Gold film deposition by infrared laser photothermal treatment on 3D-printed electrodes: electrochemical performance enhancement and application.

3D printing has attracted the interest of researchers due to its creative freedom, low cost, and ease of operation. Because of these features, this technology has produced different types of electroanalytical platforms. Despite their popularity, the thermoplastic composites used for electrode fabrication typically have high electrical resistance, resulting in devices with poor electrochemical performance. Herein, we propose a new strategy to improve the electrochemical performance of 3D-printed electrodes and to gain chemical selectivity towards glucose detection. The approach involves synthesising a nanostructured gold film using an infrared laser source directly on the surface of low-contact resistance 3D-printed electrodes. The laser parameters, such as power, focal distance, and beam scan rate, were carefully optimised for the modification steps. Scanning electronic microscopy and energy-dispersive X-ray spectroscopy confirmed the morphology and composition of the nanostructured gold film. After modification, the resulting electrodes were able to selectively detect glucose, encouraging their use for sensing applications. When compared with a gold disc electrode, the gold-modified 3D-printed electrode provided a 44-fold current increase for glucose oxidation. As proof of concept, the devices were utilised for the non-enzymatic catalytic determination of glucose in drink samples, demonstrating the gold film's catalytic nature and confirming the analytical applicability with more precise results than commercial glucometers.

Challenges faced with 3D-printed electrochemical sensors in analytical applications.

Prototyping analytical devices with three-dimensional (3D) printing techniques is becoming common in research laboratories. The attractiveness is associated with printers' price reduction and the possibility of creating customized objects that could form complete analytical systems. Even though 3D printing enables the rapid fabrication of electrochemical sensors, its wider adoption by research laboratories is hindered by the lack of reference material and the high "entry barrier" to the field, manifested by the need to learn how to use 3D design software and operate the printers. This review article provides insights into fused deposition modeling 3D printing, discussing key challenges in producing electrochemical sensors using currently available extrusion tools, which include desktop 3D printers and 3D printing pens. Further, we discuss the electrode processing steps, including designing, printing conditions, and post-treatment steps. Finally, this work shed some light on the current applications of such electrochemical devices that can be a reference material for new research involving 3D printing.

Leveraging the third dimension in microfluidic devices using 3D printing: no longer just scratching the surface.

3D printers utilize cutting-edge technologies to create three-dimensional objects and are attractive tools for engineering compact microfluidic platforms with complex architectures for chemical and biochemical analyses. 3D printing's popularity is associated with the freedom of creating intricate designs using inexpensive instrumentation, and these tools can produce miniaturized platforms in minutes, facilitating fabrication scaleup. This work discusses key challenges in producing three-dimensional microfluidic structures using currently available 3D printers, addressing considerations about printer capabilities and software limitations encountered in the design and processing of new architectures. This article further communicates the benefits of using three-dimensional structures, including the ability to scalably produce miniaturized analytical systems and the possibility of combining them with multiple processes, such as mixing, pumping, pre-concentration, and detection. Besides increasing analytical applicability, such three-dimensional architectures are important in the eventual design of commercial devices since they can decrease user interferences and reduce the volume of reagents or samples required, making assays more reliable and rapid. Moreover, this manuscript provides insights into research directions involving 3D-printed microfluidic devices. Finally, this work offers an outlook for future developments to provide and take advantage of 3D microfluidic functionality in 3D printing. Graphical abstract Creating three-dimensional microfluidic structures using 3D printing will enable key advances and novel applications in (bio)chemical analysis.

Sulfanilamide Electrochemical Sensor Using Phenolic Substrates and CO2 Laser Pyrolysis.

