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Takuma Yagasaki Kazuhiro Himoto Tatsuya Nakamura Masakazu Matsumoto 《Molecular simulation》2015,41(10-12):868-873
We present the recent development of simulation studies on structure and dynamics of high-pressure ices and filled ices. After surveying the representative structures of ices, focus is placed on some properties of one of the ice polymorphs, plastic ice, which has been theoretically predicted but not yet been found experimentally. Its intervention between ice VII and liquid water enables to account for large discrepancies among various experimental melting curves of ice VII. We also examine the dynamical properties of the filled ice in which hydrogen molecules are contained in void space of the low-pressure cubic ice. In contrast to the plastic ice, which has a bearing on ice VII, it exhibits a gradual change to each rotator phase of guest hydrogen and/or host water molecules. 相似文献
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Freeze-dried microarterial allografts 总被引:7,自引:0,他引:7
Rehydrated freeze-dried microarterial allografts were implanted to bridge arterial defects using New Zealand White rabbits as the experimental model. Segments of artery from the rabbit ear and thigh were harvested and preserved for a minimum of 2 weeks after freeze-drying. These allografts, approximately 1 mm in diameter and ranging from 1.5 to 2.5 cm in length, were rehydrated and then implanted in low-pressure and high-pressure arterial systems. Poor patency was noted in low-pressure systems in both allografts and autografts, tested in 12 rabbits. In the high-pressure arterial systems, allografts that were freeze-dried and reconstituted failed in a group of 10 rabbits with an 8-week patency rate of 30 percent. Gamma irradiation in an effort to reduce infection and antigenicity of grafts after freeze-drying was associated with a patency rate of 10 percent at 8 weeks in this system in another group of 10 rabbits. Postoperative cyclosporin A therapy was associated with a patency rate of 22.2 percent in the high-pressure arterial system in a 9-rabbit group. Control autografts in this system in a group of 10 rabbits showed a 100 percent patency at 8 weeks. Microarterial grafts depend on perfusion pressure of the vascular bed for long-term patency. Rehydrated freeze-dried microarterial allografts do not seem to function well in lengths of 1 to 2.5 cm when implanted in a high-pressure arterial system. Freeze-dried arterial allografts are probably not antigenic. 相似文献
4.
Nina Bloecher Kevin Frank Morten Bondø Deni Ribicic Per Christian Endresen Biao Su 《Biofouling》2013,29(7):805-817
To avoid the negative impacts caused by biofouling development, aquaculture nets around the world are periodically cleaned using high-pressure washers. Net cleaning is labour-intense and costly, can damage antifouling coatings on the nets, and pose contamination as well as fish health and welfare risks. To support the environmental sustainability of the growing aquaculture sector, novel net cleaning methods are needed. This study examined low-pressure-, cavitation-, and suction-based cleaning technologies as alternatives to conventional high-pressure cleaning. Using field experiments, cleaning efficacy, cleaning waste generation, and the impact of cleaning on coating integrity and net strength were evaluated. Cavitation and high-pressure cleaning achieved considerably higher cleaning efficacy than low-pressure and suction cleaning. However, a single high-pressure treatment caused up to 53% coating degradation, compared to 2% for cavitation. All technologies produced similar cleaning waste and neither reduced net strength significantly. This study identifies cavitation cleaning as promising technology for biofouling control on aquaculture nets. 相似文献
