Microbial bioremediation of oil‐contaminated sites is still a challenge due to the slower rate and susceptibility of microbes to a higher concentration of oil. The poor bioavailability, ...hydrophobicity, and non‐polar nature of oil slow down microbial biodegradation. In this study, biodegradation of crude oil is performed in fed‐batch mode using an oil‐degrader Pseudomonas aeruginosa to address the issue of substrate toxicity. The slower biodegradation was integrated with faster biosorption for effective oil remediation. Highly fibrous and porous sugarcane bagasse was surface modified with hydrophobic octyl groups to improve the surface‐oil interactions. The microbe showed 2 folds enhanced oil degradation in the fed‐batch study, which was further increased by 1·5 folds in the integrated biosorption coupled biodegradation approach. The biosorption‐assisted biodegradation approach supported the microbial growth to 2 folds higher than the fed‐batch study without biosorbent. The analysis of biosurfactant production indicated the 3 folds higher concentration in fed‐batch modes as compared to batch study. In the integrated strategy, the concentration of contaminant (oil) reduces to quite a tolerable level to microbes, which improved effective metabolism and thus overall biodegradation. This study puts forward a promising strategy for improved degradation of hazardous hydrophobic contaminants in a sustainable, economic and eco‐friendly manner.
Significance and Impact of the Study: Crude oil bioremediation exploits the hydrocarbon utilization ability of microbes for the synthesis of biosurfactants. The viscous complex mixtures of hazardous hydrocarbons make the crude oil poorly bioavailable decreasing the overall microbial biodegradation and biosurfactant production. This study puts forward an approach of integration of biosorption coupled microbial biodegradation technique in a fed‐batch mode. While hydrophobically modified biosorbent improves the oil affinity and thus bioavailability towards the microbes. The Fed‐batch approach further decreases the risk of substrate toxicity by intermittently feeding a lower concentration of oil. This approach thus improved biomass growth and in turn resulted in better oil degradation. Overall, this bioremediation approach mitigates the hazardous effects of crude oil and explores it as a potential substrate for microbial degradation and also biosurfactant production.
The incidence of acute kidney injury (AKI) in pregnancy is declining in developing countries but still remains a major cause of maternal and fetal morbidity and mortality. The aim of the study was to ...analyze the changing trends in pregnancy related AKI (PR-AKI) over a period of thirty-three years. Clinical characteristics of PR-AKI with respect to incidence, etiology and fetal and maternal outcomes were compared in three study periods, namely 1982-1991,1992-2002 and 2003-2014. The incidence of PR-AKI decreased to 10.4% in 1992-2002, from 15.2% in 1982-1991, with declining trend continuing in 2003-2014 (4.68%).Postabortal AKI decreased to 1.49% in 2003-2014 from 9.4% in 1982-1991of total AKI cases.The AKI related to puerperal sepsis increased to 1.56% of all AKI cases in 2003-2014 from 1.4% in 1982-1991. Preeclampsia/eclampsia associated AKI decreased from 3.5% of total AKI cases in 1982-1991 to 0.54% in 2003-2014. Pregnancy associated - thrombotic microangiopathy and acute fatty liver of pregnancy were uncommon causes of AKI. Hyperemesis gravidarum associated AKI was not observed in our study. Incidence of renal cortical necrosis (RCN) decreased to 1.4% in 2003-2014 from 17% in 1982-1991.Maternal mortality reduced to 5.79% from initial high value 20% in 1982-1991. The progression of PR-AKI to ESRD decreased to1.4% in 2003-2014 from 6.15% in 1982-1991. The incidence of PR-AKI has decreased over last three decades, mainly due to decrease in incidence of postabortal AKI. Puerperal sepsis and obstetric hemorrhage were the major causes of PR-AKI followed by preeclampsia in late pregnancy. Maternal mortality and incidence and severity of RCN have significantly decreased in PR-AKI. The progression to CKD and ESRD has decreased in women with AKI in pregnancy in recent decade. However, the perinatal mortality did not change throughout study period.
