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排序方式: 共有1447条查询结果,搜索用时 15 毫秒
981.
Connected autonomous vehicles (CAVs) have the potential to deal with the steady increase in road traffic while solving transportation related issues such as traffic congestion, pollution, and road safety. Therefore, CAVs are becoming increasingly popular and viewed as the next generation transportation solution. Although modular advancements have been achieved in the development of CAVs, these efforts are not fully integrated to operationalize CAVs in realistic driving scenarios. This paper surveys a wide range of efforts reported in the literature about the CAV developments, summarizes the CAV impacts from a statistical perspective, explores current state of practice in the field of CAVs in terms of autonomy technologies, communication backbone, and computation needs. Furthermore, this paper provides general guidance on how transportation infrastructures need to be prepared in order to effectively operationalize CAVs. The paper also identifies challenges that need to be addressed in near future for effective and reliable adoption of CAVs.  相似文献   
982.
Theoretical and Mathematical Physics - We adopt a new approach to the study of homothetic vector fields of locally rotationally symmetric Bianchi type- I spacetimes. The obtained results are...  相似文献   
983.
This work was undertaken to explore the phytochemical composition, antioxidant, and enzyme-inhibiting properties of Neurada procumbens L. extracts/fractions of varying polarity (methanol extract and its fractions including n-hexane, chloroform, n-butanol, and aqueous fractions). A preliminary phytochemical study of all extracts/fractions, HPLC-PDA polyphenolic quantification, and GC-MS analysis of the n-hexane fraction were used to identify the phytochemical makeup. Antioxidant (DPPH), enzyme inhibition (against xanthine oxidase, carbonic anhydrase, and urease enzymes), and antibacterial activities against seven bacterial strains were performed for biological investigation. The GC-MS analysis revealed the tentative identification of 22 distinct phytochemicals in the n-hexane fraction, the majority of which belonged to the phenol, flavonoid, sesquiterpenoid, terpene, fatty acid, sterol, and triterpenoid classes of secondary metabolites. HPLC-PDA analysis quantified syringic acid, 3-OH benzoic acid, t-ferullic acid, naringin, and epicatechin in a significant amount. All of the studied extracts/fractions displayed significant antioxidant capability, with methanol extract exhibiting the highest radical-scavenging activity, as measured by an inhibitory percentage of 81.4 ± 0.7 and an IC50 value of 1.3 ± 0.3. For enzyme inhibition experiments, the n-hexane fraction was shown to be highly potent against xanthine oxidase and urease enzymes, with respective IC50 values of 2.3 ± 0.5 and 1.1 ± 0.4 mg/mL. Similarly, the methanol extract demonstrated the strongest activity against the carbonic anhydrase enzyme, with an IC50 value of 2.2 ± 0.4 mg/mL. Moreover, all the studied extracts/fractions presented moderate antibacterial potential against seven bacterial strains. Molecular docking of the five molecules β-amyrin, campesterol, ergosta-4,6,22-trien-3β-ol, stigmasterol, and caryophyllene revealed the interaction of these ligands with the investigated enzyme (xanthine oxidase). The results of the present study suggested that the N. procumbens plant may be evaluated as a possible source of bioactive compounds with multifunctional therapeutic applications.  相似文献   
984.
Amylase and glucosidase enzymes are the primary harmful source in the development of the chronic condition known as diabetes mellitus. The main function of these enzymes is to break the macromolecules into simple sugar units which are directly involved in the solubility of blood, hence increasing blood glucose levels. To overcome this effect, there is a need for a potent and effective inhibitor that inhibits the conversion of macromolecules of sugar into its smaller units. In this regard, we synthesized thiazolidinone-based indole derivatives (1–20). The synthesized derivatives were evaluated for α-amylase and α-glucosidase inhibitory activity. Different substituted derivatives were found with moderate to good potentials having IC50 values ranging, for α-amylase, from 1.50 ± 0.05 to 29.60 ± 0.40 μM and, for α-glucosidase, from IC50 = 2.40 ± 0.10 to 31.50 ± 0.50 μM. Among the varied substituted compounds, the most active analogs four (1.80 ± 0.70 and 2.70 ± 0.70), five (1.50 ± 0.05 and 2.40 ± 0.10, respectively) of the series showed few folds better inhibitory activity than standard drug acarbose (IC50 = 10.20 ± 0.10 and 11.70 ± 0.10 μM, respectively). Moreover, structure–activity relationship (SAR) was established and binding interactions were analyzed for ligands and proteins (α-amylase and α-glucosidase) through a molecular docking study.  相似文献   
985.
