scholarly journals A Nano-Silver Loaded PVA/Keratin Hydrogel With Strong Mechanical Properties Provides Excellent Antibacterial Effect for Delayed Sternal Closure

Author(s):  
Yanjun Pan ◽  
Pengfei Li ◽  
Fubang Liang ◽  
Jingyi Zhang ◽  
Jiang Yuan ◽  
...  

Delayed chest closure (DSC) is widely performed during the treatment of congenital heart diseases. However, the high prevalence of surgical site infection (SSI) in patients undergoing DSC affects prognosis negatively. Herein, we designed a suturable poly (vinyl alcohol)/keratin film loaded with silver nanoparticles (AgNPs) as an alternative material for DSC, which was named PVA/Keratin/AgNPs. The PVA/Keratin/AgNPs films exhibited significantly enhanced mechanical strength after crosslinking by sodium trimetaphosphate (STMP). These films were non-toxic, and cells proliferated with good morphology after 1 week of culture. In addition, PVA/Keratin/AgNPs films provided superior antibacterial ability, as evidenced by the eradication and lower growth rate of Staphylococcus aureus and Escherichia coli. Finally, the PVA/Keratin/AgNPs films were demonstrated to successfully cover the chest cavity temporarily and protect the chest cavity from bacterial infection. These results indicated that the PVA/Keratin/AgNPs films have great prospects to be further exploited for clinical applications in DSC.

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 809
Author(s):  
Alexandros Polyzois ◽  
Diana Kirilovsky ◽  
Thi-hanh Dufat ◽  
Sylvie Michel

Cryptophycin-1 is a cyanotoxin produced by filamentous cyanobacteria. It has been evaluated as an anticancer agent with great potential. However, its synthesis provides insufficient yield for industrial use. An alternative solution for metabolite efficient production is to stress cyanobacteria by modifying the environmental conditions of the culture (Nostoc sp. ATCC 53789). Here, we examined the effects of light photoperiod, wavelength, and intensity. In light photoperiod, photoperiods 24:0 and 16:8 (light:dark) were tested while in wavelength, orange-red light was compared with blue. Medium, high, and very high light intensity experiments were performed to test the effect of light stress. For a 10-day period, growth was measured, metabolite concentration was calculated through HPLC, and the related curves were drawn. The differentiation of light wavelength had a major effect on the culture, as orange-red filter contributed to noticeable increase in both growth and doubled the cyanotoxin concentration in comparison to blue light. Remarkably, constant light provides higher cryptophycin yield, but slightly lower growth rate. Lastly, the microorganism prefers medium light intensities for both growth and metabolite expression. The combination of these optimal conditions would contribute to the further exploitation of cryptophycin.


2021 ◽  
Vol 56 (3) ◽  
pp. 1-7
Author(s):  
Monika Witoszek ◽  
Małgorzata Kalaga

The Yta antigen from the Cartwright blood group system is a high-prevalence antigen found in 99.8% of the population. The literature data shows that antibodies anti-Yta demonstrate the variable clinical significance and are rarely the cause of a hemolytic post-transfusion reaction. The study aims to present the difficulties related to the selection and sustainable supply of blood for transfusion for the patient of the Silesian Centre for Heart Diseases with anti-Yta alloantibodies, qualified for a heart transplant. If Yt(a-) blood is not available Institute of Hematology and Transfusion Medicine in Warsaw, referring to reports in the publications, allowed transfusion of the least incompatible red blood cells in indirect antiglobulin test. One hour after transfusion of leucocyte-depleted concentrate of red blood cells (RBCs), issued in accordance with the above recommendations by Regional Blood Donation Center in Katowice as the least incompatible, the patient was observed to experience symptoms of an adverse post-transfusion reaction. For subsequent transfusions, RBCs from Yt(a-) donors were selected, of which only eight were registered in Poland at that time. Medical decisions on RBCs transfusion in patients for whom no compatible blood can be selected is very difficult, and the benefits of incompatible transfusion should be weighed against the risk of possible complications. To avoid this, it should be remembered that the early identification of antibodies increases the chance of finding serologically compatible blood and in many cases allows to supply blood for a patient with autologous donations.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Brendan Cornwell ◽  
Katrina Armstrong ◽  
Nia S Walker ◽  
Marilla Lippert ◽  
Victor Nestor ◽  
...  

