811 research outputs found
A design principle for improved 3D AC electro-osmotic pumps
Three-dimensional (3D) AC electro-osmotic (ACEO) pumps have recently been
developed that are much faster and more robust than previous planar designs.
The basic idea is to create a ``fluid conveyor belt'' by placing opposing ACEO
slip velocities at different heights. Current designs involve electrodes with
electroplated steps, whose heights have been optimized in simulations and
experiments. Here, we consider changing the boundary conditions--rather than
the geometry--and predict that flow rates can be further doubled by fabricating
3D features with non-polarizable materials. This amplifies the fluid conveyor
belt by removing opposing flows on the vertical surfaces, and it increases the
slip velocities which drive the flow.Comment: 4 pages, 4 figures, submitted to Physical Review
The Spin-Off of Scientific Services of Novartis into a New, Independent Technology Company Offering Services to the Pharmaceutical, Chemical, and Nutrition Industry
Starting on October 1, 1999, the three sections 'Central Analytics', 'Physics', and 'Catalysis Synthesis Services' of the Scientific Services of Novartis will operate as an independent company. The new company will have about 180 employees and will offer services to customers in the pharmaceutical, chemical, and nutrition industry as well as to authorities and service firms active in these fields. The focus of activities for the new company is the chemical and physical characterization (analytics), optimization of products and processes, and the development and application of special synthetic methods, in particular by utilizing catalysis. Support is offered via single services, comprehensive service packages, or by taking over assignments for entire areas. The combination of a high scientific and technical standard built up on an ISO 9001 quality-management system, including cGMP and GLP, with an attractive working environment will be the basis for an innovative center of chemical and physical expertise
Osteoradionecrosis of the Mandible: Minimized Risk Profile Following Intensity-Modulated Radiation Therapy (IMRT)
Background and Purpose:: Osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12-46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance. Results:: Using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm3 were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with lingual decortication, was observed. Conclusion:: Using IMRT, only very small partial volumes of the mandibular bone are exposed to high radiation doses. This is expected to translate into a further reduction of ON and improved osseointegration of dental implant
Adherence to ESMO clinical recommendations for prophylaxis of chemotherapy-induced nausea and vomiting
Background: We assessed adherence to the European Society of Medical Oncology (ESMO)/Multinational Association of Supportive Care in Cancer recommendations for prophylaxis of chemotherapy-induced nausea and vomiting (CINV) at our institution. Patients and methods: The charts of 299 patients starting a new chemotherapy between November 2008 and April 2009 were reviewed. Baseline characteristics and prophylaxis of CINV during the first cycle were recorded, and adherence to ESMO recommendations was determined. Chi-square tests and logistic regression were used to test for predictors of adherence. Results: Prophylaxis of acute CINV was not adherent in 39% of the patients: 39 of 54 patients with low emetogenic chemotherapy had a serotonin antagonist, and 24 of 100 with moderately emetogenic therapy had a neurokinin antagonist. Nevertheless, 71% of the patients treated with highly emetogenic therapy received the guideline-specified prescription. Prophylaxis of delayed CINV was not adherent in 89% of the patients: 101 of 125 patients with highly or moderately emetogenic single-day chemotherapy received a serotonin antagonist. Male gender (odds ratio (OR) 0.484, 95% confidence interval (CI) 0.291-0.806; P = 0.005) and hematologic neoplasia (OR 2.151, 95% CI 1.19-3.887; P = 0.011) were independent predictors of non-adherence. Age (OR 0.981, 95% CI 0.964-0.998; P = 0.029) and inpatient treatment (OR 0.457, 95% CI 0.25-0.836; P = 0.011) indicated a lower risk of non-adherence. Conclusion: Contrary to older studies reporting frequent omissions of corticosteroids, the current study demonstrated significant overuse of serotonin antagonists for prophylaxis of delayed CIN
Caveats when interpreting intravenous urograms following ileal orthotopic bladder substitution
The aim of this study was to evaluate the appearance of the upper urinary tract following cystectomy and ileal orthotopic bladder substitution. Intravenous urograms (IVUs) performed preoperatively and at regular intervals postoperatively on 87 long-term survivors (minimum survival, 5 years) following ileal orthotopic bladder substitution were reviewed. Distention of the collecting system with blunted or rounded fornices was defined as dilatation. If in addition contrast medium excretion was delayed on the 5-min film, this was defined as obstruction. Collecting system dilatation was present on all IVU films obtained from most patients (80%) within 6 months of surgery, even in the absence of urinary tract obstruction. In contrast, dilatation was commonly seen only on the 20-min postinjection films (79%) on urograms performed more than 1 year following surgery, but not encountered on the other two postinjection radiographs (at 5 and 60min). Five years after surgery, permanent obstruction was observed in only five (3%) renoureteral units. Dilatation of the upper urinary tract after ileal orthotopic bladder substitution is a frequent finding on the 5-min, 20-min, and 60-min films during the early postoperative period but is found only on the 20-min film 1 year and later after surgery. These findings should not be overinterpreted as obstructio
Digitalisation of the Brief Visuospatial Memory Test-Revised and Evaluation with a Machine Learning Algorithm.
