Microfluidic concentration of bacteria by on-chip electrophoresis     

Puchberger-Enengl D  Podszun S  Heinz H  Hermann C  Vulto P  Urban GA 《Biomicrofluidics》2011,5(4):044111-044111-10

In this contribution, we present a system for efficient preconcentration of pathogens without affecting their viability. Development of miniaturized molecular diagnostic kits requires concentration of the sample, molecule extraction, amplification, and detection. In consequence of low analyte concentrations in real-world samples, preconcentration is a critical step within this workflow. Bacteria and viruses exhibit a negative surface charge and thus can be electrophoretically captured from a continuous flow. The concept of phaseguides was applied to define gel membranes, which enable effective and reversible collection of the target species. E. coli of the strains XL1-blue and K12 were used to evaluate the performance of the device. By suppression of the electroosmotic flow both strains were captured with efficiencies of up to 99%. At a continuous flow of 15 μl/min concentration factors of 50.17 ± 2.23 and 47.36 ± 1.72 were achieved in less than 27 min for XL1-blue and K12, respectively. These results indicate that free flow electrophoresis enables efficient concentration of bacteria and the presented device can contribute to rapid analyses of swab-derived samples.  相似文献   

Determinants of bone mineral density in patients on haemodialysis or peritoneal dialysis – a cross-sectional,longitudinal study     

Mads Nybo  Bente Jespersen  Michael Aarup  Charlotte Ejersted  Anne Pernille Hermann  Kim Brixen 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(3):342-350

Introduction:

The aim of the study was to identify biomarkers of alteration in bone mineral density (BMD) in patients on haemodialysis (HD) and peritoneal dialysis (PD).

Materials and methods:

In a cross-sectional, longitudinal study dual-energy X-ray absorptiometry scans were performed in 146 HD-patients and 28 PD-patients. Follow-up after 14 months (mean) was conducted in 73 patients. As potential biomarkers we investigated parathyroid hormone (PTH), 25-hydroxy vitamin-D, ionised calcium, albumin, phosphate, and total alkaline phosphatases (t-ALP).

Results:

Both groups of dialysis patients had lower BMD in the femoral neck (BMD_neck) (P < 0.001) and forearm (BMD_forearm) (P < 0.001) compared to healthy controls, but comparable BMD in the lumbar spine (BMD_spine). BMD did not differ between dialysis types, but patients ever-treated with glucocorticoids had significantly lower BMD, while patients with polycystic kidney disease had higher BMD. BMD correlated with body weight, actual age, age at initiation of dialysis, duration of dialysis and levels of PTH and t-ALP. However, t-ALP only remained associated with low BMD_spine after adjusting for other factors (P = 0.001). In the follow-up study all patients had decreased BMD in all three locations, but only for the lumbar spine there was a significant association between BMD and the bone markers t-ALP (P = 0.009) and PTH (P = 0.013).

Conclusions:

Both HD and PD patients have low BMD, and increased concentrations of t-ALP is associated BMD_spine after adjustment, while PTH and t-ALP is associated with decrease in BMD_spine over time. This substantiates the use of these biomarkers in both types of dialysis patients.  相似文献   

Karl Jaspers     

Hermann Horn 《Prospects》1993,23(3-4):721-739

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„Von Weimar nach PISA“     

Hermann Lange 《Zeitschrift für Erziehungswissenschaft》2003,6(3):449-457

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Zwischen Kontrolle und Demokratisierung: Die Sportpolitik der französischen Besatzungsmacht in Südwest     

Stefanie Woite-Wehle  Hermann Rieder 《Sportwissenschaft》2002,32(4):453-458

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The development of archival science as a scholarly discipline     

Hermann Rumsch?ttel 《Archival Science》1987,1(2):143-155

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Engineering Education and the Status of Industry     

Hermann Bayer  Peter Lawrence 《European Journal of Engineering Education》1977,2(3):223-227

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The supply of information on chemical reactions in the IDC system     

Robert Fugmann  Günter Kusemann  Jakob Hermann Winter 《Information processing & management》1979,15(6):303-323

The possibilities and limitations of chemical reaction names as the basis for retrieving literature dealing with reaction types are briefly reviewed, as well as the capability of a mere substructure search in a file of reactants and products. It is demonstrated that reaction indexing ideally should be based on the identification of the reaction sites of the molecules involved, as well as on the representation of various kinds of relations between these reactive centers. The GREMAS reaction indexing of IDC is discussed as an example. Before a chemist can request information on reaction types that appear promising for a certain target molecule, he must be aware of their existence. The task of computer-assisted synthesis design is to submit suggestions of conceivable synthetic pathways to a target structure and so to alert the chemist to syntheses of which he had not yet been aware. The “reverse retrieval” technique is demonstrated to constitute a fundamental principle for this kind of information supply. If sufficiently developed and assisted by an effective system for the documentation and classification of reaction types, it can provide suggestions for syntheses at a considerable efficiency without requiring completion by additional principles. The IDC system of (Sub-) Structure search seems to be able to serve this purpose too, due to its flexibility, economics, and precision. The reverse retrieval offers solutions to a number of problems hitherto unresolved in information science.  相似文献   

History of Science in Physics Teaching     

Jardim  Wagner Tadeu  Guerra  Andreia  Schiffer  Hermann 《Science & Education》2021,30(3):609-638

Science educators are increasingly using a historical approach to pedagogy as a way to enable students to understand the process of the construction of science in a more contextualized manner. Considering the meaning of context in a broader sense, this article has two objectives. First, it aims to explore how physics lessons using a Cultural History of Science approach allowed the development of activities that encouraged students to have discussions about science where their own socio-cultural context was considered, referring to Brazilian scientific production. Second, the article to investigate which understandings about scientific practices could be developed by students from in-class discussions inspired by the Cultural History of Science approach focusing on a historical and students’ own social contexts. The historical episode selected to be introduced in their physics lessons was the development of the Leiden jar in Europe, in the eighteenth century, focusing on the quotidian practices and habits that enabled the construction and use of this artifact. The lessons developed from the Cultural History approach seemed to allow the students to understand that science was developed by many different social actors, in sites that exceed the laboratory and by actions performed in various dimensions. The findings suggest that this approach in science teaching can be a strategy to historically contextualize the development of science while allowing students to reflect about the scientific production in their social context.

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Bihemifield visual stimulation reveals reduced lateral bias in dyslexia     

Howard T. Hermann  Nancy L. Sonnabend  Yehoshua Y. Zeevi 《Annals of dyslexia》1986,36(1):154-175

Orton (1936) observed that dyslexic readers display not only obvious linguistic processing errors, but also diminished lateralized specialization of other cerebral hemispheric functions. To explore his “intergrading” hypothesis, six developmental dyslexics (DDs) and a group of good readers (GRs) were tested on measures of interhemispheric coordination. All subjects (ages 16 to 47) demonstrated normal oculomotor control and visual acuity prior to testing. Subjects were instructed to track three different point-light source patterns, (single stimulus in one hemifield, dual stimuli in one hemifield and a pair of simultaneous, symmetric, bihemifield stimuli [SSBS]), presented in random sequence and arrayed horizontally at ±5, ±10, and ±15 degrees eccentricity. Tested with unihemifield stimuli, all subjects showed normal saccadic latencies and trajectories. In response to SSBS, all GRs showed pronounced directional preference, choosing largely to track one side over the other. DDs showed reduced laterality bias (p<.025). DDs showed significantly longer response latencies to SSBS than to unihemifield stimulation (p<.01) and differed significantly from GRs (p<.05).  相似文献