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1.
Rev Esp Quimioter ; 35 Suppl 3: 84-88, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36285865

ABSTRACT

In January 2019, the European Committee for the Study of Antimicrobial Susceptibility (EUCAST) introduced some changes in the definitions of clinical categories for antibiotic susceptibility. The objective of these changes was to improve the credibility of category "I", optimizing and lengthening the survival and use of available antibiotics in the face of increasing antimicrobial resistance. This article aims to describe and explain these changes in the EUCAST criteria as well as make a short review about the factors on which the antibiotic susceptibility criteria depend.


Subject(s)
Anti-Bacterial Agents , Anti-Infective Agents , Humans , Microbial Sensitivity Tests , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use
2.
Rev Esp Quimioter ; 34 Suppl 1: 8-11, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34598414

ABSTRACT

The year 2020 was the year of infectious diseases with the arrival of SARS-CoV-2, which represented a profound change in the world we knew. However, we present a brief description of some of the top infectious diseases articles from 2020 not related with SARS-CoV-2. We reviewed a selection of the most important and relevant achievements in diagnosis and therapy related to bacteremia, nosocomial pneumonia, skin and soft tissue infections, infections by Clostridioides difficile, mycobacterial infections and invasive fungal infections. This year entailed a significant step forward in the indisputable value of the health care stewardship programs.


Subject(s)
Bacteremia , COVID-19 , Clostridium Infections , Communicable Diseases , Communicable Diseases/drug therapy , Communicable Diseases/epidemiology , Humans , SARS-CoV-2
3.
JCO Glob Oncol ; 6: 453-461, 2020 03.
Article in English | MEDLINE | ID: mdl-32160013

ABSTRACT

PURPOSE: To evaluate the feasibility of brigade-style, multiphasic cancer screening in Honduras, exploring data from 3 screening events that each tested for multiple cancers on single occasions. METHODS: This series of 3 studies each used a single-arm, post-test-only design to explore the feasibility of implementing multiphasic, community-based cancer screening at the same rural location in 2013, 2016, and 2017. The 2013 event for women screened for 2 cancers (breast and cervix), and the 2016 event for women screened for 3 cancers (breast, cervix, and thyroid). The 2017 event for men screened for 5 cancers (skin, prostate, colorectal, oropharynx, and testes). RESULTS: Totals of 473 and 401 women participated in the 2013 and 2016 events, respectively, and 301 men participated in the 2017 event. Staffing for each event varied from 33 to 44 people and relied primarily on in-country medical students and local community members. High rates (mean, 88%) of compliance with referral for follow-up testing at clinics and primary care facilities were observed after the screening events. CONCLUSION: The multiphasic, community-based approach proved feasible for both women and men and resulted in high rates of compliance with follow-up testing. This approach appears highly replicable: it was conducted multiple times across the years with different screening targets, which could be further scaled elsewhere using the same technique.


Subject(s)
Early Detection of Cancer , Neoplasms , Feasibility Studies , Female , Honduras/epidemiology , Humans , Male , Multiphasic Screening , Neoplasms/diagnosis , Neoplasms/epidemiology
4.
Article in English, Spanish | MEDLINE | ID: mdl-31955951

ABSTRACT

PURPOSE: We reviewed the clinical features of post-traumatic infections produced by Clostridium celerecrescens reported in the literature. C. celerecrescens is an emerging pathogen involved in traumatic wound infection that progresses to deep infection and osteomyelitis. METHODS: We found only 4 cases reported in the literature with enough data to be analysed and we added our own case and experience with this type of infection. The identification was performed by matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI TOF) or API gallery, and 16S rRNA gene sequencing were performed to confirm identification in all cases. RESULTS: Identification of the bacteria is discrepant according to the method used due to the genetic and phenotypic similarities of other species of the genus. Identification through MALDI-TOF and API gallery is not suitable for determining the specie, confirmation by 16S rRNA sequencing being necessary. Treatment of the infection included complex antibiotic combinations and surgical treatment together with skin and soft tissue dressings due to the persistence of the pathogen over time. CONCLUSION: This report supports the pathogenic role of C. celerecrescens in post-traumatic infections and the need to improve the management of these difficult-to-treat infections.

