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The standardization of secondary electrolytic conductivity cells requires the use of a certified reference material. The accepted certification method involves electrochemical impedance spectroscopy (EIS) to estimate the material’s solution resistance. This method normally assumes that the impedance’s imaginary component can be neglected; and hence, the measured impedance approximates the real impedance. Thus, a linear extrapolation of the impedance versus the period (inverse frequency) yields solution resistance. However, experimental impedance data usually do not exhibit a linear behavior over the spectra of frequency, which strongly suggest that the ideal capacitive assumption may not strictly apply. To account for the observed nonlinear behavior, we have proposed to introduce the concept of a constant phase element (CPE) to the analysis of impedance. This approach leads to the development of a relationship that improves the fitting of experimental data and improves the accuracy of the estimation, by establishing a critical frequency where extrapolation should be done. Finally, we are presenting simulated results to demonstrate how sizeable capacitive effects can influence the determination of solution resistance, and a final analysis to estimate the impact on constant cell or electrolytic conductivity values.

Silver, zinc, and copper nanoparticles were reductively crystallized on thymine-containing single-stranded DNA decanucleotides, in aqueous solutions containing the corresponding metal ions and sodium borohydride, at 4 °C, pH 11.8, and 15 mM of NaCl. Iron nanoparticles were not formed under these conditions. Formation of aggregates was monitored by UV-Vis spectrophotometry, and characterized by scanning electron microscopy and dynamic light scattering. The absorption spectra for most Ag+-containing samples showed a major band centered around 425 nm and a shoulder between 500 and 600 nm, indicative of the presence of silver particles in a wide size distribution, in the 0.1–5 μm range. This was verified by micrographs and size distribution observed in scattering profiles. Silver-particle morphology indicates formation of cubic structures instead of spherical geometries. For the case of zinc and copper nanoparticles, quasi-spherical structures of approximately 100 nm were crystallized along the DNA chains by reduction reaction, and then released to the bulk solvent. Thymine residues show a higher effectiveness in nucleation of metallic cations in comparison to other DNA nucleobases, particularly in their deprotonated form, at high pH values. Adenines flanking central runs of deprotonable bases in the model oligonucletide chain affect the production of silver crystals on the DNA decamers. pH value and NaCl concentration have a significant effect on the production of silver particles, as alkaline and moderate-ionic-strength conditions are required to crystallize such structures. The tuning of size and morphology of metallic nanoparticles by the proper choice of oligonucleotide sequence and physical conditions may have interesting applications in the field of nanobiotechnology.

© 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Background: The Lancet Commission on Global Surgery established the Three Delays framework, categorising delays in accessing timely surgical care into delays in seeking care (First Delay), reaching care (Second Delay), and receiving care (Third Delay). Globally, knowledge gaps regarding delays for fracture care, and the lack of large prospective studies informed the rationale for our international observational study. We investigated delays in hospital admission as a surrogate for accessing timely fracture care and explored factors associated with delayed hospital admission. Methods: In this prospective observational substudy of the ongoing International Orthopaedic Multicenter Study in Fracture Care (INORMUS), we enrolled patients with fracture across 49 hospitals in 18 low-income and middle-income countries, categorised into the regions of China, Africa, India, south and east Asia, and Latin America. Eligible patients were aged 18 years or older and had been admitted to a hospital within 3 months of sustaining an orthopaedic trauma. We collected demographic injury data and time to hospital admission. Our primary outcome was the number of patients with open and closed fractures who were delayed in their admission to a treating hospital. Delays for patients with open fractures were defined as being more than 2 h from the time of injury (in accordance with the Lancet Commission on Global Surgery) and for those with closed fractures as being a delay of more than 24 h. Secondary outcomes were reasons for delay for all patients with either open or closed fractures who were delayed for more than 24 h. We did logistic regression analyses to identify risk factors of delays of more than 2 h in patients with open fractures and delays of more than 24 h in patients with closed fractures. Logistic regressions were adjusted for region, age, employment, urban living, health insurance, interfacility referral, method of transportation, number of fractures, mechanism of injury, and fracture location. We further calculated adjusted relative risk (RR) from adjusted odds ratios, adjusted for the same variables. This study was registered with ClinicalTrials.gov, NCT02150980, and is ongoing. Findings: Between April 3, 2014, and May 10, 2019, we enrolled 31 255 patients with fractures, with a median age of 45 years (IQR 31–62), of whom 19 937 (63·8%) were men, and 14 524 (46·5%) had lower limb fractures, making them the most common fractures. Of 5256 patients with open fractures, 3778 (71·9%) were not admitted to hospital within 2 h. Of 25 999 patients with closed fractures, 7141 (27·5%) were delayed by more than 24 h. Of all regions, Latin America had the greatest proportions of patients with delays (173 [88·7%] of 195 patients with open fractures; 426 [44·7%] of 952 with closed fractures). Among patients delayed by more than 24 h, the most common reason for delays were interfacility referrals (3755 [47·7%] of 7875) and Third Delays (cumulatively interfacility referral and delay in emergency department: 3974 [50·5%]), while Second Delays (delays in reaching care) were the least common (423 [5·4%]). Compared with other methods of transportation (eg, walking, rickshaw), ambulances led to delay in transporting patients with open fractures to a treating hospital (adjusted RR 0·66, 99% CI 0·46–0·93). Compared with patients with closed lower limb fractures, patients with closed spine (adjusted RR 2·47, 99% CI 2·17–2·81) and pelvic (1·35, 1·10–1·66) fractures were most likely to have delays of more than 24 h before admission to hospital. Interpretation: In low-income and middle-income countries, timely hospital admission remains largely inaccessible, especially among patients with open fractures. Reducing hospital-based delays in receiving care, and, in particular, improving interfacility referral systems are the most substantial tools for reducing delays in admissions to hospital. Funding: National Health and Medical Research Council of Australia, Canadian Institutes of Health Research, McMaster Surgical Associates, and Hamilton Health Sciences.