Hydrazones are active compounds having an azomethine –NHN=CH group and are widely studied owing to their ease of preparation and diverse pharmacological benefits. Novel isonicotinic hydrazone derivatives of vanillin aldehyde and salicyl aldehyde were synthesized that had azomethine linkages and were characterized by UV–Visible, FTIR, EI-MS, 1H-NMR and 13C-NMR spectroscopy. The compounds were screened for their antibacterial activity against Staphylococcus aureus, Bacillus subtilus, and Escherichia coli using disc diffusion and minimum inhibitory concentration (MIC) methods. For cytotoxicity, a brine shrimp lethality test was performed to calculate the lethal concentration (LC50). The results demonstrated appreciable antibacterial activities against the applied strains, amongst which the compounds coded NH3 and NH5 showed maximum inhibition and MIC responses. In terms of cytotoxic activity, the maximum effect was observed in compound NH5 and NH6 treatments with minimum survival percentages of 36.10 ± 3.45 and 32.44 ± 2.0, respectively. These hydrazones could be potential candidates in antitumorigenic therapy against various human cancer cells.  相似文献   
986.
This work suggests a new model for anisotropic compact stars with quintessence in f(T)gravity by us-ing the off-diagonal tetrad and the power-law as f(T)=βTn,where T is the scalar torsion andβand n are real con-stants.The acquired field equations incorporating the anisotropic matter source along with the quintessence field,in f(T)gravity,are investigated by making use of the specific character of the scalar torsion T for the observed stars PSRJ1614-2230,4U1608-52.CenX-3,EXO1785-248,and SMCX-1.It is suggested that all the stellar struc-tures under examination are advantageously independent of any central singularity and are stable.Comprehensive graphical analysis shows that various physical features which are crucially important for the emergence of the stellar structures are conferred.  相似文献   
987.
Vanjare  Balasaheb D.  Mahajan  Prasad G.  Dige  Nilam C.  Raza  Hussain  Hassan  Mubashir  Han  Yohan  Kim  Song Ja  Seo  Sung-Yum  Lee  Ki Hwan 《Molecular diversity》2021,25(4):2089-2106
Molecular Diversity - We have created a novel series of mushroom tyrosinase inhibitors with 1,2,4-triazole as fundamental skeleton. The target compound 1,2,4-triazol-3-ylthio)-N-phenyl acetamide...  相似文献   
988.
The copolymerization of ethylene‒diene conjugates (butadiene (BD), isoprene (IP) and nonconjugates (5-ethylidene-2-norbornene (ENB), vinyl norbornene VNB, 4-vinylcyclohexene (VCH) and 1, 4-hexadiene (HD)), and terpolymerization of ethylene-propylene-diene conjugates (BD, IP) and nonconjugates (ENB, VNB, VCH and HD) using two traditional catalysts of C2-symmetric metallocene—silylene-bridged rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (complex A) and ethylene-bridged rac-Et(Ind)2ZrCl2 (complex B)—with a [Ph3C][B(C6F5)4] borate/TIBA co-catalyst, were intensively studied. Compared to that in the copolymerization of ethylene diene, the catalytic activity was more significant in E/P/diene terpolymerization. We obtained a maximum yield of both metallocene catalysts with conjugated diene between 3.00 × 106 g/molMt·h and 5.00 × 106 g/molMt·h. ENB had the highest deactivation impact on complex A, and HD had the most substantial deactivation effect on complex B. A 1H NMR study suggests that dienes were incorporated into the co/ter polymers’ backbone through regioselectivity. ENB and VNB, inserted by the edo double bond, left the ethylidene double bond intact, so VCH had an exo double bond. Complex A’s methyl and phenyl groups rendered it structurally stable and exhibited a dihedral angle greater than that of complex B, resulting in 1, 2 isoprene insertion higher than 1, 4 isoprene that is usually incapable of polymerization coordination. High efficiency in terms of co- and ter- monomer incorporation with higher molecular weight was found for complex 1. The rate of incorporation of ethylene and propylene in the terpolymer backbone structure may also be altered by the conjugated and nonconjugated dienes. 13C-NMR, 1H-NMR, and GPC techniques were used to characterize the polymers obtained.  相似文献   
989.
In this paper, we introduce a new one-step iterative process to approximate common fixed points of two multivalued nonexpansive mappings in a real uniformly convex Banach space. We establish weak and strong convergence theorems for the proposed process under some basic boundary conditions.  相似文献   
990.
Russian Journal of Electrochemistry - Nowadays, industrial waste from feedstock contains a lot of organic acids, which are being discharged into the water streams causing environment load with...  相似文献   
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