Characterizing the biofilm stoichiometry and kinetics on the media in situ based on pulse-flow respirometer coupling with a new breathing reactor

Chemosphere ◽  
2020 ◽  
Vol 252 ◽  
pp. 126378 ◽  
Author(s):  
Zichuan Lu ◽  
Deyong Li ◽  
Lugao Jiang ◽  
Gaofeng Chen ◽  
Kaibin Li ◽  
...  
Keyword(s):  
Pulse Flow ◽  
The Media

scholarly journals Degradation Mechanism of Porous Metal-Organic Frameworks by In Situ Atomic Force Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Ioanna Christodoulou ◽  
Tom Bourguignon ◽  
Xue Li ◽  
Gilles Patriarche ◽  
Christian Serre ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Degradation Mechanism ◽  
Metal Organic Frameworks ◽  
Porous Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
The Media ◽  
Ph Conditions

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs’ stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

scholarly journals Implantation in Coronary Circulation Induces Morphofunctional Transformation of Radial Grafts From Muscular to Elastomuscular

Circulation ◽  
2005 ◽  
Vol 112 (9_supplement) ◽  
Author(s):  
Mario Gaudino ◽  
Francesco Prati ◽  
Eugenio Caradonna ◽  
Carlo Trani ◽  
Francesco Burzotta ◽  
...  
Keyword(s):  
Internal Thoracic Artery ◽  
Coronary Circulation ◽  
Ultrasound Examination ◽  
Artery Bypass ◽  
Elastic Tissue ◽  
The Media ◽  
The Mean ◽  
Muscular Architecture

Background— The purpose of this research was to investigate the in vivo morphofunctional changes induced in the radial artery (RA) by its use as coronary artery bypass conduit by comparing the morphological features and vasoreactivity of the native RA versus the coronary RA graft in the same patient. Methods and Results— Ten years after surgery, 10 patients were submitted to intravascular ultrasound examination of the RA graft of the controlateral (in situ) RA and of the internal thoracic artery (ITA) graft and to vasoactive challenges with acetylcholine and serotonin. Quantitative angiographic assessment showed that the mean diameter of the RA coronary grafts was significantly larger than that of the in situ RA and of the ITA (2.89±0.40 mm RA grafts, 2.14±0.52 mm in situ RA, 2.25±0.53 mm ITA grafts; P <0.001). The in situ RA demonstrated a typical muscular architecture, whereas RA coronary grafts showed a clear reduction of the thickness of the medial layer and had a less well-defined muscular component of the media with interposition of elastic tissue. Serotonin endovascular infusion elicited a strong spastic reaction in in situ RAs; the same challenge induced only moderate constriction in RA and ITA coronary grafts. Conclusions— Implantation in the coronary circulation leads to major anatomic and vasoreactive modifications of the RAs that tend to lose the morphofunctional features of a muscular conduit and assume those of an elastomuscular artery, such as the ITA.

scholarly journals Formation and remediation simulation of an in-situ reactive zone with nanoiron for a nitrobenzene-contaminated aquifer

2018 ◽  
Vol 18 (6) ◽  
pp. 2071-2080
Author(s):  
Li Hui ◽  
Zhang Xue-qing
Keyword(s):  
Fine Sand ◽  
Coarse Sand ◽  
Water Yield ◽  
Permeability Change ◽  
Contaminated Aquifer ◽  
Permeability Constant ◽  
Sand Box ◽  
Reactive Zone ◽  
The Media

Abstract A two-dimensional simulated sand box was built to investigate the formation and remediation of an in-situ reactive zone (IRZ) of nanoscale zero-valent iron (NZVI) for a nitrobenzene-contaminated aquifer, and the permeability change of the zone was calculated through the loss of waterhead. The experimental results demonstrated that the remediation area in coarse sand was obviously larger than that in fine sand. The nitrobenzene concentration reached a stable level of 87.24 and 170.24 mg/L in coarse and fine sand by 50 d and 40 d, respectively; after 60 d, the concentration of aniline as the reduction end-product of nitrobenzene was 97.02 and 49.40 mg/L, corresponding to a mean production rate of 40.1% and 20.8%, respectively. This indicated that a wider zone will be formed in the media with a larger size, which is beneficial for pollution remediation. The water yield of the aquifer declined by 13.8% and 11.9% in coarse and fine sand after 60 d, and the final permeability constant was 22.94 and 1.82 m/d (declining by 60.9% and 70.6%), respectively. The reactive zone remained stable and the injection of NZVI slurry could not cause any dramatic changes in the aquifer permeability.

