Feature issue introduction: temporal and spatiotemporal metamaterials.

Temporal modulation of material parameters provides a new degree of freedom for metamaterials, metasurfaces and wave-matter interactions as a whole. In time-varying media the electromagnetic energy may not be conserved, and the time reversal symmetry may be broken, which may lead to novel physical effects with potential applications. Currently, theoretical and experimental aspects of this field are rapidly advancing, expanding our understanding of wave propagation in such complex spatiotemporal platforms. This field promises novel possibilities and directions in research, innovation and exploration.

On-fiber high-resolution photonic nanojets via high refractive index dielectrics.

In this manuscript, we present high spatial resolution focusing of electromagnetic waves at telecommunication wavelengths (λ0 = 1.55 µm) by using high-refractive index mesoscale dielectrics placed at the end of an optical fiber. Our approach exploits photonic nanojets (PNJs) to achieve high-intensity, spatially narrow focal spots. The response of the device is evaluated in detail considering 2-dimensional (2D) and 3-dimensional (3D) configurations using high-index mesoscale cylindrical and spherical dielectrics, respectively, placed on top of an optical fiber. It is shown how the PNJs can be shifted towards the output surface of the mesoscale high-index dielectric by simply truncating its 2D/3D cylindrical/spherical output profile. With this setup, a PNJ with a high transversal resolution is obtained using the 2D/3D engineered mesoscale dielectric particles achieving a Full-Width at Half-Maximum of FWHM = 0.28λ0 (2D truncated dielectric), and FWHMy = 0.17λ0 and FWHMx = 0.21λ0 (3D truncated dielectric). The proposed structure may have potential in applications where near-field high spatial resolution is required, such as in sensing and imaging systems.

Development of an Isavirus minigenome system to study the function of the pocket RNA-binding domain of the viral nucleoprotein (NP) in salmon cells.

The Isavirus is an orthomyxovirus with a genome composed of eight segments of negative single-strand RNA (-ssRNA). It has been proposed that the eight genomic segments of the Isavirus are organized as a ribonucleoprotein (RNP) complex called a minigenome, which contains all the viral RNA segments, a viral heterotrimeric polymerase and multiple copies of the viral nucleoprotein (NP). Here, we develop an Isavirus minigenome system and show the importance of the formation of active RNPs and the role of viral NP R189, R194, R302 and K325 residues in the NP RNA-binding domain in the context of RNPs. The results indicate it is possible to generate a minigenome in salmon cells, a composite ISAV RNPs with EGFP-based chimeric vRNA with heterotrimeric polymerase (PB1, PB2, PA) and NP protein using CMV-based auxiliary plasmids. It was also shown that NP R189, R194, R302 and K325 residues are important to generate viral mRNA from the constituted RNPs and a detectable reporter protein. This work is the first salmon cell-based minigenome assay for the Isavirus, which was evaluated by a bioinformatic and functional study of the NP protein in viral RNPs, which showed that correct NP-vRNA interaction is key to the functioning of RNPs.

Using a repositioning splint to determine reproducibility in the color registers of a dental spectrophotometer.

OBJECTIVES: The purpose of this study was to assess if the use of intraoral positioning guides could increase the reproducibility of color measurements with a dental spectrophotometer. METHODS: Twenty-three subjects were selected, and positioning guides for the maxillary arch of each participant were fabricated with clear 4 mm thermo-sheets. One orifice was made in the center of the clinical crown of the upper-right central incisor and another in the canine, with an external 6 mm diameter trephine. Color measurements were performed with a Vita EasyShade Compact IV dental spectrophotometer by the same operator in the same conditions. Forty measurements were taken per patient, 20 for each tooth, 10 with a positioning guide, and 10 without one. Before each measurement, the spectrophotometer was calibrated following the manufacturer's instructions. RESULTS: Using the Wilcoxon test to evaluate nonparametric variables, there are statistically significant differences (P < .05) between the use or not of positioner for color recording with spectrophotometer. Greater repeatability of the measurements is obtained using repositioning split. CONCLUSIONS: Within the limitations of this study, the use of positioning guides provides greater reproducibility in spectrophotometer measurements for all parameters of tooth 11 and for some parameters of tooth 13. CLINICAL SIGNIFICANCE: The use of a positioning guide for color measurement with a dental spectrophotometer allows a greater reproducibility of the measurements to be obtained. Achieving repeatable measurements is essential for studying the same area of the tooth, for example, in bleaching treatments and in color checks for prosthetic treatments.

Influence of treatment duration on the efficacy of at-home bleaching with daytime application: a randomized clinical trial.

