550 research outputs found
Intelligent Reflecting Surfaces Assisted UAV Communications for IoT Networks : Performance Analysis
The increasing demand for wireless connectivity and the emergence of the notion of the Internet of Everything require new communication paradigms that will ultimately enable a plethora of new applications and new disruptive technologies. In this context, the present contribution investigates the use of the recently introduced intelligent reflecting surface (IRS) concept in unmanned aerial vehicles (UAV) enabled communications aiming to extend the network coverage and improve the communication reliability as well as spectral efficiency of Internet of Things (IoT) networks. In particular, we first derive tractable analytic expressions for the achievable symbol error rate (SER), ergodic capacity, and outage probability of the considered set up. Following this, we also derive tight upper and lower bounds on the average signal-to-noise ratio (SNR). Our derivations are then compared with the corresponding asymptotic performance, based on the central limit theorem (CLT) assumption, which reveals that the asymptotic SNR falls within the area between derived bounds, and approaches either bound depending on the number of reflective elements (REs). We further show that the asymptotic SER becomes in a tight agreement with the corresponding exact simulation SER for N≥16. In addition, the offered results demonstrate that the use of the IRS is significantly effective as they assist in improving the achievable SER by five orders of magnitude. We further demonstrate that, in terms of achievable ergodic capacity, IRS-assisted UAV communication systems can exhibit ten times higher capacity compared to conventional UAV communications. Based on the above, these results and related insights are anticipated to be useful in the design and deployment of IRS-assisted UAV systems in the context of beyond 5G communications, such as 6G communications.acceptedVersionPeer reviewe
Novel quinazoline-based sulfonamide derivative (3D) induces apoptosis in colorectal cancer by inhibiting JAK2–STAT3 pathway
Introduction: Colorectal cancer (CRC) is a major worldwide health problem owing to its high
prevalence and mortality rate. Developments in screening, prevention, biomarker, personalized
therapies and chemotherapy have improved detection and treatment. However, despite these
advances, many patients with advanced metastatic tumors still succumb to the disease. New
anticancer agents are needed for treating advanced stage CRC as most of the deaths occur due to
cancer metastasis. A recently developed novel sulfonamide derivative 4-((2-(4-(dimethylamino)
phenyl)quinazolin-4-yl)amino)benzenesulfonamide (3D) has shown potent antitumor effect;
however, the mechanism underlying the antitumor effect remains unknown.
Materials and methods: 3D-mediated inhibition on cell viability was evaluated by MTT and
real-time cell proliferation was measured by xCelligence RTDP instrument. Western blotting
was used to measure pro-apoptotic, anti-apoptotic proteins and JAK2-STAT3 phosphorylation.
Flow cytometry was used to measure ROS production and apoptosis.
Results: Our study revealed that 3D treatment significantly reduced the viability of human CRC
cells HT-29 and SW620. Furthermore, 3D treatment induced the generation of reactive oxygen
species (ROS) in human CRC cells. Confirming our observation, N-acetylcysteine significantly
inhibited apoptosis. This is further evidenced by the induction of p53 and Bax; release of cytochrome
c; activation of caspase-9, caspase-7 and caspase-3; and cleavage of PARP in 3D-treated cells. This
compound was found to have a significant effect on the inhibition of antiapoptotic proteins Bcl2 and
BclxL. The results further demonstrate that 3D inhibits JAK2–STAT3 pathway by decreasing the
constitutive and IL-6-induced phosphorylation of STAT3. 3D also decreases STAT3 target genes
such as cyclin D1 and survivin. Furthermore, a combination study of 3D with doxorubicin (Dox)
also showed more potent effects than single treatment of Dox in the inhibition of cell viability.