The disease multiple sclerosis (MS) is characterized by various neurological symptoms. This paper deals with a novel tool to assess cognitive dysfunction. The Brief Visuospatial Memory Test-Revised (BVMT-R) is a recognized method to measure optical recognition deficits and their progression. Typically, the test is carried out on paper. We present a way to make this process more efficient, without losing quality by having the patients using a tablet App and having the drawings rated with the use of a machine learning (ML) algorithm. A dataset of 1'525 drawings were digitalized and then randomly split in a training dataset and in a test dataset. In addition to the training dataset the already trained drawings from a preliminary paper were added to the training dataset. The ratings done by two neuropsychologists matched for 81% of the test dataset. The ratings done automatically with the ML algorithm matched 72% with the ones of the first neuropsychologist and 79% of the ones of the second neuropsychologist. For a semi-automated rating we defined a threshold value for the reliability of the rating of 78.8%, under which the drawing is routed for manual rating. With this threshold value the ML algorithm matched 80.3% and 86.6% of the ratings of the first and second neuropsychologists. The neuropsychologists have in that case to manually check 17.4% of the drawings. With our results is it possible to execute the BVMT-R Test in a digital way. We found out, that our ML algorithms have with the semi-automated method the similar matching as the two professional raters
Manipulation of environmental oxygen modifies reactive oxygen and nitrogen species generation during myogenesis
Regulated changes in reactive oxygen and nitrogen species (RONS) activities are important in maintaining the normal sequence and development of myogenesis. Both excessive formation and reduction in RONS have been shown to affect muscle differentiation in a negative way. Cultured cells are typically grown in 20% O2 but this is not an appropriate physiological concentration for a number of cell types, including skeletal muscle. The aim was to examine the generation of RONS in cultured skeletal muscle cells under a physiological oxygen concentration condition (6% O2) and determine the effect on muscle myogenesis. Primary mouse satellite cells were grown in 20% or 6% O2 environments and RONS activity was measured at different stages of myogenesis by real-time fluorescent microscopy using fluorescent probes with different specificities i.e. dihydroethidium (DHE), 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM DA) and 5-(and-6)-chloromethyl-2′,7′ -dichlorodihydrofluorescein diacetate (CM-DCFH-DA). Data demonstrate that satellite cell proliferation increased when cells were grown in 6% O2 compared with 20% O2. Myoblasts grown in 20% O2 showed an increase in DCF fluorescence and DHE oxidation compared with myoblasts grown at 6% O2. Myotubes grown in 20% O2 also showed an increase in DCF and DAF-FM fluorescence and DHE oxidation compared with myotubes grown in 6% O2. The catalase and MnSOD contents were also increased in myoblasts and myotubes that were maintained in 20% O2 compared with myoblasts and myotubes grown in 6% O2. These data indicate that intracellular RONS activities in myoblasts and myotubes at rest are influenced by changes in environmental oxygen concentration and that the increased ROS may influence myogenesis in a negative manner
In situ neutron diffraction for analysing complex coarse-grained functional materials
Complex functional materials play a crucial role in a broad range of energy-related applications and in general for materials science. Revealing the structural mechanisms is challenging due to highly correlated coexisting phases and microstructures, especially for in situ or operando investigations. Since the grain sizes influence the properties, these microstructural features further complicate investigations at synchrotrons due to the limitations of illuminated sample volumes. In this study, it is demonstrated that such complex functional materials with highly correlated coexisting phases can be investigated under in situ conditions with neutron diffraction. For large grain sizes, these experiments are valuable methods to reveal the structural mechanisms. For an example of in situ experiments on barium titanate with an applied electric field, details of the electric-field-induced phase transformation depending on grain size and frequency are revealed. The results uncover the strain mechanisms in barium titanate and elucidate the complex interplay of stresses in relation to grain sizes as well as domain-wall densities and mobilities
Electronic structure of PrCaMnO near the Fermi level studied by ultraviolet photoelectron and x-ray absorption spectroscopy
We have investigated the temperature-dependent changes in the near-
occupied and unoccupied states of PrCaMnO which shows the
presence of ferromagnetic and antiferromagnetic phases. The
temperature-dependent changes in the charge and orbital degrees of freedom and
associated changes in the Mn 3 - O 2 hybridization result in varied O
2 contributions to the valence band. A quantitative estimate of the charge
transfer energy () shows a larger value compared to the earlier
reported estimates. The charge localization causing the large is
discussed in terms of different models including the electronic phase
separation.Comment: 19 pages, 7 figures, To be published in Phy. Rev.
The absence of a mature cell wall sacculus in stable Listeria monocytogenes L-form cells is independent of peptidoglycan synthesis
L-forms are cell wall-deficient variants of otherwise walled bacteria that maintain the ability to survive and proliferate in absence of the surrounding peptidoglycan sacculus. While transient or unstable L-forms can revert to the walled state and may still rely on residual peptidoglycan synthesis for multiplication, stable L-forms cannot revert to the walled form and are believed to propagate in the complete absence of peptidoglycan. L-forms are increasingly studied as a fundamental biological model system for cell wall synthesis. Here, we show that a stable L-form of the intracellular pathogen Listeria monocytogenes features a surprisingly intact peptidoglycan synthesis pathway including glycosyl transfer, in spite of the accumulation of multiple mutations during prolonged passage in the cell wall-deficient state. Microscopic and biochemical analysis revealed the presence of peptidoglycan precursors and functional glycosyl transferases, resulting in the formation of peptidoglycan polymers but without the synthesis of a mature cell wall sacculus. In conclusion, we found that stable, non-reverting L-forms, which do not require active PG synthesis for proliferation, may still continue to produce aberrant peptidoglycan
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