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BackgroundMonolithic chromatography using convective interaction media (CIM) disks or columns can be used in the separation step of speciation analysis. When different monolithic disks are placed in one housing, forming conjoint liquid chromatography (CLC) monolithic column, two-dimensional separation is achieved in a single chromatographic run.MethodsHere, we assembled low-pressure (maximum 50 bar) CLC monolithic column, which consists of two 0.34 mL shallow CIM monolithic disks and high-pressure CLC column (maximum 150 bar) from 0.1 mL analytical high performance short bed CIMac monolithic disks. Both the CLC columns constructed from affinity Protein G and weak anion exchange diethylamine (DEAE) disks, were applied for the speciation of cisplatin, oxaliplatin and carboplatin in spiked standard serum proteins, spiked human serum and serum of cancer patients. The analytical performances of the CLC columns used were evaluated by comparing their robustness, selectivity, repeatability and reproducibility. The separated serum proteins were detected on-line by ultraviolet (UV) and eluted Pt species by inductively coupled plasma mass spectrometry (ICP-MS). For accurate quantification of the separated Pt species (unbound Pt-based chemotherapeutic from species associated to transferrin (Tf), human serum albumin (HSA) and Immunoglobulin G (IgG)), post column isotope dilution (ID)-ICP-MS was used.ResultsThe data from analyses showed that both tested CLC monolithic columns gave statistically comparable results, with the low-pressure CLC column exhibiting better resolving power and robustness. It also enables more effective cleaning of monolithic disks and to analyse larger series of serum samples than the high-pressure CLC column. Analyses of serum samples of cancer patients treated with cisplatin or carboplatin showed that Pt-chemotherapeutics were bound preferentially to HSA (around 80%). The portion of unbound Pt in general did not exceed 2%, up to 5% of Pt was associated with Tf and approximately 20% with IgG. Column recoveries, calculated as a ratio between the sum of concentrations of Pt species eluted and concentration of total Pt in serum samples, were close to 100%.ConclusionsLow-pressure CLC column exhibited greater potential than high-pressure CLC column, and can be thus recommended for its intended use in speciation analysis of metal-based biomolecules. 相似文献
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González-López A Astudillo A García-Prieto E Fernández-García MS López-Vázquez A Batalla-Solís E Taboada F Fueyo A Albaiceta GM 《American journal of physiology. Lung cellular and molecular physiology》2011,301(4):L500-L509
High-pressure ventilation triggers different inflammatory and matrix remodeling responses within the lung. Although some of them may cause injury, the involvement of these mediators in repair is largely unknown. To identify mechanisms of repair after ventilator-induced lung injury (VILI), mice were randomly assigned to baseline conditions (no ventilation), injury [90 min of high-pressure ventilation without positive end-expiratory pressure (PEEP)], repair (injury followed by 4 h of low-pressure ventilation with PEEP), and ventilated controls (low-pressure ventilation with PEEP for 90 and 330 min). Histological injury and lung permeability increased during injury, but were partially reverted in the repair group. This was accompanied by a proinflammatory response, together with increases in TNF-α and IFN-γ, which returned to baseline during repair, and a decrease in IL-10. However, macrophage inflammatory protein-2 (MIP-2) and matrix metalloproteinases (MMP)-2 and -9 increased after injury and persisted in being elevated during repair. Mortality in the repair phase was 50%. Survivors showed increased cell proliferation, lower levels of collagen, and higher levels of MIP-2 and MMP-2. Pan-MMP or specific MMP-2 inhibition (but not MIP-2, TNF-α, or IL-4 inhibition) delayed epithelial repair in an in vitro wound model using murine or human alveolar cells cultured in the presence of bronchoalveolar lavage fluid from mice during the repair phase or from patients with acute respiratory distress syndrome, respectively. Similarly, MMP inhibition with doxycycline impaired lung repair after VILI in vivo. In conclusion, VILI can be reverted by normalizing ventilation pressures. An adequate inflammatory response and extracellular matrix remodeling are essential for recovery. MMP-2 could play a key role in epithelial repair after VILI and acute respiratory distress syndrome. 相似文献
