Goat milk proteins have gained increasing attention especially the bioactive peptides released from the parent proteins by digestive enzymes. Specifically, the interest in bioactives of goat milk is ...intensifying due to its reduced allergenicity compared to bovine milk. In this study, proteins of goat milk were fractionated into caseins (GCP) and whey proteins (GWP), hydrolyzed by pepsin and the generated peptides were examined for radical scavenging activities. The hydrolysates of whey (P-GWP) and casein (P-GCP) proteins exhibited potent superoxide anion (O2･−) scavenging activity in a dose-dependent manner, as investigated using the natural xanthine/xanthine oxidase (X/XOD) system. The P-GWP and P-GCP dramatically quenched the O2･− flux but had negligible effect on the catalytic function of the enzyme, indicating specificity to scavenge O2･− but not oxidase inhibition. Further, both P-GWP and P-GCP were able to remarkably quench the chemical DPPH radical. Fractionation of hydrolysates by size-exclusion chromatography produced four fractions (F1-F4) from both hydrolysates, with variable O2･− scavenging activities. However, the slow eluting fractions (F4) of both hydrolysates and fast eluting fraction (F2) of P-GCP contained peptides with the highest scavenging activities. Peptides in the active fractions of P-GWP and P-GCP, isolated by reversed phase-HPLC, exhibited significantly strong O2･− scavenging activities. MALDI-TOF-MS allowed the identification of several antioxidant peptides derived from both caseins and whey proteins, with β-casein and β-lactoglobulin being the major contributors, respectively. The results demonstrate that digestion with pepsin generates multiple soluble peptides from goat milk protein fractions with remarkable ability to scavenge superoxide radicals and thus providing a fascinating opportunity for their potential candidacy as antioxidant bioactive peptides.
•Whey and casein protein fractions of goat milk were hydrolyzed with pepsin.•In vitro antioxidant activities were evaluated by O2·− generating XOD and DPPH assays.•Hydrolysates demonstrated potent antioxidant activities.•The RP-HPLC sub-fractions exhibited superior activities to their hydrolysates.•Potent antioxidant peptides were identified by MALDI-TOF/MS.
Liver disease causes millions of deaths per year worldwide, and approximately half of these cases are due to cirrhosis, which is an advanced stage of liver fibrosis that can be accompanied by liver ...failure and portal hypertension. Early detection of liver fibrosis helps in improving its treatment and prevents its progression to cirrhosis. In this work, we present a novel noninvasive method to detect liver fibrosis from tagged MRI images using a machine learning‐based approach. Specifically, coronal and sagittal tagged MRI imaging are analyzed separately to capture cardiac‐induced deformation of the liver. The liver is manually delineated and a novel image feature, namely, the histogram of the peak strain (HPS) value, is computed from the segmented liver region and is used to classify the liver as being either normal or fibrotic. Classification is achieved using a support vector machine algorithm. The in vivo study included 15 healthy volunteers (10 males; age range 30–45 years) and 22 patients (15 males; age range 25–50 years) with liver fibrosis verified and graded by transient elastography, and 10 patients only had a liver biopsy and were diagnosed with a score of F3‐F4. The proposed method demonstrates the usefulness and efficiency of extracting the HPS features from the sagittal slices for patients with moderate fibrosis. Cross‐validation of the method showed an accuracy of 83.7% (specificity = 86.6%, sensitivity = 81.8%).
A novel method has been presented for detecting liver fibrosis in tagged MRI images. The method is based on extracting a new set of features representing the distribution of the peak strains in the liver. The results show that the proposed method can achieve an accuracy of 83.7% for patients with moderate to severe fibrosis.
•The worldwide COVID-19 pandemic has heavily hit small tourism enterprises.•Resilience directly and indirectly influence sustainable tourism development.•Performance mediates relationship between ...resilience and sustainable development.•Enterprise type significantly affect the results and the research model.•Small restaurant owner-managers showed more resilience than their hotel counterpart.
Tourism is one of the hardest-hit industries by the global pandemic of Novel Coronavirus (COVID-19). Small tourism enterprises have been heavily affected and have had difficulty in business recovery. This research is an early attempt to explore the direct impact of small hospitality enterprises’ resilience on sustainable tourism development as well as indirect impact through performance. A pre-tested questionnaire survey was self-administered to owner-managers of small hospitality enterprises in Greater Cairo, Egypt. The results of structural equation modeling (SEM) using AMOS showed a positive, direct, and significant impact of resilience (planned and adaptive) on sustainable tourism development and indirect influence through performance. The results of the multi-group analysis showed that enterprise type has a significant effect on the results, where restaurant owner-managers expressed more resilience than their hotel counterparts. Several theoretical (for scholars) and practical implications for tourism policy-makers and owner-managers have been discussed and elaborated.