5.
Dent Mater ; 35(6): 883-892, 2019 06.
Article in English | MEDLINE | ID: mdl-30975483

ABSTRACT

OBJECTIVES: To compare biofilm formation on the surface of different ceramic biomaterials to be used in implant dentistry. METHODS: In vitro biofilm formation was investigated from mixtures of standard reference strains of Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Sterile ceramic calcium hydroxyapatite discs (HA) as control, sterile Al2O3/Ce-TZP nanocomposite sandblasted discs (material A1) and sterile Al2O3/Ce-TZP nanocomposite sandblasted discs and coated with two types of antimicrobial glasses (materials A2 and A3) were used. Biofilms were grown on the four surfaces and evaluated after 12, 24, 48 and 72 h of incubation. Biofilms were examined by confocal laser scanning microscopy (CLSM). In addition, counts of live bacterial cells of the target species A. actinomycetemcomitans, F. nucleatum and P. gingivalis were calculated by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA). For data analysis, bacterial counts were compared with a multivariate general lineal model. RESULTS: Using CLSM, cell vitality decreased in A2 and A3. With qPCR-PMA, significant differences in vitality were observed forA. actinomycetemcomitans in A3 after 48 and 72 h of incubation. With respect to the development of the biofilms, a significant increase in counts on HA and materials A1 and A2 was observed for A. actinomycetemcomitans and F. nucleatum. Conversely, for P. gingivalis, no differences were found for HA and materials A1 and A2. SIGNIFICANCE: Differences in biofilm formation were detected among the different tested materials. The ceramic material A3 has an effect on the vitality of A. actinomycetemcomitans growing in an in vitro biofilm model.


Subject(s)
Biocompatible Materials , Fusobacterium nucleatum , Biofilms , Ceramics , Porphyromonas gingivalis , Streptococcus oralis
6.
Rev Esp Quimioter ; 32(1): 68-72, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30547503

ABSTRACT

OBJECTIVE: Our objective was to evaluate the in vitro activity of ceftolozane-tazobactam against multidrug resistant (MDR) and extensively drug-resistant (XDR) non metallo-ß-lactamase producing Pseudomonas aeruginosa clinical isolates at Hospital Universitario Miguel Servet (Zaragoza, Spain) from February 2016 to October 2017. METHODS: We evaluated the in vitro activity of ceftolozane-tazobactam and other antipseudomonal antibiotics against 12 MDR and 117 XDR non metallo-ß-lactamase producing P. aeruginosa isolates. Ceftolozane-tazobactam minimal inhibitory concentrations (MICs) were determined by MIC gradient diffusion test strip. RESULTS: Among the 129 MDR/XDR isolates included, 119 (92.2%) were susceptible to ceftolozane-tazobactam, and ten (7.8%) were resistant. MIC50 was 2 mg/L, and MIC90 4 mg/L. Ceftolozane-tazobactam was the second most active antibiotic after colistin, overtaking amikacin. CONCLUSIONS: Ceftolozane-tazobactam is a valuable treatment option for MDR and XDR P. aeruginosa infections in our setting.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Cross Infection/microbiology , Drug Resistance, Multiple, Bacterial/drug effects , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/drug effects , Tazobactam/pharmacology , Adult , Aged , Aged, 80 and over , Amikacin/pharmacology , Colistin/pharmacology , Female , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Pseudomonas aeruginosa/enzymology , Spain , beta-Lactamases
7.
Eur J Pain ; 22(1): 114-126, 2018 01.
Article in English | MEDLINE | ID: mdl-28845556

ABSTRACT

BACKGROUND: The objective of this study was to estimate the association between sleep quality (SQ) and improvements in low back pain (LBP) and disability, among patients treated for LBP in routine practice. METHODS: This prospective cohort study included 461 subacute and chronic LBP patients treated in 11 specialized centres, 14 primary care centres and eight physical therapy practices across 12 Spanish regions. LBP, leg pain, disability, catastrophizing, depression and SQ were assessed through validated questionnaires upon recruitment and 3 months later. Logistic regression models were developed to assess: (1) the association between the baseline score for SQ and improvements in LBP and disability at 3 months, and (2) the association between improvement in SQ and improvements in LBP and disability during the follow-up period. RESULTS: Seventy-three per cent of patients were subacute. Median scores at baseline were four points for both pain and disability, as assessed with a visual analog scale and the Roland-Morris Questionnaire, respectively. Regression models showed (OR [95% CI]) that baseline SQ was not associated with improvements in LBP (0.99 [0.94; 1.06]) or in disability (0.99 [0.93; 1.05]), although associations existed between 'improvement in SQ' and 'improvement in LBP' (4.34 [2.21; 8.51]), and 'improvement in SQ' and 'improvement in disability' (4.60 [2.29; 9.27]). CONCLUSIONS: Improvement in SQ is associated with improvements in LBP and in disability at 3-month follow-up, suggesting that they may reflect or be influenced by common factors. However, baseline SQ does not predict improvements in pain or disability. SIGNIFICANCE: In clinical practice, sleep quality, low back pain and disability are associated. However, sleep quality at baseline does not predict improvement in pain and disability.