Medial morphometry and mechanics of sequential rabbit ear arteries and myograph ring segments

1983 ◽  
Vol 245 (5) ◽  
pp. H840-H848
Author(s):  
J. G. Walmsley ◽  
M. P. Owen ◽  
J. A. Bevan
Keyword(s):  
Side Branch ◽  
Internal Diameter ◽  
Terminal Branch ◽  
Average Value ◽  
Ear Artery ◽  
Rabbit Ear ◽  
Valid Comparison ◽  
The Media

The medial structure of three different branching orders of arteries in the rabbit ear was studied to assess the possible significance with regard to mechanical behavior determined with the in vitro myograph. The central ear artery, its main side branch, and a terminal branch were fixed while dilated in situ at 100 mmHg; this resulted in internal diameters of 960, 456, and 251 micron, respectively. The average ratio of medial thickness to internal diameter was 0.0293 for arteries in situ and 0.0487 for arterial rings in vitro. Measurements undertaken for the determination of smooth muscle (SM) stress included the percentage of SM in the media (74%) and the pitch of SM (0.89 degrees). These parameters were not significantly different in the three various-sized arteries or for the two myographs. Stereological estimates of SM cell volume, length, and diameter were based on counts of SM nuclei and their length. In evaluating the ring preparation of the vessel myographs, the damage due to the wires (20%) and cut edges (6.4%) was considered. The maximum active SM stress was approximately the same in the different-sized vessels with an average value of 3.14 X 10(5) N/m2. Since this stress is comparable to measurements made by others on different mechanical apparatus and consistent for the three arterial orders, these in vitro myographs should allow for valid comparison of arterial mechanical properties over the size range studied.

High quality and uniformity GaN grown on 150 mm Si substrate using in-situ NH 3 pulse flow cleaning process

2017 ◽  
Vol 104 ◽  
pp. 112-117 ◽  
Author(s):  
Panfeng Ji ◽  
Xuelin Yang ◽  
Yuxia Feng ◽  
Jianpeng Cheng ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Cleaning Process ◽  
Si Substrate ◽  
High Quality ◽  
Pulse Flow

Influence of Medial Collagen Organization and Axial In Situ Stretch on Saccular Cerebral Aneurysm Growth

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Thomas Eriksson ◽  
Martin Kroon ◽  
Gerhard A. Holzapfel
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Aneurysm ◽  
Cerebral Artery ◽  
Collagen Fibers ◽  
Circumferential Direction ◽  
Thickness Increase ◽  
Aneurysm Wall ◽  
Aneurysm Growth ◽  
The Media

A model for saccular cerebral aneurysm growth, proposed by Kroon and Holzapfel (2007, “A Model for Saccular Cerebral Aneurysm Growth in a Human Middle Cerebral Artery,” J. Theor. Biol., 247, pp. 775–787; 2008, “Modeling of Saccular Aneurysm Growth in a Human Middle Cerebral Artery,” ASME J. Biomech. Eng., 130, p. 051012), is further investigated. A human middle cerebral artery is modeled as a two-layer cylinder where the layers correspond to the media and the adventitia. The immediate loss of media in the location of the aneurysm is taken to be responsible for the initiation of the aneurysm growth. The aneurysm is regarded as a development of the adventitia, which is composed of several distinct layers of collagen fibers perfectly aligned in specified directions. The collagen fibers are the only load-bearing constituent in the aneurysm wall; their production and degradation depend on the stretch of the wall and are responsible for the aneurysm growth. The anisotropy of the surrounding media was modeled using the strain-energy function proposed by Holzapfel et al. (2000, “A New Constitutive Framework for Arterial Wall Mechanics and a Comparative Study of Material Models,” J. Elast., 61, pp. 1–48), which is valid for an elastic material with two families of fibers. It was shown that the inclusion of fibers in the media reduced the maximum principal Cauchy stress and the maximum shear stress in the aneurysm wall. The thickness increase in the aneurysm wall due to material growth was also decreased. Varying the fiber angle in the media from a circumferential direction to a deviation of 10 deg from the circumferential direction did, however, only show a little effect. Altering the axial in situ stretch of the artery had a much larger effect in terms of the steady-state shape of the aneurysm and the resulting stresses in the aneurysm wall. The peak values of the maximum principal stress and the thickness increase both became significantly higher for larger axial stretches.

