Global folding of proteins using a limited number of distance constraints

A Monte Carlo method is presented which can obtain the correcttertiary fold of a protein given the secondary structure andas few as three interactions between each secondary structureunit. This method was used to fold hemerythrin, Qavodoxin, bovinepancreatic trypsin inhibitor and a variable light domain froman immunoglobulin using the known secondary structures of theseproteins. Each of the proteins was successfully folded to obtaina structure resembling the initial X-ray structure. Reasonablesuccess was also achieved when using a secondary structure predictionalgorithm to assign secondary structure. The r.m.s. deviationsbetween the folded proteins and the crystal structures are inthe order of 3–5 A for the backbone coordinates. Evaluationof the r.m.s. deviations between members of the globin familyindicates that two equivalent overall folds may have r.m.s.deviations of this or even larger magnitude. The limiting numberof constraints necesssary to achieve the correct fold is discussed.     

A noninvasive technique for detecting obstructive and central sleepapnea

A new noninvasive method to detect obstructive and central sleep apnea [(OSA) and (CSA)] events is described. Data were collected from ten volunteer subjects with a previous diagnosis of OSA while they were titrated for continuous positive airway pressure (CPAP) therapy. Apneic events were identify by analyzing of estimated airway impedance determined from pressure and airflow signals delivered from CPAP. To enhance performance of this technique, a single-frequency (5 Hz with 0.5 cmH₂O peak-to-peak amplitude) probing signal was superimposed on the applied CPAP pressure. The results indicated that estimated airway impedance during OSA (mean: 17.9, SD: 3.4, N=50) was significantly higher then during CSA (mean: 4.1, SD: 1.7, N=50). When the estimated impedance of OSA and CSA events were compared to a fixed threshold, 100% of all events can be correctly categorized. These results indicate that it may be possible to diagnose OSA and CSA noninvasively based upon this technique. The instrument and the algorithm required are relatively simple and can be incorporated in a home-based device. If this method was used for prescreening apnea patients, it could reduce cost, waiting time, and discomfort associated with traditional diagnostic procedures     

Selective molecular recognition, C-H bond activation, and catalysis in nanoscale reaction vessels

Supramolecular chemistry represents a way to mimic enzyme reactivity by using specially designed container molecules. We have shown that a chiral self-assembled M4L6 supramolecular tetrahedron can encapsulate a variety of cationic guests with varying degrees of stereoselectivity. Reactive iridium guests can be encapsulated, and the C-H bond activation of aldehydes occurs with the host cavity controlling the ability of substrates to interact with the metal center based upon size and shape. In addition, the host container can act as a catalyst by itself. By restricting reaction space and preorganizing the substrates into reactive conformations, it accelerates the sigmatropic rearrangement of enammonium cations.     

Schizophrenic patients in the psychiatric interview: An experimental study of their effectiveness at manipulation.

This study attempted to examine whether chronic schizophrenic patients could effectively engage in the manipulative strategy of impression management in an evaluative interview situation. The data supported the expectation that schizophrenic mental patients can effectively present themselves as "sick" or "healthy," whichever is more suited to their needs and goals. Thus, when the patients' open ward status was questioned, they convincingly presented themselves in the interview as "healthy" and eligible for open ward living; when their residency status was questioned, they convincingly presented themselves as "sick" and ineligible for discharge. These findings were interpreted as supporting assumptions of patient effectiveness in implementing goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodische Untersuchungen zur phasentrennenden Fraktionierung von Polycaprolactam,

The carbonyl group concentration was determined with C-14 labelled 2,4-dinitrophenylhydrazine in the following substances: pergamin, filterpaper, cellophane, polyethylene and polypropylen. For standardizing the method, the MALAPRADE-splitting of the C₂? C₃-bond in the glucosidic unit of celluloses was used. The reactivity towards NaJO₄ increased in the following way: cellophane < filterpaper < pergamin.     

Development and evaluation of microarray-based whole-genome hybridization for detection of microorganisms within the context of environmental applications

The detection and identification of microorganisms in natural communities is a great challenge to biologists. Microarray-based genomic technology provides a promising high-throughput alternative to traditional microbial characterization. A novel prototype microarray containing whole genomic DNA, termed community genome array (CGA), was constructed and evaluated. Microarray hybridizations at 55 degrees C using 50% formamide permitted the examined bacteria to be distinguished at the species level, while strain-level differentiation was obtained at hybridization temperatures of 65 or 75 degrees C. The detection limit was estimated to be approximately 0.2 ng with genomic DNA from a single pure culture using a reduced hybridization volume (3 microL). Using mixtures of known amounts of DNA or a known number of cells from 14 or 16 different species, respectively, about 5 ng of genomic DNA or 2.5 x 10(5) cells were detected under the hybridization conditions used. In addition, strong linear relationships were observed between hybridization signal intensity and target DNA concentrations for pure cultures, a mixture of DNA templates, and a population of mixed cells (r2 = 0.95-0.98, P < 0.01). Finally, the prototype CGA revealed differences in microbial community composition in soil, river, and marine sediments. The results suggest that CGA hybridization has potential as a specific, sensitive, and quantitative tool for detection and identification of microorganisms in environmental samples.     

Water/moisture and fat analysis by time-domain NMR

Time-domain nuclear magnetic resonance (TD-NMR) is widely used within food industries for QC/QA applications. Precise determination of moisture and water is of fundamental interest. To determine moisture and water in the presence of lipids, the minispec makes use of differences in their respective NMR relaxation properties. The minispec applications analysing bound water are well-known and have become International standard methods. Different methods to analyse food samples with high water content or free water, like some dairy products, are addressed in this paper. Explicitly, the well-known pre-drying methods are compared to NMR diffusion experiments and a combined relaxation time analysis. Finally the single-sided NMR approach is discussed to analyse packages food.