The concentration of environmental pollutants needs to be monitored constantly by reliable analytical methods since they pose a public health risk. Developing simple and affordable sensors for such pollutants can allow for large-scale monitoring economically. Here, we develop a simple electrochemical sensor for sulfanilamide (SFD) quantification using a phenolic resin substrate and a CO2 laser to pyrolyze the sensor geometry over the substrate. The sensors are modified with carbon nanotubes via a simple drop-casting procedure. The carbon nanotube loading effect the electrochemical performance toward a redox probe and analytical performance for SFD detection is investigated, showing no net benefit beyond 1 mg L-1 of carbon nanotubes. The effects of the modification on the SFD oxidation are shown to be more than just an electrode area effect and possibly attributed to the fast electron transfer kinetics of the carbon nanotubes. SFD detection is performed at small solution volumes under static (800 µL) and hydrodynamic conditions (3 mL) in a fully integrated, miniaturized batch-injection analyses cell. Both methods have a similar linear range from 10.0 to 115.0 µmol L-1 and high selectivity for SFD determination. Both systems are used to quantify SFD in real samples as a proof of concept, showcasing the proposed device's applicability as a sensor for environmental and public health monitoring of SFD.

Paper-based electrochemical biosensors for the diagnosis of viral diseases.

Paper-based electrochemical analytical devices (ePADs) have gained significant interest as promising analytical units in recent years because they can be fabricated in simple ways, are low-cost, portable, and disposable platforms that can be applied in various fields. In this sense, paper-based electrochemical biosensors are attractive analytical devices since they can promote diagnose several diseases and potentially allow decentralized analysis. Electrochemical biosensors are versatile, as the measured signal can be improved by using mainly molecular technologies and nanomaterials to attach biomolecules, resulting in an increase in their sensitivity and selectivity. Additionally, they can be implemented in microfluidic devices that drive and control the flow without external pumping and store reagents, and improve the mass transport of analytes, increasing sensor sensitivity. In this review, we focus on the recent developments in electrochemical paper-based devices for viruses' detection, including COVID-19, Dengue, Zika, Hepatitis, Ebola, AIDS, and Influenza, among others, which have caused impacts on people's health, especially in places with scarce resources. Also, we discuss the advantages and disadvantages of the main electrode's fabrication methods, device designs, and biomolecule immobilization strategies. Finally, the perspectives and challenges that need to be overcome to further advance paper-based electrochemical biosensors' applications are critically presented.

Patterning (Electro)chemical Treatment-Free Electrodes with a 3D Printing Pen.

A simple fabrication method to make electrochemical sensors is reported. The electrodes were fabricated with a commercial filament based on polylactic acid and carbon black (PLA/CB). They were engineered with a three-dimensional (3D) printing pen and poly(methyl methacrylate) template. The optimization parameters included the thickness and diameters of the electrodes. The electrode diameter was restricted by the 3D printing pen's nozzle dimension, and larger diameters generated small cracks on the electrode surface, compromising their analytical signal. The electrode thickness can increase the electrical resistance, affecting their electrochemical response. The fabrication showed reproducibility (RSD = 4%). The electrode surface was easily renewed by sanding the electrodes, making them reusable. Additionally, the proposed sensor provided comparable electrochemical responses over traditional glassy carbon electrodes. Moreover, no (electro)chemical surface treatment was required for sensing applications due to the compromise between the thickness and diameters of the electrodes, effectively translating the filaments' electrical properties to resulting materials. The electrodes' analytical performance was shown for organic and inorganic species, including paraquat, Pb2+, and caffeic acid. As proof of concept, the analytical applicability was demonstrated for total polyphenolic quantification in tea samples. Therefore, this work provides an alternative to fabricating miniaturized electrodes, bringing valuable insights into PLA/CB 3D-printed sensors and opening possibilities for designing electrode arrays. Moreover, the proposed electrodes are promising platforms for paper-based microfluidic systems.

Paper-based analytical devices for point-of-need applications.

