Bragg scattering of stochastic beams in PT-symmetric photonic lattices.

The propagation of a Gaussian-Schell beam through a PT-symmetric optical lattice, whose index of refraction is represented by a sinusoidal type of function, is theoretically investigated. Within the framework of standard coherence theory, one is able to access and elucidate unexpected consequences of the interplay between the spatial coherence properties of the beam and the non-Hermitian nature of the photonic lattice. We describe how one may use a non-Hermitian periodic medium to enhance the spatial coherence properties of a partially coherent beam.

Optics in South America: introduction.

South American optics research has seen remarkable growth over the past 50 years, with significant contributions in areas such as quantum optics, holography, spectroscopy, nonlinear optics, statistical optics, nanophotonics and integrated photonics. The research has driven economic development in sectors like telecom, biophotonics, biometrics, and agri-sensing. This joint feature issue between JOSA A and JOSA B exhibits cutting-edge optics research from the region, fostering a sense of community and promoting collaboration among researchers.

Low coherence-induced resonance in double-layer structures having parity-time symmetry.

We derive simple formulas for the transmittance T and reflectance R of Gaussian-Schell beams incident upon any stratified dielectric structure by using second-order classical coherence theory in the space-frequency picture. The formalism is applied to a particular structure consisting of a double layer, with balanced gain and loss, satisfying parity-time symmetry conditions. It is shown that sources with a low degree of spatial coherence, on the order of the wavelength, can induce large resonant peaks in the transmitted and reflected amplitudes. The resonance peaks vanish as the spatial coherence increases.

Non-Hermitian spectral changes in the scattering of partially coherent radiation by periodic structures.

The physical aspects of partially coherent radiation interacting with deterministic non-Hermitian periodic materials remain largely unexplored in the statistical optics literature. Here, we consider the scattering of partially coherent radiation by a deterministic periodic medium, symmetric under the simultaneous transformations of parity inversion and time reversal, i.e., a parity-time-symmetric periodic medium. Taking into account light fluctuations, one is able to describe the spectrum changes on propagation and the influence of the coherence-driven angular divergence effect. The far-field spectral density profile is found to depend crucially on the loss/gain properties of the material, giving rise to unexpected and contrasting spectral diffraction profiles when compared to the Hermitian ones.

Assistive devices: an effective strategy in non-pharmacological treatment for hand osteoarthritis-randomized clinical trial.

This study aims to evaluate the use of assistive devices as a strategy in non-pharmacological treatment for hand osteoarthritis (HOA). This is a randomized, prospective, parallel, assessor-blinded clinical trial, in which patients with a diagnosis of HOA were randomly allocated to an intervention group (IG), where they received assistive devices for daily life activities, or to a control group (CG), where they received a guideline leaflet with information on joint protection and disease features. The primary outcomes considered were occupational performance, measured by the Canadian Occupational Performance Measure (COPM), and hand function was evaluated through the Score for the Assessment and Quantification of Chronic Rheumatoid Affections of the Hands (SACRAH). The secondary outcomes were pain, measured by the visual analog scale (VAS), and quality of life, measured by the World Health Organization Quality of Life Instrument, Short Form (WHOQOL-BREF). We compared both outcomes before and after interventions and outcomes between groups. Participants from the two groups were assessed at the time of inclusion in the study, 30, and 90 days after initial evaluation. Out of the 39 patients included, 19 were allocated to the IG and 20 to the CG. Only two patients from the CG did not complete the follow-up period. The patients' hand function and occupational performance improved after intervention (30 days-SACRAH-p < 0.05; COPM-p < 0.05; VAS-p < 0.05). When comparing results between the groups, there was a statistical difference in COPM (performance-p < 0.001; and satisfaction-p < 0.001), in the first reevaluation carried out. The use of assistive devices has proved to be an effective alternative in non-pharmacological treatment for HOA. CLINICAL TRIAL REGISTRATION: NCT02667145.

The association of HPV genotype with the regression, persistence or progression of low-grade squamous intraepithelial lesions.

