL). Although 15 travelers to Mexico who had EAEC-associated diarrhea had a median concentration of 0 pg/mL for both IL-8 and IL-1β, 2 had high levels of IL-8 (1853 and 11,786 pg/mL), and 5 showed elevated levels of IL-1β (1-1240 pg/mL). Samples from patients in India who had pathogen-negative diarrhea or from patients in Mexico who had asymptomatic EAEC infection were negative for cytokines. Bacterial pathogens causing traveler's diarrhea commonly produce intestinal inflammation, although a subset of patients with EAEC-associated diarrhea fail to develop an inflammatory respons

A Local Role for the Small Ribosomal Subunit Primary Binder rpS5 in Final 18S rRNA Processing in Yeast

In vivo depletion of the yeast small ribosomal subunit (SSU) protein S5 (rpS5) leads to nuclear degradation of nascent SSUs and to a perturbed global assembly state of the SSU head domain. Here, we report that rpS5 plays an additional local role at the head/platform interface in efficient SSU maturation. We find that yeast small ribosomal subunits which incorporated an rpS5 variant lacking the seven C-terminal amino acids have a largely assembled head domain and are exported to the cytoplasm. On the other hand, 3′ processing of 18S rRNA precursors is inhibited in these ribosomal particles, although they associate with the putative endonuclease Nob1p and other late acting 40S biogenesis factors. We suggest that the SSU head component rpS5 and platform components as rpS14 are crucial constituents of a highly defined spatial arrangement in the head – platform interface of nascent SSUs, which is required for efficient processing of the therein predicted SSU rRNA 3′ end. Positioning of rpS5 in nascent SSUs, including its relative orientation towards platform components in the head-platform cleft, will depend on the general assembly and folding state of the head domain. Therefore, the suggested model can explain 18S precursor rRNA 3′ processing phenotypes observed in many eukaryotic SSU head assembly mutants

Assessment of Parotid Gland Tumors by Means of Quantitative Multiparametric Ultrasound (mpUS)

Objective: The preoperative diagnostical differentiation of parotid gland tumor (PGT) is not always simple due to several different entities. B-mode-ultrasound (US) remains the imaging modality of choice, while histopathology serves as the gold standard for finalizing the diagnosis. We aimed to evaluate the use of multiparametric US (mpUS) in the assessment of PGT. Methods: We included 97 PGTs from 96 patients. A standardized mpUS protocol using B-mode-US, shear-wave elastography (SWE), and standardized contrast-enhanced ultrasound (CEUS) was performed prior to surgical intervention. SWE was assessed by real-time measurement conducting a minimum of five measurements, while quantitative CEUS parameters were assessed with a post-processing perfusion software. Results: SWE allowed differentiation between benign PGT (Warthin's Tumor (WT) paired with lymph nodes (LN) and pleomorphic adenoma (PA)), and WT and LN were softer compared to PA. WT showed lower velocities than squamous cell carcinoma (SCC): the most common malignant PGT. CEUS parameters showed significant group differences between WT and PA, WT and malignant lesions, WT and SCC, WT paired with LN versus PA, and WT paired with LN versus SCC. Conclusion: MpUS seems to be beneficial in the assessment of PGT characterization, with benign PGT appearing to be softer in SWE than tumors with malignant tendencies. The quantitative CEUS parameter shows higher perfusion in WT than in PA, and malignant PGTs are less vascularized than WTs

Cluster-induced crater formation

Using molecular-dynamics simulation, we study the crater volumes induced by energetic impacts ($v= 1- 250$ km/s) of projectiles containing up to N=1000 atoms. We find that for Lennard-Jones bonded material the crater volume depends solely on the total impact energy $E$. Above a threshold \Eth, the volume rises linearly with $E$. Similar results are obtained for metallic materials. By scaling the impact energy $E$ to the target cohesive energy $U$, the crater volumes become independent of the target material. To a first approximation, the crater volume increases in proportion with the available scaled energy, $V=aE/U$. The proportionality factor $a$ is termed the cratering efficiency and assumes values of around 0.5.Comment: 9 page

Prevalence of dental caries in children with congenital heart disease

Background: Congenital heart defects (CHD) affect about 8 out of 1000 births worldwide. Most of the patients reach adulthood and are exposed to an increased risk of endocarditis. Since bacteria already enter the bloodstream during everyday activities, oral hygiene is given special importance in the prevention of endocarditis. Methods: In this study 81 boys (55.1%) and 66 (44.9%) girls with CHD received a dental exam and additionally an assessment using the DIAGNOdent (R) pen. This study group consisting of patients with CHD was matched with a healthy epidemiological control group in Germany. Results: Eighty-one boys (55.1%) and 66 (44.9%) girls were examined. The mean age was 11 & PLUSMN; 4 years. 38.8% showed at least one untreated carious lesions. 37.4% had a dmft/DMFT & GE;2 and thus represented a group with an increased caries risk. The dmft value was 2.12 & PLUSMN; 1.25 in the age group 3-6 year olds. In the group of the 7-12 year old patients the DMFT/dmft was 2.06 & PLUSMN; 2.27, whereas DMFT in 13-17 year olds was at 2.12 & PLUSMN; 1.58. However, children and adolescents with CHD had a higher DMF index than healthy children in the same age group. Conclusions: The present study reveals that more than one third of those examined have a dental condition in need of rehabilitation. In future, close interdisciplinary cooperation between pediatric cardiologists and dentists should ensure regular dental check-ups