Subject(s)
Disabled Persons , Low Back Pain/physiopathology , Sleep/physiology , Adult , Aged , Catastrophization/complications , Catastrophization/physiopathology , Depression/complications , Depression/physiopathology , Female , Humans , Low Back Pain/complications , Male , Middle Aged , Pain Measurement , Primary Health Care , Prospective Studies , Surveys and Questionnaires , Young Adult
8.
Sci Rep ; 7: 44922, 2017 03 21.
Article in English | MEDLINE | ID: mdl-28322343

ABSTRACT

Dense (>98 th%) and homogeneous ceramic/metal composites were obtained by spark plasma sintering (SPS) using ZrO2 and lamellar metallic powders of tantalum or niobium (20 vol.%) as starting materials. The present study has demonstrated the unique and unpredicted simultaneous enhancement in toughness and strength with very high flaw tolerance of zirconia/Ta composites. In addition to their excellent static mechanical properties, these composites also have exceptional resistance to fatigue loading. It has been shown that the major contributions to toughening are the resulting crack bridging and plastic deformation of the metallic particles, together with crack deflection and interfacial debonding, which is compatible with the coexistence in the composite of both, strong and weak ceramic/metal interfaces, in agreement with predictions of ab-initio calculations. Therefore, these materials are promising candidates for designing damage tolerance components for aerospace industry, cutting and drilling tools, biomedical implants, among many others.

9.
Rev Clin Esp (Barc) ; 217(4): 212-221, 2017 May.
Article in English, Spanish | MEDLINE | ID: mdl-28314657

ABSTRACT

This article summarises the objectives, methodology and initial conclusions of the project "Commitment to Quality of the Spanish Scientific Societies", coordinated by the Ministry of Health, Social Services and Equality, the Spanish Society of Internal Medicine and the Aragon Institute of Health Sciences, in which 48 scientific societies participate. This project's objectives are to decrease the use of unnecessary medical interventions, which are those that have shown no efficacy, have little or questionable effectiveness or are not cost-effective; decrease variability in clinical practice; promote the commitment among physicians and patients to properly use healthcare resources; and to promote clinical safety. The document includes 135 final recommendations for what not to do, prepared by 30 Spanish scientific societies.

10.
J Affect Disord ; 211: 92-98, 2017 Mar 15.
Article in English | MEDLINE | ID: mdl-28107668

ABSTRACT

BACKGROUND: Neuritin-1 is a neurotrophic factor involved in synaptic plasticity that has been associated with depressive disorders, schizophrenia and cognitive performance. The study of genotype-phenotype relationships in healthy individuals is a useful framework to investigate the etiology of brain dysfunctions. We therefore aimed to investigate in a non-clinical sample whether NRN1 gene contributes to the psychopathological profile, with a particular focus on the clinical dimensions previously related to the NRN1 gene (i.e. depressive and psychotic). Furthermore, we aimed to analyze: i) the role of NRN1 on executive functions, ii) whether the association between either NRN1-psychopathological profile or NRN1-cognitive performance is moderated by the BDNF gene. METHODS: The sample comprised 410 non-clinical subjects who filled in the self-reported Brief Symptom Inventory (BSI) and were assessed for executive performance (Verbal Fluency, Wisconsin Card Sorting Test (WCST) and Letter-Number subscale (WAIS-III)). Genotyping included nine SNPs in NRN1 and one in BDNF. RESULTS: i) GG homozygotes (rs1475157-NRN1) showed higher scores on BSI depressive dimension and on total scores compared to A carriers (corrected p-values: 0.0004 and 0.0003, respectively). ii) a linear trend was detected between GG genotype of rs1475157 and a worse cognitive performance in WCST total correct responses (uncorrected p-value: 0.029). iii) Interaction between rs1475157-NRN1 and Val66Met-BDNF was found to modulate depressive symptoms (p=0.001, significant after correction). LIMITATIONS: Moderate sample size; replication in a larger sample is needed. CONCLUSIONS: NRN1 is associated with depressive symptoms and executive function in a non-clinical sample. Our results also suggest that the role of NRN1 seems to be modulated by BDNF.