BACKGROUND: Human papillomavirus (HPV) is a highly prevalent sexually transmitted virus causing cytological alterations that precede cervical cancer. Approximately 130 genotypes have been sequenced. Low-grade squamous intraepithelial lesions (LSIL) are the most frequent cytological alteration and have an uncertain behavior. OBJECTIVES: To analyze the frequency of HPV types in LSIL and their association with the regression, persistence or progression of these lesions. METHODS: A cohort study of forty patients with LSIL cytology was conducted from December 2007 to March 2011. The follow-up lasted two years and included cytology and colposcopy. HPV detection was performed using PCR, and genotyping was performed using PCR-specific and RFLP techniques. RESULTS: DNA-HPV was detected in 87% (35/40) of the cases, with oncogenic HPV accounting for 76%; type 16 in 32% (11/35) and type 18 in 20%. LSIL regression, persistence and progression rates at the end of the study were 60%, 23% and 17%, respectively. There was 50% regression in lesions in the high oncogenic risk group (types 16 and 18). CONCLUSION: HPV 16 was the most frequent genotype found in LSIL. The persistence and progression of the LSIL were related to the persistence of oncogenic HPV. The longer the follow-up time, the lower the LSIL persistence rate and the higher its regression rate; the progression rate remained stable. In addition to the presence of oncogenic HPV, other factors are necessary for the progression of LSIL.

Bulk plasmon polariton-gap soliton-induced transparency in one-dimensional Kerr-metamaterial superlattices.

We have performed a theoretical study of various arrangements of one-dimensional heterostructures composed by bilayers made of nondispersive (A)/dispersive linear (B) materials and illuminated by an obliquely incident electromagnetic wave, which are shown to exhibit a robust bulk-like plasmon-polariton gap for frequencies below the plasma frequency. The origin of this gap stems from the coupling between photonic and plasmonic modes that may be of a magnetic (electric) origin in a transversal electric (traversal magnetic) configuration yielding a plasmon-polariton mode. By substituting the nondispersive linear layer by a nonlinear Kerr layer, we have found that, for frequencies close to the edge of the plasmon-polariton gap, the transmission of a finite superlattice presents a multistable behavior and it switches from very low values to the maximum transparency at particular values of the incident power. At these frequencies, for those singular points where transmission becomes maximum, we find localized plasmon-polariton-gap solitons of various orders depending on the particular value of the incident power. Present results reveal, therefore, new gap plasmon-soliton solutions that are hybrid modes stemming from the resonant coupling between the incoming electromagnetic wave and the plasmonic modes of the dispersive material, leading to the transparency of a stack with nonlinear inclusions.

Optical spin-to-orbital plasmonic angular momentum conversion in subwavelength apertures.

Within the framework of the Huygens-Fresnel approach, we evaluate the coherent superposition of surface plasmon (SP) modes excited by an incident circularly polarized light propagating through an array of subwavelength holes. Numerical results of the plasmonic distribution exhibit a rich structure that reveals the creation and annihilation of vortex arrays in the field phase. These phase singularities stem from total transfer of the spin angular momentum (AM) of the incident radiation to the orbital AM of the SP.

Non-Markovian damping of Rabi oscillations in semiconductor quantum dots.

A systematic investigation is performed on the damping of Rabi oscillations induced by an external electromagnetic field interacting with a two-level semiconductor system. We have considered a coherently driven two-level system coupled to a dephasing reservoir and shown that, to explain the dependence of the dephasing rate on the driving intensity, it is essential to consider the non-Markovian character of the reservoir. Moreover, we have demonstrated that intensity-dependent damping may be induced by various dephasing mechanisms due to stationary as well as non-stationary effects caused by coupling with the environment. Finally, present results are able to explain a variety of experimental measurements available in the literature.

Patterns of genotype distribution in multiple human papillomavirus infections.