Climate change is dramatically changing ecosystem composition and productivity, leading scientists to consider the best approaches to map natural resistance and foster ecosystem resilience in the face of these changes. Here we present results from a large-scale experimental assessment of coral bleaching resistance, a critical trait for coral population persistence as oceans warm, in 221 colonies of the coral Acropora hyacinthus across 37 reefs in Palau. We find that bleaching resistant individuals inhabit most reefs but are found more often in warmer microhabitats. Our survey also found wide variation in symbiont concentration among colonies, and that colonies with lower symbiont load tended to be more bleaching resistant. By contrast, our data show that low symbiont load comes at the cost of lower growth rate, a tradeoff that may operate widely among corals across environments. Corals with high bleaching resistance have been suggested as a source for habitat restoration or selective breeding in order to increase coral reef resilience to climate change. Our maps show where these resilience corals can be found, but the existence of tradeoffs with heat resistance may suggest caution in unilateral use of this one trait in restoration.


Author(s):  
Paulina Gebauer ◽  
Luis Giménez ◽  
Iván Hinojosa ◽  
Kurt Paschke

Settlement and metamorphosis are two crucial processes in organisms with a biphasic life cycle, forming the link between the pelagic larva and benthic juvenile-adult. In general, these processes occur during the final larval stage. Among crustaceans, settlement behavior and the cues that trigger settlement and metamorphosis have been studied in greater depth in barnacles than in decapods, likely a result of the former losing the ability to move after they join the benthic juvenile-adult population, undergoing metamorphosis. Both barnacles and decapods respond to different environmental cues associated with the adult habitat, such as substratum, biofilm, and the presence of conspecifics. In the absence of cues, larvae can delay their metamorphosis for a period of time. This ability to prolong the development can be advantageous because it increases the probability of settling in a suitable habitat. However, delayed metamorphosis has also associated costs (e.g., smaller size, lower growth rate, and higher mortality), which may be carried over to subsequent development stages, with consequences for recruitment.


2002 ◽  
Vol 74 (1) ◽  
pp. 135-144 ◽  
Author(s):  
A. Belenguer ◽  
J. Balcells ◽  
M. Fondevila ◽  
C. Torre

AbstractThe present study compares estimates of caecotrophes production from urinary purine derivatives (PD) excretion with that from preventing caecotrophy by using a neck collar. A total of 64 New Zealand growing male rabbits were used to study the effect of diet composition on caecotrophes production. Diets were formulated using two sources of structural carbohydrates (fibre): alfalfa hay (AH) and sugar-beet pulp (SBP), mixed at two constant proportions, (0·75: 0·25) AH diets and (0·25: 0·75) SBP diets. Both diets included either barley or maize grain at two fibre: grain ratios (F/G, 80: 20 and 45: 55). Diets were given ad libitum. Growth rate, dry matter intake and digestibility were not modified by the grain source, although high F/G diets resulted in a lower growth rate (19·8 v. 26·4 g/day; P < 0·001). Between fibre sources, dry-matter intake and growth were higher in AH than in SBP diets (122·5 and 25·6 v. 101·6 and 20·4 g/day, respectively, P < 0·001 and P < 0·01). Rabbits given high F/G ratio and AH diets excreted more caecotrophes than those given low F/G ratio and SBP diets (19·5 and 20·9 v. 16·3 and 14·85 g/day, respectively). Microbial-N recycling through the caecotrophy process was higher when considering data from PD excretion (1·33 g/d) than when estimated by preventing caecotrophy (0·72 g/day).


2015 ◽  
Vol 778 ◽  
pp. 389-427 ◽  
Author(s):  
M. J. Philipp Hack ◽  
Tamer A. Zaki

Modal and non-modal perturbation growth in boundary layers subjected to time-harmonic spanwise wall motion are examined. The superposition of the streamwise Blasius flow and the spanwise Stokes layer can lead to strong modal amplification during intervals of the base-flow period. Linear stability analysis of frozen phases of the base state demonstrates that this growth is due to an inviscid instability, which is related to the inflection points of the spanwise Stokes layer. The generation of new inflection points at the wall and their propagation towards the free stream leads to mode crossing when tracing the most unstable mode as a function of phase. The fundamental mode computed in Floquet analysis has a considerably lower growth rate than the instantaneous eigenfunctions. Furthermore, the algebraic lift-up mechanism that causes the formation of Klebanoff streaks is examined in transient growth analyses. The wall forcing significantly weakens the wall-normal velocity perturbations associated with lift-up. This effect is attributed to the formation of a pressure field which redistributes energy from the wall-normal to the spanwise velocity perturbations. The results from linear theory explain observations from direct numerical simulations of breakdown to turbulence in the same flow configuration by Hack & Zaki (J. Fluid Mech., vol. 760, 2014a, pp. 63–94). When bypass mechanisms are dominant, the flow is stabilized due to the weaker non-modal growth. However, at high amplitudes of wall oscillation, transition is promoted due to fast growth of the modal instability.