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Seung Yun Yang 《Journal of biomolecular structure & dynamics》2013,31(12):1490-1496
Diamond-anvil cell, pressure-tuning infrared (IR), and Raman microspectroscopic measurements have been undertaken to examine the effects of high pressures up to about 45?kbar on the vibrational spectra of the four DNA bases, adenine, cytosine, guanine, and thymine. Small structural changes were evident for all the four bases, viz., for adenine and cytosine at 28–31?kbar; for guanine at 16–19?kbar; and for thymine at 25–26?kbar. These changes are most likely associated with alterations in the intermolecular hydrogen-bonding interactions. The pressure dependences of the main peaks observed in the IR spectra of the two phases of guanine lie in the ?0.07–0.66 (low-pressure phase) and 0.06–0.91 (high-pressure phase) cm?1/kbar ranges. Also, in the Raman spectra of this nucleoside base, the dν/dP values range from ?0.07–0.31 (low-pressure phase) to 0.08–0.50 (high-pressure phase) cm?1/kbar. Similar ranges of dν/dP values were obtained for the other three nucleoside bases. 相似文献
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The relationship between membrane damage and loss of viability following pressure treatment was examined in Escherichia coli strains C9490, H1071, and NCTC 8003. These strains showed high, medium, and low resistance to pressure, respectively, in stationary phase but similar resistance to pressure in exponential phase. Loss of membrane integrity was measured as loss of osmotic responsiveness or as increased uptake of the fluorescent dye propidium iodide. In exponential-phase cells, loss of viability was correlated with a permanent loss of membrane integrity in all strains, whereas in stationary-phase cells, a more complicated picture emerged in which cell membranes became leaky during pressure treatment but resealed to a greater or lesser extent following decompression. Strain H1071 displayed a very unusual pressure response in stationary phase in which survival decreased to a minimum at 300 MPa but then increased at 400 to 500 MPa before decreasing again. Membranes were unable to reseal after treatment at 300 MPa but could do so after treatment at higher pressures. Membrane damage in this strain was thus typical of exponential-phase cells under low-pressure conditions but of stationary-phase cells under higher-pressure conditions. Heat shock treatment of strain H1071 cells increased pressure resistance under low-pressure conditions and also allowed membrane damage to reseal. Growth in the presence of IPTG (isopropyl-beta-D-thiogalactopyranoside) increased resistance under high-pressure conditions. The mechanisms of inactivation may thus differ at high and low pressures. These studies support the view that membrane damage is an important event in the inactivation of bacteria by high pressure, but the nature of membrane damage and its relation to cell death may differ between species and phases of growth. 相似文献
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Eliane M.Z. Michielin Ana A. Salvador Carlos A.S. Riehl Artur Smnia Jr. Elza F.A. Smnia Sandra R.S. Ferreira 《Bioresource technology》2009,100(24):6615-6623
The present study describes the chemical composition and the antibacterial activity of extracts from Cordia verbenacea DC (Borraginaceae), a traditional medicinal plant that grows widely along the southeastern coast of Brazil. The extracts were obtained using different extraction techniques: high-pressure operations and low-pressure methods. The high-pressure technique was applied to obtain C. verbenacea extracts using pure CO2 and CO2 with co-solvent at pressures up to 30 MPa and temperatures of 30, 40 and 50 °C. Organic solvents such as n-hexane, ethyl acetate, ethanol, acetone and dichloromethane were used to obtain extracts by low-pressure processes. The antibacterial activity of the extracts was also subjected to screening against four strains of bacteria using the agar dilution method. The extraction yields were up to 5.0% w/w and up to 8.6% w/w for supercritical fluid extraction with pure CO2 and with ethyl acetate as co-solvent, respectively, while the low-pressure extraction indicates yields up to 24.0% w/w in the soxhlet extraction using water and aqueous mixture with 50% ethanol as solvents. The inhibitory activity of the extracts in Gram-positive bacteria was significantly higher than in Gram-negative. The quantification and the identification of the extracts recovered were accomplished using GC/MS analysis. The most important components identified in the extract were artemetin, β-sitosterol, α-humulene and β-caryophyllene, among others. 相似文献