OBJECTIVE: The aim of this study is to determine whether prolonging the daytime at-home bleaching treatment by 1 week increases the bleaching effect without causing more side effects. MATERIALS AND METHODS: Fifty participants were randomly divided into two groups, (A) with a 14-day treatment and (B) with a 21-day treatment. A gel with 10% carbamide peroxide was applied for 2 h a day in custom trays. Color measurement was performed using a dental spectrophotometer on the right maxillary central incisor and the canine at baseline, at the end of treatment, and 1 and 6 months afterwards. Daily, participants recorded their tooth sensitivity and gingival irritation. RESULTS: At the end of the treatment, the ΔE00 of group B (5.77 ± 2.15) was significantly higher than the ΔE00 of group A (4.74 ± 1.94) (p = 0.005 (95% CI: - 2.13 to - 0.39)). After 6 months, tooth color was more stable in group B. The ΔSGU values between the different appointment times were higher in the 3-week group. Participants from group B reported more side effects, but statistically, there were no differences compared with group A (p = 0.225 for tooth sensitivity and p = 0.758 for gingival irritation). CONCLUSIONS: Daytime application of at-home bleaching for 3 weeks achieves greater bleaching results than for 2 weeks, immediately after treatment and 1 and 6 months afterwards. However, slightly more side effects could occur. CLINICAL RELEVANCE: When daytime application of at-home bleaching is required, the treatment duration should be prolonged from 2 to 3 weeks to achieve greater and more stable results.

Nanoimprinted Chiral Plasmonic Substrates with Three-Dimensional Nanostructures.

We report a large-area fabrication method to prepare chiral substrates patterned with arrays of multilayer, three-dimensional nanostructures using a combination of nanoimprint lithography and glancing angle deposition. Several structures are successfully fabricated using this method, including L-shaped, twisted arc and trilayer twisted Au nanorod structures, demonstrating its generality. As one typical example, arrays of L-shaped nanostructures, consisting of two layers of orthogonally oriented Au nanorods separated by a Ge dielectric layer in the thickness direction, exhibit giant optical chirality in the infrared region with an experimentally achieved g-factor as high as 0.38. Electromagnetic simulations show that the optical chirality results from plasmon hybridization between the two orthogonal Au segments. To demonstrate scalability, a 1 cm2 chiral substrate is fabricated with uniform chiral optical property. This method combines both high throughput and precise geometrical control and is therefore promising for applications of chiral metamaterials.

Efficacy of different protocols for at-home bleaching: A randomized clinical trial.

PURPOSE: To evaluate the efficacy of two products used for at-home bleaching with different application times. METHODS: 80 participants were enrolled and divided into four groups, (1) 10% carbamide peroxide 1 hour a day; (2) 10% carbamide peroxide overnight; (3) 7.5% hydrogen peroxide 1 hour a day; and (4) 7.5% hydrogen peroxide overnight. The duration of treatment was 14 days. Color measurement was performed using a dental spectrophotometer on the right maxillary central incisor and the canine, at baseline and 2 weeks after. Participants recorded daily tooth sensitivity. To evaluate the influence of concentration and time on bleaching results (ΔE) the one-way ANOVA with Bonferroni post-hoc test and the Student's t-test were used. RESULTS: Group 2 showed the highest value of ΔE (ΔE = 10.59 ± 2.68), followed by Group 4 (ΔE = 8.95 ± 2.32), Group 1 (ΔE = 8.05 ± 3.86), and Group 3 (ΔE = 7.08 ± 1.99). There were differences between Groups 2 and 3 (P= 0.001) and between Groups 2 and 1 (P= 0.032). The same product applied overnight was more effective than applied 1 hour a day (P< 0.05). Different concentrations during the same application time achieved similar results. The reported tooth sensitivity was mild. CLINICAL SIGNIFICANCE: At-home bleaching is time but not concentration dependent and its secondary effects depend on the active agent concentration; therefore, there is no need to use high concentration products. The most effective protocol is low concentrations (10% carbamide peroxide) with overnight use.

Designing alternative splicing RNA-seq studies. Beyond generic guidelines.

