Although, the application of tannic acid (TA), gallic acid (GA), natural hydrolysable tannins (HT)‐rich ingredients, and HT‐rich feeds in ruminant feeding have been explored in order to modify or ...manipulate microbial activities of digestive tract of animals, the interaction between HT and gastrointestinal microbiota and the fate of HT metabolites (GA, ellagic acid, pyrogallol, resorcinol, phloroglucinol, catechol and urolithin) derived from gastrointestinal microbial HT metabolism in the animal as a whole and animal products are missing. Incomplete biotransformation of HT and TA to GA, pyrogallol, resorcinol, phloroglucinol and other phenolic metabolites is a prevalent phenomenon discovered by researchers who examine the fate of HT metabolites in ruminant. While the rest of fellow researchers do not even examine the fate of HT metabolites and assume the complete biotransformation and fermentation of HT metabolites to volatile fatty acids (VFA). Only three studies have successfully identified the complete biotransformation and fermentation of HT metabolites to VFA in ruminant. The HT metabolites, mostly pyrogallol, produced through incomplete biotransformation of HT have adverse effects on gastrointestinal microbiota and host animal. Lack of awareness regarding the metabolism of HT metabolites and its consequences would compromise ruminant gastrointestinal microbiota, animal welfare, our environment and the power of research papers’ findings. In this perspective paper, I will bring to attention a new angle on the biotransformation and fermentation of HT metabolites in gastrointestinal tract, the role of gastrointestinal microbiota and deficiency of current approach in isolating tannin‐degrading bacteria from rumen. Also, suggestions for better monitoring and understanding HT metabolisms in ruminant are presented.
Significance and Impact of the Study: Different metabolic pathways by gastrointestinal microbiota have been suggested for gastrointestinal hydrolysable tannin (HT) metabolism. We argue that complete biotransformation and fermentation of HT metabolites especially pyrogallol to volatile fatty acids is a unique and evolutionary microbial process and have to be examined separately. Exploring the fate of HT metabolites derived from gastrointestinal microbial HT metabolism in whole animal needs to be closely examined in studies that focuses on application of HT ingredients and its effects on ruminant animal performance. We highlight that making inference based on studies that focused on feeding HT ingredients in ruminant nutrition without considering the fate of HT metabolites; will path a strand of literature that may be questionable. Therefore, the future research should consider the fate of HT metabolites to have a reliable result inference.
We report, for the first time, the use of a 13-amino-acid peptide sequence derived from the calcium-binding site of E-cadherin in the fabrication of an electrochemical peptide-based (E-PB) Pb(II) ...sensor. The sensing mechanism is analogous to that of previously developed E-PB sensors. Binding of Pb(II) rigidifies the surface-immobilized and methylene blue (MB)-modified peptide probe, thereby limiting the accessibility of the tethered MB to the electrode surface. This change in probe flexibility results in a reduction in the MB current that is dependent on the target concentration. The sensor behaves as a “signal-off” sensor in alternating current voltammetry and cyclic voltammetry, but it can behave as a “signal-on” sensor in differential pulse voltammetry when a longer pulse width is employed. It is capable of specific detection of Pb(II) and is selective enough to be employed in realistically complex samples such as diluted tap water, saliva, and urine samples. The detection is fast; signal saturation can be achieved in <60 s. The sensor can also be fabricated on gold-plated screen-printed carbon electrodes, electrode substrates that are ideal for cost-effective analysis of Pb(II) in real-world settings.
The study examined photosynthetic efficiency of two barley landraces (cvs. Arabi Abiad and Arabi Aswad) through a prompt fluorescence technique under influence of 14 different abiotic stress factors. ...The difference in the behavior of photosynthetic parameters under the same stress factor in–between cv. Arabi Abiad and cv. Arabi Aswad indicated different mechanisms of tolerance and strategies for the conversion of light energy into chemical energy for both the landraces. This study confirmed the suitability of some chlorophyll fluorescence parameters as reliable biomarkers for screening the plants at the level of photosynthetic apparatus.