The relationship between severe-grade cervical lesions and clusters of human papillomavirus (HPV) genotypes in a taxonomic classification was surveyed in 232 women with previous abnormal cytology. HPV co-infections were clustered according to phylogenetic criteria. Multiple infections were detected in 22.0% of the entire sample. Clade A10 (represented by HPV-6 and HPV-11) appeared more frequently in multiple infections than clade A9, which was represented by five of the most common high-risk types, including HPV-16. Although HPV-16 was the most frequent genotype, it was not more prevalent in multiple infections. Abortion and two or more sexual partners were risk-factors associated with HPV co-infections. Severe cervical dysplasia was associated with co-infections with oncogenic types from different clades, with the association being significant for the high-risk clades A7 and A9.

Effects of essential oils on Aedes aegypti larvae: alternatives to environmentally safe insecticides.

The essential oils from leaves of Hyptis fruticosa (Lamiaceae) Salzm., H. pectinata (Lamiaceae) Poit., and Lippia gracilis (Verbenaceae) HBK were investigated for their larvicidal activity against Aedes aegypti and analyzed by GC/MS. Fifty-nine compounds, representing 91.28-98.39% of the essential oils, have been identified. A standard solution was used to make 20 mL solutions ranging from 30 to 2000 ppm. Twenty larvae between third and fourth stages were added to the essential oil solution. A mortality count was conducted 24 h after treatment. Essential oils LC50 and their confidence limits at 95% probability were calculated by the methods of Reed-Muench and Pizzi, respectively. The essential oil of Lippia gracilis showed potent insecticidal effect against Aedes aegypti larvae, the vector of dengue fever. Carvacrol and caryophyllene oxide were the main responsible for the activity of L. gracilis and H. pectinata. Minor compounds are probably acting synergistically to achieve H. fruticosa activity.

Optimization of nanostructured lipid carriers for Zidovudine delivery using a microwave-assisted production method.

An adapted methodology for obtaining lipid nanoparticles that only uses the microwave reactor in the synthesis process was developed. The method has the following features: one-pot, one-step, fast, practical, economical, safe, readiness of scaling-up, lack of organic solvents and production of nanoparticles with low polydispersity index (PDI) (below 0.3). This new method was applied for the development of nanostructured lipid carriers (NLC) loaded with a hydrophilic drug, the antiretroviral agent zidovudine (AZT). The aim of the present work was to develop, evaluate and compare optimized NLC formulations produced by two different methods - hot ultrasonication and microwave-assisted method. The development and optimization of the NLC formulations were supported by a Quality by Design (QbD) approach. All formulations were physicochemically characterized by the same parameters. The optimized formulations presented a suitable profile for oral administration (particle size between 100 and 300 nm, PDI < 0.3 and negative zeta potential >-20 mV). Furthermore, the morphologies assessed by TEM showed spherical shape and confirmed the results obtained by DLS. Both AZT loaded formulations were physically stable for at least 45 days and non-toxic on Jurkat T cells. Drug release studies showed a controlled release of AZT under gastric and plasma-simulated conditions.

Photonic band structure and symmetry properties of electromagnetic modes in photonic crystals.

Within the Maxwell framework and using a transfer-matrix technique we have determined a general equation which governs the photonic band structure and the density of states of one-dimensional superlattices composed of two alternate layers characterized by different refractive indexes, which may take on positive as well as negative values. Besides the usual well-known results, we have found null-gap points for commensurate values of the optical path lengths of each layer. Furthermore, we have been able to characterize non-Bragg gaps that show up in frequency regions in which the average refractive index is null.

Repellency and Larvicidal Activity of Essential oils from Xylopia laevigata, Xylopia frutescens, Lippia pedunculosa, and Their Individual Compounds against Aedes aegypti Linnaeus.