Paper-based analytical devices (PADs) are powerful platforms for point-of-need testing since they are inexpensive devices fabricated in different shapes and miniaturized sizes, ensuring better portability. Additionally, the readout and detection systems can be accomplished with portable devices, allying with the features of both systems. These devices have been introduced as promising analytical platforms to meet critical demands involving rapid, reliable, and simple testing. They have been applied to monitor species related to environmental, health, and food issues. Herein, an outline of chronological events involving PADs is first reported. This work also introduces insights into fundamental parameters to engineer new analytical platforms, including the paper type and device operation. The discussions involve the main analytical techniques used as detection systems, such as colorimetry, fluorescence, and electrochemistry. It also showed recent advances involving PADs, especially combining optical and electrochemical detection into a single device. Dual/combined detection systems can overcome individual barriers of the analytical techniques, making possible simultaneous determinations, or enhancing the devices' sensitivity and/or selectivity. In addition, this review reports on distance-based detection, which is also considered a trend in analytical chemistry. Distance-based detection offers instrument-free analyses and avoids user interpretation errors, which are outstanding features for analyses at the point of need, especially for resource-limited regions. Finally, this review provides a critical overview of the practical specifications of the recent analytical platforms involving PADs, demonstrating their challenges. Therefore, this work can be a highly useful reference for new research and innovation.

Candida species causing fungal keratitis: molecular identification, antifungal susceptibility, biofilm formation, and clinical aspects.

The study aimed to evaluate the clinical aspects, molecular identification, biofilm formation, and antifungal susceptibility profile of Candida species isolated from fungal keratitis. Thirteen Candida isolates from 13 patients diagnosed with Candida keratitis were retrieved and grown in pure culture. Species identification was performed by micromorphology analysis and ITS-rDNA sequencing. The broth microdilution method tested the minimum inhibitory concentration (MIC) of four antifungal drugs (fluconazole, amphotericin B, voriconazole, and anidulafungin). The biofilms were cultured and incubated with antifungal drugs for 24 h. The XTT reduction assay measured the biofilm activity. Biofilm MICs were calculated based on a 50% reduction in metabolic activity compared with the activity of the drug-free control. Among isolates, two were C. albicans, 10 were C. parapsilosis (sensu stricto), and one was C. orthopsilosis. All isolates were classified as susceptible or intermediate to all four antifungal drugs. Four isolates were very low biofilm producers (30%). Nine isolates were biofilm producers, and all biofilm samples were unsusceptible to all drugs tested. Previous ocular surgery was the most common underlying condition for fungal keratitis (84.6%), and C. parapsilosis was the most frequent Candida species (76.9%). Four patients (30.7%) needed keratoplasty, whereas two (15.3%) required evisceration. The biofilm formation ability of Candida isolates decreased antifungal susceptibility compared with planktonic cells. Despite in vitro antifungal susceptibility, almost half of the patients were unresponsive to clinical treatment and needed surgery.

Hemodynamic depression after carotid surgery: Incidence, risk factors and outcomes.

INTRODUCTION: Hemodynamic Depression (HD) characterized by hypotension and bradycardia is a complication of carotid surgery due to direct autonomic stimulation in the carotid sinus. The authors believe the incidence of HD is high and possibly related to major cardiac complications. METHODS: Analysis of patient records during admissions for carotid surgery between January 2014 and December 2018 in two hospitals. HD was defined as bradycardia or hypotension in the first 24 postoperative hours. Bradycardia was defined as heart rate < 50bpm; hypotension as systolic blood pressure < 90 mmHg, continuous use of vasopressors, or a drop in SBP > 20% compared to preoperative values. Myocardial infarction, stroke, and cardiovascular death were defined as adverse events. RESULTS: Overall, 237 carotid surgeries (178 endarterectomies, 59 angioplasties) were studied, and the global incidence of HD was 54.4% (hypotension in 50.2%, bradycardia in 11.0%, and hypotension and bradycardia in 6.8%). The independent predictors of HD were asymptomatic carotid stenosis (OR = 1.824; 95% CI 1.014-3.280; p = 0.045), endovascular surgery (OR = 3.319; 95% CI 1.675-6.576; p = 0.001) and intraoperative hypotension or bradycardia (OR = 2.144; 95% CI 1.222-3.762; p = 0.008). Hypotension requiring continuous vasopressor infusion was the only factor independently associated with adverse cardiovascular events (OR = 5.504; 95% CI 1.729-17.529; p = 0.004). DISCUSSION/CONCLUSION: Incidence of Hemodynamic Depression after carotid surgery is high and independently associated with surgical technique, symptomatic repercussion of the carotid stenosis, and intraoperative hypotension or bradycardia. Hypotension requiring the continuous infusion of vasopressors was independently associated with the occurrence of MACE.