Subject(s)
Brain-Derived Neurotrophic Factor/genetics , Depression/genetics , Depressive Disorder/genetics , Polymorphism, Genetic , Adult , Executive Function , Female , Genetic Predisposition to Disease , Genotype , Heterozygote , Humans , Male , Neuronal Plasticity , Schizophrenia/genetics
11.
Rev Sci Instrum ; 87(8): 085116, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27587169

ABSTRACT

A method and its system to study the structural evolution on soft magnetic amorphous and nanocrystalline ribbon shaped alloys are presented. With only one sample, a complete set of magnetic and electric data at room and at high temperature are obtained in a relatively short period of time, allowing us to elucidate the structural changes occurring in the alloy and to determine the optimal soft magnetic properties annealing conditions.

12.
Biomed Mater ; 11(4): 045014, 2016 08 10.
Article in English | MEDLINE | ID: mdl-27509353

ABSTRACT

Two types of antimicrobial glass fibers containing ZnO and CaO, with diameters ranging from tens of nanometers to 1 µm, were successfully fabricated by a laser spinning technique. The antimicrobial performance was corroborated according to ISO 20743:2013, by using gram-negative (Escherichia coli) and gram-positive (Streptococcus oralis, Streptococcus mutans and Staphylococcus aureus) bacteria, and yeast (Candida krusei) (more than 3 logs of reduction). The metabolic activity and endosomal system of eukaryotic cells were not altered by using eluents of CaO glass submicrometric fibers and ZnO fibers at 1 : 10 dilution as cellular media (viability rates over 70%). A dental material was functionalized by embedding ZnO nanofibers above the percolation threshold (20% wt), creating a three-dimensional (3D) fiber network that added an antimicrobial profile. This new ZnO glass fiber composite is proved non-cytotoxic and preserved the antimicrobial effect after immersion in human saliva. This is the first time that a fiber-reinforced liner with strong antimicrobial-activity has been created to prevent secondary caries. The potential of developing new fiber-reinforced composites (FRCs) with antimicrobial properties opens up an extensive field of dental applications where most important diseases have an infectious origin.


Subject(s)
Anti-Infective Agents/chemistry , Dental Materials/chemistry , Glass/chemistry , Resin Cements/chemistry , Animals , Calcium Compounds/chemistry , Candida , Composite Resins , Dental Stress Analysis , Escherichia coli , Humans , Methacrylates/chemistry , Mice , Microbial Sensitivity Tests , NIH 3T3 Cells , Oxides/chemistry , Saliva/chemistry , Saliva/drug effects , Staphylococcus aureus , Streptococcus mutans , Streptococcus oralis , Zinc/chemistry , Zinc Oxide/chemistry
13.
Eur J Clin Microbiol Infect Dis ; 35(10): 1701-8, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27393491

ABSTRACT

The purpose of this study was to prospectively evaluate the impact of the use of L. plantarum I1001 applied vaginally on Vulvovaginal Candidiasis (VVC) time-until-recurrence after treatment with single-dose vaginal clotrimazole. This was a clinical open-label, prospective study of two non-randomized parallel cohorts with symptomatic acute VVC: (1) 33 sexually active women 18-50 years old, prescribed a standard single-dose 500 mg vaginal tablet of clotrimazole followed by vaginal tablets with L. plantarum I1001 as adjuvant therapy, and (2) 22 women of similar characteristics but prescribed single-dose clotrimazole only. Use of the probiotic and factors that might influence recurrence risk (age, recurrent VVC within previous year, antibiotic prior to study enrolment, diaphragm or IUD contraception, among others) were included in a multivariate Cox regression model to adjust for potential between-cohort differences. Probiotic use was associated with a three-fold reduction in the adjusted risk of recurrence (HR [95 %CI]: 0.30 [0.10-0.91]; P = 0.033). Adjusted free-survival recurrence was 72.83 % and 34.88 % for the probiotic and control groups, respectively. A higher cumulative recurrence was also observed in cases with use of antibiotics prior to enrolment (HR [95 %CI]: 10.46 [2.18-50.12]; P = 0.003). Similar findings were found at six months after azole treatment in women with RVVC. Overall, good compliance with the probiotic was reported for 91.3 % of women. The study suggests that follow-up therapy with vaginal tablets with L. plantarum I1001 could increase the effectiveness of single-dose 500 mg clotrimazole at preventing recurrence of VVC, an effect that was also observed in women with recurrent vulvovaginal candidiasis (RVVC) after six months of azole treatment.


