261 research outputs found
Perilaku Konsumen dalam Memilih Jasa Layanan Operator Mobile Phone yang Berbasis Cdma dan Gsm (Studi pada Pelajar dan Mahasiswa Kelompok N-gens di Kota Malang dari Perpektif Stratejik)
An objective of this research is to (1) identify factors that customer consider in choosing mobile phone operator service (whether CDMA and GSM), (2) identify dominant variable that influences consumer behavior. Kind of this research is applied research with a research method of causal study. This research is intended to student and university student segments in Malang City, which these are included into Net Generation group (born between 1977-1997) with age minimal limitation for respondent of 17 years. Sample framework for this research is user of CDMA and GSM cards of 175 respondents. Moreover, for its sample technique used is non-probability sampling with purposive sample method, and the second is quota sampling. Extraction result of 34 variables is 7 new factors, which it is labeled as follow: (1) product image factor, (2) service factor, (3) environment influence factor, (4) promotion factor, (5) individual factor, (6) price factor, and (7) process factor. From discriminant analysis, the contrary result with the hypothesis is found, that is price variable, rather than dominant variable in differentiating consumer behavior of CDMA operator to GSM operator. They are more sensitive to product process. Product image to persue subscriber for student of SMU and university as subscriber “Smart” group. Research result conclude are to build competitive advantage, the operator must be to get positional advantage as differentiation “content” service which result are process, as result from product positioning aplication
Analisis Perilaku Konsumen dalam Memilih Jasa Layanan Operator Mobile Phone yang Berbasis Cdma dan Gsm
Objective of this research are (1) to identify factors that customer consider in choosing mobile phone operator service (whether CDMA and GSM), (2) to identify dominant variable that influences consumer behavior. Kind of this research is applied research with a research method of causal study. This research is intended to student and university student segments in Malang City, which these are included into Net Generation group (born between 1977-1997) with age minimal limitation for respondent of 17 years. Sample framework for this research is user of CDMA and GSM cards of 175 respondents. Moreover, for its sample technique used is non-probability sampling with purposive sample method, and the second is quota sampling. Extraction result of 34 variables are seven new factors, which are labeled as follow: (1) product image factor, (2) service factor, (3) environment influence factor, (4) promotion factor, (5) individual factor, (6) price factor, and (7) process factor. From discriminant analysis, the contrary result with the hypothesis is found, that is price variable, rather than dominant variable in differentiating consumer behavior of CDMA operator to GSM operator. They are more sensitive to product process. Product image to persue subscriber for student of SMU and university as subscriber “Smart” group. Research result conclude are to build competitive advantage, the operator must be to get positional advantage as differentiation “content” service which result are process, as result from product positioning aplication
The Role of Structural Biology Task Force: Validation of the Binding Mode of Repurposed Drugs Against SARS-CoV-2 Protein Targets: Focus on SARS-CoV-2 Main Protease (Mpro): A Promising Target for COVID-19 Treatment
The main protease (Mpro) of SARS-CoV-2, a cysteine protease that plays a key role in generating the active proteins essential for coronavirus replication, is a validated drug target for treating COVID-19. The structure of Mpro has been elucidated by macromolecular crystallography, but owing to its conformational flexibility, finding effective inhibitory ligands was challenging. Screening libraries of ligands as part of EXaSCale smArt pLatform Against paThogEns (ExScalate4CoV) yielded several potential drug molecules that inhibit SARS-CoV-2 replication in vitro. We solved the crystal structures of Mpro in complex with repurposed drugs like myricetin, a natural flavonoid, and MG-132, a synthetic peptide aldehyde. We found that both inhibitors covalently bind the catalytic cysteine. Notably, myricetin has an unexpected binding mode, showing an inverted orientation with respect to that of the flavonoid baicalein. Moreover, the crystallographic model validates the docking pose suggested by molecular dynamics experiments. The mechanism of MG-132 activity against SARS-CoV-2 Mpro was elucidated by comparison of apo and inhibitor-bound crystals, showing that regardless of the redox state of the environment and the crystalline symmetry, this inhibitor binds covalently to Cys145 with a well-preserved binding pose that extends along the whole substrate binding site. MG-132 also fits well into the catalytic pocket of human cathepsin L, as shown by computational docking, suggesting that it might represent a good start to developing dual-targeting drugs against COVID-1
Structure and metal-binding properties of PA4063, a novel player in periplasmic zinc trafficking by Pseudomonas aeruginosa
The capability to obtain essential nutrients in hostile environments is a critical skill for pathogens. Under zinc-deficient conditions, Pseudomonas aeruginosa expresses a pool of metal homeostasis control systems that is complex compared with other Gram-negative bacteria and has only been partially characterized. Here, the structure and zinc-binding properties of the protein PA4063, the first component of the PA4063-PA4066 operon, are described. PA4063 has no homologs in other organisms and is characterized by the presence of two histidine-rich sequences. ITC titration detected two zinc-binding sites with micromolar affinity. Crystallographic characterization, performed both with and without zinc, revealed an α/β-sandwich structure that can be classified as a noncanonical ferredoxin-like fold since it differs in size and topology. The histidine-rich stretches located at the N-terminus and between β3 and β4 are disordered in the apo structure, but a few residues become structured in the presence of zinc, contributing to coordination in one of the two sites. The ability to bind two zinc ions at relatively low affinity, the absence of catalytic cavities and the presence of two histidine-rich loops are properties and structural features which suggest that PA4063 might play a role as a periplasmic zinc chaperone or as a concentration sensor useful for optimizing the response of the pathogen to zinc deficiency