Hemodynamic depression after carotid surgery: Incidence, risk factors and outcomes

Abstract Introduction: Hemodynamic Depression (HD) characterized by hypotension and bradycardia is a complication of carotid surgery due to direct autonomic stimulation in the carotid sinus. The authors believe the incidence of HD is high and possibly related to major cardiac complications. Methods: Analysis of patient records during admissions for carotid surgery between January 2014 and December 2018 in two hospitals. HD was defined as bradycardia or hypotension in the first 24 postoperative hours. Bradycardia was defined as heart rate < 50bpm; hypotension as systolic blood pressure < 90 mmHg, continuous use of vasopressors, or a drop in SBP > 20% compared to preoperative values. Myocardial infarction, stroke, and cardiovascular death were defined as adverse events. Results: Overall, 237 carotid surgeries (178 endarterectomies, 59 angioplasties) were studied, and the global incidence of HD was 54.4% (hypotension in 50.2%, bradycardia in 11.0%, and hypotension and bradycardia in 6.8%). The independent predictors of HD were asymptomatic carotid stenosis (OR = 1.824; 95% CI 1.014 −3.280; p = 0.045), endovascular surgery (OR = 3.319; 95% CI 1.675−6.576; p = 0.001) and intraoperative hypotension or bradycardia (OR = 2.144; 95% CI 1.222−3.762; p = 0.008). Hypotension requiring continuous vasopressor infusion was the only factor independently associated with adverse cardiovascular events (OR = 5.504; 95% CI 1.729-17.529; p = 0.004). Discussion/conclusion: Incidence of Hemodynamic Depression after carotid surgery is high and independently associated with surgical technique, symptomatic repercussion of the carotid stenosis, and intraoperative hypotension or bradycardia. Hypotension requiring the continuous infusion of vasopressors was independently associated with the occurrence of MACE.

A novel miniaturized electroanalytical device integrated with gas extraction for the voltammetric determination of sulfite in beverages.

Voltammetry and amperometry are inexpensive and high-performance analytical techniques. However, their lack of selectivity limits their use in complex matrices such as biological, environmental, and food samples. Therefore, voltammetric and amperometric analyses of these samples usually require time-consuming and laborious sample pretreatments. In this study, we present a simple and cost-effective approach to fabricate a miniaturized electrochemical cell that can be easily coupled to a head space-like gas extraction procedure in such a way the sample pretreatment and voltammetric detection are performed in a single step. As a proof of concept, we have used the proposed system to quantify sulfite in beverage samples after its conversion to SO2(g). Despite the simplicity and low cost of the proposed system, it provided good analytical performance and a limit of detection of 4.0 µmol L-1 was achieved after only 10 min of extraction. The proposed system is quite versatile since it can be applied to quantify any volatile electroactive species. Also, the proposed system provides a unique way to assess real-time extraction curves, which are essential to study and optimize new gas extraction procedures. Therefore, the approach described in this study could contribute to both applied and fundamental Analytical Chemistry.

A deep descriptor for cross-tasking EEG-based recognition.