Forced convective of a nanofluid that consists of water and Al
2O
3 in horizontal tubes has been studied numerically. Computed results were validated with existing well established correlation. ...Two-phase Eulerian model has been implemented for the first time to study such a flow field. A single-phase model and two-phase mixture model formulations were also used for comparison. The comparison of calculated results with experimental values shows that the mixture model is more precise. It is illustrated that the single-phase model and the two-phase Eulerian model underestimates the Nusselt number. Effects of nanoparticles concentration on the thermal parameters are also discussed.
We report for the first time the use of hexavalent chromium (Cr(VI)) as an electrocatalyst in electrochemical DNA sensing. For both stem-loop probe and linear probe electrochemical DNA sensors, the ...increase in probe rigidity upon target hybridization alters the accessibility of Cr(VI) to the methylene blue label on the surface-immobilized DNA probes. This change results in an enhancement in the electrocatalytic current when the sensors are interrogated using cyclic voltammetry at a slow scan rate. The incorporation of this electrocatalyst does not affect the normal “signal-off” sensing behavior observed in alternating current voltammetry; instead it enables simultaneous “signal-on” and “signal-off” detection of the target, while maintaining noted attributes of this class of folding- and dynamics-based sensors such as reusability and high selectivity. It is also capable of improving the limit of detection of the sensors by an order of magnitude. Importantly, this accessibility-based electrocatalytic sensing strategy is versatile and can potentially be used with other folding- and dynamics-based electrochemical biosensors.
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•Graphene-Fe3O4 nanoparticles coated by oleic acid were synthesized.•Ultra-stable kerosene based nanofluid was produced from Graphene-Fe3O4 nanohybrid.•Rheological and thermal ...properties of nanofluids were investigated.•Significant enhancement in thermal characteristics of nanofluid was observed.
This research deals with a novel synthesis method for preparation of Fe3O4 decorated Graphene and its application as a kerosene-based nanofluid with the purpose of heat transfer enhancement. In order to stabilize the Graphene-Fe3O4 nanoparticles, oleic acid was grafted on the surface of nanoparticles by chemisorption. Synthesized nanohybrid was characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Dynamic light scattering (DLS) and UV–Vis spectrophotometer. The nanofluid remains stable for more than five months without any sedimentation. Moreover, rheological and thermal properties of nanofluids were measured. Viscosity increment, especially in low concentrations of nanoparticles was negligible enough for industrial applications and density enhancement is completely negligible even in high concentrations. The thermal conductivity was improved 31% at 50°C, compared to the base fluid. In order to examine convective heat transfer enhancement, an experimental setup was designed and measurements were examined in Reynolds numbers between 2166 and 4553. The maximum heat transfer enhancement was 66% at Reynolds number of 4553 and 0.3wt.% of nanoparticle. Increase in particles loading and Reynolds number causes convective heat transfer coefficient to improve.
We report the design and fabrication of a “signal-on” electrochemical aptamer-based sensor for detection of cadmium (Cd(II)). A 36-base thiolated and methylene blue (MB)-modified aptamer was used in ...the fabrication of the sensor. In the absence of Cd(II), the surface-immobilized aptamer probe is presumed to be partially folded. Upon binding to Cd(II), the aptamer probe changes its confirmation and flexibility, which alters the electron transfer kinetics between the tethered MB label and the underlying electrode, resulting in an increase in the MB signal. Parameters affecting the detection of Cd(II) were systematically optimized and the electrochemical performance of the sensor was assessed using both alternating current voltammetry and cyclic voltammetry. The sensor has demonstrated good selectivity and can be employed directly in complex samples such as 50% saliva. Furthermore, it has a fast-response time; the analysis can be completed in ~1min. Similar to other folding- and dynamics-based electrochemical biosensors, it is also regenerable and reusable. With further optimization, it could find applications in the analysis of Cd(II) in biological and environmental samples.
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•A DNA aptamer is used in the design of a “signal-on” electrochemical Cd(II) sensor.•Both AC voltammetry and cyclic voltammetry can be used for sensor interrogation.•The sensor is reagentless and can be reused for three times.•The sensor's response to the target is fast (~1min).•The sensor is selective and can function well in complex samples.
