Economy of description by parsers,DPDA's,and PDA's

It is shown that there is a sequence of languages E₁, E₂,… such that every correct prefix parser (one which detects errors at the earliest possible moment, e.g., LR or LL parsers) for E_n has size 2^cn, yet a deterministic PDA recognizing E_n exists and has size O(n²). There is another easily described sequence of languages N₁, N₂,… for which N has a nondeterministic PDA of size O(n²), but no deterministic PDA of size less than 2^cn. It is shown moreover, that this latter gap can be made arbitrarily large for different sequences of languages.     

Biodegradation of oxo-alcohol ethoxylates in the continuous flow activated sludge simulation test

Biodegradation of two alpha-methyl branched oxo-alcohol ethoxylates (OAE) of different polydispersity: LIAL 125/14 BRD (LIALB) (broad M.W. distribution) and LIAL 125/14 NRD (LIALN) (narrow M.W. distribution), both having an average of 14 oxyethylene subunits (EO) and a C(12-15) alkyl moiety were tested under the continuous flow activated sludge conditions of the classical Husmann plant. Primary biodegradation and concentration of metabolites: free oxo-alcohol fraction (FOA) and poly(ethylene glycols) (PEG), were measured. PEG were divided into two fractions: short-chained PEG (PEGshch) (1-4 EO) and long-chained PEG (PEGlch) (>4 EO). The indirect tensammetric technique combined with an adequate separation was used for analysis. Central fission was found to be a highly dominating pathway, as is the case with fatty alcohol ethoxylates. OAE are highly primarily biodegraded (above 95%). High concentrations of FOA and PEG are formed. Once formed the PEGlch are further fragmented into the PEGshch. Free alcohol fraction compounds are biodegraded sooner when alkyl moiety is shorter. OAE polydispersity has an influence on the kinetics of biodegradation; PEG formed from LIALN are biodegraded slower and to a lower degree than those from LIALB.     

Determination of short-chained poly(ethylene glycols) and ethylene glycol in environmental samples

A method for the determination of ethylene glycol (EG), di(ethylene glycol) (E2) and tri(ethylene glycol) (E3) in environmental samples (raw and treated sewage, river water) has been developed. These substances are important by-products in the biotransformation of non-ionic surfactants (NS). The method is based on sequential liquid-liquid extraction with ethyl acetate and chloroform (resulting in the separation of poly(ethylene glycols) (PEG) and EG from the water matrix), precipitation of long-chained PEG (PEGlch) with Dragendorff reagent, extraction of short-chained PEG (PEGsh) (EG, E2 and E3) from a filtrate with chloroform and the final determination using alternating current voltammetry. The precision of the method is 7.3%, the recovery 95% and a detection limit of 1.5 microg in the sample, i.e. 10 microg l(-1) was achieved. As evidenced by F and t tests, the developed method is equivalent to the indirect PEGsh determination by the difference approach where concentration of PEGsh is determined by the difference of the total PEG and PEGlch. The PEGsh fraction was found to be present in considerable concentrations in raw and treated sewage, river water, as well as being a major biotransformation by-product in the continuous flow activated sludge testing of fatty alcohol ethoxylates.     

EVs from BALF—Mediators of Inflammation and Potential Biomarkers in Lung Diseases

Extracellular vesicles (EVs) have been identified as key messengers of intracellular communication in health and disease, including the lung. EVs that can be found in bronchoalveolar lavage fluid (BALF) are released by multiple cells of the airways including bronchial epithelial cells, endothelial cells, alveolar macrophages, and other immune cells, and they have been shown to mediate proinflammatory signals in many inflammatory lung diseases. They transfer complex molecular cargo, including proteins, cytokines, lipids, and nucleic acids such as microRNA, between structural cells such as pulmonary epithelial cells and innate immune cells such as alveolar macrophages, shaping mutually their functions and affecting the alveolar microenvironment homeostasis. Here, we discuss this distinct molecular cargo of BALF-EVs in the context of inducing and propagating inflammatory responses in particular acute and chronic lung disorders. We present different identified cellular interactions in the inflammatory lung via EVs and their role in lung pathogenesis. We also summarize the latest studies on the potential use of BALF-EVs as diagnostic and prognostic biomarkers of lung diseases, especially of lung cancer.     