Due to the application of vital signs in expert systems, new approaches have emerged, and vital signals have been gaining space in biometrics. One of these signals is the electroencephalogram (EEG). The motor task in which a subject is doing, or even thinking, influences the pattern of brain waves and disturb the signal acquired. In this work, biometrics with the EEG signal from a cross-task perspective are explored. Based on deep convolutional networks (CNN) and Squeeze-and-Excitation Blocks, a novel method is developed to produce a deep EEG signal descriptor to assess the impact of the motor task in EEG signal on biometric verification. The Physionet EEG Motor Movement/Imagery Dataset is used here for method evaluation, which has 64 EEG channels from 109 subjects performing different tasks. Since the volume of data provided by the dataset is not large enough to effectively train a Deep CNN model, it is also proposed a data augmentation technique to achieve better performance. An evaluation protocol is proposed to assess the robustness regarding the number of EEG channels and also to enforce train and test sets without individual overlapping. A new state-of-the-art result is achieved for the cross-task scenario (EER of 0.1%) and the Squeeze-and-Excitation based networks overcome the simple CNN architecture in three out of four cross-individual scenarios.

Thermoplastic electrodes as a new electrochemical platform coupled to microfluidic devices for tryptamine determination.

This study reports a new electrochemical method for tryptamine determination using a paper-based microfluidic device and a thermoplastic electrode (TPE) as an amperometric detector. Tryptamine (Tryp) is a biogenic amine present in drinks and foods. Even though this compound has some beneficial effects on human health, the ingestion of foods with high concentrations of Tryp may be detrimental, which justifies the need for monitoring the Tryp levels. The TPEs were made from 50% carbon black and 50% polycaprolactone and characterized by cyclic voltammetry, demonstrating enhancement in the analytical response compared to other carbon composites. TPEs also showed a better antifouling effect for Tryp compared to conventional glassy carbon electrodes. Once characterized, the electrodes were incorporated into the microfluidic device to determine Tryp in water and cheese samples using amperometry. A linear range was achieved from 10 to 75 µmol L-1 with limits of detection and quantification of 3.2 and 10.5 µmol L-1, respectively. Therefore, this work shows promising findings of the electrochemical determination of Tryp, bringing valuable results regarding the electrochemical properties of thermoplastic composites.

Visual Field Characteristics of Type I Boston Keratoprosthesis Patients Without Glaucoma.

PURPOSE: To determine visual field findings in Boston type 1-KPro (BI-KPro) patients without glaucoma. Characterize normal threshold values and global indices using standard automated perimetry and characterize visual field amplitude using Goldmann's manual perimetry. METHODS: This cross-sectional prospective noninterventional study included patients (n=6 patients, 6 eyes) with BI-KPro who had normal optical coherence tomography and fundoscopic evaluation of the optic disc and retina. None had a previous history of glaucoma. Visual acuity, reliable and reproducible standard automated perimetry (24-2 and 30-2), and manual perimetry examinations were obtained from all patients. Each patient answered the National Eye Institute Visual Function Questionnaire, and the results were correlated with visual field indices. RESULTS: The mean visual acuity was 0.35±0.31 logMAR (0.84 to 0.10). All visual fields had good reliability indices. The standard automated perimetry mean deviation values were -7.25±3.63 decibels (dB) and -7.75±3.23 (24-2 and 30-2 values, respectively), whereas pattern SD values were 2.72±0.82 and 3.30±1.13 (24-2 and 30-2, respectively). The manual visual field mean values of the 4 quadrants (superior, temporal, inferior, and nasal), were 39.7±4.5, 61.8±6.2, 54.0±4.3, and 48.2±7.6 degrees, respectively. The authors found a significant correlation between the VFQ-25 indexes of general sight and close-range activities with the values of total deviation at 10 degrees. VFQ-25 peripheral vision indexes also correlated significantly with values of total deviation at 30 degrees (outermost locations in the 30-degree area). CONCLUSIONS: Patients with BI-KPro presented reliable and reproductive visual field measurements. The authors found a consistent reduction in visual field extension and a global sensitivity reduction in these patients. Despite visual field changes, our patients had a good quality of life scores. Overall, these results could be useful to improve early glaucoma diagnosis and to follow-up BI-KPro patients.