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•CoxMn0.5−xZn0.5Fe2O4 nanoferrites prepared by chemical Co-precipitation method.•Structure and magnetic properties were characterized by XRD and VSM respectively.•Magnetic results ...exhibited a super-paramagnetic behavior for some of the samples.•DC electrical resistivity were measured by two-probe technique at 25–250 °C range.•Thermal behavior of resistivity showed an abnormal peak near the Tc of each sample.
In this study, Cobalt-Manganese-Zinc nanoferrites with the formula CoxMn0.5−xZn0.5Fe2O4 with x = 0.0, 0.1, 0.3, and 0.5 prepared by chemical Co-precipitation method. Then the structure and morphology of the synthesized nanoparticles were characterized by X-ray diffraction (XRD) and transmitting electron microscopy (TEM), respectively. The XRD patterns indicated the formation of single-phased cubic structure of spinel ferrite in nanometer size with no minor phase. The TEM image showed the formation of nanoparticles with average size of about 40 nm and normal size distribution. The magnetic measurements of the nanoparticles were done at room temperature using a vibrating sample magnetometer (VSM). Results exhibited a super-paramagnetic like behavior for some of the samples. DC electrical resistivity measurements were carried out by two-probe technique from 25 to 250 °C and showed decreasing of the resistivity with temperature meanwhile passing a transition to form of a peak. The peaks values observed near the Curie temperatures of samples suggest that anomaly behavior can attributed to spin canting associated with the phase transition from para to ferromagnetic state at TC.
•Stable MWNTs and graphene nanofluids were used in a mechanical wet cooling tower.•Thermal and rheological properties of nanofluids were investigated.•Nanofluids enhanced the efficiency, cooling ...range and tower characteristic.•Water consumption reduced significantly for both MWNTs and graphene nanofluids.
This study deals with an experimental investigation on the thermal performance of a mechanical wet cooling tower with counter flow arrangement by using multi-walled carbon nanotubes (MWNTs) and nanoporous graphene nanofluids. Stable nanofluids were prepared through two-step procedure by using water with properties taken from a working cooling tower in the South of Iran. Zeta potential revealed suitable stability of MWNTs and nanoporous graphene nanofluids. Thermal and rheological properties of the nanofluids were investigated. It was found that thermal conductivity increases by 20% and 16% at 45°C for MWNTs and nanoporous graphene nanofluids, respectively. The increase in density and viscosity, particularly in low concentrations of nanoparticles, was insignificant enough for industrial applications. Moreover, it was found that by using nanofluids, efficiency, cooling range and tower characteristic (KaV/L) are enhanced in comparison to water. For instance, at inlet water temperature of 45°C and water/air (L/G) flow ratio of 1.37, the cooling range increases by 40% and 67% for MWNTs and nanoporous graphene nanofluids (0.1wt.%), respectively. On the other hand water consumption is reduces by 10% and 19% at inlet water temperature of 45°C for MWNTs and nanoporous graphene nanofluids, respectively.
Head and neck cancers (HNSCC) are highly immunosuppressive. Plasma-derived exosomes of HNSCC patients carry immunomodulatory molecules, and their cargo correlates with clinical parameters. Here, we ...evaluated the exosomal molecular profile for early detection of treatment failure in locally advanced HNSCC patients treated with conventional therapy.
Plasma from 17 HNSCC patients was collected before, during, and after treatment by surgery with adjuvant (chemo)radiation and at recurrence. Exosomes were isolated by size-exclusion chromatography. Total exosomal protein (TEP) was used to estimate exosome load and on-bead flow cytometry to evaluate relative fluorescence intensity (RFI) of tumour-associated and immunoregulatory proteins on exosomes. Exosomal effects on the activity of and adenosine production by T cells was assessed by flow cytometry and mass spectrometry.
TEP and the ratio of tumour-/immune-cell-derived exosomes varied during and after therapy with an overall decrease in the tumour-free follow-up but an increase at recurrence. RFI values of immunoregulatory proteins on exosomes, their ability for T cell inhibition and adenosine production changed during and after therapy. PD-L1 was the earliest discriminator for treatment failure and disease-free survival.
Monitoring of plasma exosomes during therapy represents a promising opportunity for early detection of treatment failure and risk stratification to delay/avoid recurrence.
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