Subject(s)
Candidiasis, Vulvovaginal/prevention & control , Lactobacillus plantarum/growth & development , Probiotics/administration & dosage , Adolescent , Adult , Antifungal Agents/therapeutic use , Candidiasis, Vulvovaginal/drug therapy , Clotrimazole/therapeutic use , Female , Humans , Middle Aged , Prospective Studies , Recurrence , Secondary Prevention , Treatment Outcome , Young Adult
14.
Biomaterials ; 76: 313-20, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26561930

ABSTRACT

Metals and ceramics are commonly used in orthopaedics, dentistry and other load bearing applications. However, the use of ceramic matrix composites reinforced with biocompatible metals for heavy load-bearing hard tissue replacement applications has not previously been reported. In order to improve the reliability and the mechanical properties of biomedical implants, new zirconia-Nb composites have been recently developed. The aim of this study was to investigate the biological tolerance of these new zirconia/Nb biocermets implants with both in vitro and in vivo approaches. At first, human bone marrow derived mesenchymal stem cells were cultured on sintered biocermet discs with polished surfaces and were compared with responses to niobium metal. In vitro, the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Furthermore, the biocermet showed a higher percentage of cell proliferation than Nb metal. On the other hand, the bone response to these new zirconia/Nb biocermets was studied. Cylinders of biocermets, as well as commercially Nb rod were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. The slides were observed in normal transmitted light microscope. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present. This study concluded that zirconia/Nb composites are biocompatible and osteoconductive. The ceramic-metal composite has even better osteointegration ability than pure Nb. In conclusion, zirconia-Nb biocermet is suitable for heavy load-bearing hard tissue replacement from the point of view of both mechanical properties and biocompatibility.


Subject(s)
Biocompatible Materials , Niobium , Zirconium , Animals , Cells, Cultured , Humans , In Vitro Techniques , Mesenchymal Stem Cells/cytology , Rabbits
16.
Development ; 142(18): 3210-21, 2015 Sep 15.
Article in English | MEDLINE | ID: mdl-26395145

ABSTRACT

During embryo implantation, the blastocyst interacts with and regulates the endometrium, and endometrial fluid secreted by the endometrial epithelium nurtures the embryo. Here, we propose that maternal microRNAs (miRNAs) might act as transcriptomic modifier of the pre-implantation embryo. Microarray profiling revealed that six of 27 specific, maternal miRNAs were differentially expressed in the human endometrial epithelium during the window of implantation--a brief phase of endometrial receptivity to the blastocyst--and were released into the endometrial fluid. Further investigation revealed that hsa-miR-30d, the expression levels of which were most significantly upregulated, was secreted as an exosome-associated molecule. Exosome-associated and free hsa-miR-30d was internalized by mouse embryos via the trophectoderm, resulting in an indirect overexpression of genes encoding for certain molecules involved in the murine embryonic adhesion phenomenon--Itgb3, Itga7 and Cdh5. Indeed, this finding was supported by evidence in vitro: treating murine embryos with miR-30d resulted in a notable increase in embryo adhesion. Our results suggest a model in which maternal endometrial miRNAs act as transcriptomic modifiers of the pre-implantation embryo.