Rapid Analysis in Continuous-Flow Electrochemical Paper-Based Analytical Devices.

A simple and low-cost continuous-flow (CF) electrochemical paper-based analytical device (ePAD) coupled with thermoplastic electrodes (TPEs) was developed. The fast, continuous flow combined with flow injection analysis was made possible by adding two inlet reservoirs to the same paper-based hollow channel flowing over detection electrodes, terminating in a fan-shaped pumping reservoir. The upstream inlet reservoir was filled with buffer and provided constant flow through the device. Sample injections were performed by adding 2 µL of the sample to the downstream sample inlet. Differences in flow resistance resulted in sample plugs displacing buffer as the solution flowed over the working electrodes. The electrodes were fabricated by mixing carbon black and polycaprolactone (50% w/w). CF-TPE-ePADs were characterized with chronoamperometry using ferrocenylmethyl trimethylammonium as the electrochemical probe. Optimized flow rates and injection volumes gave analysis times roughly an order of magnitude faster than those of previously reported flow injection analysis ePADs. To demonstrate applicability, the CF-TPE-ePADs were used to quantify caffeic acid in three different tea samples. The proposed method had a linear range from 10 to 500 µmol L-1 and limits of detection and quantification of 2.5 and 8.3 µmol L-1, respectively. Our approach is promising for fabricating simple, inexpensive, yet high-performance, flow injection analysis devices using paper substrates and easy-to-make electrodes that do not require external mechanical pumping systems or complicated valves.

Identification of 170 New Long Noncoding RNAs in Schistosoma mansoni.

Long noncoding RNAs (lncRNAs) are transcripts generally longer than 200 nucleotides with no or poor protein coding potential, and most of their functions are also poorly characterized. Recently, an increasing number of studies have shown that lncRNAs can be involved in various critical biological processes such as organism development or cancer progression. Little, however, is known about their effects in helminths parasites, such as Schistosoma mansoni. Here, we present a computational pipeline to identify and characterize lncRNAs from RNA-seq data with high confidence from S. mansoni adult worms. Through the utilization of different criteria such as genome localization, exon number, gene length, and stability, we identified 170 new putative lncRNAs. All novel S. mansoni lncRNAs have no conserved synteny including human and mouse. These closest protein coding genes were enriched in 10 significant Gene Ontology terms related to metabolism, transport, and biosynthesis. Fifteen putative lncRNAs showed differential expression, and three displayed sex-specific differential expressions in praziquantel sensitive and resistant adult worm couples. Together, our method can predict a set of novel lncRNAs from the RNA-seq data. Some lncRNAs are shown to be differentially expressed suggesting that those novel lncRNAs can be given high priority in further functional studies focused on praziquantel resistance.

Fibromatosis agresiva en edad pediátrica / Aggressive Fibromatosis in Pediatric Age

Introducción: la fibromatosis agresiva es rara, benigna, con alto grado de agresividad y recidivante. Objetivo: caracterizar la fibromatosis en pacientes atendidos en el Hospital Pediátrico Provincial de Holguín. Método: se realizó un estudio, transversal y retrospectivo de los pacientes, en edad pediátrica, con diagnósticos de fibromatosis profunda que incluyó los años 2002-2012. Resultados: la prevalencia de la fibromatosis fue de 2,1 por cada 100 000 habitantes. Predominó el sexo femenino. La localización glútea fue más frecuente seguida del cuello y la pared abdominal. La etiología fue desconocida en el 75 %. La biopsia por aspiración con aguja fina no fue útil para el diagnóstico. El tratamiento inicial fue quirúrgico e incompleto. La regresión espontánea ocurrió en el 50 % de la recidiva. La quimioterapia y la radioterapia se emplearon sin resultados satisfactorios. Conclusiones: debe considerarse el tratamiento inicial expectante, pues la regresión espontánea se ve en muchos casos y la cirugía no previene la recidiva independientemente del grado de resección tumoral.