Conclusion: Taken together, these findings indicate that 3D induces ROS-mediated apoptosis
and inhibits JAK2–STAT3 signaling in CRC
Feature Selection by Multiobjective Optimization: Application to Spam Detection System by Neural Networks and Grasshopper Optimization Algorithm
Networks are strained by spam, which also overloads email servers and blocks mailboxes with unwanted messages and files. Setting the protective level for spam filtering might become even more crucial for email users when malicious steps are taken since they must deal with an increase in the number of valid communications being marked as spam. By finding patterns in email communications, spam detection systems (SDS) have been developed to keep track of spammers and filter email activity. SDS has also enhanced the tool for detecting spam by reducing the rate of false positives and increasing the accuracy of detection. The difficulty with spam classifiers is the abundance of features. The importance of feature selection (FS) comes from its role in directing the feature selection algorithm’s search for ways to improve the SDS’s classification performance and accuracy. As a means of enhancing the performance of the SDS, we use a wrapper technique in this study that is based on the multi-objective grasshopper optimization algorithm (MOGOA) for feature extraction and the recently revised EGOA algorithm for multilayer perceptron (MLP) training. The suggested system’s performance was verified using the SpamBase, SpamAssassin, and UK-2011 datasets. Our research showed that our novel approach outperformed a variety of established practices in the literature by as much as 97.5%, 98.3%, and 96.4% respectively.©2022 the Authors. Published by IEEE. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/fi=vertaisarvioitu|en=peerReviewed
In vitro and in vivo anthelmintic efficacy of condensed tannins extracted from the seeds of alfalfa (Medicago sativa L.) against Haemonchus contortus infection
This study was designed to examine in vitro and in vivo anthelmintic efficacy of condensed tannins (CT) extracted from seeds of Medicago sativa on Haemonchus contortus in sheep. CT's in vitro anthelmintic effect was assessed at a 300 μg/ml concentration compared with albendazole (reference drug) at 10 μg/ml. The results showed that CT had a nematocidal effect on H. contortus, and the cuticle of the adult worm appeared to be its initial target. For the in vivo experiment, nine 3-month-old helminths-free lambs were distributed into three groups. Group 1 (n=3) was challenged only as infected untreated controls; Group 2 (n=3) was treated with condensed tannin, and Group 3 (n=3) was treated with albendazole. Fecal and blood samples were collected every 3 days until the end of the experiment; for fecal egg count (FEC) and anti- H. contortus IgG titers determination, respectively. The lambs treated with the CT in G2 exhibited a pronounced decrease of mean FEC with great FECR% detected from the first-week post-treatment (PT) until the end of the experiment compared with G1 animals. The antibody levels gradually increased in G2 following the 2nd dose of CT treatment compared to other groups. A brilliant consistent relation between the elevation of IgG response and reduction of FEC was observed following the second booster dosing of the CT in G2. In conclusion, the CT evoked strongly in vitro and in vivo anthelmintic activity against H. contortus and could be used as a natural alternative treatment of high potency against haemonchosis in sheep
Synthesis 4-[2-(2-mercapto-4-oxo-4H-quinazolin-3-yl)-ethyl]-benzenesulfonamides with subnanomolar carbonic anhydrase II and XII inhibitory properties
Condensation of substituted anthranilic acids with 4-isothiocyanatoethyl-benzenesulfonamide led to series
of heterocyclic benzenesulfonamides incorporating 2-mercapto-quinazolin-4-one tails. These sulfonamides
were investigated as inhibitors of the human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms hCA I
and II (cytosolic isozymes), as well as hCA XII (a transmembrane, tumor-associated enzyme also involved
in glaucoma-genesis). The new sulfonamides acted as medium potency inhibitors of hCA I (KIs of 28.5–
2954 nM), being highly effective as hCA II (KIs in the range of 0.62–12.4 nM) and XII (KIs of 0.54–
7.11 nM) inhibitors. All substitution patterns present in these compounds (e.g., halogens, methyl and
methoxy moieties, in positions 6, 7 and/or 8 of the 2-mercapto-quinazolin-4-one ring) led to highly effective
hCA II/XII inhibitors. These compounds should thus be of interest as preclinical candidates in
pathologies in which the activity of these enzymes should be inhibited, such as glaucoma (CA II and
XII as targets) or some tumors in which the activity of isoforms CA II and XII is dysregulated
Synthesis and evaluation of anticancer, antiphospholipases, antiproteases, and antimetabolic syndrome activities of some 3H-quinazolin-4-one derivatives
Some new 3H-quinazolin-4-one derivatives were synthesised and screened for anticancer, antiphospholipases, antiproteases, and antimetabolic syndrome activities. Compound 15d was more potent in reducing the cell viabilities of HT-29 and SW620 cells lines to 38%, 36.7%, compared to 5-FU which demonstrated cell viabilities of 65.9 and 42.7% respectively. The IC50 values of 15d were ∼20 µg/ml. Assessment of apoptotic activity revealed that 15d decreased the cell viability by down regulating Bcl2 and BclxL. Moreover, compounds, 8j, 8d/15a/15e, 5b, and 8f displayed lowered IC50 values than oleanolic acid against proinflammatory isoforms of hGV, hG-X, NmPLA2, and AmPLA2. In addition, 8d, 8h, 8j, 15a, 15b, 15e, and 15f showed better anti-α-amylase than quercetin, whereas 8g, 8h, and 8i showed higher anti-α-glucosidase activity than allopurinol. Thus, these compounds can be considered as potential antidiabetic agents. Finally, none of the compounds showed higher antiproteases or xanthine oxidase activities than the used reference drugs
SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
Parasitic infection caused by blood flukes of the genus Schistosoma is a major global health problem. More than 200 million people are infected. Identifying and characterizing the constituent enzymes of the parasite's biochemical pathways should reveal opportunities for developing new therapies (i.e., vaccines, drugs). Schistosomes feed on host blood, and a number of proteolytic enzymes (proteases) contribute to this process. We have identified and characterized a new protease, SmCL3 (for Schistosoma mansoni cathepsin L3), that is found within the gut tissue of the parasite. We have employed various biochemical and molecular biological methods and sequence similarity analyses to characterize SmCL3 and obtain insights into its possible functions in the parasite, as well as its evolutionary position among cathepsin L proteases in general. SmCL3 hydrolyzes major host blood proteins (serum albumin and hemoglobin) and is expressed in parasite life stages infecting the mammalian host. Enzyme substrate specificity detected by positional scanning-synthetic combinatorial library was confirmed by molecular modeling. A sequence analysis placed SmCL3 to the cluster of other cathepsins L in accordance with previous phylogenetic analyses
Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study
Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
- …