Crude glycerol (CG) is a by-product from the biodiesel industry; its application in the chemical industry is limited by its complex composition (glycerol, methanol, surfactants, and salts). The electrochemical valorization of CG is a promising alternative for this waste because it can be used without purification. To this end, highly active nanomaterials to carry efficiently its electro-oxidation reaction are needed. Herein, Pd, and PdM (M is a noble metal: Ru, Ir and Pt) bimetallic nanomaterials were obtained to assess the effect of the co-metal on the crude glycerol electro-oxidation reaction (crude GEOR) in alkaline media. For this purpose, the crystallite size, and the particle size (~7 nm), the metal-support ratio (~20 wt%) and the Pd mass composition in the bimetallic nanomaterials (~20 wt%) were kept similar to avoid surface effects. The activity was analyzed varying the fuel and electrolyte concentrations, and the operating temperature. It was found through these experiments that the bimetallic nanomaterials displayed an improvement in the onset potential to oxidize 1.5 M crude glycerol in 1 M KOH, following the trend: PdPt (−0.37 V vs. NHE) > PdRu, PdIr (−0.24 V vs. NHE) > Pd (−0.2 V vs. NHE). Additionally, PdPt achieved the highest current density (jp, 172.29 mA mgPd−1), being 2.8, 1.6 and 2.1 times higher to the achieved for Pd, PdRu and PdIr, respectively. PdRu resulted to be the most stable electrocatalyst maintaining 97% of its starting current after 500 cycles. We found that the capability of PdPt to oxidize glycerol and methanol found in CG without any fuel adsorption/oxidation competition was the reason that this material displayed the highest activity in contrast with Pd and the bimetallic PdIr and PdRu nanomaterials.

Resumen. La ventilacion natural en invernaderos produce altas tasas de intercambio de aire; sin embargo, este comportamiento se producen cerca de las ventanas, lo que ocasiona un bajo intercambio de aire en la zona central del invernadero, debido a un efecto de estancamiento que reduce la distribucion del viento en todo el invernadero. La prediccion de los gradientes en un invernadero con ventilacion natural es dificil de lograr, debido a la naturaleza inherentemente estocastica del flujo de aire. Las Redes bayesianas son tecnicas numericas de incertidumbre que se pueden utilizar para estudiar este problema. Se obtuvo un conjunto de datos experimentales: temperatura del aire, humedad del aire, velocidad del viento, y concentracion de CO2 a uno y tres metros sobre el suelo, en el espacio de cultivo. El conjunto de datos fue discretizado y utilizado para desarrollar un modelo de Red Bayesiana que describe las relaciones entre las variables estudiadas. El modelo muestra las diferencias que nos permitan identificar el grado de dependencia de las variables, asi como cuantificar su inferencia.