In order to find new alternatives for vector control and personal protection, we evaluated the larvicidal and repellent activity of essentials oils from plants found in the Northeast of Brazil against Aedes aegypti Linnaeus mosquitoes. The plants tested include Xylopia laevigata, Xylopia frutescens, and Lippia pedunculosa and their major compounds, piperitenone oxide, and (R)-limonene. The essential oil of L. pedunculosa and its major volatile compounds were shown to be toxic for Ae. aegypti larvae with a LC50 lower than 60 ppm. The essential oil of plants from the Xylopia genus, on the other hand, showed no activity against Ae. aegypti, proving to be toxic to mosquito larvae only when concentrations were higher than 1000 ppm. All plants tested provided some degree of protection against mosquitoes landing, but only the essential oil of L. pedunculosa and the volatile compound piperitenone oxide suppressed 100% of mosquitoes landing on human skin, in concentrations lower than 1%. Among the plants studied, the essential oil of L. pedunculosa and its volatiles compounds have shown the potential for the development of safe alternative for mosquito larvae control and protection against Ae. aegypti mosquito bites.

Detection and Distribution of V1016Ikdr Mutation in the Voltage-Gated Sodium Channel Gene in Aedes aegypti (Diptera: Culicidae) Populations From Sergipe State, Northeast Brazil.

Aedes aegypti (L.) resistance to pyrethroids was recorded in Brazil few years after its introduction as the adulticide in the National Dengue Control Program campaigns. Altered susceptibility to pyrethroids had been reported in the state of Sergipe, northeast Brazil, through biological assays, even before its use against Ae. aegypti in the state. Metabolic and target-site resistance mechanisms were also revealed in samples from Aracaju, the capital of Sergipe. Herein, we investigated the presence and distribution of the kdr mutation V1016Ikdr in Ae. aegypti populations from different municipalities of the state. Aedes aegypti eggs were collected from seven municipalities located in areas showing different climatic types and infestation levels. Approximately 20 Ae. aegypti females from each municipality (total of 135 subjects) were individually submitted to allele-specific polymerase chain reaction (AS-PCR) for the 1016 site of the voltage-gated sodium channel (NaV). The V1016Ikdr mutation was found in subjects from all the municipalities under study with a high frequency of heterozygotes in several locations. Homozygous recessive subjects (resistant kdr genotype) were found only in one municipality. The results suggest a wide distribution of the V1016Ikdr mutation in the northeast Brazil, which indicates urgent need for monitoring the effectiveness of the pyrethroids currently used for vector control.

Human papillomavirus infection in Rio de Janeiro, Brazil: a retrospective study.

There is considerable data to support a central role for human papillomavirus (HPV) in the etiology of cervical cancer. More than a 100 HPV types have been described, and 40 have been isolated from benign and malignant genital lesions. Consequently, there is strong motivation to evaluate HPV testing for cervical cancer screening. Few studies concerning the natural history of HPV infection have been conducted in the state of Rio de Janeiro. We determined the prevalence of HPV types in female genital lesions by using Hybrid Capture Assay (HCA) and we retrospectively analyzed the course of HPV infection. Our sample included 788 women attended at Laboratórios Sérgio Franco. The average age of the participants was 29.6 years. HPV prevalence and cytological diagnosis were determined. The overall prevalence of HPV DNA in the study group was 50.1% (395/788), ranging from 25% (NORMAL) to 100% in high-grade intraepithelial lesions (HSIL). High risk HPV was found in 12% inflammatory, 58.3% HPV, 63.2% LSIL and 100% HSIL. A retrospective analysis of 78 patients showed that 22 presented persistent lesions, 2 had progressive lesions, 4 had regressive lesions, 13 showed latent infections, 18 were transiently infected and 19 were submitted to curative treatment. No cases of cancer were registered in this population, which can afford private medical care and regular follow-up exams. We suggest that HCA be used in specific cases involving persistent and recurrent lesions.

Non-Bragg-gap solitons in one-dimensional Kerr-metamaterial Fibonacci heterostructures.

