High-yield and chirality-selective isolation of single-walled carbon nanotubes using conjugated polymers and small molecular chaperones.

Single-walled carbon nanotubes (SWCNTs) have potential for a wide range of applications in diverse fields, but the heterogeneous properties of the synthesized mixtures of SWCNT types hinder the realization of these aspirations. Recent developments in extractive purification methods of polychiral SWCNT mixtures have somewhat gradually alleviated this problem, but either the yield or purity of the obtained fractions remains unsatisfactory. In this work, we showed the possibility of simultaneously achieving both the aforementioned goals, commonly considered mutually exclusive, via the enhancement of the capabilities of the conjugated polymer extraction (CPE) technique. We found that combining small molecular species, which alone are unwanted in the system, with a selective poly(9,9'-dioctylfluorenyl-2,7-diyl-alt-6,6'-(2,2'-bipyridine)) polymer increased the concentration of the harvested SWCNTs by an order of magnitude while maintaining near-monochiral purity of the materials. The conducted modeling revealed that the presence of these additives facilitated the folding of conjugated polymers around (6,5) SWCNTs, leading to a substantial increase in the concentration and quality of the SWCNT suspension. The obtained results lay the foundation for the widescale implementation of the CPE of usually scarcely available chirality-defined SWCNTs owing to the molecular chaperones expediting the folding of the conjugated polymers.

Untargeted screening for novel autoantibodies with prognostic value in first-episode psychosis.

Immunological and inflammatory reactions have been suggested to have a role in the development of schizophrenia, a hypothesis that has recently been supported by genetic data. The aim of our study was to perform an unbiased search for autoantibodies in patients with a first psychotic episode, and to explore the association between any seroreactivity and the development of a Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) disorder characterized by chronic or relapsing psychotic symptoms. We collected plasma samples from 53 patients when they were treated for their first-episode psychosis, and 41 non-psychotic controls, after which the patients were followed for a mean duration of 7 years. Thirty patients were diagnosed with schizophrenia, delusional disorder, schizoaffective disorder, bipolar disorder or a long-term unspecified nonorganic psychosis during follow-up, whereas 23 patients achieved complete remission. At the end of follow-up, plasma samples were analyzed for IgG reactivity to 2304 fragments of human proteins using a multiplexed affinity proteomic technique. Eight patient samples showed autoreactivity to the N-terminal fragment of the PAGE (P antigen) protein family (PAGE2B/PAGE2/PAGE5), whereas no such autoreactivity was seen among the controls. PAGE autoreactivity was associated with a significantly increased risk of being diagnosed with schizophrenia during follow-up (odds ratio 6.7, relative risk 4.6). An immunohistochemistry analysis using antisera raised against the N-terminal fragment stained an unknown extracellular target in human cortical brain tissue. Our findings suggest that autoreactivity to the N-terminal portion of the PAGE protein family is associated with schizophrenia in a subset of patients with first-episode psychosis.

Molecular and biochemical characterization of the involvement of cyclin-dependent kinase A during the early development of tomato fruit.

Following fruit set, the early development of tomato (Lycopersicon esculentum Mill.) fruit comprises two distinct phases: a cell division phase and a consecutive phase of cell expansion until the onset of ripening. In this study, we analyzed cytological and molecular changes characterizing these early phases of tomato fruit development. First we investigated the spatial and temporal regulation of the mitotic activity during fruit development. The DNA content of isolated nuclei from the different fruit tissues was determined by flow cytometry analysis. The results confirm the data of mitotic activity measurements and show that cell differentiation, leading to expanded cells, is characterized by endoreduplication. Second, we isolated two cDNAs, named Lyces;CDKA1 (accession no. Y17225) and Lyces;CDKA2 (accession no. Y17226), encoding tomato homologs of the cyclin-dependent kinase (CDK) p34(cdc2). Tomato CDKA gene expression was followed at both the transcriptional and translational levels during fruit development. The transcripts for Lyces;CDKA1 and Lyces;CDKA2 and the corresponding CDKA proteins are predominantly accumulated during the phase of cell division between anthesis and 5 d post anthesis (DPA). In whole fruits, the maximum CDK activity was obtained between 5 and 10 DPA. The determination of the kinase activity using protein extracts from the different fruit tissues was in agreement with mitotic activity analysis. It showed the particular disappearance of the activity in the gel tissue as early as 15 DPA. The overall data of CDK activity measurements suggest a strong post-translational regulation of CDK at the temporal and spatial levels during early tomato fruit development.

Metabolic regulation of asparagine synthetase gene expression in maize (Zea mays L.) root tips.