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The relationships between behaviour and synoptic-scale weather patterns and wind speeds for wandering (Diomedea exulans), black-browed (D. melanophrys) and light-mantled sooty (Phoebetria palpebrata) albatrosses were examined using observations collected from ships in the Southern Ocean south of Tasmania, Australia. Wandering albatrosses were found in high-pressure systems in significantly higher numbers than expected than in low-pressure systems. Wandering albatrosses were also found more frequently at lower latitudes than were black-browed and light-mantled sooty albatrosses. Light-mantled sooty and black-browed albatrosses showed no significant association with high- or low-pressure systems, suggesting that they can use either pressure system for travel. High-pressure systems may act as "traps" for wandering albatrosses, due to the lower wind speeds generally associated with these systems. 相似文献
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G. Schwedt H.H. Bussemas Ch. Lippmann 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1977,143(3):259-266
The possibilities were examined for the high-pressure liquid chromatographic analysis of cortisol with methods of adsorption, distribution and reversed-phase chromatography. Free cortisol in urine can be determined by extraction with chloroform and subsequent adsorption chromatography on silica gel with a mobile phase consisting of 1.5% methanol and 0.2% water in chloroform.The time needed for this chromatographic analysis is 10–15 min; the limit of determination is 3 ng of cortisol for one injection. 相似文献
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Keith Carr Anders Rane Jürgen C. Frlich 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1978,145(3):421-427
A simplified high-pressure liquid chromatographic method for determination of furose-mide in plasma and urine has been developed using a fluorometric detector directly coupled to the column effluent. The method includes an ether extraction from acidified biologic samples. The mobile phase used for chromatography on a reversed-phase column (C18 hydro-carbon permanently bonded to silica particles) is sufficiently acidic to induce fluorescence of furosemide. The methylester of furosemide is employed as an internal standard. The sensitivity is 0.1 and 0.25 μg per ml plasma and urine, respectively. The applicability to pharmacokinetic studies of furosemide is shown. 相似文献
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Background
The aim of this study is to accurately assess whether the duration of intraoperative carbon dioxide pneumoperitoneum (CDP) is associated with the induction of hepatic injury.Methods
We conducted a systematic review of PubMed, Embase, and Cochrane Library databases (through February 2014) to identify case-match studies that compared high-pressure CDP with low-pressure CDP or varied the duration of CDP in patients who underwent abdominal surgery. The outcome of interest was postoperative liver function (ALT, AST, TB).Results
Eleven comparative studies involving 2,235 participants were included. Overall, levels of ALT, AST, and TB (on postoperative days 1, 3, and 7) were significantly elevated in the study groups. However, the results of the subanalyses of those who underwent laparoscopic colorectal cancer resection (LCR) versus open colorectal cancer resection (OCR) and those who underwent laparoscopic gastric bypass (LGBP) versus open gastric bypass (OGBP) were inconsistent.Conclusions
The current evidence suggests that the duration of CDP during laparoscopic abdominal surgery may be associated with hepatic injury. Additional large-scale, randomized, controlled trials are urgently needed to further confirm this. 相似文献14.