Differences in microbial fermentation of barley straw induced by its treatment with anhydrous ammonia

1997 ◽  
Vol 65 (1) ◽  
pp. 111-119 ◽  
Author(s):  
M. Fondevila ◽  
G. Muñoz ◽  
C. Castrillo ◽  
F. Vicente ◽  
S. M. Martín-Orúe
Keyword(s):  
Ammonia Nitrogen ◽  
Gas Production ◽  
Barley Straw ◽  
Microbial Fermentation ◽  
Rumen Degradation ◽  
Rumen Ph ◽  
The Media ◽  
The Mean

AbstractThe effect of ammonia treatment of straw on both the rumen environment and the extent of its microbial fermentation was studied. Four rumen cannulated sheep were randomly given 700 g/day of untreated straw plus urea (US), ammonia-treated straw (TS) and alfalfa hay (AH) in a change-over design with three periods. Rumen pH was lower and ammonia-nitrogen and total volatile fatty acid (VFA) concentrations were higher (P < 0·001) with AH than with US or TS. With the straw diets, TS promoted a lower pH than US (P < 0·05), but differences were less than 0·3 units and the mean pH was never below 6·5. There were no differences between the straw diets in ammonia-nitrogen or VFA concentration (P > 0·05). When untreated barley straw (BS) and treated straw (TS) were incubated in situ disappearance of dry matter (dDM) at 12, 24 and 48 h (P < 0·01) and neutral-detergent fibre (dNDF) at 48 h (P < 0·001) were higher with TS. In vitro incubation showed a higher gas production with TS only after 36 h (P < 0·05) whereas gas from BS fermentation was higher up to 14 h (P < 0·05). Among diets, dDM, dNDF and gas production with US were numerically higher than with TS or AH throughout, although few significant differences were observed, except for a higher dDM at 12 (P < 0·01) and 24 (P < 0·10) h and a higher dNDF at 12 h (P < 0·10). Particle-associated enzymes were extracted from BS and TS incubated in the rumen for 4, 8, 22 and 24 h. Results ofxylanase and cellulase activities support those of straw incubation, with a drop between 4 and 8 h in TS diet. The concentration of residual phenolics per unit of incubated straws after 12 and 24 h show that phenolics release to the media was higher with the TS diet. Daily changes of phenolic concentration into rumen liquid was also higher with TS than with US (P < 0·001). The increased release of straw phenolics by ammoniation reduced the potential for rumen degradation of straw, mainly in the first hours of the fermentation period.

scholarly journals In situ ultrastructural characterization of chondroitin sulfate proteoglycans in normal rabbit aorta.

1992 ◽  
Vol 40 (2) ◽  
pp. 251-263 ◽  
Author(s):  
Z S Galis ◽  
M Z Alavi ◽  
S Moore
Keyword(s):  
Chondroitin Sulfate ◽  
Rabbit Aorta ◽  
Specific Information ◽  
In Situ Characterization ◽  
Tissue Sections ◽  
Ultrastructural Characterization ◽  
The Media ◽  
Very High

We used a monoclonal antibody recognizing chondroitin sulfate (CS) to investigate by immunocytochemistry the characteristics displayed in situ by aortic proteoglycans (PG) containing CS side chains. The antibody specifically precipitated metabolically labeled PG from aortic extracts. Anti-CS specificity was also tested directly on tissue sections and was confirmed by the virtual abolition of immunolabeling on those previously digested with CS-specific enzymes. The overall CS-PG distribution assessed by light microscopy after embedding in Lowicryl KM4 by silver-enhanced immunogold recapitulated that obtained on frozen sections with immunoperoxidase. Extracellular concentrations of CS-PG were very high in the innermost regions of aorta and decreased in the media. The reaction was weak and diffuse in the adventitia. By electron microscopy, the detailed labeling of CS-PG discriminated patterns of organization at both the regional and the molecular level and enabled morphometric estimations. In relation to other components of the extracellular matrix, we found that CS-PG and elastin mutually excluded each other, while two types of CS-PG were differently associated with collagen within media or adventitia. The use of high-resolution immunodetection for the in situ characterization of aortic CS-PG could add specific information relevant to many biological processes in which these molecules have been implicated.

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