208 research outputs found
Effect of Copper Acyclovir Complexes on Herpes Simplex Virus Type 1 and Type 2 (HSV-1, HSV-2) Infection in Cultured Cells
We have found that when copper, zinc or cobalt is bound to a suitable ligand, the
appropriate complex exhibited a significant anti-HSV effect (Varadinova et al., 1993; 1996).
Recently published data by Sagripanti et al. (1997) also show that the inhibition of HSV by
copper was enhanced by reducing agents and that mechanism of the inactivation is similar
as for copper-mediated DNA damage (Aruoma, et al. 1991; Dizdaroglu, et al., 1991;
Toyokuni and Sagripanti, 1994). Therefore it was interesting to study the efect of Cu(ll)
coordination compounds with acyclovir (ACV) on the replication of HSV in cultured cells.
The experiments on cytotoxicity as well as on the activity of three different Cu-ACV
complexes [Cu(ACV)2Cl2(H2O)2] = (A); [Cu(ACV)2(H2O)3](NO3)2.H2O = (B) and [Cu(ACV)2(H2O)2](NO3)2] = (C) towards virus replication, with special attention on the growth of
ACV-resistant strain R-100 were performed on MDBK cells. ACV was used as a reference
compound. The following results were obtained: 1) Increased cell’s viability in the presence
of 20-40(g/ml ACV and decreased one in the presence of Cu-ACV complexes with relative
level (A) >> (B) > (C); 2) Cu-ACV complexes are more cytotoxic than the ligand - ACV and the
relative level is (C)>(B)>(A); 3) The anti-HSV effect of ACV can be modulated by copper at
levels depending on the specificity of the particular virus strain: (i) for the ACV sensitive strain
DA (HSV-1) - ACV ((A) > (C) > (B); (ii) for the ACV sensitive strain Bja (HSV-2) (A) > ACV > (C) > (B); (iii) for strain R-100 (ACVR, TKa) - (A) > ACV > (C) > (B). This findings are consistent with
previously published data and undoubtedly show that Cu-ACV complexes could be useful in
the treatment of HSV infections, especially when the causative agent is a resistant to ACV
mutant
Structural characterization and antitumor activity of platinum(II) complexes with phenothiazine and N-methylphenothiazine
Cisplatin is one of the most used anticancer agents, and along with carboplatin and
oxaliplatin, is a part of more than 50% of clinically applied anticancer regimens [1]. However,
the side effects of cisplatin are severe and include dose-limiting toxicity, such as neurotoxicity,
nephrotoxicity and ototoxicity. Platinum(II) complexes with different structure from cisplatin
provide many opportunities for design of novel antitumor drugs with improved
pharmacological properties. Considering this, in the present study, new platinum(II) complexes
with phenothiazine (phtz) and N-methylphenothiazine (N-Mephtz), [PtCl2(phtz)(CH3CN)] (1)
and [PtCl2(N-Mephtz)(CH3CN)] (2), were synthesized. These complexes were characterized by
elemental microanalysis, NMR (1H and 13C) and IR spectroscopic measurements, while the
structure of complex 1 was determined by single-crystal X-ray diffraction analysis. The
antitumor activity of the platinum(II) complexes was tested in vitro against a panel of human
cancer cell lines, including A549 (lung cancer), A375 (melanoma, skin cancer), MDA-MB-231
(breast cancer), and HCT116 (colon cancer). To check the selectivity of the synthesized
complexes 1 and 2, a healthy MRC-5 cell line (lung fibroblasts) was also included in this study.Book of abstract:16th International Symposium
on Applied Bioinorganic Chemistry
(16-ISABC)
11-14th June
University of Ioannina
Greec
Symmetry and Topology in Superconductors - Odd-frequency pairing and edge states -
Superconductivity is a phenomenon where the macroscopic quantum coherence
appears due to the pairing of electrons. This offers a fascinating arena to
study the physics of broken gauge symmetry. However, the important symmetries
in superconductors are not only the gauge invariance. Especially, the symmetry
properties of the pairing, i.e., the parity and spin-singlet/spin-triplet,
determine the physical properties of the superconducting state. Recently it has
been recognized that there is the important third symmetry of the pair
amplitude, i.e., even or odd parity with respect to the frequency. The
conventional uniform superconducting states correspond to the even-frequency
pairing, but the recent finding is that the odd-frequency pair amplitude arises
in the spatially non-uniform situation quite ubiquitously. Especially, this is
the case in the Andreev bound state (ABS) appearing at the surface/interface of
the sample. The other important recent development is on the nontrivial
topological aspects of superconductors. As the band insulators are classified
by topological indices into (i) conventional insulator, (ii) quantum Hall
insulator, and (iii) topological insulator, also are the gapped
superconductors. The influence of the nontrivial topology of the bulk states
appears as the edge or surface of the sample. In the superconductors, this
leads to the formation of zero energy ABS (ZEABS). Therefore, the ABSs of the
superconductors are the place where the symmetry and topology meet each other