Introduction: aggressive fibromatosis is an uncommon, benign and recurrent disease. Objective: to characterize fibromatosis in patients attended al Provincial Pediatric Hospital of Holguín. Method: a retrospective cross-sectional study on aggressive fibromatosis in children younger than 19 years old was done during 2002 to 2012. Results: fibromatosis prevalence was 2.1 per 100 000 inhabitants. Females prevailed over males. The tumor was mainly localized in the gluteal region followed by the neck and the abdominal wall. The etiology was unknown in 75 % of cases. Fine needle aspiration biopsy was not useful for diagnosis. The initial treatment was 100 % surgical but incomplete; nevertheless, spontaneous regression of recurrence was seen in 50 % of cases. Chemotherapy and radiotherapy were applied to recurrence without successful results. Conclusions: the procedure, as the first line of treatment, should be considered because of tumor spontaneous regression. Surgical resection degree of the tumor does not prevent recurrence.

Preoperative Use of Dexamethasone in Rhinoplasty: A Randomized, Double-blind, Placebo-Controlled Clinical Trial.

IMPORTANCE: Postoperative edema and ecchymosis following rhinoplasty are a cause of anxiety for both patients and physicians and can affect the cosmetic results. Corticosteroids have been used to reduce these events. OBJECTIVE: To determine whether preoperative use of dexamethasone sodium phosphate alters the occurrence of edema and ecchymosis following rhinoplasty. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind, placebo-controlled clinical trial at an institutional referral center among a sample of individuals with rhinomegaly. INTERVENTIONS: Patients were randomized into 2 groups. In group 1, dexamethasone was intravenously injected before surgery. In group 2, normal saline solution was intravenously injected before surgery. MAIN OUTCOMES AND MEASURES: When patients returned at 1 week after surgery, standardized photographs were obtained. The photographs were analyzed by 5 plastic surgeons who were blinded as to whether dexamethasone or normal saline solution had been injected. The plastic surgeons rated the degree of edema and ecchymosis. RESULTS: Forty-two patients participated in the study. Randomization by lottery resulted in 20 patients in group 1 and 22 patients in group 2. Group 1 showed lower rates of postoperative ecchymosis than group 2; the difference of 0.62 (P = .02) reflects less perceived ecchymosis when dexamethasone was administered. Group 1 also showed lower rates of postoperative edema than group 2; the difference of 0.68 (P = .01) reflects less perceived edema when dexamethasone was administered. CONCLUSIONS AND RELEVANCE: Preoperative use of dexamethasone reduced edema and ecchymosis at 7 days after rhinoplasty. Rigorous methods in this trial demonstrate the beneficial effect of preoperative corticosteroid administration in this surgical procedure. LEVEL OF EVIDENCE: 1.

Culture-area relation in Axelrod's model for culture dissemination.

Axelrod's model for culture dissemination offers a nontrivial answer to the question of why there is cultural diversity given that people's beliefs have a tendency to become more similar to each other's as they interact repeatedly. The answer depends on the two control parameters of the model, namely, the number F of cultural features that characterize each agent, and the number q of traits that each feature can take on, as well as on the size A of the territory or, equivalently, on the number of interacting agents. Here, we investigate the dependence of the number C of distinct coexisting cultures on the area A in Axelrod's model, the culture-area relationship, through extensive Monte Carlo simulations. We find a non-monotonous culture-area relation, for which the number of cultures decreases when the area grows beyond a certain size, provided that q is smaller than a threshold value qc = qc (F) and F > or = 3. In the limit of infinite area, this threshold value signals the onset of a discontinuous transition between a globalized regime marked by a uniform culture (C = 1), and a completely polarized regime where all C = qF possible cultures coexist. Otherwise, the culture- area relation exhibits the typical behavior of the species- area relation, i.e., a monotonically increasing curve the slope of which is steep at first and steadily levels off at some maximum diversity value.