MOTIVATION: Designing an RNA-seq study depends critically on its specific goals, technology and underlying biology, which renders general guidelines inadequate. We propose a Bayesian framework to customize experiments so that goals can be attained and resources are not wasted, with a focus on alternative splicing. RESULTS: We studied how read length, sequencing depth, library preparation and the number of replicates affects cost-effectiveness of single-sample and group comparison studies. Optimal settings varied strongly according to the target organism or tissue (potential 50-500% cost cuts) and, interestingly, short reads outperformed long reads for standard analyses. Our framework learns key characteristics for study design from the data, and predicts if and how to continue experimentation. These predictions matched several follow-up experimental datasets that were used for validation. We provide default pipelines, but the framework can be combined with other data analysis methods and can help assess their relative merits. AVAILABILITY AND IMPLEMENTATION: casper package at www.bioconductor.org/packages/release/bioc/html/casper.html, Supplementary Manual by typing casperDesign() at the R prompt. CONTACT: rosselldavid@gmail.com SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Terahertz epsilon-near-zero graded-index lens.

An epsilon-near-zero graded-index converging lens with planar faces is proposed and analyzed. Each perfectly-electric conducting (PEC) waveguide comprising the lens operates slightly above its cut-off frequency and has the same length but different cross-sectional dimensions. This allows controlling individually the propagation constant and the normalized characteristic impedance of each waveguide for the desired phase front at the lens output while Fresnel reflection losses are minimized. A complete theoretical analysis based on the waveguide theory and Fermat's principle is provided. This is complemented with numerical simulation results of two-dimensional and three-dimensional lenses, made of PEC and aluminum, respectively, and working in the terahertz regime, which show good agreement with the analytical work.

Protective effect of nitroglycerin ointment and dimethyl sulfoxide on necrosis of skin flaps in rats.

OBJECTIVE: To compare the protective effect of nitroglycerin ointment 2% and Dimethylsulfoxide (DMSO) in dorsal flaps of the rat. METHODS: A blind, experimental study was conducted in 24 male Wistar rats, with a mean weight of 320 (286-376) grams. Group 1: Control. Petrolatum jelly (Vaseline), n = 8, Group 2: Nitroglycerin (NTG) ointment 2% (Nitro-Bid, Altana Co.) n = 8, and Group 3: DMSO gel 90% (Neogen corp. Lexington KY, 40611), n = 8. RESULTS: A total of 24 rats were operated on in the 6-month period of this study. Using a non-parametric Mann-Whitney U-test analysis, a statistically significant p was obtained between the control group and 2% NTG ointment, both in the area of necrosis and in the healthy area (p = 0.026). In contrast, the comparison between DMSO [CH3) 2SO] and the control group (p = 0.180) and between both study groups, with a p = 0.18, was not significant. CONCLUSIONS: Our study concluded that there is a protective effect of 2% NTG ointment for flap survival in relation to the control group (petrolatum). DMSO administered topically did not show a protective effect, compared to the control group.

OBJETIVO: Comparar el efecto protector del ungüento de nitroglicerina 2% y el dimetilsulfoxido 90% en colgajos dorsales en ratas. MÉTODOS: Se realizó un estudio experimental ciego en 24 ratas Wistar macho, con un peso medio de 320 gramos. Grupo 1: Control. Petrolato n = 8, Grupo 2: Nitroglicerina unguento al 2 % (Nitro-Bid, Altana Co.), n = 8, Grupo 3. Dimetilsulfóxido al 90% (Neogen corp. Lexington KY.), n = 8. RESULTADOS: Un total de 24 ratas fueron operadas en el período de 6 meses de este estudio. Mediante un análisis no paramétrico de la prueba U de Mann Whitney, se obtuvo una p estadísticamente significativa entre el grupo control y la pomada de nitroglicerina al 2%, tanto en el área de necrosis como en el área sana (p = 0.026). Por el contrario, la comparación entre DMSO y el grupo control (p = 0.180) y entre ambos grupos de estudio, con una p = 0.18, no fue significativa. CONCLUSIONES: Nuestro estudio concluyó que existe un efecto protector de la pomada de nitroglicerina al 2% para la supervivencia del colgajo en relación al grupo control (vaselina). El DMSO administrado por vía tópica no mostró un efecto protector, en comparación con el grupo de control.

Time derivatives via interconnected waveguides.

Electromagnetic wave-based analogue computing has become an interesting computing paradigm demonstrating the potential for high-throughput, low power, and parallel operations. In this work, we propose a technique for the calculation of derivatives of temporal signals by exploiting transmission line techniques. We consider multiple interconnected waveguides (with some of them being closed-ended stubs) forming junctions. The transmission coefficient of the proposed structure is then tailored by controlling the length and number of stubs at the junction, such that the differentiation operation is applied directly onto the envelope of an incident signal sinusoidally modulated in the time domain. The physics behind the proposed structure is explained in detail and a full theoretical description of this operation is presented, demonstrating how this technique can be used to calculate higher order or even fractional temporal derivatives. We envision that these results may enable the development of further time domain wave-based analogue processors by exploiting waveguide junctions, opening new opportunities for wave-based single operators and systems.