2016 ◽  
Vol 30 (06) ◽  
pp. 1650059
Author(s):  
Jingjing Gao ◽  
Mingwen Chen ◽  
Zidong Wang

The convection of ambient flow field has a significant influence on the pattern formation of growing particles. In this paper, we investigate the shape evolution of particles growing in supersaturated solution affected by straining flows. By using the multiple variable asymptotic expansion method, we obtain the asymptotic solution. The solution indicates that the interface microstructure is greatly affected by the straining flows. The flow results in a higher growth rate in the surface where it is incoming and a lower growth rate where it is outgoing. Besides, the flow also has effects on the concentration distribution.


Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 438-444 ◽  
Author(s):  
William H. Ahrens ◽  
E. W. Stoller

Triazine-susceptible (S) and -resistant (R) biotypes of smooth pigweed (Amaranthus hybridusL.) were grown in the field under competitive conditions at varying initial proportions of S and R plants. R plants were less competitive than S plants as measured by accumulation of total above-ground dry weight and seed dry weight. S and R plants were also grown in the field under non-competitive conditions at 100, 40, and 10% light. Growth rate at 10% light did not differ between S and R plants. At the two higher light intensities, dry-matter accumulation 11 weeks after seeding was about 40% less in the R plants. At 100% light, relative growth rate and net assimilation rate were lower in the R plants by about 3.5 and 19%, respectively. The light- and CO2-saturated rates of CO2fixation in intact leaves of glasshouse-grown R plants were 20% less than those in S plants. An apparent 10 and 20% greater number of chlorophyll molecules per photosystem II reaction center in R plants (as compared with S plants) grown in the field at 40 and 100% light, respectively, did not explain differences between the S and R biotypes in photo synthetic capacity. The S and R plants did not differ in specific leaf weight or chlorophyll content on a leaf-area basis. Lower growth rate of R plants may be responsible for inferior competitive ability of R biotypes and could be the result of an impaired photosynthetic capacity.


2013 ◽  
Vol 79 (13) ◽  
pp. 4145-4148 ◽  
Author(s):  
Takanori Awata ◽  
Mamoru Oshiki ◽  
Tomonori Kindaichi ◽  
Noriatsu Ozaki ◽  
Akiyoshi Ohashi ◽  
...  

ABSTRACTThe phylogenetic affiliation and physiological characteristics (e.g.,Ksand maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “CandidatusScalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “CandidatusScalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species.


2015 ◽  
Vol 47 (7) ◽  
pp. 264-273 ◽  
Author(s):  
Kate Keogh ◽  
Sinéad M. Waters ◽  
Alan K. Kelly ◽  
Alastair R. G. Wylie ◽  
David A. Kenny

The objective of this study was to characterize the effect of feed restriction and compensatory growth during re-alimentation on the functionality of the somatotropic axis. We blocked 60 bulls into one of two groups: 1) restricted feed allowance for 125 days ( period 1) (RES, n = 30) followed by ad libitum feeding for 55 days ( period 2) or 2) ad libitum access to feed throughout (ADLIB, n = 30). A growth hormone releasing hormone (GHRH) challenge was performed during each period. At the end of each period, 15 animals from each treatment were slaughtered and hepatic tissue collected. Hepatic expression of 13 genes of the somatotropic axis was measured by qRT-PCR. RES displayed a lower growth rate during period 1 (0.6 vs. 1.9 kg/day; P < 0.001), subsequently gaining more than ADLIB animals during period 2 (2.5 vs. 1.4 kg/day; P < 0.001). Growth hormone response to GHRH was not different between treatments at either time-point ( P > 0.05); however, resultant plasma IGF-1 was lower in period 1 and greater in period 2 in RES animals ( P < 0.05). Expression of IGFBP2 was higher ( P < 0.01) and IGF1 ( P < 0.001) and GHRIA ( P < 0.05) lower in RES compared with ADLIB during period 1, with no difference evident in period 2 ( P > 0.05). Collectively, the results of this study are consistent with uncoupling of the somatotropic axis following feed restriction. However, there is no evidence from this study that the somatotropic axis per se is a significant contributor to compensatory growth.


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