A detailed study of non-Bragg-gap solitons in one-dimensional Kerr-metamaterial quasiperiodic Fibonacci heterostructures is performed. The transmission coefficient is numerically obtained by combining the transfer-matrix formalism in the metamaterial layers with a numerical solution of the nonlinear differential equation in the Kerr slabs, and by considering the loss effects in the metamaterial slabs. A switching from states of no transparency in the linear regime to high-transparency states in the nonlinear regime is observed for both zero-order and plasmon-polariton gaps. The spatial localization of the non-Bragg-gap solitons is also examined, and the symmetry properties of the soliton waves are briefly discussed.

An environmentally safe larvicide against Aedes aegypti based on in situ gelling nanostructured surfactant systems containing an essential oil.

HYPOTHESIS: Liquid crystalline precursors, which are in situ gelling nanostructured surfactant systems, can undergo phase transition in aqueous solution and become more structured aggregates, controlling release of larvicides and acting as biotechnology alternatives for dengue control. Such systems can contain bioactive substances as Citrus sinensis essential oil (CSEO) which exhibits biological activity against Aedes aegypti (Ae. aegypti) larvae. EXPERIMENTS: The formulations were composed by fixed concentration of CSEO stabilized by Polyoxypropylene (5) Polyoxyethylene (20) Cetyl Ether (PPG-5 CETETH-20): oleic acid (OA) 2:1, increasing water content. The phase diagram was established and systems structure was evaluated by polarized light microscopy (PLM), small angle X-ray scattering (SAXS) and rheology. Median lethal concentration was determined against Ae. aegypti larvae. FINDINGS: The phase diagram exhibited four regions: liquid crystal (LC), emulsion, microemulsion (ME) and phase separation. The PLM and SAXS distinguished microemulsions, lamellar and hexagonal LC structures. Flow and oscillatory tests showed that increasing water content increases elasticity from Newtonian to non-newtonian behavior confirming the in situ gelation behavior. The larvicidal activity of formulations indicates that these nanostructured systems improved the oil solubility in aqueous medium and in addition are potential environmental larvicide against Ae. aegypti larvae.

Gene/longevity association studies at four autosomal loci (REN, THO, PARP, SOD2).

The possibility that four loci (REN, THO, PARP, SOD2) are associated with longevity was explored by comparing the genotypic pools of subjects older than 100 years with those of younger subjects matched for sex and geographic area (northern and southern Italy). The markers (all located within the respective gene) were HUMREN4; HUMTHO1; HUMPARP (gt)845nt; SOD2(C/T)401nt. In order to reduce the number of genotypes, multiallelic polymorphisms were recoded as diallelic according to allele size and frequency patterns (small: S, and large: L, alleles). A significant loss of LL homozygous genotypes was found at the THO locus in male but not in female centenarians with respect to matched controls. On the other hand no significant difference was found between case/control genotypic frequencies at REN, PARP, SOD2 loci. The latter loci therefore do not affect inter-individual variability in life expectancy (at least in terms of qualitative variants associated with the tested markers). However, the data is consistent with an association between the THO locus and longevity.

alpha-Amino-3-hydroxy-5-methyl-isoxazole-4-propionate receptors in spinal cord motor neurons are altered in transgenic mice overexpressing human Cu,Zn superoxide dismutase (Gly93-->Ala) mutation.

There are many evidences implicating glutamatergic toxicity as a contributory factor in the selective neuronal injury occurring in amyotrophic lateral sclerosis (ALS). This neurodegenerative disorder is characterized by the progressive loss of motor neurons, whose pathogenesis is thought to involve Ca(2+) influx mediated by alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate receptors (AMPARs). In the present study we report alterations in the AMPARs function in a transgenic mouse-model of the human SOD1(G93A) familial ALS. Compared with those expressed in motor neurons carrying the human wild type gene, AMPAR-gated channels expressed in motor neurons carrying the human mutant gene exhibited modified permeability, altered agonist cooperativity between the sites involved in the process of channel opening and were responsible for slower spontaneous synaptic events. These observations demonstrate that the SOD1(G93A) mutation induces changes in AMPAR functions which may underlie the increased vulnerability of motor neurons to glutamatergic excitotoxicity in ALS.