Development of a Novel Design of Microfluidic Impedance Cytometry for Improved Sensitivity and Cell Identification.

A long-standing issue for microfluidic impedance cytometry devices is the accuracy in determining the size of cells during counting and measurements. In this paper, we introduce a novel design that produces a homogeneous electric field in the sensing region and demonstrates higher accuracy than traditional designs in cell counting and sizing, reducing the reliance on cell focusing and signal postprocessing. The concept is validated, and the increased accuracy of the device over traditional designs is demonstrated through the use of finite element simulations to generate suitable data sets for particle trajectories and model expected signal variations.

Plasmonic meniscus lenses.

Controlling and manipulating the propagation of surface plasmons has become a field of intense research given their potential in a wide range of applications, such as plasmonic circuits, optical trapping, sensors, and lensing. In this communication, we exploit classical optics techniques to design and evaluate the performance of plasmonic lenses with meniscus-like geometries. To do this, we use an adapted lens maker equation that incorporates the effective medium concepts of surface plasmons polaritons travelling in dielectric-metal and dielectric-dielectric-metal configurations. The design process for such plasmonic meniscus lenses is detailed and two different plasmonic focusing structures are evaluated: a plasmonic lens with a quasi-planar output surface and a plasmonic meniscus lens having a convex-concave input-output surface, respectively. The structures are designed to have an effective focal length of 2λ0 at the visible wavelength of 633 nm. A performance comparison of the two plasmonic lenses is shown, demonstrating improvements to the power enhancement, with a 22% and 16.5% increase when using 2D (ideal) or 3D (realistic plasmonic) meniscus designs, respectively, compared to the power enhancement obtained with convex-planar lenses. It is also shown that the depth of focus of the focal spot presents a 19.8% decrease when using meniscus lenses in 2D and a 34.3% decrease when using the proposed 3D plasmonic meniscus designs. The broadband response of a plasmonic meniscus lens (550-750 nm wavelength range) is also studied along with the influence of potential fabrication errors on the generated effective focal length. The proposed plasmonic lenses could be exploited as alternative focusing devices for surface plasmons polaritons in applications such as sensing.

Madelung Formalism for Electron Spill-Out in Nonlocal Nanoplasmonics.

Current multiscale plasmonic systems pose a modeling challenge. Classical macroscopic theories fail to capture quantum effects in such systems, whereas quantum electrodynamics is impractical given the total size of the experimentally relevant systems, as the number of interactions is too large to be addressed one by one. To tackle the challenge, in this paper we propose to use the Madelung form of the hydrodynamic Drude model, in which the quantum effect electron spill-out is incorporated by describing the metal-dielectric interface using a super-Gaussian function. The results for a two-dimensional nanoplasmonic wedge are correlated to those from nonlocal full-wave numerical calculations based on a linearized hydrodynamic Drude model commonly employed in the literature, showing good qualitative agreement. Additionally, a conformal transformation perspective is provided to explain qualitatively the findings. The methodology described here may be applied to understand, both numerically and theoretically, the modular inclusions of additional quantum effects, such as electron spill-out and nonlocality, that cannot be incorporated seamlessly by using other approaches.

MXene supported surface plasmons on telecommunications optical fibers.

MXenes, an emerging class of two-dimensional materials, exhibit characteristics that promise significant potential for their use in next generation optoelectronic sensors. An interplay between interband transitions and boundary effects offer the potential to tune the plasma frequencies over a large spectral range from the near-infrared to the mid-infrared. This tuneability along with the 'layered' nature of the material not only offer the flexibility to produce plasmon resonances across a wide range of wavelengths, but also add a degree of freedom to the sensing mechanism by allowing the plasma frequency to be modulated. Here we show, numerically, that MXenes can support plasmons in the telecommunications frequency range and that surface plasmon resonances can be excited on a standard MXene coated side polished optical fiber. Thus, presenting the tantalising prospect of highly selective distributed optical fiber sensor networks.

Does the length of the history influence the outcome of pneumatic reduction of intussusception in children?