which offer the stage of rich physics. In this review, we discuss the physics
of ABS from the viewpoint of the odd-frequency pairing, the topological
bulk-edge correspondence, and the interplay of these two issues. It is
described how the symmetry of the pairing and topological indices determines
the absence/presence of the ZEABS, its energy dispersion, and properties as the
Majorana fermions.Comment: 91 pages, 38 figures, Review article, references adde
Psychometric properties of three measures of “Facebook engagement and/or addiction” among a sample of English speaking Pakistani university students
For researchers interested in measuring the construct of “Facebook engagement and/or addiction,” there are a number of existing measures including the Bergen Facebook Addiction Scale, the Facebook Intensity Scale, and the Addictive Tendencies Scale. Currently, there is limited data on the psychometric properties of these three scales, especially among South Asian samples. The present aim was to address this shortfall. A sample of 308 English-speaking Pakistani university students completed the scales, in their original English versions, on two occasions separated by four weeks. Results demonstrated that for each of the scales, across both administrations, satisfactory psychometric properties were found, including internal reliability, temporal stability, and construct validity. Moreover, for these three scales, using confirmatory factor analysis, a one-factor structure was generally found to be a good description of the data for both male and female samples. These data provide further evidence for the reliability and validity of three scales concerned with “Facebook engagement and/or addiction.
The Behavioral Roots of Information Systems Security:Exploring Key Factors Related to Unethical IT Use
Unethical information technology (IT) use, related to activities such as hacking, software piracy, phishing, and spoofing, has become a major security concern for individuals, organizations, and society in terms of the threat to information systems (IS) security. While there is a growing body of work on this phenomenon, we notice several gaps, limitations, and inconsistencies in the literature. In order to further understand this complex phenomenon and reconcile past findings, we conduct an exploratory study to uncover the nomological network of key constructs salient to this phenomenon, and the nature of their interrelationships. Using a scenario-based study of young adult participants, and both linear and nonlinear analyses, we uncover key nuances of this phenomenon of unethical IT use. We find that unethical IT use is a complex phenomenon, often characterized by nonlinear and idiosyncratic relationships between the constructs that capture it. Overall, ethical beliefs held by the individuals, along with economic, social, and technological considerations are found to be relevant to this phenomenon. In terms of practical implications, these results suggest that multiple interventions at various levels may be required to combat this growing threat to IS security
Problematic social media use: results from a large-scale nationally representative adolescent sample
Despite social media use being one of the most popular activities among adolescents, prevalence estimates among teenage samples of social media (problematic) use are lacking in the field. The present study surveyed a nationally representative Hungarian sample comprising 5,961 adolescents as part of the European School Survey Project on Alcohol and Other Drugs (ESPAD). Using the Bergen Social Media Addiction Scale (BSMAS) and based on latent profile analysis, 4.5% of the adolescents belonged to the at-risk group, and reported low self-esteem, high level of depression symptoms, and elevated social media use. Results also demonstrated that BSMAS has appropriate psychometric properties. It is concluded that adolescents at-risk of problematic social media use should be targeted by school-based prevention and intervention programs
Formation and physicochemical properties of crystalline and amorphous salts with different stoichiometries formed between ciprofloxacin and succinic acid
YesMulti-ionizable compounds, such as dicarboxylic
acids, offer the possibility of forming salts of drugs with
multiple stoichiometries. Attempts to crystallize ciprofloxacin,
a poorly water-soluble, amphoteric molecule with succinic acid
(S) resulted in isolation of ciprofloxacin hemisuccinate (1:1)
trihydrate (CHS-I) and ciprofloxacin succinate (2:1) tetrahydrate
(CS-I). Anhydrous ciprofloxacin hemisuccinate (CHS-II)
and anhydrous ciprofloxacin succinate (CS-II) were also
obtained. It was also possible to obtain stoichiometrically
equivalent amorphous salt forms, CHS-III and CS-III, by spray
drying and milling, respectively, of the drug and acid. Anhydrous CHS and CS had melting points at ∼215 and ∼228 °C, while
the glass transition temperatures of CHS-III and CS-III were ∼101 and ∼79 °C, respectively. Dynamic solubility studies revealed