Cellulose Acetate and Cardanol Based Seed Coating for Intraspecific Weeding Coupled with Natural Herbicide Spraying
Abstract: Agricultural pesticides can become persistent environmental pollutants and their use is destined to be reduced. Consequently, weed control is shifting to green products and strategies. A combined approach, made of pelargonic acid based herbicide spraying and interspecific competition (i.e. seeding of plants species competing for growth against weeds) could boost the weeding effect. In case of the contemporary seeding and spraying, needed to reduce costs, seed coating is necessary as barrier to herbicide toxic effects but, at the same time, the coating has to be endowed with the right features to allow germination. This work aims to verify the feasibility of using cellulose acetate/cardanol (CA/Card) as seed coating polymer–plasticizer blend and to identify possible relationship between material features and germination rate. For these purposes, untreated and pelargonic acid herbicide treated coated seeds coated through solvent evaporation methods (CA/Card ratios from 0/0 to 100/0) were subjected to germination test. Coatings were characterized through SEM, EDX, media uptake, DSC and mechanical analysis with and without conditioning in seeding conditions. Germination test showed that 70/30 seeds, treated and untreated with herbicide, presented the best germination rate. Germination assays showed that coating presence reduced and slowed (without stopping) seeds germination equally with and without herbicide treatment. Consequently, was possible to conclude that CA/Card coatings allowed germination and presented a barrier effect against herbicide. Thus coating resulted suitable for seed coating in herbicide spraying/interspecific combined applications. No strong correlations were found between material features and germination, but it is plausible to hypothesize that both water absorption and mechanical properties of the coating play an important role and have to be optimized to improve germination rate avoiding difficulty in sprouting. Finally, the study opened a new perspective in the use of cellulose acetate for seed coating from waste sources such as cigarette filters. Graphic Abstract: [Figure not available: see fulltext.]
Crystal chemistry and temperature behavior of the natural hydrous borate colemanite, a mineral commodity of boron
Colemanite, CaB3O4(OH)3*H2O, is the most common hydrous Ca-borate, as well as a major mineral commodity of boron. In this study, we report a thorough chemical analysis and the low-temperature behavior of a natural sample of colemanite by means of a multi-methodological approach. From the chemical point of view, the investigated sample resulted to be relatively pure, its composition being very close to the ideal one, with only a minor substitution of Sr2+for Ca2+. At about 270.5 K, a displacive phase transition from the centrosymmetric P21/a to the acentric P21 space group occurs. On the basis of in situ single-crystal synchrotron X-ray (down to 104 K) and neutron diffraction (at 20 K) data, the hydrogen-bonding configuration of both the polymorphs and the structural modifications at the atomic scale at varying temperatures are described. The asymmetric distribution of ionic charges along the [010] axis, allowed by the loss of the inversion center, is likely responsible for the reported ferroelectric behavior of colemanite below the phase transition temperature
Palladium(II)-η3-Allyl Complexes Bearing N-Trifluoromethyl N-Heterocyclic Carbenes: A New Generation of Anticancer Agents that Restrain the Growth of High-Grade Serous Ovarian Cancer Tumoroids
The first palladium organometallic compounds bearing N-trifluoromethyl N-heterocyclic carbenes have been synthesized. These η3-allyl complexes are potent antiproliferative agents against different cancer lines (for the most part, IC50 values fall in the range 0.02–0.5 μm). By choosing 1,3,5-triaza-7-phosphaadamantane (PTA) as co-ligand, we can improve the selectivity toward tumor cells, whereas the introduction of 2-methyl substituents generally reduces the antitumor activity slightly. A series of biochemical assays, aimed at defining the cellular targets of these palladium complexes, has shown that mitochondria are damaged before DNA, thus revealing a behavior substantially different from that of cisplatin and its derivatives. We assume that the specific mechanism of action of these organometallic compounds involves nucleophilic attack on the η3-allyl fragment. The effectiveness of a representative complex, 4 c, was verified on ovarian cancer tumoroids derived from patients. The results are promising: unlike carboplatin, our compound turned out to be very active and showed a low toxicity toward normal liver organoids
The anticancer activity of an air-stable Pd(i)-NHC (NHC = N-heterocyclic carbene) dimer
A new dinuclear Pd(i) complex coordinating two bis(NHC) ligands revealed an unsuspected stability despite the unsaturation of the two metal centres. Even more surprisingly, the compound showed high and selective antiproliferative activity against different cancer cell lines and ovarian cancer tumoroids, and the mechanism of action was different from that of cisplatin
The anticancer activity of an air-stable Pd(i)-NHC (NHC = N-heterocyclic carbene) dimer
A new dinuclear Pd(i) complex coordinating two bis(NHC) ligands revealed an unsuspected stability despite the unsaturation of the two metal centres. Even more surprisingly, the compound showed high and selective antiproliferative activity against different cancer cell lines and ovarian cancer tumoroids, and the mechanism of action was different from that of cisplatin
The anticancer activity of an air-stable Pd(i)-NHC (NHC = N-heterocyclic carbene) dimer
A new dinuclear Pd(i) complex coordinating two bis(NHC) ligands revealed an unsuspected stability despite the unsaturation of the two metal centres. Even more surprisingly, the compound showed high and selective antiproliferative activity against different cancer cell lines and ovarian cancer tumoroids, and the mechanism of action was different from that of cisplatin
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