Shivani Patel Donna McKeon Kimheak Sao Changsong Yang Nicole M. Naranjo Tatyana M. Svitkina Ryan J. Petrie 《Molecular biology of the cell》2021,32(7):579
Human fibroblasts can switch between lamellipodia-dependent and -independent migration mechanisms on two-dimensional surfaces and in three-dimensional (3D) matrices. RhoA GTPase activity governs the switch from low-pressure lamellipodia to high-pressure lobopodia in response to the physical structure of the 3D matrix. Inhibiting actomyosin contractility in these cells reduces intracellular pressure and reverts lobopodia to lamellipodial protrusions via an unknown mechanism. To test the hypothesis that high pressure physically prevents lamellipodia formation, we manipulated pressure by activating RhoA or changing the osmolarity of the extracellular environment and imaged cell protrusions. We find RhoA activity inhibits Rac1-mediated lamellipodia formation through two distinct pathways. First, RhoA boosts intracellular pressure by increasing actomyosin contractility and water influx but acts upstream of Rac1 to inhibit lamellipodia formation. Increasing osmotic pressure revealed a second RhoA pathway, which acts through nonmuscle myosin II (NMII) to disrupt lamellipodia downstream from Rac1 and elevate pressure. Interestingly, Arp2/3 inhibition triggered a NMII-dependent increase in intracellular pressure, along with lamellipodia disruption. Together, these results suggest that actomyosin contractility and water influx are coordinated to increase intracellular pressure, and RhoA signaling can inhibit lamellipodia formation via two distinct pathways in high-pressure cells. 相似文献
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Yang Qiu Dilip Rajagopalan Susan C. Connor Doris Damian Lei Zhu Amir Handzel Guanghui Hu Arshad Amanullah Steve Bao Nathaniel Woody David MacLean Kwan Lee Dana Vanderwall Terence Ryan 《Metabolomics : Official journal of the Metabolomic Society》2008,4(4):337-346
Recent advances in genomics, metabolomics and proteomics have made it possible to interrogate disease pathophysiology and
drug response on a systems level. The analysis and interpretation of the complex data obtained using these techniques is potentially
fertile but equally challenging. We conducted a small clinical trial to explore the application of metabolomics data in candidate
biomarker discovery. Specifically, serum and urine samples from patients with type 2 diabetes mellitus (T2DM) were profiled
on metabolomics platforms before and after 8 weeks of treatment with one of three commonly used oral antidiabetic agents,
the sulfonyurea glyburide, the biguanide metformin, or the thiazolidinedione rosiglitazone. Multivariate classification techniques
were used to detect serum or urine analytes, obtained at baseline (pre-treatment) that could predict a significant treatment
response after 8 weeks. Using this approach, we identified three analytes, measured at baseline, that were associated with
response to a thiazolidinedione after 8 weeks of treatment. Although larger and longer-term studies are required to validate
any of the candidate biomarkers, pharmacometabolomic profiling, in combination with multivariate classification, is worthy
of further exploration as an adjunct to clinical decision making regarding treatment selection and for patient stratification
within clinical trials.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Post-operative cognitive dysfunction (POCD), especially in elderly patients, has been reported in many studies. Although increasing age, duration of anesthesia, postoperative infections, and respiratory complications were regarded as the risk factors for POCD, no extracerebral diagnostic biomarkers have been identified as indicators of POCD. Ninety-five patients, ages 65-80?years, scheduled for major orthopedic or abdominal surgery were enrolled. Twenty-two patients aged between 20 and 40?years undergoing the same procedures served as controls. Subjects received neuropsychological tests one-day prior and one week post procedure.?To determine the presence of POCD, the criteria were used as described in most previous studies. Morning urine samples were obtained one day before surgery and on day 1, day 2 and day 7 post operatively. Urine formaldehyde was determined with high-performance liquid chromatography. The urine formaldehyde level of all patients with and without POCD increased on the first 2?days after surgery. But the formaldehyde concentration (on day 7) in patients with POCD was significantly higher than that in patients without POCD (p?0.01). In the young control group, no patient was diagnosed with POCD. Although the changes in urine formaldehyde of young patients during perioperative period were similar to those in elderly patients without POCD, the formaldehyde concentrations measured at four time points were all significantly lower than those in elderly patients (p?0.05). Levels of urine formaldehyde were elevated in the perioperative period, with the highest levels at day 7 in patients with POCD. This suggests that the increase on day 7 may provide a new physiologic marker along with neuropsychological assessments to assist in the diagnosis of POCD. 相似文献
17.