PURPOSE: Intussusception is the most common cause of acute abdomen in infants and preschool children. Nonoperative reduction using air enema is an established treatment in children with intussusception. The aim of this study was to determine whether length of the history influences the outcome of pneumatic reduction of intussusception in children? METHODS: The medical records of 256 consecutive children with intussusception between July 1998 and June 2010, who underwent air enema reduction regardless of the length of the history were reviewed. In all 256 patients, intussusception was confirmed by ultrasound before proceeding to air enema. RESULTS: The length of history ranged from 2 to 240 h with median time of 18.5 h. The median age in 256 patients was 7 months (range 1 day to 12 years). The presenting clinical features included irritability/abdominal pain (77%), vomiting (80%), bleeding per rectum (36%) and palpable abdominal mass (50%). Air enema reduction was successful in 234 (91.5%) of the 256 patients. In 22 (8.5%) patients, air enema failed to reduce the intussusception and 3 (1.1%) of these patients had colonic perforation during the procedure. All 22 patients required surgery. The duration of symptoms did not influence the outcome of pneumatic reduction. 37 (14%) patients developed recurrence after successful pneumatic reduction of intussusception, with 58% presenting within 48 h of the initial procedure. CONCLUSION: Our data suggest that pneumatic reduction should be first-line treatment in all children with intussusception regardless of the length of the history.

Limited Phenotypic Variation in Vulnerability to Cavitation and Stomatal Sensitivity to Vapor Pressure Deficit among Clones of Aristotelia chilensis from Different Climatic Origins.

Aristotelia chilensis (Molina) Stuntz is a promising species in the food industry as it provides 'super fruits' with remarkable antioxidant activity. However, under the predicted climate change scenario, the ongoing domestication of the species must consider selecting the most productive genotypes and be based on traits conferring drought tolerance. We assessed the vulnerability to cavitation and stomatal sensitivity to vapor pressure deficit (VPD) in A. chilensis clones originated from provenances with contrasting climates. A nursery experiment was carried out for one growing season on 2-year-old potted plants. Measurements of stomatal conductance (gs) responses to VPD were taken in spring, summer, and autumn, whereas vulnerability to cavitation was evaluated at the end of spring. Overall, the vulnerability to cavitation of the species was moderate (mean P50 of -2.2 MPa). Parameters of the vulnerability curves (Kmax, P50, P88, and S50) showed no differences among clones or when northern and southern clones were compared. Moreover, there were no differences in stomatal sensitivity to VPD at the provenance or the clonal level. However, compared with other studies, the stomatal sensitivity was considered moderately low, especially in the range of 1 to 3 kPa of VPD. The comparable performance of genotypes from contrasting provenance origins suggests low genetic variation for these traits. Further research must consider testing on diverse environmental conditions to assess the phenotypic plasticity of these types of traits.

Robustifying Experimental Tracer Design for13C-Metabolic Flux Analysis.

13C metabolic flux analysis (MFA) has become an indispensable tool to measure metabolic reaction rates (fluxes) in living organisms, having an increasingly diverse range of applications. Here, the choice of the13C labeled tracer composition makes the difference between an information-rich experiment and an experiment with only limited insights. To improve the chances for an informative labeling experiment, optimal experimental design approaches have been devised for13C-MFA, all relying on some a priori knowledge about the actual fluxes. If such prior knowledge is unavailable, e.g., for research organisms and producer strains, existing methods are left with a chicken-and-egg problem. In this work, we present a general computational method, termed robustified experimental design (R-ED), to guide the decision making about suitable tracer choices when prior knowledge about the fluxes is lacking. Instead of focusing on one mixture, optimal for specific flux values, we pursue a sampling based approach and introduce a new design criterion, which characterizes the extent to which mixtures are informative in view of all possible flux values. The R-ED workflow enables the exploration of suitable tracer mixtures and provides full flexibility to trade off information and cost metrics. The potential of the R-ED workflow is showcased by applying the approach to the industrially relevant antibiotic producer Streptomyces clavuligerus, where we suggest informative, yet economic labeling strategies.

Diffraction limited photonic hook via scattering and diffraction of dual-dielectric structures.

Photonic hooks have demonstrated to be great candidates for multiple applications ranging from sensing up to optical trapping. In this work, we propose a mechanism to produce such bent structured light beams by exploiting the diffraction and scattering generated by a pair of dielectric rectangles immersed in free space. It is shown how the photonic hooks are generated away from the output surface of the dielectrics by correctly engineering each individual dielectric structure to generate minimum diffraction and maximum scattering along the propagation axis. Different scenarios are studied such as dual-dielectric structures having different lateral dimensions and refractive index as well as cases when both dielectrics have the same lateral dimensions. The results are evaluated both numerically and theoretically demonstrating an excellent agreement between them. These results may open new avenues for optical trapping, focusing and sensing devices via compact and simple dual-dielectric structures.