Abstract
We study the effect of magnetic braking due to a primordial magnetic field in the context of the formation of massive (≳104M⊙) direct-collapse black holes (DCBHs) at high redshifts. Under ...the assumption of axial symmetry, we analytically compute the effect of magnetic braking on the angular momentum of gas collapsing into the potential well of massive dark matter haloes (≃107−9M⊙) which are spun up by gravitational tidal torques. We find that a primordial magnetic field of strength B0 ≃ 0.1 nG (comoving) can remove the initial angular momentum gained by the in-falling gas due to tidal torques, thus significantly lowering the angular momentum barrier to the formation of DCBHs. These magnetic field strengths are consistent with the bounds on primordial fields from astrophysical and cosmological measurements and they are large enough to seed observed galactic magnetic fields.
Diagnosis and therapy of brain cancer was often limited due to low permeability of delivery materials across the blood-brain barrier (BBB) and their poor penetration into the brain tissue. This study ...explored the possibility of utilizing theranostic d-alpha-tocopheryl polyethylene glycol 1000 succinate mono-ester (TPGS) liposomes as nanocarriers for minimally invasive brain-targeted imaging and therapy (brain theranostics). The aim of this work was to formulate transferrin conjugated TPGS coated theranostic liposomes, which contain both docetaxel and quantum dots (QDs) for imaging and therapy of brain cancer. The theranostic liposomes with and without transferrin decoration were prepared and characterized for their particle size, polydispersity, morphology, drug encapsulation efficiency, in-vitro release study and brain theranostics. The particle sizes of the non-targeted and targeted theranostic liposomes were found below 200 nm. Nearly, 71% of drug encapsulation efficiency was achieved with liposomes. The drug release from transferrin conjugated theranostic liposomes was sustained for more than 72 h with 70% of drug release. The in-vivo results indicated that transferrin receptor-targeted theranostic liposomes could be a promising carrier for brain theranostics due to nano-sized delivery and its permeability which provided an improved and prolonged brain targeting of docetaxel and QDs in comparison to the non-targeted preparations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this paper, we explore the possibility of accreting primordial black holes as the source of heating for the collapsing gas in the context of the direct collapse black hole scenario for the ...formation of super-massive black holes (SMBHs) at high redshifts,
z
∼
6–7. One of the essential requirements for the direct collapse model to work is to maintain the temperature of the in-falling gas at
≈
10
4
K. We show that even under the existing abundance limits, the primordial black holes of masses
≳
10
-
2
M
⊙
, can heat the collapsing gas to an extent that the
H
2
formation is inhibited. The collapsing gas can maintain its temperature at
10
4
K till the gas reaches a critical density
n
c
≈
10
3
cm
-
3
, at which the roto-vibrational states of
H
2
approaches local thermodynamic equilibrium and
H
2
cooling becomes inefficient. In the absence of
H
2
cooling, the temperature of the collapsing gas stays at
≈
10
4
K even as it collapses further. We discuss scenarios of subsequent angular momentum removal and the route to find collapse through either a supermassive star or a supermassive disk.
Biphasic calcium phosphate (BCP) consists of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP). BCP is mainly used in artificial tooth and bone implants due to higher protein adsorption and ...osteoinductivity compared to HA alone. Although, many studies have been investigated on radio frequency (RF) magnetron sputtering of HA on Ti and its alloy, however, limited studies are available on BCP coating by this process and its bioactivity and adhesion behavior. Thus, in order to obtain a better understanding and applications of BCP films, RF magnetron sputtering is used to deposit BCP films on Ti-6Al-4V in the present study. The effect of film thickness on wettability, mechanical properties and in vitro bioactivity at a particular set of sputtering parameters are investigated. BCP film thickness of 400 nm, 700 nm and 1000 nm are obtained when sputtered for 4 h, 6 h and 8 h, respectively. Although the phase compositions are almost same for all films, the surface roughness values varies around 112–153 nm with rise in film thickness. This in turn enhances hydrophilicity in accordance to Wenzel relation as the contact angle decreases from 89.6 ± 2° to 61.2 ± 2°. It is found that the 1000 nm film possess highest micro-hardness and surface scratch resistance. No cracking of film up to scratch load of 2.3 N and no significant delamination up to load of 7.8 N are observed, indicating very good adhesion between BCP films and Ti-6Al-4V substrate. There is a great improvement in wt% apatite layer formation on all films when dipped in simulated body fluid (SBF) for 14 days. Among these, 1000 nm sputtered film results the highest increase in wt% apatite layer from 44.87% to 86.7%. The apatite layer possess small globular as well as elliptical structure are nucleated and grew on all the BCP films. Thus, sputtering of BCP films improves wettability, mechanical properties as well as bioactivity of Ti-6Al-4V, which can be applied for orthopedic implants.