the metastable nature of CS-I in aqueous media, resulting in a transformation of CS-I to a mix of CHS-I and ciprofloxacin 1:3.7
hydrate, consistent with the phase diagram. CS-III was observed to dissolve noncongruently leading to high and sustainable drug
solution concentrations in water at 25 and 37 °C, with the ciprofloxacin concentration of 58.8 ± 1.18 mg/mL after 1 h of the
experiment at 37 °C. This work shows that crystalline salts with multiple stoichiometries and amorphous salts have diverse
pharmaceutically relevant properties, including molecular, solid state, and solubility characteristics.Solid State Pharmaceutical Cluster (SSPC), supported by Science Foundation Ireland under grant number 07/SRC/ B1158
Superconducting phases of f-electron compounds
Intermetallic compounds containing f-electron elements display a wealth of
superconducting phases, that are prime candidates for unconventional pairing
with complex order parameter symmetries. For instance, superconductivity has
been found at the border of magnetic order as well as deep within ferro- and
antiferromagnetically ordered states, suggesting that magnetism may promote
rather than destroy superconductivity. Superconductivity near valence
transitions, or in the vicinity of magneto-polar order are candidates for new
superconductive pairing interactions such as fluctuations of the conduction
electron density or the crystal electric field, respectively. The experimental
status of the study of the superconducting phases of f-electron compounds is
reviewed.Comment: Rev. Mod. Phys. in print; 75 pages, 23 figures; comments welcom
Probing the competition among different coordination motifs in metal-ciprofloxacin complexes through IRMPD spectroscopy and DFT calculations
The vibrational spectra of ciprofloxacin complexes with monovalent (Li+, Na+, K+, Ag+) and polyvalent (Mg2+, Al3+) metal ions are recorded in the range 1000-1900 cm(-1) by means of infrared multiple-photon dissociation (IRMPD) spectroscopy. The IRMPD spectra are analyzed and interpreted in the light of density functional theory (DFT)-based quantum chemical calculations in order to identify the possible structures present under our experimental conditions. For each metal-ciprofloxacin complex, four isomers are predicted, considering different chelation patterns. A good agreement is found between the measured IRMPD spectrum and the calculated absorption spectrum of the most stable isomer for each complex. Metal ion size and charge are found to drive the competition among the different coordination motifs: small size and high charge density metal ions prefer to coordinate the quinolone between the two carbonyl oxygen atoms, whereas large-size metal ions prefer the carboxylate group as a coordination site. In the latter case, an intramolecular hydrogen bond compensates the weaker interaction established by these cations. The role of the metal cation on the stabilization of ionic and nonionic structures of ciprofloxacin is also investigated. It is found that large-size metal ions preferentially stabilize charge separated motifs and that the increase of metal ion charge has a stabilizing effect on the zwitterionic form of ciprofloxacin
Advances in Social Media Research:Past, Present and Future
Social media comprises communication websites that facilitate relationship forming between users from diverse backgrounds, resulting in a rich social structure. User generated content encourages inquiry and decision-making. Given the relevance of social media to various stakeholders, it has received significant attention from researchers of various fields, including information systems. There exists no comprehensive review that integrates and synthesises the findings of literature on social media. This study discusses the findings of 132 papers (in selected IS journals) on social media and social networking published between 1997 and 2017. Most papers reviewed here examine the behavioural side of social media, investigate the aspect of reviews and recommendations, and study its integration for organizational purposes. Furthermore, many studies have investigated the viability of online communities/social media as a marketing medium, while others have explored various aspects of social media, including the risks associated with its use, the value that it creates, and the negative stigma attached to it within workplaces. The use of social media for information sharing during critical events as well as for seeking and/or rendering help has also been investigated in prior research. Other contexts include political and public administration, and the comparison between traditional and social media. Overall, our study identifies multiple emergent themes in the existing corpus, thereby furthering our understanding of advances in social media research. The integrated view of the extant literature that our study presents can help avoid duplication by future researchers, whilst offering fruitful lines of enquiry to help shape research for this emerging field
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