Differential hybridization of a cDNA library constructed with poly(A)+ mRNA from 24 h starved maize (Zea mays L.) root tips, resulted in the isolation of a cDNA (called pZSS1) that was highly induced during glucose deprivation. The nucleotide sequence analysis of the full-length cDNA allowed its identification by comparison with sequence data bases. The 586 amino acid sequence encoded by pZSS1 was shown to be about 60% identical to sequences of asparagine synthetases (EC 6.3.5.4) from Asparagus officinalis, Pisum sativum, Arabidopsis thaliana and Brassica oleracea. Southern blot analysis of maize genomic DNA showed that asparagine synthetase may be encoded by at least two genes. The use of a specific probe for the 3' untranslated region of pZSS1 in Northern blot experiments, revealed that the isolated AS gene was essentially expressed in roots of maize seedlings. Time course analysis revealed that maximal expression of the gene corresponding to pZSS1 occurs between 18 and 24 h after the onset of the starvation treatment. The steady-state levels of transcripts in maize root tips were found to change under various incubation conditions. Exogenous supply of metabolizable sugars downregulated the gene expression, while carbohydrate deprivation or feeding with non-metabolizable sugars resulted in the induction of gene expression. In addition to carbohydrate deprivation, the effects of nitrogen metabolite supply and stress conditions indicate that gene expression might be under metabolic control in maize root tips. The intracellular nitrogen to carbon ratio might be an important factor for the regulation of asparagine synthetase gene expression.

Failure to thrive: a case obvious to physicians is perplexing to the court.

Proving a failure to thrive case in court can be difficult unless all professionals prepare in advance for consistent testimony which educates the court in a simple and straightforward manner. This case highlights the importance of a physician being alert to non-organic failure to thrive, as a cause of abuse or neglect. A bizarre array of confusing biological and psychosocial facts may prove difficult to categorise for forensic purposes. Physicians can themselves complicate future court presentations by failing to use growth charts to evaluate children and using non-speaking phrases such as 'well-nourished'. Although non-organic failure to thrive can often be determined medically; attorneys, police and other healthcare personnel may benefit from the review of physical, psychosocial, and familial characteristics of failure to thrive children. A multi-disciplinary team approach best serves the interests of these abused children as well as the interests of justice.

Phase statistics of interferograms with applications to synthetic aperture radar.

Interferometric methods are well established in optics and radio astronomy. In recent years, interferometric concepts have been applied successfully to synthetic aperture radar (SAR) and have opened up new possibilities in the area of earth remote sensing. However interferometric SAR applications require thorough phase control through the imaging process. The phase accuracy of SAR images is affected by decorrelation effects between the individual surveys. We analyze quantitatively the influence of decorrelation on the phase statistics of SAR interferograms. In particular, phase aberrations as they occur in typical SAR processors are studied in detail. The dependence of the resulting phase bias and variance on processor parameters is presented in several diagrams.

Differing substomatal and chloroplastic CO2 concentrations in water-stressed wheat.

Gas exchanges of wheat (Triticum aestivum L. cv. Courtot) shoots were measured before and during a water stress. While photosynthesis, transpiration and dark respiration decreased because of the stress, photorespiration increased initially, up to a maximum of 50% above its initial value. The CO2 concentration in the intercellular space was calculated from gas-diffusion resistances, and remained approximately constant before and during the stress. On the other hand, the CO2 concentration in the chloroplast, in the vicinity of Ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco), was evaluated from the ratio of CO2 to O2 uptake, using the known kinetic constants of the oxygenation and carboxylation reactions which compete for Rubisco. In the well-watered plants, the calculated chloroplastic concentration was slightly smaller than the substomatal concentration. During water stress, this concentration decreased while the substomatal CO2 concentration remained constant. Hypotheses to explain this difference between substomatal and chloroplastic CO2 concentrations are discussed.

[Experiences with non-swimmers in the rehabilitation of adult clients (author's transl)]. / Erfahrungen mit Nichtschwimmern in der Rehabilitation Erwachsener.

The experiences with 595 adult non-swimmers receiving swimming instruction during the years 1974-1976 are discussed on the basis of selected and cited tape interviews. Theoretical reference systems are described against this background of empirical observations, e.g., Alfred Adler's interpretation of individual psychology - that one's style of living is influenced by early childhood experiences, human indifference or hostility. Recent works of brain physiologists are mentioned, which deal with the two forms of human consciousness: the verbalisation of linear, logic and abstract thoughts in the left hemisphere (in the case of right handed persons), and the specialisation of the right hemisphere in the perception of symbols, pictures and irrational feelings. The helpful effect of a non-directive, client-centered atomosphere is discussed. The behavioural changes in patients who learned to swim are compared with the hypothesis formulated by Hoppe - that psychosomatic diseases might be caused by a functional disconnection of the two hemispheres.