Iron overload is now recognized as a health problem in industrialized countries, as excessive iron is highly toxic for liver and spleen. The potential use of curcumin as an iron chelator has not been ...clearly identified experimentally in iron overload condition. Here, we evaluate the efficacy of curcumin to alleviate iron overload-induced hepatic and splenic abnormalities and to gain insight into the underlying mechanisms.
Three groups of male adult rats were treated as follows: control rats, rats treated with iron in a drinking water for 2 months followed by either vehicle or curcumin treatment for 2 more months. Thereafter, we studied the effects of curcumin on iron overload-induced lipid peroxidation and anti-oxidant depletion.
Treatment of iron-overloaded rats with curcumin resulted in marked decreases in iron accumulation within liver and spleen. Iron-overloaded rats had significant increases in malonyldialdehyde (MDA), a marker of lipid peroxidation and nitric oxide (NO) in liver and spleen when compared to control group. The effects of iron overload on lipid peroxidation and NO levels were significantly reduced by the intervention treatment with curcumin (P<0.05). Furthermore, the endogenous anti-oxidant activities/levels in liver and spleen were also significantly decreased in chronic iron overload and administration of curcumin restored the decrease in the hepatic and splenic antioxidant activities/levels.
Our study suggests that curcumin may represent a new horizon in managing iron overload-induced toxicity as well as in pathological diseases characterized by hepatic iron accumulation such as thalassemia, sickle cell anemia, and myelodysplastic syndromes possibly via iron chelation, reduced oxidative stress derived lipid peroxidation and improving the body endogenous antioxidant defense mechanism.
At present, anti-virulence drugs are being considered as potential therapeutic alternatives and/or adjuvants to currently failing antibiotics. These drugs do not kill bacteria but inhibit virulence ...factors essential for establishing infection and pathogenesis through targeting non-essential metabolic pathways reducing the selective pressure to develop resistance. We investigated the effect of naturally isolated plant compounds on the repression of the quorum sensing (QS) system which is linked to virulence/pathogenicity in
Pseudomonas aeruginosa
. Our results show that
trans
-cinnamaldehyde (CA) and salicylic acid (SA) significantly inhibit expression of QS regulatory and virulence genes in
P. aeruginosa
PAO1 at sub-inhibitory levels without any bactericidal effect. CA effectively downregulated both the
las
and
rhl
QS systems with
lasI
and
lasR
levels inhibited by 13- and 7-fold respectively compared to 3- and 2-fold reductions with SA treatment, during the stationary growth phase. The QS inhibitors (QSI) also reduced the production of extracellular virulence factors with CA reducing protease, elastase and pyocyanin by 65%, 22% and 32%, respectively. The QSIs significantly reduced biofilm formation and concomitantly with repressed rhamnolipid gene expression, only trace amount of extracellular rhamnolipids were detected. The QSIs did not completely inhibit virulence factor expression and production but their administration significantly lowered the virulence phenotypes at both the transcriptional and extracellular levels. This study shows the significant inhibitory effect of natural plant-derived compounds on the repression of QS systems in
P. aeruginosa
.
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Angiotensin-converting enzyme (ACE) plays a central role in blood pressure regulation by producing the vasoconstrictor angiotensin II. The inhibition of ACE with natural inhibitors, ...as alternatives to avoid the side effect of synthetic drugs, is a major target in the prevention of hypertension. In this study, we examined the separated caseins and whey proteins of goat milk for the presence of ACE inhibitory peptides. Digestion of isolated whey proteins and caseins of goat milk by gastric pepsin generated soluble hydrolysates exhibiting significant inhibition of ACE compared to weak inhibition by undigested proteins. The hydrolysates were fractionated by size exclusion chromatography, Sephacryl S-100 column, into four fractions (F1–F4). The late-eluting fraction (F4) of either whey or caseins exhibited greater ACE inhibition. Peptides in both F4 fractions, isolated by RP-HPLC, exhibited variable ACE inhibitory activities with the hydrophobic peptide peaks being the most potent ACE inhibitors. MALDI-TOF MS/MS resulted in identification of three potent ACE inhibitory peptides: PEQSLACQCL from β-lactoglobulin (residues 113–122), QSLVYPFTGPI from β-casein (residues 56–66), and ARHPHPHLSFM from κ-casein (residues 96–106). The peptides from whey and caseins exert significant ACE inhibitory activities comparable to that of captopril, an antihypertensive drug, exhibiting IC50 values of 4.45μM and 4.27μM, respectively. The results introduce, for the first time, new potent ACE-inhibitory peptides that can be released by gastric pepsin of goat milk whey and caseins and thus may pave the way for their candidacy as anti-hypertensive bioactive peptides and prevention of associated disorders.