Subject(s)
Blastocyst/metabolism , Embryonic Development/physiology , Endometrium/metabolism , Gene Expression Regulation, Developmental/physiology , MicroRNAs/metabolism , Transcriptome/physiology , Animals , Blotting, Western , Female , Humans , Immunohistochemistry , Mice , Microarray Analysis , Microscopy, Electron, Transmission , Microscopy, Fluorescence , Polymerase Chain Reaction , Transcriptome/genetics
17.
J Environ Manage ; 159: 68-77, 2015 Aug 15.
Article in English | MEDLINE | ID: mdl-26046989

ABSTRACT

Accurate determination of flammability is required in order to improve knowledge about vegetation fire risk. Study of the flammability of different plant species is essential for the Mediterranean area, where most ecosystems are adapted to natural fire but vulnerable to recurrent human-induced fires, which are the main cause of forest degradation. However, the methods used to evaluate vegetation flammability have not yet been standardized. Cupressus sempervirens is a native or naturalized forest tree species in the Mediterranean area that is able to tolerate prolonged drought and high temperatures. The aim of this study was to characterize the flammability of C. sempervirens var. horizontalis at particle level by using different bench-scale calorimetry techniques (mass loss calorimeter, epiradiator and oxygen bomb) to determine the main flammability descriptors (ignitability, sustainability, combustibility and consumability) in live crown and litter samples. Our findings indicate that this variety of cypress is relatively resistant to ignition because of the high ash content, the high critical heat flux, the high time to ignition displayed by both crown and litter samples and the ability of the leaves to maintain a high water content during the summer. We also discuss the possibility of exploiting some morphological, functional and ecological traits of the species to construct a barrier system (with selected varieties of cypress) as a promising complementary land management tool to reduce the fire spread and intensity in a Mediterranean context.


Subject(s)
Cupressus/chemistry , Fires/prevention & control , Calorimetry , Cupressus/physiology , Droughts , Ecosystem , Forests , Humans , Mediterranean Region , Plant Leaves , Risk Management/methods , Seasons , Water
18.
Reprod Fertil Dev ; 2015 May 05.
Article in English | MEDLINE | ID: mdl-25940376

ABSTRACT

Successful implantation relies on the interaction between a competent embryo and a receptive endometrium. The aim of the present study was to investigate genes differentially expressed in early invasive embryonic tissue versus decidual tissue in mice. Samples were obtained from the ectoplacental cone, the immediately surrounding deciduas and from deciduas from interimplantation sites. Microarray analysis showed that 817 genes were differentially expressed between extra-embryonic tissue and the surrounding decidua and that 360 genes were differentially expressed between the different deciduas, with a high representation of developmental processes. Genes differentially expressed in the maternal compartment included chemokines, lipoproteins, growth factors and transcription factors, whereas the embryonic invasive tissue expressed genes commonly observed in invasive tumour-like processes. These results provide information about genes involved in early embryonic invasion and the control exerted by the surrounding decidua. This information may be useful to find targets involved in pathologies associated with implantation failure and early pregnancy loss.

19.
Langmuir ; 31(3): 917-24, 2015 Jan 27.
Article in English | MEDLINE | ID: mdl-25548830

ABSTRACT

The self-assembly of nanoparticles into clusters and the effect of the different parameters of the competing interaction potential on it are investigated. For a small number of particles, the structural organization of the clusters is almost unaffected by the attractive part of the potential, and for an intermediate number of particles the configuration strongly depends on the strength of it. The cluster size is controlled by the range of the interaction potential, and the structural arrangement is guided by the strength of the potential: i.e., the self-assembled cluster transforms from a faceted configuration at low strength to a spherical shell-like structure at high strength. Nonmonotonic behavior of the cluster size is found by increasing the interaction range. An approximate analytical expression is obtained that predicts the smallest cluster for a specific set of potential parameters. A Mendeleev-like table is constructed for different values of the strength and range of the attractive part of the potential in order to understand the structural ordering of the ground-state configuration of the self-assembled clusters.

20.
Article in English | MEDLINE | ID: mdl-24730841

ABSTRACT

Diffusive properties of interacting magnetic dipoles confined in a parabolic narrow channel and in the presence of a periodic modulated (corrugated) potential along the unconfined direction are studied using Brownian dynamics simulations. We compare our simulation results with the analytical result for the effective diffusion coefficient of a single particle by Festa and d'Agliano [Physica A 90, 229 (1978)] and show the importance of interparticle interaction on the diffusion process. We present results for the diffusion of magnetic dipoles as a function of linear density, strength of the periodic modulation and commensurability factor.

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