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141.
142.
An innovative self-cleaning shell-and-tube heat exchanger is presented. Inside each interior tube (through which the product flows) a scraping rod is fitted. This rod moves in reciprocal manner and the scraping elements mounted on the rod fully clean the tube wall surface. Additionally, the macroscopic displacements of the flow, induced by the insert device motion, promote high flow mixing. Consequently, tube-side heat transfer coefficients are enhanced. Thermal-hydraulic and scraping power measurements are performed in laminar regime for motionless and dynamic conditions. An extended performance evaluation criterion is proposed, in order to balance the augmentation of heat transfer and the increased power consumption (pumping and scraping power) of the device. This study allows stating guidelines for the operation of the device, concluding that the performance of the heat exchanger is irrespective of the velocity ratio. The scraper can be used intermittently, or at the minimum scraping frequency that ensures fouling mitigation. 相似文献
143.
A Ducastaing JL Azanza JM Robin J Raymond P Créac'h 《Canadian Metallurgical Quarterly》1976,58(7):771-782
Horse spleen cathepsin D (3.4.23.5.) was purified from crude extract by sodium chloride and ethanol precipitation, column chromatography fractionation on DEAE cellulose and CM Sephadex, re-chromatography on DEAE cellulose and gel filtration. The enzyme has been purified about 3.000 folds with a yield of 30 per cent. The purified enzyme seems to be homogeneous on Sephadex G100, one protein band is apparent on disc electrophoresis. Determined by dansylation the N-terminal amino acid is glycine. A molecular weight of 42,500 +/- 3,000 was obtained with Sephadex G100 gel filtration and light scattering measurements. Amino acid analysis and chemical determinations were performed: cathepsin D is a glycoprotein (2 or 3 osamine residues) including 344 amino acids and 4 disulfide bonds. Spectrophotometric data show that E1cm/1 mg/ml = 1.01 at lambda = 280 nm. ORD measurements indicate about 20 per cent of helicoidal content in the molecule. 相似文献
144.
Molecular modeling of immunoglobulin light chains implicates hydrophobic residues in non-amyloid light chain deposition disease 总被引:3,自引:0,他引:3
Deret S; Chomilier J; Huang DB; Preud'homme JL; Stevens FJ; Aucouturier P 《Protein engineering, design & selection : PEDS》1997,10(10):1191-1197
Light chain deposition disease is a severe complication of certain
immunoproliferative disorders, due to the secretion of a monoclonal light
chain which precipitates close to basement membranes of several tissues. A
kappa isotype restriction and an unusual frequency of a variable region
subgroup (VkappaIV) suggest that precise structural features govern the
propensity of pathogenic light chains to precipitate in extracellular
spaces. We studied primary structures of light chains from six patients
with light chain deposition disease in comparison with light chains from
other pathological conditions. Sequence alignment revealed the presence of
certain amino acids only in light chain deposition disease, in particular
non-polar replacing hydrophilic residues. To determine the role of these
residues, structures of the variable domain from four kappa chains
belonging to VkappaI and VkappaIV subgroups responsible for deposition
disease were modeled using known immunoglobulins as templates. The most
evident structural features shared by all pathogenic light chains were
hydrophobic residues exposed to the solvent in complementarity determining
regions 1 or 3. In contrast to immunoglobulin light chain- related
amyloidosis, where deposition of organized material might be due to
electrostatic interactions between light chain dimers, hydrophobic
interactions could enhance amorphous precipitation in non- amyloid light
chain deposition disease.
相似文献
145.
Julia Oto Raquel Herranz Emma Plana Jos Vicente Snchez-Gonzlez Javier Prez-Ardavín David Hervs lvaro Fernndez-Pardo Fernando Cana Csar David Vera-Donoso Manuel Martínez-Sarmiento Pilar Medina 《International journal of molecular sciences》2021,22(15)
Renal cell carcinoma (RCC) is the third most frequent urinary malignancy and one of the most lethal. Current diagnostic and follow-up techniques are harmful and unspecific in low-grade tumors. Novel minimally invasive markers such as urine microRNAs (miRNAs) are under study. However, discrepancies arise among studies in part due to lack of consent regarding normalization. We aimed to identify the best miRNA normalizer for RCC studies performed in urine samples together with a miRNA profile with diagnostic value and another for follow-up. We evaluated the performance of 120 candidate miRNAs in the urine of 16 RCC patients and 16 healthy controls by RT-qPCR followed by a stability analysis with RefFinder. In this screening stage, miR-20a-5p arose as the most stably expressed miRNA in RCC and controls, with a good expression level. Its stability was validated in an independent cohort of 51 RCC patients and 32 controls. Using miR-20a-5p as normalizer, we adjusted and validated a diagnostic model for RCC with three miRNAs (miR-200a-3p, miR-34a-5p and miR-365a-3p) (AUC = 0.65; Confidence Interval 95% [0.51, 0.79], p = 0.043). let-7d-5p and miR-205-5p were also upregulated in patients compared to controls. Comparing RCC samples before surgery and fourteen weeks after, we identified let-7d-5p, miR-152-3p, miR-30c-5p, miR-362-3p and miR-30e-3p as potential follow-up profile for RCC. We identified validated targets of most miRNAs in the renal cell carcinoma pathway. This is the first study that identifies a robust normalizer for urine RCC miRNA studies, miR-20a-5p, which may allow the comparison of future studies among laboratories. Once confirmed in a larger independent cohort, the miRNAs profiles identified may improve the non-invasive diagnosis and follow-up of RCC. 相似文献
146.