Both gallic and citrate are well-established antioxidants that show promise as new selective anti-cancer drugs. Gold nanoparticles (AuNPs) as well can be developed as flexible and nontoxic ...nano-carriers for anti-cancer drugs. This article evaluating the efficiency and biocompatibility of gallic acid and citrate capping gold nanoparticles to be used as anti-cancer drug. The biosafety and therapeutic efficiency of prepared nano-formulations were tested on Hela and normal BHK cell line. Gold nanospheres coated with citrate and gallate were synthesized via wet chemical reduction method. The prepared nano-formulations, citrate and gallate coated gold nanospheres (Cit-AuNPs and Ga-AuNPs), were characterized with respect to their morphology, FTIR spectra, and physical properties. In addition, to assess their cytotoxicity, cell cycle arrest and flow cytometry to measure biological response were performed. Cit-Au NPs and Ga-Au NPs were shown to significantly reduce the viability of Hela cancer cells. Both G0/G cell cycle arrest and comet assay results showed that genotoxic effect was induced in Hela cells by Cit-Au NPs and Ga-Au NPs. The results of this study showed that Cit-Au NPs and Ga-AuNPs inhibit the growth of metastatic cervical cancer cells, which could have therapeutic implications.
Spectrum congestion has motivated the recent introduction of integrated sensing and communication (ISAC) systems where radar and communications functionalities co-exist and share the same spectrum. ...This is accompanied by extensive research in the area of reconfigurable intelligent surfaces (RIS), thanks to their ability to improve the ISAC systems. In this paper, the physical layer security of a multiuser multiple-input single-output (MU-MISO) ISAC system is investigated when the system is subject to eavesdropping by a malicious unmanned aerial vehicle (UAV). In particular, we propose using an active RIS to maximize the achievable secrecy rate of the system through jointly designing the radar receive beamformers, the active RIS reflection coefficients matrix and the transmit beamformers at the dual-function base station of the ISAC system. This is done while taking into account a minimum radar detection signal-to-noise ratio (SNR) and total system power budget constraints. The resulting non-convex optimization problem is tackled by exploiting fractional programming (FP) and majorization-minimization (MM) techniques to achieve a solution. Our numerical results show the superiority of active RIS to achieve the goal when compared with passive RIS or with an ISAC without an RIS. Results also show that passive RIS could still be a viable solution to achieve this goal but at the expense of a much larger needed size especially when lower power budgets are available.
•Effects of design parameters on the performance of the Savonius turbine are studied.•The best design is selected based on flow field characteristics around the rotor.•The new rotor design enhances ...both power coefficient and self-starting ability.
It is important to determine the most optimal configuration of a Savonius vertical axis wind turbine that attains the best performance with a high self-starting ability. Thus, the effects of several design parameters including twist angle, overlap ratio, and endplates size ratio, along with the wind velocity on the performance of the Savonius wind turbine are investigated. Novel assessment methods based on flow field characteristics such as streamlines and pressure fields around the Savonius wind turbine are carried out. This is the first contribution to understand how geometrical variables influence the aerodynamic performance of the twisted Savonius rotor. Moreover, the variation of torque, power, thrust, and static torque coefficients are estimated. Thus, a three-dimensional, incompressible unsteady Reynolds-averaged Navier-Stokes model in conjunction with k-ω shear-stress transport turbulence model is developed. The model is numerically simulated and validated using the experimental and numerical data available in literature. Results indicate that the Savonius rotor with a twist angle of 45°, an overlapping ratio of zero, and endplates size ratio of 1.1 attains the highest net output power compared to other designs. It is found that at a wind velocity of 6 m/s, the Savonius rotor achieves a maximum power coefficient of 0.223, and with further increase of the wind velocity to 10 m/s, the power coefficient reaches 0.231. In addition, the current developed design has a positive static torque coefficient at all rotor angles, and consequently, it achieves a high self-starting ability. However, for the conventional (untwisted) design, the maximum attainable power coefficient was found to be 0.174 at an overlapping ratio of 0.15, and equal endplate size ratio. In addition, negative values of the static torque coefficient were observed at a specific range of rotor angles that prevent the self-starting ability. Accordingly, the new twisted rotor design not only enhances the power coefficient but the self-starting ability as well. The findings of the current results provide another direction for researchers and designers to utilize the twisted Savonius wind turbine.
Optimum power allocation is a key enabler for maximizing data rate in wireless networks. Recently, various deep neural network models have been introduced for predicting power allocation in ...device-to-device (D2D) networks. However, they require large training samples (i.e., network layouts). On the contrary in this paper, we aim to develop a learning model for power allocation with fewer training samples, which is vital in dynamic networks (e.g., vehicular networks) with the need for fast learning of power allocation. The proposed model transforms Euclidean-based network layouts and power allocation problems into Riemannian (i.e., non-Euclidean) manifolds, which is shown to require fewer learning parameters and hence shorter learning time. Such transformation is possible thanks to the symmetric positive definite (SPD) property of spectral representation (i.e., Laplacian matrix) of network layouts. In particular, we propose a graph convolutional regression network (GCRN) for predicting power allocation over Riemannian manifolds in an unsupervised manner. Simulation results demonstrate that the proposed GCRN model approaches the maximum network rate in large-scale networks, with only 300 training samples as opposed to 10,000 in Euclidean-based learning models.
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