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•BCP (HA+β-TCP) bio-ceramic coating on Ti-6Al-4V alloy are carried out.•Films with 400, 700, and 1000 nm thickness are found.•Surface morphology, phases, micro-hardness and scratch resistance of films are studied.•Wettability improves as surface roughness increases with rise in film thickness.•In vitro bioactivity tests using SBF are done.
A single-step, thermal plasma-assisted technique is reported for size-controlled synthesis of silver-carbon (Ag-C) nanocomposites, to be used for antibacterial applications. Silver nanoparticles of ...sizes less than 10 nm can directly penetrate into the core of the bacteria, while stiff, nanocrystalline carbon may rupture the microorganisms with their sharp edges. Experiments demonstrated that silver nanoparticles nucleate anchoring tightly on carbon sheets, which can inhibit their aggregation and growth in size and becomes more effective as crystallinity of the carbon enhances further. Nanocomposite samples were synthesized using a hot graphite nozzle and with variation of ambient pressure in the sample collection chamber. The Ag-C sample synthesized at 190 mbar chamber pressure demonstrated the best antibacterial activities. The zone of inhibition was measured for this sample as 18 mm for the gram-positive E. hirae and 15 mm for the gram-negative E. coli bacteria at their corresponding minimum inhibitory values of 0.54 mg ml−1 and 0.9 mg ml−1 respectively. The crystallinity of the carbon nanosheets was measured to be the best for this particular sample and the average size of the silver nanoparticles remaining entangled on them was measured as 4.6 nm, which to our knowledge is the smallest ever synthesized by a plasma-assisted method. The gas temperature at the injection section was measured using the C2 Swan band system, (0, 0) vibrational transition located at 516.5 nm, which confirms temperature enhanced substantially in presence of the graphite nozzle, which had led to the enhanced material crystallinity and synthesis of particles with the smallest sizes.
The present study reports laser surface texturing (LST) of Ti–6Al–4V using a Nd-YAG laser with a particular set of parameters and three different overlapping factors (OF): 0%, 25% and 50%. Biphasic ...calcium phosphate (BCP) film was deposited on bare as well as textured Ti–6Al–4V specimens by using radio frequency (RF) sputtering. The simultaneous effect of texturing as well as BCP coating on different physical and biological properties was investigated. The study revealed that the surface wettability of bare Ti–6Al–4V enhanced after laser texturing (as contact angle reduced from 89° to 71°-77°). It was further improved upon BCP deposition to make the Ti–6Al–4V superhydrophilic (contact angle ≈ 17°-21°). It was also observed that the surface roughness of bare Ti–6Al–4V significantly increased from Ra ≈ 94 nm to Ra ≈ 0.98–1.84 μm for different micro-dimpled texture substrates. The dimensions of micro-dimpled texture did not change after BCP deposition; however, a non-uniform film is deposited with increase in surface roughness. Protein adsorption was found as a function of surface hydrophobicity, which increased from 5.3 to 7.11 μg/cm2 with the rise in hydrophobicity of modified surfaces. Compared to bare Ti–6Al–4V and BCP deposited bare-Ti-6Al–4V surfaces, the BCP deposited textured surfaces exhibit higher number of well spread MG63 osteoblast cells. For the same surface chemistry, increase in surface area (roughness) improves cellular behavior. With texturing of the substrate, the cell adhered percentage and average cell area improved significantly and BCP-(50% OF)–Ti–6Al–4V was found to have the maximum cell spreading and proliferation. Overall, these findings revealed that a micro-dimpled textured surface followed by BCP film deposition strategy improved the physio-chemical properties of surfaces such as surface roughness and wettability. This in turn enhanced the bioactivity, cell adhesion and proliferation of bone cells (MG63) on modified Ti–6Al–4V surfaces and based on the results we envisage that can be potentially used for orthopedic and dental applications.
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•Texturing of Ti–6Al–4V with 0%, 25% and 50%OF is carried out using Nd:YAG laser.•BCP film is deposited on textured Ti–6Al–4V using RF magnetron sputtering.•Surface topography, phases and wettability of films are investigated.•Texturing make Ti–6Al–4V hydrophilic; whereas BCP sputtering make it super-hydrophilic.•Cell adhesion and proliferation enhance with texturing and BCP deposition on Ti–6Al–4V.
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