Lía Martínez‐Montero Vicente Gotor Vicente Gotor‐Fernndez Ivn Lavandera 《Advanced Synthesis \u0026amp; Catalysis》2016,358(10):1618-1624
Both cis‐ and trans‐but‐2‐ene‐1,4‐diamines have been prepared and efficiently applied as sacrificial cosubstrates in enzymatic transamination reactions. The best results were obtained with the cis‐diamine. The thermodynamic equilibrium of the stereoselective transamination process is shifted to the amine formation due to tautomerization of 5H‐pyrrole into 1H‐pyrrole, achieving high conversions (78–99%) and enantiomeric excess (up to >99%) by using a small excess of the amine donor. Furthermore, when the reaction proceeded, a strong coloration was observed due to polymerization of 1H‐pyrrole. A structurally related compound, cis‐but‐2‐ene‐1,4‐diol, has been utilized as cosubstrate in different alcohol dehydrogenase (ADH)‐mediated bioreductions. In this case, high conversions (91–99%) were observed due to a lactonization process. Both strategies are convenient from both synthetic and atom economy points of view in the production of valuable optically active products.
147.
Ciesielczyk Tomasz Cabrera Alberto Oleksiak Ariel Piątek Wojciech Waligóra Grzegorz Almeida Francisco Blanco Vicente 《Journal of Scheduling》2021,24(5):489-505
Journal of Scheduling - Rapid growth of demand for remote computational power, along with high energy costs and infrastructure limits, has led to treating power usage as a primary constraint in... 相似文献
148.
Himer Avila-George Jose Torres-Jimenez Nelson Rangel-Valdez Abel Carrión Vicente Hernández 《The Journal of supercomputing》2012,62(2):916-945
The Covering Arrays (CAs) are mathematical objects with minimal coverage and maximum cardinality that are a good tool for the design of experiments. A?covering array is an N×k matrix over an alphabet v s.t. each N×k subset contains at least one time each combination from {0,1,??,v?1} t , given a positive integer value?t. The process of ensuring that a CA contains each of the v t combinations is called verification of CA. In this paper, we present an algorithm for CA verification and its implementation details in three different computation paradigms: (a)?sequential approach (SA); (b)?parallel approach (PA); and (c)?Grid approach (GA). Four different PAs were compared in their performance of verifying a matrix as a CA; the PA with the best performance was included in a different experimentation where the three paradigms, SA, PA, and GA were compared in a benchmark composed by 45 possible CA instances. The results showed the limitations of the different paradigms when solving the verification of CA problem, and points out the necessity of a Grid approach to solve the problem when the size of a CA grows. 相似文献
149.
In this article, we propose the application of a control-theoretic framework to human-automation interaction. The framework consists of a set of conceptual distinctions that should be respected in automation research and design. We demonstrate how existing automation interface designs in some nuclear plants fail to recognize these distinctions. We further show the value of the approach by applying it to modes of automation. The design guidelines that have been proposed in the automation literature are evaluated from the perspective of the framework. This comparison shows that the framework reveals insights that are frequently overlooked in this literature. A new set of design guidelines is introduced that builds upon the contributions of previous research and draws complementary insights from the control-theoretic framework. The result is a coherent and systematic approach to the design of human-automation-plant interfaces that will yield more concrete design criteria and a broader set of design tools. Applications of this research include improving the effectiveness of human-automation interaction design and the relevance of human-automation interaction research. 相似文献
150.
Javier de Vicente Daniel Rodríguez Vassilis Theofilis Eusebio Valero 《Computers & Fluids》2011,43(1):143-153
Three-dimensional linear instability analyses are presented of steady two-dimensional laminar flows in the lid-driven cavity defined by [15] and further analyzed in the present volume [1], as well as in a derivative of the same geometry. It is shown that in both of the geometries considered three-dimensional BiGlobal instability leads to deviation of the flow from the two-dimensional solution; the analysis results are used to define low- and high-Reynolds number solutions by reference to the flow physics. Critical conditions for linear global instability and neutral loops are presented in both geometries. 相似文献