Seven of 74 patients with early functioning cadaveric renal homografts developed acute oliguric renal failure after the second but before the ninth day post-transplantation. The syndrome characteristically begins with an abrupt and simultaneous decrease in creatinine clearance, urine volume and urine sodium concentration. After a variable period and despite a reduction in immunosuppressive therapy, a diuretic phase ensues and renal function is restored. Complications associated with the syndrome include groin hematoma, pulmonary edema and renal rupture with shock. Renal rupture does not require nephrectomy: if the hemorrhage is controlled, the transplanted organ will resume function. Angiographic studies show normal nephrograms, stretched arterial vasculature and filling defects in the veins. Percutaneous renal biopsy shows interstitial edema and hemorrhage, venous congestion and tubular necrosis. Evidence is presented to support the hypothesis that this is a form of rejection occurring as the result of injury to the renal venous system. 相似文献
18.
N. Ockman 《生物化学与生物物理学报:生物膜》1974,345(3):263-282
Polarized absorption spectra have been obtained of the antibiotic polyene, amphotericin B, interacting with monolayers of egg lecithin, cholesterol and equimolar egg lecithin-cholesterol at low and high surface pressures. An expression is derived which enables the determination from the polarization data of the orientations of the transition moments of the polyene absorption bands at 4077 and 3645 Å. For some of the systems the 3645-Å band is replaced by a previously unreported band appearing between 3610 and 3632 Å. The orientation of the 4077-Å transition moment (parallel to the long molecular axis) is found to vary from an angle of 64 ° with the surface for the low-pressure monolayers of cholesterol to 21 ° for the high-pressure films of egg lecithin-cholesterol. For the band between 3610 Å and 3645 Å, the angle varies from 90 ° for cholesterol to 18 ° for the high-pressure mixed-lipid film. It is found that a large increase in surface pressure of the cholesterol and egg lecithin-cholesterol monolayers causes a decrease in the angle of the 4077-Å moment for both films and that of the higher energy moment for the mixed film. Increasing the content of cholesterol in these monolayers rotates the orientation of the transition moments for both bands toward the surface normal, the change being greatest for the low-pressure films. The effectiveness of amphotericin B in lowering the surface tension of these lipid monolayers is related to its binding, orientation and extent of penetration. For low-pressure cholesterol films where the surface interaction with the polyene is greatest, the binding and penetration are large and the polyene molecule is oriented with its long dimension nearly perpendicular to the surface. 相似文献
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Cytometric bead array (CBA) for the measurement of cytokines in urine and plasma of patients undergoing renal rejection 总被引:4,自引:0,他引:4
Jiménez R Ramírez R Carracedo J Agüera M Navarro D Santamaría R Pérez R Del Castillo D Aljama P 《Cytokine》2005,32(1):45-50
Renal rejection is associated with an active immune response regulated by cytokines and in which immunocompetent cells are involved. Previous studies have measured high levels of cytokines in the urine and plasma in various renal dysfunction states. However, some methods used to measured cytokines hinder their use as a diagnostic tool in renal rejection. In this report, cytokine levels were determined in the plasma and urine of kidney transplant patients, with renal rejection and without it, using a cytometric bead array (CBA) technique. Concentrations of six human cytokines (IL-2, IL-4, IL-5, IL-10, TNF-alpha and INF-gamma) were established. Results show that patients who develop renal rejection presented high levels of IL-10 and IFN-gamma cytokines in plasma and urine compared to patients without renal rejection. The CBA technique displayed greater sensitivity in the determination of cytokines in urine than the conventional ELISA technique. Finally, when standard cytokines in plasma and in urine were compared, it was observed that, in plasma, levels of IL-4, IL-5, IL-10, TNF-alpha and IFN-gamma were detected, whereas in urine the levels detected were of IL-4, IL-5, IL-10 and IFN-gamma. These results indicate that the CBA assay is a sensitive method to measure cytokines in urine. In kidney transplant patients undergoing acute renal rejection, the presence of cytokines in urine reflects renal damage and could be a useful method in the diagnosis of renal rejection. 相似文献