Electronic Properties and Structure of Assemblies of CdSe Nanocrystal Quantum Dots and Ru‐Polypyridine Complexes Probed by Steady State and Time‐Resolved Photoluminescence

Chemical and electronic interactions between CdSe nanocrystal quantum dots (NQDs) and Ru‐polypyridine complexes are studied in solution. It is shown that photoluminescence (PL) can be used to effectively monitor the formation of NQD‐complex assemblies in real time. It is also shown that with the aid of Langmuir isotherm modeling, the PL studies can be used to quantitatively characterize the composition of the assemblies and the strength of electronic interactions between their components. The approach demonstrated here is general and can be applied to other systems that combine semiconductor NQDs and appropriately functionalized organometallic or organic molecules interacting with NQDs via energy transfer, charge transfer, or other mechanisms leading to quenching of NQD emission.     

Increased occurrence of esophageal hypermotility disorders in patients with arterial hypertension

BACKGROUND AND OBJECTIVE: It has been noted in previous manometric examinations of the oesophagus in patients with chest pain that abnormal motility was often associated with arterial hypertension. A systematic study of this relationship was therefore undertaken. PATIENTS AND METHODS: In 40 patients with chest pain (18 women and 22 men, mean age 54.7 [24-70] years) and in 20 healthy volunteers (12 men, 8 women, mean age 50.8 [22-63] years) standardized oesophageal manometry and arterial blood pressure monitoring were performed over 24 hours. Coronary heart disease and gastrointestinal lesions had been excluded by angiography and endoscopy, respectively. RESULTS: 20 patients (group H) had hypertension (median 24-hour blood pressure > 135/85 mmHg), while 20 patients (group N) and the normal controls (group K) were normotensive. Oesophageal manometry data differed significantly between the three groups regarding distal pressure amplitude (in hPa [hectopascals]; group H: 62 hPa*,**, group N 44 hPa* and group K 36 hPa**; [*P < 0.0005]) and the proportion of simultaneous contractions (group H 23%, group N 22%**, group K 10%***; ***P < 0.001). The hypertensive patients had significantly more frequent motility abnormalities than normal controls (13/20 vs 4/20, P < 0.001); while normotensive patients had more frequent episodes of abnormal propulsion in the oesophagus (proportion of propulsive contractions in group H: 53%, in N: 44%, in K: 59%; P < 0.01). CONCLUSION: Oesophageal motility differed significantly in patients with chest pain from that in healthy controls. Patients with chest pain and hypertension more frequently had oesophageal hypermotility. This suggests a generalized abnormality of smooth muscle.     

The Fab-7 element of the bithorax complex attenuates enhancer-promoter interactions in the Drosophila embryo

Enhancers integrate positive and negative regulatory information to direct localized patterns of gene expression in the Drosophila embryo. Here we present evidence for the occurrence of cis regulatory elements that control the levels of gene expression by modulating enhancer-promoter interactions. For this purpose we have investigated the Drosophila bithorax complex (BX-C) because genetic studies suggest that the BX-C contains as much as 300 kb of cis regulatory information. A specialized DNA element, Fab-7, has been proposed to function as a boundary element that separates the iab-6 and iab-7 cis regulatory regions within the Abd-B domain of the BX-C. A 1.2-kb Fab-7 DNA fragment was placed between divergently transcribed white and lacZ test promoters and challenged with several defined enhancers expressed in the early embryo. These studies suggest that Fab-7 functions as an attenuator, which weakens gene expression by reducing enhancer-promoter interactions. Fab-7 selectively blocks distal enhancers in an orientation-independent fashion, and can function when located far from either the distal enhancer or target promoter. Fab-7 may be related to insulator DNAs, which flank genetic loci and functionally isolate neighboring genes. We propose that specialized DNA elements, such as the Fab-7 attenuator, might play a general role in controlling the levels of gene expression by modulating enhancer-promoter interactions.     

Positioning of the RPR standard in contemporary operator environments

This article deals with the fundamentals and current standardization efforts for IEEE 802.17 resilient packet ring. Its special resilience features make this technology robust against outages of the network infrastructure. The goals of this article are threefold. First, the fundamentals of RPR and the standardization process carried out under the auspices of IEEE and ITU are overviewed. Second, potentially hazardous situations involving traffic assignments are defined and illustrated. Finally, possible situations where the simplicity, enhanced throughput, and automatic resilience features of RPR may be advantageous for network operators are identified.